heart basics and ecg

1. HEART
- DR. DARSHNA SARVAIYA
G.M.E.R.S. MEDICAL COLLEGE, GANDHINAGAR

2. HEART
ANATOMY /
PHYSIOLOGY /
CARDIAC CYCLE /
NORMAL ELECTROCARDIOGRAM/
ABNORMALITY IN ECG
7/15/2017
3:36 AM
2

3. ANATOMY OF HEART
 Goals are:
 Location , size , shape of the heart
 The chamber of the hearts
 Circulatory system of the heart
 The heart valve anatomy
 Coronary artery and vein
 Cardiac muscle tissue
 The conduction system
 The cardiac cycle
 normal ECG
 Abnormality in ECG 7/15/2017
3:36 AM
3

4. OVERVIEW OF HEART
 Heart is a muscular organ
 Act like a pump to continuous send blood throughout your body.
 Heart is a centre of circulatory system. this system consist of network of blood vessels, such as artery,
veins, and capillaries. These blood vessels carry blood to and from all area of the body.
 Electrical system regulate the heart and uses electrical signals to contract the hearts walls. When the
wall contract, blood is pumped into circulatory system.
 A system of inlet and outlet valve in the heart chamber work to ensure that blood flows in the right
direction.
 The heart is vital to your health and nearly everything that goes on in the body.
 Blood carries the oxygen and nutrients that your organs need to work normally. blood also carries carbon
dioxide, a waste product , to your lung to be passed out of the body and in to air.
7/15/2017
3:36 AM
4

5. LOCATION , SIZE , SHAPE OF THE
HEART
 Location : underneath the sternum in a thoracic compartment called mediastinum , which occupies the space
between the lungs.
 Size : man’s fist ( 250 – 350 grams )
 Shape : inverted cone shape.
 Narrow end of the heart called apex. It is directed downward and to the left and lies just above the arch of
the diaphragm at the approximate level of the fifth or sixth rib.
 The broad end of the heart is called base. And give rise to the major blood vessels , which is directed
upwards and to the right and lies at the approximate level of the second rib.
 Covering:
 1. PERICARDIUM : surrounding of the heart is a fibrous sac called the pericardium , which performs several
functions .
 Fluid within the sac lubricate the outer wall of the heart so it can beat without causing friction. It also hold
the heart in place forms a barrier against infection and help keep the heart from over expanding. 7/15/2017
3:36 AM
5

6. Pericardium made of a coronal section which comprises of two walls and a thin
intervening space.
Outer wall : thickest consist of two tissue layers. External layer is formed by a
dense irregular connective tissue and is often called the fibrous pericardium.
This layer protect the heart and anchors it to nearby organ.
At the roots of the major blood vessels, the parital pericardium reflects back
over the surface of the heart to from the inner wall of the pericardium, the
visceral pericardium. Because it is the outer layer of the heart walls , the
visceral pericardium is reffered to as a epicardium. Together, the parital and
visceral pericardial layer are also called the serous pericardium.
2. PERICARDIAL CEVITY : between the walls of the serous pericardium is the
pericardial cavity. The narrow space is normally filled with a few millilitres of
pericardial fluid, which is secret by serous membrane. The fluid reduce reduce
friction between membranes as they glide past one another during heartbeats.
7/15/2017
3:36 AM
6

7.  ENDOCARDIUM : covering the outer surface of the heart walls is the endocardium. This layer
also covers the heart valves and tendons and is continuos with the endothelium that lines the
major blood vessels that attach to the heart.
 The endocardium is made up of thin layer of simple squamous cells and areolar tissue, similar to
the epicardium. Secretions from the squamous cells help regulate the activity of the
myocardium.
 3 . HEART WALLS : composed of three tissue layers
outer layer ; covering the outer surface of the heart is the epicardium. Also refferd to the
visceral pericardium, which is inner layer of the pericardium.
 EPICARDIUM : the epicardium is a serous membrane that consist of an external layer of simple
squamous and an inner layer of areolae tissue. The squamous cells secrete lubricating fluids into
the pericardial cavity.
 MYOCARDUM : thick middle layer of the heart called myocardium. Consist of numerous layers
of cardiac muscle fibers that wrap around the heart wall. Contraction of the myocardium pumps
blood out of the heart into the aorta and pulmonary trunk arteries.
7/15/2017
3:36 AM
7

