The document discusses the cardiovascular system and heart. It provides details on heart anatomy including its location, layers, chambers and valves. It describes the coronary circulation and cardiac conduction system. The cardiac cycle and functions of each part are explained. Different terms related to heart function such as automaticity, conductivity, contractility and rhythmicity are defined. Electrocardiography and types of arrhythmias are also mentioned.

1. CARDIOVASCULAR SYSTEMCARDIOVASCULAR SYSTEM
ByBy
Yasmeen RahimYasmeen Rahim

2. OBJECTIVESOBJECTIVES
By the end of this presentation, learners will beBy the end of this presentation, learners will be
able to:able to:
Review anatomy and physiology of heart.Review anatomy and physiology of heart.
Define ECG and list indications for ECG.Define ECG and list indications for ECG.
Identify different kinds of arrhythmias.Identify different kinds of arrhythmias.
Discuss different kinds of heart blocks.Discuss different kinds of heart blocks.
Describe the nursing care for patient in blocks.Describe the nursing care for patient in blocks.
Discuss types and care for client withDiscuss types and care for client with
temporary and permanent pacemakers.temporary and permanent pacemakers.

4. HEARTHEART
Heart is a hollow muscular organ, locatedHeart is a hollow muscular organ, located
in mediastinum.in mediastinum.
It lies with the lungs on the either side andIt lies with the lungs on the either side and
the diaphragm below.the diaphragm below.
The base of heart lies parallel with theThe base of heart lies parallel with the
edge of sternum.edge of sternum.
The apex of the heart is at theThe apex of the heart is at the
midclavicular line at the 5midclavicular line at the 5thth
intercoastalintercoastal
space.space.

5. CONT.CONT.
Heart size varies according to person’sHeart size varies according to person’s
body size (closed fist).body size (closed fist).
The organ is roughly about 12 cm longThe organ is roughly about 12 cm long
and 9 cm wide.and 9 cm wide.
The heart is enclosed by a thick doubleThe heart is enclosed by a thick double
wall sac called pericardium.wall sac called pericardium.
Pericardium is composed of three layers;Pericardium is composed of three layers;
epicardium, myocardium and endocardium.epicardium, myocardium and endocardium.

6. LAYERS OF HEARTLAYERS OF HEART
EPICARDIUM:EPICARDIUM: the outermost layer ofthe outermost layer of
heart, composed of a serous membrane.heart, composed of a serous membrane.
MYOCARDIUM:MYOCARDIUM: it makes up the largestit makes up the largest
portion of the heart’s wall. This layer ofportion of the heart’s wall. This layer of
muscle tissue contracts with each beat.muscle tissue contracts with each beat.
ENDOCARDIUM:ENDOCARDIUM: the innermost layer ofthe innermost layer of
the heart wall composed of endothelialthe heart wall composed of endothelial
cells that lines the heart chamber andcells that lines the heart chamber and
valves.valves.

8. CHAMBERS OF HEARTCHAMBERS OF HEART
The heart is divided into four chambers:The heart is divided into four chambers:
Right atriumRight atrium
Right ventricleRight ventricle
Left atriumLeft atrium
Right atriumRight atrium

9. VALVESVALVES
Heart has four valves:Heart has four valves:
– Tricuspid valveTricuspid valve
– Bicuspid valveBicuspid valve
– Pulmonic valvePulmonic valve
– Aortic valveAortic valve
Valves close and open in response toValves close and open in response to
change in pressure within the chamber.change in pressure within the chamber.
They serve as one way door in order toThey serve as one way door in order to
prevent regurgitation of blood from oneprevent regurgitation of blood from one
chamber to another.chamber to another.

11. PULMONARY CIRCULATIONPULMONARY CIRCULATION

12. CORONARY CIRCULATION

13. CORONARY CIRCULATIONCORONARY CIRCULATION

14. Cont…Cont…
Coronary arteries originate from aorta,Coronary arteries originate from aorta,
immediately above aortic valveimmediately above aortic valve
2 main branches: Right and Left coronary2 main branches: Right and Left coronary
arteryartery
LCA has 2 major branches: Left anteriorLCA has 2 major branches: Left anterior
descending (LAD) and Left circumflexdescending (LAD) and Left circumflex
artery (LCA)artery (LCA)

16. CARDIAC CONDUCTIONCARDIAC CONDUCTION
Sinoatrial (SA) node – Fires at 60–100Sinoatrial (SA) node – Fires at 60–100
beats/minutebeats/minute
Intranodal pathwayIntranodal pathway
Atrioventricular (AV) node – Fires at 40-60Atrioventricular (AV) node – Fires at 40-60
beats/minutebeats/minute
Atrioventricular bundle of HisAtrioventricular bundle of His
– Ventricular tissue fires at 20-40 beats/minuteVentricular tissue fires at 20-40 beats/minute
and can occur at this point and downand can occur at this point and down
Right and left bundle branchesRight and left bundle branches
Purkinje fibersPurkinje fibers

18. ELECTROCARDIOGRAMELECTROCARDIOGRAM
ConductionConduction
of an actionof an action
potentialpotential
through thethrough the
heart canheart can
be shownbe shown
by anby an
electrocardielectrocardi
ogramogram
(ECG).(ECG).

19. CARDIAC CYCLECARDIAC CYCLE
SystoleSystole ==
period ofperiod of
ventricularventricular
contraction.contraction.
DiastoleDiastole ==
period ofperiod of
ventricularventricular
relaxation.relaxation.

20. CARDIAC CYCLECARDIAC CYCLE
Contraction of the myocardium generatesContraction of the myocardium generates
pressure changes which result in thepressure changes which result in the
orderly movement of blood.orderly movement of blood.
Blood flows from an area ofBlood flows from an area of highhigh
pressurepressure to an area ofto an area of low pressurelow pressure,,
unless flow is blocked by a valve.unless flow is blocked by a valve.
Events on the right and left sides of theEvents on the right and left sides of the
heart are the same, but pressures areheart are the same, but pressures are
lower on the right side of the heart.lower on the right side of the heart.

21. ATRIAL SYSTOLEATRIAL SYSTOLE
The heart is full of blood and the ventriclesThe heart is full of blood and the ventricles
are relaxed and are about ¾ full.are relaxed and are about ¾ full.
Both the atria contract and 30% bloodBoth the atria contract and 30% blood
passes down to the ventricles (atrial kick)passes down to the ventricles (atrial kick)
The atrio-ventricular valves open due toThe atrio-ventricular valves open due to
blood pressure.blood pressure.
70% of the blood flows70% of the blood flows passivelypassively down todown to
the ventricles as a result of pressurethe ventricles as a result of pressure
difference b/w atrias and ventriclesdifference b/w atrias and ventricles

23. VENTRICULAR SYSTOLEVENTRICULAR SYSTOLE
The first part of ventricular systole is known asThe first part of ventricular systole is known as
isovolumetric contraction period.isovolumetric contraction period.
It begins with the closure of AV valve (lub sound).It begins with the closure of AV valve (lub sound).
In additional 0.02 to 0.03 sec semilunar valvesIn additional 0.02 to 0.03 sec semilunar valves
remain closed.remain closed.
During this period volume remain same but theDuring this period volume remain same but the
ventricles are contracting (ventricles are contracting (↑↑pressure)pressure)
The atrias are relax.The atrias are relax.
IVC is an interval between the closing of the AVIVC is an interval between the closing of the AV
valves and the opening of the semilunar valvesvalves and the opening of the semilunar valves
(aortic and pulmonary valves).(aortic and pulmonary valves).