8. 7/15/2017
3:36 AM
8

9. THE CHAMBERS OF THE HEARTS
 The heart is made up of the four chambers.
 The superior chamber : consist of the right atrium and the left atrium, which lies
primarily on the posterior side of the heart. Extending anteriorly from each thin
walled atrium is a small , ear- shaped appandages called aurical that expand the
volume of the chamber.
 Blood drains into the atria from the pulmonary and systemic circulatory system.
 Lower chambers : are right ventricle and left ventricle, which are much larger
than the atria. The right ventricle pumps blood through the pulmonary circulation
system and thicker walled left ventricle pumps blood through the longer systemic
circulation system. Internally , the two ventricles are separated by a thick
myocardial wall called the intraventricular septum.
7/15/2017
3:36 AM
9

10.  ANTERIOR SURFACE : intraventricular septum is marked
by a shallow diagonal groove known as the anterior
intraventricular sulcus, which is occupied the anterior
intraventricular artery, great cardiac vein and adipose
tissue.
 POSTERIOR SURFACE : the ventrical are separated by
the posterior intraventricular sulcus , which contains the
posterior interior artery , ,middle cardiac vein and adipose
tissue.
7/15/2017
3:36 AM
10

11. 7/15/2017
3:36 AM
11

12. THE CIRCULATORY SYSTEM
 The major blood vessels of the heart are the large arteries and veins that attach to the atria , ventricles
and transport blood to and from the systemic circulatory system . and pulmonary circulation system.
 Blood is delivered to the right atrium from the systemic circulation system by two veins.
 The superior vena cava transport oxygen- depleted blood from the upper extremities, head and neck.
 Inferior vena cava transport oxygen- depleted blood from the thorax, abdomen, and lower extremities.
 Blood exit the right ventricle through the pulmonary trunk artery. Approximately two inches superior to
the base of the heart, this vessels branches into the left and right pulmonary arteries, which transport
blood into the lungs. The left pulmonary veins and right pulmonary veins return oxygen- ated blood from the
lung to the left atrium.
 Blood passes from the left atrium into the left ventricle and then is pumped into the systemic circulatory
system through a large elastic artery called aorta.
7/15/2017
3:36 AM
12

13. 7/15/2017
3:36 AM
13

14. THE HEART VALVE ANATOMY
 Four valve – maintain---unidirectional flow---through the heart.
 Valve location : between each atrium and ventricle
 : between two arteries and ventricles.
 Composed : fibrous connective tissue that originate and extend from the heart walls.
 external surface of the valve covered from the endocardium.
 TRICUSPID VALVE : composed of three cusps or flaps and control blood flow from the right
atrium to the right ventricle.
 BICUSPID VALVE : made up of two cusps or flaps and control blood flow from the left atrium to
the left ventricle. The term mitral valve is also commonly applied because the left av valve is
shaped somewhat like a bishop’s miter.
7/15/2017
3:36 AM
14

15.  CORDAE TENDINEAE : thin tendon like cord called chordae tendineae connect the AV valve
to cone shaped papillary muscles that extend upward from the myocardium.
 The chordae tendiene and papillary muscles together the AV valve to the ventricLE walls.
This allows the valve to close properly and not bulge into the atria.
 SEMILUNAR VALVE : directed blood flow from the ventricle into the aorta and pulmonary
trunk artery.
 The valve are located in the vessels just above the the opening to ventricles. Each consist of
the three cusps that curve upwards to from small pockets.
 BLOOD FLOW : the four heart valve open and close in response to the pressure changes
that occur in the ventricle during each cardiac cycle.
 When the ventricle relax their pressure drop below those of the atria, pulmonary trunk
artery and aorta. This allows the AV valve to open as their cusps passively drop down.
 The pressure changes additionally permits blood to flow into the ventricle from the atria
without restriction.
 Semilunar valve close during the same period as blood flowing toward the ventricle collect in
the pocket of cusps. Closure of the semilunar valve prevents blood from re- entering the
ventricles contract and their rising pressure forces blood up towards the atria and into the
pulmonary trunk and aorta.
7/15/2017
3:36 AM
15

16.  blood pushing up under the cusps causes the atrioventricular valves to close.
 As a result , blood enters the atria from the pulmonary veins but not from the
ventricles. At the same time , rising pressure in pulmonary trunk artery and
aorta forces the semilunar valves to open and blood flow into systemic and
pulmonary circulatory systems.
 When the ventricle begin to relax , pressure in the chamber drop again and a
new cardiac cycle begins.
 Semilunar valve close during the same period as blood flowing toward the
ventricle collect in the pocket of cusps. Closure of the semilunar valve
prevents blood from re- entering the ventricles contract and their rising
pressure forces blood up towards the atria and into the pulmonary trunk and
aorta.
7/15/2017
3:36 AM
16

17. 7/15/2017
3:36 AM
17

18. CORONARY ARTERIES
 The heart receives nutrition and gases from its own set of arteries, veins and capillaries called the coronary
circulatory system. Blood enters the coronary circulatory system through the left coronary artery and the
right coronary artery, which exit the aorta just above the cusps of the semilunar valves.
 After running a short distance between the pulmonary trunk artery and left auricle, the left coronary artery
emerges onto the anterior surface of the heart. Near this point, it branches into the anterior
intraventricular artery and left circumflex artery.
 ANTERIOR INTRAVENTRICULAR ARTERY : lies in the anterior intraventricular sulcus and gives off
branches that supply blood to the anterior ventricle and intraventricular septum.
 LEFT CIRCUMFLEX ARTERY : runs along the coronary sulcus ( between the left atrium and ventricle ) to the
posterior side of the heart, where it usually ends in an anastomosis with the right coronary artery.
 One or more left marginal arteries typically branch from the left circumflex artery as it travels around the
heart.
7/15/2017
3:36 AM
18

19.  LEFT CIRCUMFLEX ARTERY : artery and its branches supply blood
to the left atrium and the lateral and posterior portion of the
ventricle.
 RIGHT CORONARY ARTERY : travels along the coronary sulcus (
between the right atrium and ventricle ) where it typically gives off
smaller branches to the right atrium. AV nodes and SA nodes .
 Larger right marginal arteries also diverge from the right coronary
as it continuous around the heart.
 RIGHT MARGINAL ARTERY : supply blood to the lateral wall of the
right ventricle. On the posterior surface of the heart, the right
coronary artery typically gives rise to the posterior intraventricular
artery or posterior descending artery, which runs along the
posterior intraventricular sulcus and the posterior intraventricular
septum.
7/15/2017
3:36 AM
19

20. 7/15/2017
3:36 AM
20

21. CORONARY VEINS
 After flowing through the myocardium, most of the oxygen- depleted blood returned to the
right atrium by several prominent veins that run along the surface of the heart. Draining blood
from the anterior ventricle is the great cardiac vein.
 This vessel originate at the apex of the heart and runs superiorly along the anterior
intraventricular sulcus( next to anterior intraventricular artery). Near the right atrium , the
great cardiac vein veers to the left and enters the coronary sulcus ( between the left atrium and
ventricle ), where it extends to the back side of the heart.
 One or more left marginal veins typically merge with the great cardiac vein as it transverse the
lateral ventricular wall. Small anterior cardiac veins also drain blood from the anterior right
ventricle directly into the right atrium.
 Blood is removed from the lateral and posterior right ventricle by small cardiac vein , which
travels to the posterior surface of the heart, the great and small cardiac veins merge with the
coronary sinus, which empties into the right atrium . the coronary sinus also receive blood from
the middle cardiac vein that ascends along the posterior intraventricular groove and the
posterior vein of the left ventricle.
7/15/2017
3:36 AM
21