25. VENTRICULAR SYSTOLEVENTRICULAR SYSTOLE
Second phase of ventricular systole isSecond phase of ventricular systole is
known as ejection phase.known as ejection phase.
The increase pressure of blood in theThe increase pressure of blood in the
ventricles opens the semi-lunar valves.ventricles opens the semi-lunar valves.
Blood passes into the aorta andBlood passes into the aorta and
pulmonary arteries due to pressurepulmonary arteries due to pressure
difference.difference.

27. VENTRICULAR DIASTOLEVENTRICULAR DIASTOLE
This phase is known as isovolumetricThis phase is known as isovolumetric
relaxation phase.relaxation phase.
Pressure in the ventricles falls below that inPressure in the ventricles falls below that in
the arteriesthe arteries
Blood under high pressure in the arteriesBlood under high pressure in the arteries
causes the semi lunar valves to shut.causes the semi lunar valves to shut.
This produces the second heart sound, ‘dub’.This produces the second heart sound, ‘dub’.
During diastole, all the muscle in the heartDuring diastole, all the muscle in the heart
relaxes for 0.03 to 0.06 secs.relaxes for 0.03 to 0.06 secs.

29. VENTRICULAR DIASTOLEVENTRICULAR DIASTOLE
This phase is marked by ventricular filling.This phase is marked by ventricular filling.
When pressure in ventricles become lessWhen pressure in ventricles become less
than atria, AV valves open and blood flowsthan atria, AV valves open and blood flows
into ventricles.into ventricles.
This is known as rapid filling period.This is known as rapid filling period.
Ventricular blood volume at the end ofVentricular blood volume at the end of
diastole is 120 ml (EDV) and ESV is 50diastole is 120 ml (EDV) and ESV is 50
ml.ml.
Atria contract in the later half of thisAtria contract in the later half of this
phase.

33. FUNCTIONARY TERMSFUNCTIONARY TERMS
Automaticity:Automaticity: the ability of specialized cells inthe ability of specialized cells in
the heart known as pacemaker cells tothe heart known as pacemaker cells to
spontaneously generate an action potential,spontaneously generate an action potential,
thus causing depolarization.thus causing depolarization.
Conductivity:Conductivity: the ability of cardiac cells tothe ability of cardiac cells to
conduct action potentials, thus transmitting theconduct action potentials, thus transmitting the
electrical signal from one cell to another.electrical signal from one cell to another.
Contractility:Contractility: the ability of cardiac muscle tothe ability of cardiac muscle to
shorten in response to depolarization.shorten in response to depolarization.

34. Cont..Cont..
Excitability:Excitability: the ability of cardiac tissue tothe ability of cardiac tissue to
respond to a stimulus and generate an actionrespond to a stimulus and generate an action
potential.potential.
Rhythmicity:Rhythmicity: the ability of cardiac cells tothe ability of cardiac cells to
spontaneously generate an action potentialspontaneously generate an action potential
at a regular rate.at a regular rate.
STROKE VOLUMESTROKE VOLUME is the amount of bloodis the amount of blood
ejected per ventricular contraction.ejected per ventricular contraction.
Normal value is 60 – 100 ml / beat.Normal value is 60 – 100 ml / beat.
Stroke volume = EDV - ESVStroke volume = EDV - ESV

35. Cont..Cont..
CARDIAC OUTPUTCARDIAC OUTPUT is the amount of bloodis the amount of blood
ejected from left ventricle (in liters) in eachejected from left ventricle (in liters) in each
minute.minute.
Cardiac output = Heart rateCardiac output = Heart rate ×× Stroke volume.Stroke volume.
Normal CO for an adult ranges from 4 – 8Normal CO for an adult ranges from 4 – 8
L/minL/min
CARDIAC INDEXCARDIAC INDEX is cardiac output per squareis cardiac output per square
meter of body surface area.meter of body surface area.
Ranges from 2.8 – 4.2 L/minute/mRanges from 2.8 – 4.2 L/minute/m2.2.
CI = CO / body surface areaCI = CO / body surface area

36. HEART RATEHEART RATE
Heart rateHeart rate
determinesdetermines
the frequencythe frequency
with which thewith which the
blood isblood is
ejected fromejected from
heart.heart.
Therefore ifTherefore if
HR increasesHR increases
then CO willthen CO will
increase andincrease and
vice versa.vice versa.

37. REGULATION OF HRREGULATION OF HR
Heart rate is under autonomic and adrenalHeart rate is under autonomic and adrenal
catecholamine influence.catecholamine influence.
Sympathetic NS (norepinephrine increasesSympathetic NS (norepinephrine increases
depolarization rate)depolarization rate)
Parasympathetic NS (acetylcholine decreaseParasympathetic NS (acetylcholine decrease
rate of depolarization)rate of depolarization)
Adrenal medulla secretes epinephrine andAdrenal medulla secretes epinephrine and
norepinephrine (act on heart same way asnorepinephrine (act on heart same way as
SNS)SNS)

38. REGULATION OF STROKEREGULATION OF STROKE
VOLUMEVOLUME
Factors involved in regulation of strokeFactors involved in regulation of stroke
volume are:volume are:
PreloadPreload
AfterloadAfterload
ContractilityContractility

39. PRELOADPRELOAD
Preload is aPreload is a passive stretching forcepassive stretching force exertedexerted
on the ventricular muscle at the end of diastoleon the ventricular muscle at the end of diastole
or just before systoleor just before systole
It is work imposed on heart before contractionIt is work imposed on heart before contraction
begins.begins.
Preload is caused by the volume of blood inPreload is caused by the volume of blood in
the ventricle at the end of diastole.the ventricle at the end of diastole.
It is determined by venous return and stretchIt is determined by venous return and stretch
of muscle fibre.of muscle fibre.

40. FRANK STARLING’S LAWFRANK STARLING’S LAW
Force of myocardial contraction is determinedForce of myocardial contraction is determined
by the length of muscle cell fibersby the length of muscle cell fibers
Increasing myocardial stretch increases theIncreasing myocardial stretch increases the
force of systoleforce of systole
Amount of blood entering right atrium (CVP)Amount of blood entering right atrium (CVP)
Right heart preload decrease when personRight heart preload decrease when person
holds breath and bear down and vice versaholds breath and bear down and vice versa

42. AFTERLOADAFTERLOAD
Afterload is the force or pressure againstAfterload is the force or pressure against
which a cardiac chamber must eject bloodwhich a cardiac chamber must eject blood
during systoleduring systole
The most critical factor determiningThe most critical factor determining
afterload is vascular resistance : systemicafterload is vascular resistance : systemic
vascular resistance (LV) and pulmonaryvascular resistance (LV) and pulmonary
vascular resistancevascular resistance (RV).(RV).
Decrease SVR will increase SV and viceDecrease SVR will increase SV and vice
versa.versa.
Afterload increases in stenosis of aorticAfterload increases in stenosis of aortic
valve.valve.