22. 7/15/2017
3:36 AM
22

23. CARDIAC MUSCLE TISSUE
 Cardiac muscle cells make up the myocardium portion of the heart wall.
 They are relatively short, branched fibres that measure approximately 10- 20 micrometre in
diameter and 50-100 micrometre in length.
 Typically each cardiac myocyte contains a single nucleus, which is centrally positioned.
 Thick and thin myofilaments are present and organized into myofibrils. Their overlapping
arrangement creates alternating dark (A) and light ( I) bands or striations, similar to those seen
in skeletal muscle tissue. Sarcoplasmic reticulum tubules surround the myofibrils . However,
there are not well organised and do not terminal cisternae.
 T- tubules are also present, but run along the z- discs ( instead of the myofilaments overlap
zones.)
 The mitochondria in cardiac myocytes are larger and numerous. They supply the ATP needed for
repeat contraction of the heart. 7/15/2017
3:36 AM
23

24.  Unlike, other type of muscle tissue, cardiac myocyte are joined end
to end by intercalated discs.
 These complex, highly convoluted couplings contain both anchoring
junction and electrical junctions. Forming the anchoring junctions
are facia adhere and desmosomes, which arrach the adjacent
myocyte.
 The electrical junctions are composed of connexion protein channel,
which usually occur in cluster referred to as gap junctions.
 Connexon proteins span the distance between adjacent plasma
membrane and ions can travel through the channel pores.
 The ion movements allows action potential to pass directly from cell
to cell. This property makes the entire myocardium act like a single
cell.
7/15/2017
3:36 AM
24

25. 7/15/2017
3:36 AM
25

26. THE CONDUCTION SYSTEM
 The conducting system of the heart consist of cardiac muscle cells and conducting fibres that
are specialized for initiating impulses and conducting them rapidly through the heart. They
initiate the normal cardiac cycle and co-ordinate the conductions of cardiac chamber.
 The conducting system provide the heart its automatic rhythmic beat. For the heart to pump
effently and the systemic and pulmonary circulations to operate in synchrony, the events in the
cardiac cycle must be co-ordinated.
 Sino atrial (SA) node is a spindle- shaped structure composed of a fibrous tissue matrix with
closely packed cells. It is 10-20 mm long, 2-3- mm wide, and thick, tending to narrow caudally
toward the inferior vena cava. The SA node is located less than 1 mm from the epicardial
surface, laterally in the right sulcus terminalis at the junction of the anteromedial aspect of the
superior vena cava and the right atrium.
7/15/2017
3:36 AM
26

27.  The middle intermodal tract :begins at the superior and posterior margins of the sinus node,
travels behind the SVC to the crest of the interatrial septum, and descends in the interatrial
septum septum to the superior margin of the AV node.
 POSTERIOR INTERNODAL TRACT : START AT THE POSTERIOR MARGIN OF THE
SINUS NODE AND TRAVELS POSTERIORLY around the SVC and along the crista terminalis
to the Eustachian ridge and then into the interatrial septum above the coronary sinus, where it
joins the posterior portion of the AV node . These groups of intermodal tissue are best
referred to as intermodal atrial myocardium , not tracts, as they do not appear to be
histologically discrete specialized tract.
 In 85-90% of human heart, the atrial supply to the AV node is a branch from the right
coronary artery which originate at the posterior intersection of the AV and interventricular
groove. In the remaining 10-15% of the heart, a branch of the left circumflex coronary artery
provides the AV nodal artery. Fibers in the lower part of the AV node may exhibit automatic
impulse formation.
 The main function of the AV node is modulation of the atrial impulse transmission to the
ventricle to co-ordinate atrial and ventricle contractions.
7/15/2017
3:36 AM
27