45. CONTRACTILITYCONTRACTILITY
Contractility refers to the ability of cardiacContractility refers to the ability of cardiac
muscle fibers to shorten when stimulatedmuscle fibers to shorten when stimulated
and is considered to be independent ofand is considered to be independent of
preload and afterload.preload and afterload.
It is strongly influenced by number ofIt is strongly influenced by number of
calcium ions that are available tocalcium ions that are available to
participate in the contractile process (actinparticipate in the contractile process (actin
myosin filament interaction)myosin filament interaction)

47. PATIENT ASSESSMENTPATIENT ASSESSMENT
CARDIOVASCULAR SYSTEMCARDIOVASCULAR SYSTEM

48. HISTORY OF PRESENT ILLNESSHISTORY OF PRESENT ILLNESS
Symptoms analysis: normal baseline, onset, Precipitating andSymptoms analysis: normal baseline, onset, Precipitating and
palliative factors, quantity and quality, region and radiation,palliative factors, quantity and quality, region and radiation,
severity and time.severity and time.
Chest painChest pain
Nausea and/or vomitingNausea and/or vomiting
DyspneaDyspnea
EdemaEdema
PalpitationsPalpitations
Syncope/dizzinessSyncope/dizziness
Cough and hemoptysisCough and hemoptysis
CyanosisCyanosis
Extremity pain or paresthesiasExtremity pain or paresthesias
FatigueFatigue
OrthopneaOrthopnea
Past medical historyPast medical history
MedicationsMedications
Risk factors (age, diet, smoking, sedentary life style etc)Risk factors (age, diet, smoking, sedentary life style etc)

49. PHYSICAL EXAMPHYSICAL EXAM
InspectionInspection
– General appearanceGeneral appearance
– Jugular venousJugular venous
distension (JVD)distension (JVD)
– SkinSkin
– ExtremitiesExtremities
PalpationPalpation
– PulsesPulses
PercussionPercussion
AuscultationAuscultation
– Good stethoscopeGood stethoscope
– PositioningPositioning
– Normal tones – SNormal tones – S11/S/S22
– MurmursMurmurs

50. MURMURSMURMURS
TimingTiming
LocationLocation
TransmissionTransmission
PitchPitch
QualityQuality
IntensityIntensity
Grade 1 – Barely audibleGrade 1 – Barely audible
Grade 2 – Clearly audibleGrade 2 – Clearly audible
Grade 3 – ModeratelyGrade 3 – Moderately
loudloud
Grade 4 – Loud with aGrade 4 – Loud with a
thrillthrill
Grade 5 – Very loud withGrade 5 – Very loud with
an easily palpable thrillan easily palpable thrill
Grade 6 – Very loud, noGrade 6 – Very loud, no
stethoscope needed,stethoscope needed,
palpable and visible thrillpalpable and visible thrill

52. IMPORTANT CARDIAC LABSIMPORTANT CARDIAC LABS
Coagulation studies – PTT, APTT and PT/INR,Coagulation studies – PTT, APTT and PT/INR,
platelet, fibrinogen level etc.platelet, fibrinogen level etc.
Electrolytes – Potassium, magnesium, and calcium.Electrolytes – Potassium, magnesium, and calcium.
Lipid studies – Cholesterol, LDL, HDL, triglycerides.Lipid studies – Cholesterol, LDL, HDL, triglycerides.
Enzymes – CK-MM, CK-MB, CK-BB, Troponin.Enzymes – CK-MM, CK-MB, CK-BB, Troponin.
Hematological studies – RBC, HB, HCT, WBC, ESRHematological studies – RBC, HB, HCT, WBC, ESR
Blood chemistry – electrolytes, ABGs, BUN, Cr,Blood chemistry – electrolytes, ABGs, BUN, Cr,
proteins etc.proteins etc.
CRP, D- dimerCRP, D- dimer

53. DIAGNOSTIC STUDIESDIAGNOSTIC STUDIES
Standard 12 lead Electrocardiogram.Standard 12 lead Electrocardiogram.
Continuous cardiac monitoringContinuous cardiac monitoring
Electrophysiology studies (Holter monitoring)Electrophysiology studies (Holter monitoring)
Chest radiographyChest radiography
EchocardiographyEchocardiography
TransesophagealTransesophageal EchocardiographyEchocardiography
Exercise stress testingExercise stress testing
CT scanningCT scanning
MRIMRI
Cardiac catheterizationCardiac catheterization
Coronary angiographyCoronary angiography

54. 12 LEAD12 LEAD
ELECTROCARDIOGRAM (ECG)ELECTROCARDIOGRAM (ECG)
The electrocardiogram is a graphic record ofThe electrocardiogram is a graphic record of
the direction and magnitude of the electricalthe direction and magnitude of the electrical
activity that is generated by the depolarizationactivity that is generated by the depolarization
and repolarization of the atria and ventricles.and repolarization of the atria and ventricles.
The electrocardiogram (ECG) is aThe electrocardiogram (ECG) is a
representation of the electrical events of therepresentation of the electrical events of the
cardiac cycle.cardiac cycle.
Each event has a distinctive waveform, theEach event has a distinctive waveform, the
study of which can lead to greater insight into astudy of which can lead to greater insight into a
patient’s cardiac pathophysiology.patient’s cardiac pathophysiology.

55. Cont.Cont.
P wave of ECG represents depolarizationP wave of ECG represents depolarization
of SA nodeof SA node
QRS complex represents depolarization ofQRS complex represents depolarization of
ventricular conduction systemventricular conduction system
T wave occur during the last half of systoleT wave occur during the last half of systole
and represents repolarization of theand represents repolarization of the
ventriclesventricles

57. CHEST LEADSCHEST LEADS
V1:V1: fourth intercostal space, right of thefourth intercostal space, right of the
sternum.sternum.
V2:V2: fourth intercostal space to the left of thefourth intercostal space to the left of the
sternum.sternum.
V3:V3: Between leads V2 and V4Between leads V2 and V4
V4:V4: fifth intercostal space in the mid-clavicularfifth intercostal space in the mid-clavicular
lineline
V5:V5: horizontally even with V4, but in thehorizontally even with V4, but in the
anterior axillary line.anterior axillary line.
V6:V6: horizontally even with V4 and V5 in thehorizontally even with V4 and V5 in the
midaxillary line.midaxillary line.

58. LIMB LEADSLIMB LEADS
RA:RA: on the right arm.on the right arm.
LA:LA: on the left arm.on the left arm.
RL:RL: on the right leg. (ground lead or earth lead)on the right leg. (ground lead or earth lead)
LL:LL: on the left leg.on the left leg.
Lead I is the voltage between the left arm (LA)Lead I is the voltage between the left arm (LA)
electrode and right arm (RA) electrode.electrode and right arm (RA) electrode.
Lead II is the voltage between the left leg (LL)Lead II is the voltage between the left leg (LL)
electrode and the right arm (RA) electrode.electrode and the right arm (RA) electrode.
Lead III is the voltage between the left leg (LL)Lead III is the voltage between the left leg (LL)
electrode and the left arm (LA) electrode.electrode and the left arm (LA) electrode.

60. AUGMENTED LEADSAUGMENTED LEADS
LeadLead augmented vector right (aVR)augmented vector right (aVR) has thehas the
positive electrode on the right arm. The negativepositive electrode on the right arm. The negative
electrode is a combination of the left armelectrode is a combination of the left arm
electrode and the left leg electrode.electrode and the left leg electrode.
LeadLead augmented vector left (aVL)augmented vector left (aVL) has thehas the
positive electrode on the left arm. The negativepositive electrode on the left arm. The negative
electrode is a combination of the right armelectrode is a combination of the right arm
electrode and the left leg electrode.electrode and the left leg electrode.
LeadLead augmented vector foot (aVF)augmented vector foot (aVF) has thehas the
positive electrode on the left leg. The negativepositive electrode on the left leg. The negative
electrode is a combination of the right armelectrode is a combination of the right arm
electrode and the left arm electrode.electrode and the left arm electrode.