28.  BUNDLE OF HIS : the bundle of his is a structure that connects with the distal part if the
compact AV node, perforates the central fibrous body and continues through the annulus
fibrous, where it is called the non branching portion as it penetrats the membranous septum
encloses the penetrating portion of the AV bundles, which may send out extention into the
central fibrous body.
 Proximal cells of the penetrating portion are heterogenous and resembles those of the compact
AV node , distal cells are similar to cells in the proximal bundle branches.
 Branches from the anterior and posterior descending coronary arteries supply the upper
muscular interventricular septum with blood, which makes the conduction system at this site
more impervious to the ischemic damage, unless the ischemia is extensive.
 BUNDLE BRANCHES : the bundle branches originate at the superior margin of the muscle
interventricular septum, immediately below the membranous septum with the cells of the left
bundle branch cascading downward as a continuous sheet onto the septum beneath the non
coronary aortic cusp.
 The right bundle branch continuous intramycardially as an unbranched extension of the AV
bundle down the right side of the interventricular septum to the apex of the right ventricle
and the base of the anterior papillary muscle. The anatomy of the left bundle branch system
may be variable and may not conform to a constant bifascicular division. 7/15/2017
3:36 AM
28

29.  PURKINJIE FIBERS : purkinjie fibers connect with the end of the bundle
branches to form interwearving network on the endocardial surface of both
ventricles.
 These fibers transmit the cardiac impulse almost simultaneous to the entire
right and left ventricle endocardium.
 Purkinjie fibre tend to be less concentrated at the base of the ventricles and
the papillary muscle tips and only penetrate the inner third of the
endocardium . they appear to be more resist to ischemia than ordinary
myocardial fibers.
7/15/2017
3:36 AM
29

30. 7/15/2017
3:36 AM
30

31. CARDIAC CYCLE
 It is the period from the beginning to one heart beat to the beginning of next one.
 Two parts : ventricular contraction ( systole ) ,
ventricular relaxation ( diastole ).
 Each part of the cardiac cycle ----several phases
1. pressure changes with constant volume.
2.volume changes with constant pressure.
7/15/2017
3:36 AM
31

32. SYSTOLE
 Isovolumetric contraction
 ejection
DIASTOLE
 Isovolumetric relaxation
 Rapid ventricular filling
 Slow ventricular filling
 atrial contraction
7/15/2017
3:36 AM
32

33.  NOTES :
 Duration of the cardiac cycle inversely proportional to the heart rate.
 Normal heart rate is 75/min. & cardiac cycle is 0.8 second.
 Under resting condition : systole occupy – 1/3
 diastole occupy – ½ of cardiac cycle.
 When heart rate , diastole duration
but more than the duration of the systole.
7/15/2017
3:36 AM
33

34.  IMPORTANT POINTS :
 Event of the heart
 Pressure and volume changes in both the atria and ventricle.
 Pressure changes in right atrium seen in recording of venous pulse.
 Pressure changes in arteries called arterial pressure.
 Electrical activity of heart ------electrocardiogram.
 Heart sounds or phono cardiogram.
7/15/2017
3:36 AM
34

35. ISOVOLUMETRIC CONTRACTION
 HEART :
 ventricle contract due to ventricular depolerization.
 ventricular pressure increase
 after ventricular contraction begin, pressure in the ventricle is increase .– so, AV valve close.
 Semilunar valve also closed. Because ventricular pressure is lower than aorta and pulmonary
artery.
 PRESSURE AND VOLUME CHANGES :
 Ventricular pressure : ventricle contract – all valve closed. So, pressure increased.
 Volume : no blood is coming. So, volume no change.
7/15/2017
3:36 AM
35

36.  Atrial pressure : AV valve bulges- in atria because increase pressure in the ventricle.
 Arteries : pressure in both systemic and pulmonary circulation decrease.
 ECG : depolerization spread from AV node septum and wall of both ventricle through
 bundle of his & purkinjie fibers.
 Ventricular depolerization causes QRS complex in ECG.
 As the same moment , atria are repolerized --- produce atrial T wave.
 HEART SOUNDS :
 During isovolumetric contraction, first heart sound appears. This heart sound causes by
 vibration of the AV valves. Adjacent myocardium and blood due to closure of AV valve.
7/15/2017
3:36 AM
36