61. CONT.CONT.
Each lead has both a positive and aEach lead has both a positive and a
negative pole.negative pole.
When electrical current travel alongWhen electrical current travel along
towards a positive pole, waveform is antowards a positive pole, waveform is an
upward deflection.upward deflection.
When current travels toward a negativeWhen current travels toward a negative
pole, deflection is downward.pole, deflection is downward.

63. ECG PAPERECG PAPER
The measurement of time is calculatedThe measurement of time is calculated
along the horizontal lines in seconds.along the horizontal lines in seconds.
– Each small square = 0.04 secEach small square = 0.04 sec
– Each large square = 0.20 secEach large square = 0.20 sec
– 5 large boxes = 1 sec5 large boxes = 1 sec
Measurement of energy (voltage orMeasurement of energy (voltage or
amplitude) is represented along theamplitude) is represented along the
vertical lines in millivolts or millimeters.vertical lines in millivolts or millimeters.
– Each small square = 0.1 mV or 1 mmEach small square = 0.1 mV or 1 mm
– Each large square = 0.5 mV or 5 mmEach large square = 0.5 mV or 5 mm

65. What types of pathology can weWhat types of pathology can we
identify and study from EKGs?identify and study from EKGs?
ArrhythmiasArrhythmias
Myocardial ischemia and infarctionMyocardial ischemia and infarction
PericarditisPericarditis
Chamber hypertrophyChamber hypertrophy
Electrolyte disturbances (i.e.Electrolyte disturbances (i.e.
hyperkalemia, hypokalemia)hyperkalemia, hypokalemia)
Drug toxicity (i.e. digoxin and drugs whichDrug toxicity (i.e. digoxin and drugs which
prolong the QT interval)prolong the QT interval)

66. ECG WAVEFORMSECG WAVEFORMS
The baseline is also known as theThe baseline is also known as the
isoelectric line.isoelectric line.
The heart’s electrical activity producesThe heart’s electrical activity produces
several waveforms.several waveforms.
The waveforms are:The waveforms are:
– P waveP wave
– QRS complexQRS complex
– T waveT wave

68. P WAVEP WAVE
Measured from the beginning of the PMeasured from the beginning of the P
wave to the end of P wave.wave to the end of P wave.
It represents Atrial depolarization.It represents Atrial depolarization.
Normal P wave precedes a QRS complex.Normal P wave precedes a QRS complex.
To evaluate P wave look for threeTo evaluate P wave look for three
characteristics:characteristics:
– LocationLocation
– ConfigurationConfiguration
– DeflectionDeflection

69. CONT.CONT.
If all of the P waves do not look alike thenIf all of the P waves do not look alike then
the impulse may be coming in the atriathe impulse may be coming in the atria
and not the SA node.and not the SA node.
If pacemaker site is in the atria, P wavesIf pacemaker site is in the atria, P waves
are upright (positive deflection).are upright (positive deflection).
If it’s at AV junction, they may be invertedIf it’s at AV junction, they may be inverted
in lead II.in lead II.
It is normally 2.5mm or less in height andIt is normally 2.5mm or less in height and
0.11 sec or less in duration.0.11 sec or less in duration.

70. QRS COMPLEXQRS COMPLEX
Q wave:Q wave: is the firstis the first negative deflectionnegative deflection
following the P wave.following the P wave.
R wave:R wave: the firstthe first positive deflectionpositive deflection
extending above baseline following the Pextending above baseline following the P
wave and Q wave.wave and Q wave.
S wave:S wave: is the firstis the first negative deflectionnegative deflection
extending below baseline following the Rextending below baseline following the R
wave.wave.

72. CONT.CONT.
QRS complex represents the ventricularQRS complex represents the ventricular
depolarization (ventricular systole).depolarization (ventricular systole).
Normal duration of QRS complex is 0.04Normal duration of QRS complex is 0.04
to 0.12 seconds.to 0.12 seconds.
It is measured from the beginning of the QIt is measured from the beginning of the Q
wave (where it begins to deviate from thewave (where it begins to deviate from the
baseline) to the end of the S wave (wherebaseline) to the end of the S wave (where
the S wave returns to the isoelectric line).the S wave returns to the isoelectric line).

73. T WAVET WAVE
T wave represents ventricularT wave represents ventricular
repolarization (ventricular diastole).repolarization (ventricular diastole).
The end of the T wave is the point where itThe end of the T wave is the point where it
returns to the isoelectric line.returns to the isoelectric line.
T wave always follows the QRS complex.T wave always follows the QRS complex.
Normal T wave is positive and upright.Normal T wave is positive and upright.
Its normal value is .10 sec to 0.25 sec.Its normal value is .10 sec to 0.25 sec.
Inverted or negative deflecting T wavesInverted or negative deflecting T waves
are suggestive of myocardial ischemia orare suggestive of myocardial ischemia or
ventricular conduction delay.ventricular conduction delay.

74. CONT.CONT.
Peaked, tall T waves usually indicatePeaked, tall T waves usually indicate
Hyperkalemia.Hyperkalemia.

75. U WAVEU WAVE
The U wave is the first gradual or abrupt slopeThe U wave is the first gradual or abrupt slope
after the end of the T wave.after the end of the T wave.
It probably represents the final stage ofIt probably represents the final stage of
repolarization of the ventricles.repolarization of the ventricles.
U wave are rounded and symmetrical.U wave are rounded and symmetrical.
U waves are measured from the beginning ofU waves are measured from the beginning of
the U wave to the end of the U wave.the U wave to the end of the U wave.
Prominent U waves may indicate hypokalemiaProminent U waves may indicate hypokalemia
and also the effect of an excessive amount ofand also the effect of an excessive amount of
digoxin in conduction system.digoxin in conduction system.

77. P-R INTERVALP-R INTERVAL
P-R interval represents the interval of timeP-R interval represents the interval of time
between atrial depolarization andbetween atrial depolarization and
ventricular depolarization.ventricular depolarization.
A normal P-R interval indicates that theA normal P-R interval indicates that the
electrical impulse is being conducted andelectrical impulse is being conducted and
travels through the atria, AV node, AVtravels through the atria, AV node, AV
junction, bundle of His, bundle branchesjunction, bundle of His, bundle branches
and Purkinje fibers.and Purkinje fibers.

78. CONT.CONT.
The P-R interval is measured from theThe P-R interval is measured from the
beginning of the P wave to the beginningbeginning of the P wave to the beginning
of the QRS complex.of the QRS complex.
Normal duration of P-R interval is 0.12 toNormal duration of P-R interval is 0.12 to
0.20 seconds.0.20 seconds.

80. QRS COMPLEXQRS COMPLEX
It is a large waveform representingIt is a large waveform representing
ventricular depolarization.ventricular depolarization.
Not all QRS complex has all threeNot all QRS complex has all three
componentscomponents
Measured from the starting of Q wave tillMeasured from the starting of Q wave till
end of S waveend of S wave
Normal QRS complex is 0.06 to 0.11Normal QRS complex is 0.06 to 0.11
seconds.seconds.

82. ST SEGMENTST SEGMENT
The ST segment marks the beginning ofThe ST segment marks the beginning of
the ventricular repolarization.the ventricular repolarization.
The ST segment extends from the end ofThe ST segment extends from the end of
the QRS complex to the beginning of the Tthe QRS complex to the beginning of the T
wave.wave.
A normal ST segment is flat on theA normal ST segment is flat on the
isoelectric line or baseline.isoelectric line or baseline.
Elevated or depressed more than 1mm ofElevated or depressed more than 1mm of
ST segment may be indicative of an MI.ST segment may be indicative of an MI.