37. EJECTION
 HEART :
 Rising ventricular pressure right– excess than pulmonary artery.
left –excess than aorta.
so, semilunar valve are opens.
 Ventricle contraction continuous and blood is ejected from left and right ventricle to the aorta
and pulmonary artery respectively, AV valve closed.
7/15/2017
3:36 AM
37

38.  PRESSURE AND VOLUME CHANGES :
 Ventricular pressure ; 1 st part of ejection – ventricular pressure rises. Blood is ejected
through artery called rapid ejection.
2 nd part of ejection – blood volume in ventricle decrease, ventricle
pressure decline.
 Pressure gradient between atria and ventricle and blood is ejected more slowly --- slow
ejection.
 atrial pressure : ventricle contract shorten shortening ventricle elongate the atria and big
veins , lowering their pressure.
 Arteries : blood pressure in big arteries rises due to rapid ejection.
 ECG : ventrical completely depolerize at the beginning of ejection – segment ST in the ECG.
T wave due to ventricular depolerization.
7/15/2017
3:36 AM
38

39.  RESTING CONDITION :
 Under resting condition , 70 ml of blood ejected from ejection.
Called systolic or stroke volume .
 60ml of blood remain in each ventricle at the end of systole called end systolic volume.
 Ratio of the stroke volume and end – diastolic one is called ejection fraction.
7/15/2017
3:36 AM
39

40. ISOVOLUMETRIC RELAXATION
 HEART :
 End of systole , ventricle relax – ventricular pressure decrease rapidly.
 Due to blood in atria , blood flows out of the ventricle – even when the pressure in large
arteries – exceeds the ventricular pressure.
 Immediately after the blood in atria overcome , the elevated pressure in aorta and pulmonary
artery pushes the blood back toward the ventricle to close semilunar valve.
 AV valve are closed because the pressure in atria is lower than the ventricular pressure.
7/15/2017
3:36 AM
40

41.  PRESSURE AND VOLUME CHANGES :
 Ventricular pressure : ventricle relax without changing blood volume in ventricle
called isovolumetric relaxation.
 Blood volume in each ventricle equals to the end – systolic volume ( about – 60 ml ) .
 Ventricular relaxation leads to a significant pressure decrease.
 Ventricular pressure at the end of an isovolumetric relaxation is close to zero in both
ventricle.
 Atrial pressure : blood flows from the veins to the atria while the AV valve are closed.
 Atrial pressure increase to produce the volume v wave in venous pulse.
 Arteries : decrease arterial pressure – interrupted by dicrotic notch – seen in aortic pulse.
 Momenterely pressure increased caused by a short period of backward blood flow immediately
before the closure of the semilunar valve.
 ECG : ventricular repolerization – completed and the end of the T wave appear in ECG.
 Hearts sounds : during isovolumetric relaxation 2 nd H.S. appear. Bcz caused by the vibration
of semilunar valve. 7/15/2017
3:36 AM
41

42. RAPID VENTRICULAR FILLING
 HEART :
 ventricular pressure falls below the arterial pressure, AV valve open.
 Blood flows rapidly from the atria to the ventricle.
 Semilunar valve are closed.
 PRESSURE AND VOLUME CHANGES :
 Ventricular pressure : ventricular rapidly filling with the blood acumlated in atria before the
opening of AV valve.
 This phase accounts for the most of ventricular filling.
 Ventricular volume increase.
 Ventricular pressure not changed, due to ventricular relaxation. 7/15/2017
3:36 AM
42

43.  Atrial pressure : negative Y wave in the venous pulse is caused by the blood evacuation from
the atria to ventricle.
 Arteries : after semilunar valve close , arteries pressure slowly decreased.
unlike pressure in ventricle , the pressure changes in large arteries falls to zero due to their
elastic property.
minimum pressure within one cardiac cycle called diastolic pressure is about 80 mmgh in
systole & pulmonary in respective.
 ECG : no electrical activity is produced by cardiac cells thus the isolation line is present in ECG.
 Heart sounds : third heart sound , which occurs rarely, is probably caused by the rapid blood
flows.
7/15/2017
3:36 AM
43

44. SLOW VENTRICULAR FILLING
 HEART :
 Atrioventricular valve remain open while semilunar valves are closed.
 PRESSURE AND VOLUME CHANGES :
 Ventricular pressure : during middle part of a diastole a small volume of blood flows into the
ventricle.
 This is the blood flowing from the veins and passing the atria to till the ventricle.
 Pressure in both ventricles is close to zero.
 Arteries : systemic and pulmonary pressure .
 ECG : end of slow ventricular filling, depolerization spreads from SA node in all directions over
the atria to produce the P wave in ECG. 7/15/2017
3:36 AM
44

45. ATRIAL SYSTOLE
 HEART :
 Atrial systole is last phase of a diastole during which the ventricular filling is completed.
 The AV valve are open . semilunar valve are closed.
 The atria contract to eject blood into the ventricle.
 PRESSURE AND VOLUME CHANGES :
 Ventricular pressure : 25% of the ventricular filling volume is ejected from the atrium to the
ventricle.
 Ventricular myocardium is relaxed, the ventricular doesn’t change significantly.
 Blood pressure in both ventricular zero.
 At the end of arterial systole – each ventricle contain 130 ml of blood . It is so called end- diastolic
volume.
7/15/2017
3:36 AM
45

46.  Atrial pressure : atrial contraction causes a rise in the atrial pressure which produce the A
wave in the venous pulse.
 Arterial : the pressure in the arteries of both systemic and pulmonary circulation decrease
constantly.
 ECG : atrial depolerization is completed and the end of the P wave appear at the beginning of
atrial systole.
 Subseqently, depolerization spreads from the atria to the AV node and PR segment is visible in
ECG.
 Heart sounds : 4 th H.S. is soft sound due to increase in ventricular pressure following an atrial
syastole.
 Very rarely occur in healthy person.
 Under pathological, condition this sound is present occurring to an increase in inter-atrial
pressure or lower compliance of ventricle.
7/15/2017
3:36 AM
46

47. ECG
LEADS, WAVES, ECG PAPER, DURATION , ABNORMALITY.

48. LEADS OF ECG
 Electrical activity originate from the cardiac muscle and spreading over the cardiac muscle.
 ELECRODE : right hand – red
left hand – green
right leg – black ( attach to earth bcz unwanted electricle impulse produced
elsewhere in the body.)
left leg – yellow.
7/15/2017
3:36 AM
48

49.  Chest leads : 1 – 4 th intercostal space in right side.
2 – 4 th intercostal space in left side.
3 – in between the 2 nd and 4 th lead.
4 – 5 th intercostal space mid clavicular line left.
5 – 5 th intercostal space anterior axillary line left side.
6 – 5 th intercostal space mid axillary line in left.
HOW TO TKE ECG ?
 first put the all limb leads.
 Put the 1 st chest leads.
 On the machine.
 Start the machine.
 Take the leads upto the v1.
 Then change the chest lead and take the v2 to v6 leads.
 Stop the machine
 Off the machine.
7/15/2017
3:36 AM
49

50.  Lead 1 : right arm to left arm – positive ( in direction to
the heart )
 Lead 2 : left arm to left leg – positive
 Lead 3 : right arm to left leg – positive
 One of the electrodes is chosen as the exploring and the
others are connected to a resistance ( 5000 ohms) to
reduce the potential to 0, thereby allowing recording of
the actual potential at the exploring electrode. Leads r :
 avR : exploring electrode on right arm.
 avL : exploring electrode on left arm.
 avF : exploring electrode on the left leg.
7/15/2017
3:36 AM
50

51.  LEADS :
 The electrical events occurring in the heart can be picked up by using appropriate electrodes
known as leads.
 In all, cases the electrodes on the right leg is used to earth the unwanted electrical impulses
produced elsewhere in the body.
 1. BIPOLAR LIMB LEADS :
 the potential recorded represents the differences in the potential transmitted from the
heart to the particular sites of electrode, between two positions. In the standard bipolar limb
leads, the electrodes are fastened as under using electrode jelly and fasteners :
 Lead 1 : right arm & left arm.
 Lead 2 : right arm & left leg
 Lead 3 : left arm & left leg
7/15/2017
3:36 AM
51