84. ST SEGMENTST SEGMENT
DEPRESSION ELEVATIONDEPRESSION ELEVATION

85. QT INTERVALQT INTERVAL
The QT interval represents the length of timeThe QT interval represents the length of time
for both ventricular depolarization andfor both ventricular depolarization and
repolarization.repolarization.
It is measured from the beginning of the QIt is measured from the beginning of the Q
wave to the end of the T wave on the isoelectricwave to the end of the T wave on the isoelectric
line.line.
Its normal value is 0.32 to 0.43 sec.Its normal value is 0.32 to 0.43 sec.
A short QT interval may indicate aA short QT interval may indicate a
hypercalcemia in patients taking digitalis.hypercalcemia in patients taking digitalis.
A prolong QT interval is caused byA prolong QT interval is caused by
antiarrhythmatics or may indicateantiarrhythmatics or may indicate
HypocalcemiaHypocalcemia

86. NORMAL QT INTERVALNORMAL QT INTERVAL

87. PROLONG QT INTERVALPROLONG QT INTERVAL

90. STEPS TO READING ECGSTEPS TO READING ECG
Is theIs the RhythmRhythm regular or irregular?regular or irregular?
What is theWhat is the RateRate? Both atrial and ventricle.? Both atrial and ventricle.
Do theDo the P wavesP waves all look the same? Is thereall look the same? Is there
a P wave for every QRS and conversely aa P wave for every QRS and conversely a
QRS complexQRS complex for every P wave?for every P wave?
Are all the complexes withinAre all the complexes within Normal TimeNormal Time
LimitsLimits? (PR interval, QRS complex and ST? (PR interval, QRS complex and ST
segment)segment)
IdentifyIdentify the rhythm and any abnormalities.the rhythm and any abnormalities.

92. RATERATE
6 SECOND METHOD:6 SECOND METHOD:
It is performed only if the rhythm is regular.It is performed only if the rhythm is regular.
Identify a 6 second strip.Identify a 6 second strip.
Locate 3 second markers (30 large boxes).Locate 3 second markers (30 large boxes).
Count complete QRS complex in a 6-secondCount complete QRS complex in a 6-second
strip and multiply it by 10.strip and multiply it by 10.
This gives you an approximate number ofThis gives you an approximate number of
beats per minutes.beats per minutes.

94. CONT.CONT.
THE SEQUENCE METHOD:THE SEQUENCE METHOD:
Locate an R wave on a dark black line of aLocate an R wave on a dark black line of a
large box.large box.
Label the consecutive heavy black lines asLabel the consecutive heavy black lines as
follows: 300, 150, 100, 75, 60 and 50.follows: 300, 150, 100, 75, 60 and 50.
If next R wave falls in between two heavyIf next R wave falls in between two heavy
black lines for e.g. between 70 and 60black lines for e.g. between 70 and 60
then the heart rate would be 65.then the heart rate would be 65.

96. # Of Big# Of Big
BoxesBoxes
RateRate
11 300300
22 150150
33 100100
44 7575
55 6060
66 5050

98. NORMAL INTERVAL TIMINGNORMAL INTERVAL TIMING
PR interval – 0.12 to 0.20 secondsPR interval – 0.12 to 0.20 seconds
QRS interval – less then 0.12QRS interval – less then 0.12
QT interval – varies with rate.QT interval – varies with rate.

99. DETERMINATION OF CARDIACDETERMINATION OF CARDIAC
RHYTHMRHYTHM
Correct determination of cardiac rhythmCorrect determination of cardiac rhythm
requires a systematic evaluation of ECG.requires a systematic evaluation of ECG.
Following steps are used to determineFollowing steps are used to determine
cardiac rhythm:cardiac rhythm:
– Calculate the atrial rate (P wave)Calculate the atrial rate (P wave)
– Calculate ventricular rate (QRS complex)Calculate ventricular rate (QRS complex)
– Determine regularity and shape of P waveDetermine regularity and shape of P wave
– Determine regularity, shape and width of QRSDetermine regularity, shape and width of QRS
– Measure the PR intervalMeasure the PR interval
– Interpret the arrhythmiaInterpret the arrhythmia

100. COMMON ARRHYTHMIASCOMMON ARRHYTHMIAS
Arrhythmias originating in the sinus node.Arrhythmias originating in the sinus node.
Arrhythmias originating in the atria.Arrhythmias originating in the atria.
Arrhythmias originating in the junction.Arrhythmias originating in the junction.
Arrhythmias originating in the ventricles.Arrhythmias originating in the ventricles.
Atrioventricular BlocksAtrioventricular Blocks

101. NORMAL SINUS RHYTHMNORMAL SINUS RHYTHM
Normal sinus rhythm record an impulse that start inNormal sinus rhythm record an impulse that start in
the sinus node and progresses to the ventriclesthe sinus node and progresses to the ventricles
through a normal conduction pathway.through a normal conduction pathway.
Atrial and ventricular rhythms: regularAtrial and ventricular rhythms: regular
Atrial and ventricular rates: 60 – 100 bpmAtrial and ventricular rates: 60 – 100 bpm
P waves: rounded, smooth, upright and precedingP waves: rounded, smooth, upright and preceding
every QRS complex.every QRS complex.
PR interval: 0.12 to 0.20 seconds.PR interval: 0.12 to 0.20 seconds.
QRS complex: 0.04 to 0.10 sec, less than 0.12 secQRS complex: 0.04 to 0.10 sec, less than 0.12 sec
T wave: uprightT wave: upright
QT interval: 0.36 sec to 0.44 secQT interval: 0.36 sec to 0.44 sec

103. SINUS ARRHYTHMIASINUS ARRHYTHMIA
Sinus arrhythmia occurs when the sinusSinus arrhythmia occurs when the sinus
node discharges irregularly.node discharges irregularly.
Associated with the phases of respiration:Associated with the phases of respiration:
during inspiration sinus node fires fasterduring inspiration sinus node fires faster
and vice versa.and vice versa.
Looks like normal sinus rhythm except forLooks like normal sinus rhythm except for
the sinus irregularity.the sinus irregularity.

106. SINUS BRADYCARDIASINUS BRADYCARDIA
Sinus bradycardia is characterized by a sinusSinus bradycardia is characterized by a sinus
rate below 60 bpm and regular rhythm.rate below 60 bpm and regular rhythm.
It may occur normally during sleep or in aIt may occur normally during sleep or in a
person with a well conditioned heart (athletes).person with a well conditioned heart (athletes).
May be a response of vagal stimulation, anyMay be a response of vagal stimulation, any
disease process (MI, raised ICP etc) anddisease process (MI, raised ICP etc) and
medications (digitalis, beta blockers, Camedications (digitalis, beta blockers, Ca
Channel blocker).Channel blocker).
Treat only if patient is symptomatic.Treat only if patient is symptomatic.

109. SINUS TACHYCARDIASINUS TACHYCARDIA
Sinus tachycardia is a sinus rhythm at aSinus tachycardia is a sinus rhythm at a
rate greater than 100 bpm.rate greater than 100 bpm.
It is normal response to exercise andIt is normal response to exercise and
emotion.emotion.
Persistent sinus tachycardia indicatesPersistent sinus tachycardia indicates
underlying problem like fever, acute bloodunderlying problem like fever, acute blood
loss, pain, shock, anxiety etc.loss, pain, shock, anxiety etc.
It is normal physiologic response toIt is normal physiologic response to
decrease cardiac output.decrease cardiac output.

111. SINUS ARRESTSINUS ARREST
Sinus arrest is a failure of the SA node toSinus arrest is a failure of the SA node to
initiate an impulse resulting in the absenceinitiate an impulse resulting in the absence
of a P wave, QRS complex and T wave.of a P wave, QRS complex and T wave.
It is also known as sinus pause or cardiacIt is also known as sinus pause or cardiac
sandstill.sandstill.
Usually with the exception of missingUsually with the exception of missing
PQRST complex, the ECG will be normal.PQRST complex, the ECG will be normal.

114. ATRIAL ARRHYTHMIASATRIAL ARRHYTHMIAS
Atrial arrhythmias the most commonAtrial arrhythmias the most common
cardiac rhythm disturbance as result fromcardiac rhythm disturbance as result from
impulses originating in areas outside theimpulses originating in areas outside the
sinoatrial node (SA node).sinoatrial node (SA node).
These arrhythmias can affect ventricularThese arrhythmias can affect ventricular
filling time.filling time.

115. PREMATURE ATRIALPREMATURE ATRIAL
CONTRACTIONCONTRACTION
Premature atrial contraction originatesPremature atrial contraction originates
outside the SA node, usually results fromoutside the SA node, usually results from
an irritable focus (ectopic pacemaker).an irritable focus (ectopic pacemaker).
Irritable focus in the atria fires before theIrritable focus in the atria fires before the
next sinus node impulse is due to fire.next sinus node impulse is due to fire.
P wave configuration is abnormal asP wave configuration is abnormal as
compare to sinus P wave.compare to sinus P wave.
Normal QRS complex .Normal QRS complex .

116. CONT.CONT.
Rhythm would be regular except whenRhythm would be regular except when
PAC occur.PAC occur.
PR interval may be normal or prolonged.PR interval may be normal or prolonged.
T wave embedded with p wave.T wave embedded with p wave.
It can occur in healthy people as a result ofIt can occur in healthy people as a result of
emotions, tobacco, alcohol and caffeine.emotions, tobacco, alcohol and caffeine.
It can also associated with diseaseIt can also associated with disease
processes like rheumatic heart diseases,processes like rheumatic heart diseases,
ischemic heart diseases, mitral stenosis,ischemic heart diseases, mitral stenosis,
heart failure, certain electrolyte imbalancesheart failure, certain electrolyte imbalances
and medications etc.and medications etc.

118. PAROXYSMAL SUPRAVENTRICULARPAROXYSMAL SUPRAVENTRICULAR
TACHYCARDIATACHYCARDIA
PSVT is the sudden onset of a rapid firingPSVT is the sudden onset of a rapid firing
from an ectopic foci resulting in a heartfrom an ectopic foci resulting in a heart
rate of 150 – 250 bpm.rate of 150 – 250 bpm.
Occurs when a single ectopic site in oneOccurs when a single ectopic site in one
of the atria takes over pacing the heartof the atria takes over pacing the heart
instead of the SA node.instead of the SA node.
The brief period of tachycardia alternatesThe brief period of tachycardia alternates
with periods of normal sinus rhythm.with periods of normal sinus rhythm.

119. CONT.CONT.
P wave may precede QRS complex, may beP wave may precede QRS complex, may be
hidden in QRS complex or may be mergedhidden in QRS complex or may be merged
with T wave.with T wave.
P wave may be negative because ofP wave may be negative because of
retrograde conduction from AV node to atria.retrograde conduction from AV node to atria.
QRS complex is usually normal.QRS complex is usually normal.
Rhythm of PSVT is regular.Rhythm of PSVT is regular.
PSVT can be terminated with vagalPSVT can be terminated with vagal
stimulation (carotid massage), Valsalvastimulation (carotid massage), Valsalva
maneuver or IV adenosine.maneuver or IV adenosine.

123. ATRIAL FLUTTERATRIAL FLUTTER
Atrial flutter is an accelerated rhythm fromAtrial flutter is an accelerated rhythm from
rapid firing of an ectopic atrial focus at raterapid firing of an ectopic atrial focus at rate
of 250 to 350 bpm.of 250 to 350 bpm.
The AV node prevent too many atrialThe AV node prevent too many atrial
impulses from reaching to the ventricles.impulses from reaching to the ventricles.
Rapid atrial rate producesRapid atrial rate produces saw toothsaw tooth PP
waves on the ECG.waves on the ECG.

124. CONT.CONT.
P wave has classic saw tooth appearanceP wave has classic saw tooth appearance
with atrial rate of 250 – 350 bpm.with atrial rate of 250 – 350 bpm.
Flutter block; 2:1, 3:1 or 4:1 (flutter toFlutter block; 2:1, 3:1 or 4:1 (flutter to
ventricular ratio).ventricular ratio).
QRS has normal configuration.QRS has normal configuration.
Atrial rhythm is regular but ventricularAtrial rhythm is regular but ventricular
rhythm would be regular or irregular both.rhythm would be regular or irregular both.
Treatment goal is to reestablish sinusTreatment goal is to reestablish sinus
rhythm and ventricular control.rhythm and ventricular control.

127. ATRIAL FIBRILLATIONATRIAL FIBRILLATION
Atrial fibrillation is characterized by rapid,Atrial fibrillation is characterized by rapid,
chaotic atrial ectopic rhythm with atrial ratechaotic atrial ectopic rhythm with atrial rate
of 350 – 500 bpm.of 350 – 500 bpm.
The ventricles respond only to thoseThe ventricles respond only to those
impulses that make it through AV node.impulses that make it through AV node.
P waves are not present.P waves are not present.
Normal QRS complex.Normal QRS complex.
Rhythm is irregular.Rhythm is irregular.

132. MULTIFOCAL ATRIALMULTIFOCAL ATRIAL
TACHYCARDIATACHYCARDIA
In this arrhythmia, atrial tachycardiaIn this arrhythmia, atrial tachycardia
occurs with three or more atrial foci firingoccurs with three or more atrial foci firing
intermittently.intermittently.
P wave morphology results from firing ofP wave morphology results from firing of
three or more atrial foci.three or more atrial foci.
Atrial rate is between 100 to 250 bpm.Atrial rate is between 100 to 250 bpm.
Rhythm is usually irregular.Rhythm is usually irregular.
QRS complex are normal.QRS complex are normal.

134. JUNCTIONAL RHYTHMJUNCTIONAL RHYTHM
Junctional rhythm originates from AV junction.Junctional rhythm originates from AV junction.
It occurs when SA node fails to conductIt occurs when SA node fails to conduct
impulses.impulses.
The Junctional rate ranges between 50 to 70The Junctional rate ranges between 50 to 70
bpm.bpm.
P wave appear inverted before QRS complex.P wave appear inverted before QRS complex.
Buried P wave inside the QRS complex.Buried P wave inside the QRS complex.
Normal QRS followed by inverted P wave.Normal QRS followed by inverted P wave.

139. PREMATURE JUNCTIONALPREMATURE JUNCTIONAL
CONTRACTIONCONTRACTION
Premature junctional contraction is anPremature junctional contraction is an
ectopic impulse from AV junction occurectopic impulse from AV junction occur
before next sinus impulse.before next sinus impulse.
QRS complex is narrow <0.12 sec.QRS complex is narrow <0.12 sec.
P wave may occur before, during or afterP wave may occur before, during or after
QRS complex.QRS complex.
Occur in healthy people or in people withOccur in healthy people or in people with
underlying heart disease.underlying heart disease.
Rhythm is irregular.Rhythm is irregular.

141. PREMATURE VENTRICULARPREMATURE VENTRICULAR
CONTRACTIONCONTRACTION
They are caused by firing of an ectopicThey are caused by firing of an ectopic
impulse in the ventricles before nextimpulse in the ventricles before next
expected impulse from SA node.expected impulse from SA node.
As a result of this, no P wave occur.As a result of this, no P wave occur.
QRS complex is wide and bizarre appearsQRS complex is wide and bizarre appears
interrupting normal sinus rhythm.interrupting normal sinus rhythm.
After a premature beat there is aAfter a premature beat there is a
compensatory pause.compensatory pause.

143. CONT.CONT.
If PVC occur after each sinus beat then itIf PVC occur after each sinus beat then it
is known as ventricular bigeminy.is known as ventricular bigeminy.
If PVC occur after two consecutive sinusIf PVC occur after two consecutive sinus
beats then it is known as ventricularbeats then it is known as ventricular
trigeminy.trigeminy.
When PVC appear in one form it is calledWhen PVC appear in one form it is called
as unifocal PVC and different PVC areas unifocal PVC and different PVC are
known as multifocal PVC.known as multifocal PVC.

149. VENTRICULAR TACHYCARDIAVENTRICULAR TACHYCARDIA
This is characterized by rapidly occurringThis is characterized by rapidly occurring
series of PVCs with no normal beats inseries of PVCs with no normal beats in
between.between.
Absent P wave.Absent P wave.
QRS is wide and bizarre with rate moreQRS is wide and bizarre with rate more
than 100 to 250 bpm.than 100 to 250 bpm.
Rhythm is regular.Rhythm is regular.
Extremely dangerous as this can result inExtremely dangerous as this can result in
low cardiac output.low cardiac output.

153. TOSARDES DE POINTESTOSARDES DE POINTES
Tosardes de pointes means twisting of points,Tosardes de pointes means twisting of points,
is a special form of ventricular tachycardia.is a special form of ventricular tachycardia.
QRS complexes rotate about the baseline,QRS complexes rotate about the baseline,
deflecting downward and upward for severaldeflecting downward and upward for several
beats.beats.
P waves are absent.P waves are absent.
QRS complex is wide and bizarre.QRS complex is wide and bizarre.
Tachycardia rate is between 100 – 300 bpm.Tachycardia rate is between 100 – 300 bpm.
Rhythm is irregular.Rhythm is irregular.
IV magnesium sulphate is drug of choice.IV magnesium sulphate is drug of choice.

157. VENTRICULAR FIBRILLATIONVENTRICULAR FIBRILLATION
Ventricular defibrillation is rapid, irregularVentricular defibrillation is rapid, irregular
and ineffective depolarization of theand ineffective depolarization of the
ventricles.ventricles.
ECG tracing display bizarre fibrillatoryECG tracing display bizarre fibrillatory
wave pattern.wave pattern.
P wave, QRS complex and T wave areP wave, QRS complex and T wave are
impossible to identify.impossible to identify.
Rate and rhythm cannot be determined.Rate and rhythm cannot be determined.

160. IDIOVENTRICULAR RHYTHMIDIOVENTRICULAR RHYTHM
Normal ventricular rate is 20 to 40 bpmNormal ventricular rate is 20 to 40 bpm
and when this rate accelerates aboveand when this rate accelerates above
sinus rate making ventricle the primarysinus rate making ventricle the primary
pacemaker.pacemaker.
Absent P wave.Absent P wave.
QRS is wide and bizarre.QRS is wide and bizarre.
It occur regularly at rate of 50 to 100 bpm.It occur regularly at rate of 50 to 100 bpm.
Rhythm is usually regular.Rhythm is usually regular.

163. VENTRICULAR ASYSTOLEVENTRICULAR ASYSTOLE
It is absence of any electrical activity.It is absence of any electrical activity.
No P wave, no QRS complex, no pulse andNo P wave, no QRS complex, no pulse and
no cardiac output.no cardiac output.
It is always fatal as patient is unresponsiveIt is always fatal as patient is unresponsive
therefore it has to be treated immediately.therefore it has to be treated immediately.
Flat line on ECG.Flat line on ECG.

166. ATRIOVENTRICULAR BLOCKATRIOVENTRICULAR BLOCK
The termThe term
AtrioventricularAtrioventricular
block is used toblock is used to
describedescribe
arrhythmias inarrhythmias in
which there iswhich there is
delay or faileddelay or failed
conduction ofconduction of
supraventricularsupraventricular
impulses into theimpulses into the
ventricles.ventricles.

167. FIRST DEGREEFIRST DEGREE
ATRIOVENTRICULAR BLOCKATRIOVENTRICULAR BLOCK
First degree AV block is defined asFirst degree AV block is defined as
prolonged AV conduction time ofprolonged AV conduction time of
supraventricular impulses into thesupraventricular impulses into the
ventricles.ventricles.
This delay usually occur in the AV nodeThis delay usually occur in the AV node
and all impulses are conducted to theand all impulses are conducted to the
ventricles but with delayed conductionventricles but with delayed conduction
times.times.
It is characterized by a constant prolongIt is characterized by a constant prolong
PR interval.PR interval.

169. CONT.CONT.
P waves are present and preceding everyP waves are present and preceding every
QRS complex.QRS complex.
It can be due to coronary artery disease,It can be due to coronary artery disease,
rheumatic heart disease, administration ofrheumatic heart disease, administration of
digitalis, beta blockers or ca channeldigitalis, beta blockers or ca channel
blockers.blockers.
Nurse should observe rhythm closely for 2Nurse should observe rhythm closely for 2
degree and 3 degree block.degree and 3 degree block.

171. SECOND DEGREE AV BLOCKSECOND DEGREE AV BLOCK
Second degree AV block occur whenSecond degree AV block occur when
impulses from AV node at time fails to beimpulses from AV node at time fails to be
conducted to the ventricles.conducted to the ventricles.
It is divided into two distinct categories:It is divided into two distinct categories:
type I block occurring in the AV node andtype I block occurring in the AV node and
type II occurring below the AV node in thetype II occurring below the AV node in the
bundle of His or bundle branch system.bundle of His or bundle branch system.

172. SECOND DEGREE AV BLOCKSECOND DEGREE AV BLOCK
MOBITZ I (WENCHEBACK)MOBITZ I (WENCHEBACK)
It refer to as Wencheback block in whichIt refer to as Wencheback block in which
there is a progressive increase inthere is a progressive increase in
conduction times of consecutive atrialconduction times of consecutive atrial
impulses into the ventricles until oneimpulses into the ventricles until one
impulse fails to conduct.impulse fails to conduct.
It is usually associated with the blockIt is usually associated with the block
above the bundle of His.above the bundle of His.
PR interval gradually lengthen until one PPR interval gradually lengthen until one P
wave fails to conduct and is not followedwave fails to conduct and is not followed
by QRS.by QRS.

176. SECOND DEGREE AV BLOCKSECOND DEGREE AV BLOCK
MOBITZ IIMOBITZ II
This type of block is due to sudden failure ofThis type of block is due to sudden failure of
conduction of an atrial impulse to the ventriclesconduction of an atrial impulse to the ventricles
without progressive increase in conduction time ofwithout progressive increase in conduction time of
consecutive P waves.consecutive P waves.
This is less common than Mobitz Type I but is moreThis is less common than Mobitz Type I but is more
serious (often precedes to 3 degree block).serious (often precedes to 3 degree block).
Conduction pattern would be occasionally orConduction pattern would be occasionally or
repetitive, 2:1, 3:1,…repetitive, 2:1, 3:1,…
PR interval remain constant although they may bePR interval remain constant although they may be
normal or slightly prolong.normal or slightly prolong.
Wide QRS complex due to bundle branch block.Wide QRS complex due to bundle branch block.

178. THIRD DEGREE AV BLOCKTHIRD DEGREE AV BLOCK
Complete AV block occurs when no PComplete AV block occurs when no P
waves are conducted to the ventricles.waves are conducted to the ventricles.
It is complete failure of conduction of allIt is complete failure of conduction of all
atrial impulses to ventricles.atrial impulses to ventricles.
The atria and ventricle are controlled byThe atria and ventricle are controlled by
independent pacemaker.independent pacemaker.
P waves and QRS are present on ECGP waves and QRS are present on ECG
but without relationship.but without relationship.

182. SUMMARY OF LEADSSUMMARY OF LEADS
Limb LeadsLimb Leads Precordial LeadsPrecordial Leads
BipolarBipolar I, II, IIII, II, III
(standard limb leads)(standard limb leads)
--
UnipolarUnipolar aVR, aVL, aVFaVR, aVL, aVF
(augmented limb leads)(augmented limb leads)
VV11-V-V66

183. PRECORDIAL LEADSPRECORDIAL LEADS

184. ARRANGEMENT OF LEADS ON THEARRANGEMENT OF LEADS ON THE
ECG PAPERECG PAPER

185. ANATOMIC GROUPSANATOMIC GROUPS
(SEPTUM)(SEPTUM)

186. ANATOMIC GROUPSANATOMIC GROUPS
(LATERAL WALL)(LATERAL WALL)

187. ANATOMIC GROUPSANATOMIC GROUPS
(INFERIOR WALL)(INFERIOR WALL)

188. ANATOMIC GROUPSANATOMIC GROUPS
(SUMMARY)(SUMMARY)

189. EFFECT OF ELECTROLYTES ON ECGEFFECT OF ELECTROLYTES ON ECG
POTASSIUM:POTASSIUM:
– It is found primarily in the intracellularIt is found primarily in the intracellular
compartment.compartment.
– It is important for cardiac cell repolarization.It is important for cardiac cell repolarization.
– It also helps in maintaining stable polarizedIt also helps in maintaining stable polarized
state of cardiac cells.state of cardiac cells.
– Two abnormalities of potassium areTwo abnormalities of potassium are
hyperkalemia and hypokalemia.hyperkalemia and hypokalemia.
– Hyperkalemia cause tall, narrow and peakedHyperkalemia cause tall, narrow and peaked
T wave.T wave.
– Hypokalemia indicate presence of prominentHypokalemia indicate presence of prominent
U wave and short T wave.U wave and short T wave.

192. CONT.CONT.
CALCIUM:CALCIUM:
– Calcium is important for initiation and propagationCalcium is important for initiation and propagation
of electrical impulses and myocardial contractility.of electrical impulses and myocardial contractility.
– Calcium abnormalities are less common thanCalcium abnormalities are less common than
potassium abnormalities.potassium abnormalities.
– Hypercalcemia causes shortening of the QTHypercalcemia causes shortening of the QT
interval as a result of short ST segment.interval as a result of short ST segment.
– Sometimes ST depression and T wave inversionSometimes ST depression and T wave inversion
can also be seen.can also be seen.
– Hypocalcemia prolong QT interval as a result ofHypocalcemia prolong QT interval as a result of
prolong ST segment.prolong ST segment.
– T wave can be inverted in some cases.T wave can be inverted in some cases.

195. CARDIAC BIOMARKERSCARDIAC BIOMARKERS
Cardiac markersCardiac markers are substances releasedare substances released
from heart muscles when it is damaged asfrom heart muscles when it is damaged as
a result of an injury.a result of an injury.
Normally these enzymes are present in lowNormally these enzymes are present in low
amounts in the blood of healthy people.amounts in the blood of healthy people.
Used in conjunction with history,Used in conjunction with history,
signs/symptoms, exam and ECG changessigns/symptoms, exam and ECG changes
to make diagnosis.to make diagnosis.

196. CHARACTERISTICSCHARACTERISTICS
Easy to measure.Easy to measure.
Inexpensive.Inexpensive.
Cardiac specific.Cardiac specific.
Direct proportional relationship betweenDirect proportional relationship between
the extent of injury and enzyme levels.the extent of injury and enzyme levels.
Rapid serum levels after injury.Rapid serum levels after injury.
Stay for long time in serum.Stay for long time in serum.

200. Cardiac Rhythm: SupraventricularCardiac Rhythm: Supraventricular
NORMAL SINUS RHYTHMNORMAL SINUS RHYTHM
Impuses originate at S-A node at normal rateImpuses originate at S-A node at normal rate
SINUS TACHYCARDIASINUS TACHYCARDIA
Impuses originate at S-A node at rapid rateImpuses originate at S-A node at rapid rate

201. Cardiac Rhythm: SupraventricularCardiac Rhythm: Supraventricular
ATRIAL FLUTTERATRIAL FLUTTER
Impulses travel in circular course in atria – No interval between T and PImpulses travel in circular course in atria – No interval between T and P
ATRIAL FIBRILLATIONATRIAL FIBRILLATION
Impuses have chaotic, random pathways in atriaImpuses have chaotic, random pathways in atria

202. Activation Sequence DisordersActivation Sequence Disorders
A-V BLOCK, FIRST DEGREEA-V BLOCK, FIRST DEGREE
Atrio-ventricular conduction lengthenedAtrio-ventricular conduction lengthened
A-V BLOCK, SECOND DEGREEA-V BLOCK, SECOND DEGREE
Sudden dropped QRS-complexSudden dropped QRS-complex

203. Pathophysiological indications ofPathophysiological indications of
EKGEKG
Shortened QT interval :Shortened QT interval : Hypercalcemia, someHypercalcemia, some
drugs.drugs.
Prolonged QT interval :Prolonged QT interval : Hypocalcemia, someHypocalcemia, some
drugs.drugs.
Flattened or inverted T waves :Flattened or inverted T waves : CoronaryCoronary
ischemia, left ventricular hypertrophy, digoxinischemia, left ventricular hypertrophy, digoxin
effect, some drugs.effect, some drugs.
Hyperacute T waves :Hyperacute T waves : Possibly the firstPossibly the first
manifestation of acute myocardial infarction.manifestation of acute myocardial infarction.
Prominent U waves :Prominent U waves : Hypokalemia.Hypokalemia.

204. GROUP ACTIVITYGROUP ACTIVITY
Cardiac cycle. Preload, afterload and contractility.Cardiac cycle. Preload, afterload and contractility.
12 lead ECG. (waves, intervals and segments). Steps12 lead ECG. (waves, intervals and segments). Steps
in reading ECG, methods of taking heart rate fromin reading ECG, methods of taking heart rate from
rhythm strip.rhythm strip.
Sinus node arrhythmias.Sinus node arrhythmias.
Atrial arrhythmias.Atrial arrhythmias.
Junctional arrhythmias and idioventricular rhythm.Junctional arrhythmias and idioventricular rhythm.
Ventricular arrhythmias.Ventricular arrhythmias.
Heart block, 1 degree and 2 degree)Heart block, 1 degree and 2 degree)
Heart block 3 degree. Cardiac enzymes.Heart block 3 degree. Cardiac enzymes.