52.  2. AUGMENTED UNIPOLAR LIMB LEADS :

 One of the electrodes is choosen as the exploring electrode and the others are connected to a
resistant ( 5000ohms ) to reduce the potential to 0. thereby allowing recording of the actual
potential electrode. The leads are as under :
 avR : exploring electrode on the right arm
 avL : exploring electrode on the left arm
 avF : exploring electrode on the left leg
 3. UNIPOLAR CHEST LEADS :
 Here, the electrode on right arm, left arm and left leg are made neutral by connecting to
appropriate resistance and the exploring electrode is placed as under on various points on the
chest.
7/15/2017
3:36 AM
52

53.  Chest leads : 1 – 4 th intercostal space in right side.
2 – 4 th intercostal space in left side.
3 – in between the 2 nd and 4 th lead.
4 – 5 th intercostal space mid clavicular line left.
5 – 5 th intercostal space anterior axillary line left side.
6 – 5 th intercostal space mid axillary line in left.
7/15/2017
3:36 AM
53

54. ELECTROCARDIOGRAPHY
 To identify the various waves , intervals and segments in a normal ECG . Study the recording
obtained through lead 2.
 It consist three upright waves viz : P,R ,T and two downword waves known as O & S ., thus
formimg PQRST complex.
 P wave represents the passage of impulse from SA nodes over the atria and is produced by
atrial depolerization .
 QRS complex represents ventricular depolerization while ST segment , normally is iso –
electrical.
7/15/2017
3:36 AM
54

55.  Study the ruling of the ECG recording paper. At a set , universal sensitivity ( which can be
varied of 1 mv = 1 cm and at set speed of paper movement of 25 mm per sec), rulling represents
 10 vertical small division ( i.e. 1 cm ) = 1 mv voltage
 25 horizontal small division ( i.e. 25 mm ) = 1 sec time
 Each small vertical division will represent 0.1 mV voltage while, each horizontal small division will
be equal to 0.04 seconds.so, 1 minute will be represented by 1500 small division or 300 big
division.
 The heart rate can be calculated by counting the number of either small division or big division
between two subsequent R waves.
 ST segment reaches the isoelectric point which is known as “ J “ point.
 If ST segment as depressed “ J “ point will shift downword and if ST segment is elevated, it
means “ J “ point is is shifted up.
7/15/2017
3:36 AM
55

56. 7/15/2017
3:36 AM
56

57.  SA node – wave of depolerization – but the current that it generates is too small to record at
the body surface.– atrial contract ( atrial stimulation ) – P WAVE .
 AV nodes – his –purkinjie fibers. – ventricular depolerization produce – QRS COMPLEX.
 P WAVE : atrial contraction --- upward
 Q WAVE : intra ventricular septum excitation – downward
 R WAVE : apex and free wall excitation --- upward
 S WAVE : base excitation --- downward
 T WAVE : Ventricular repolerization . --- upward
 U WAVE : papillary muscle repolerization.
7/15/2017
3:36 AM
57

58.  PR INTERVAL : transit time for the electrical signal to travel from the SA node to the
ventricles.
 ST SEGMENT : ventricular repolerization.
7/15/2017
3:36 AM
58

59. 7/15/2017
3:36 AM
59
 HEART RATE :
 1. 1500/ no . of horizontal small divisions
 2. 300/ no. of horizontal big division.
 PR INTERVAL : atria to ventricle impulse
 QRS duration : ventricular contraction.
 QRST duration : ventricular depolerization & repolerization.
 T DURATION : ventricular repolerization.

60.  PARAMETER OBSEVED :
 RATE : 60- 120 / min.
 RHYTHM : regular
 P- WAVE VOLTAGE : 0.2 MV
 P- WAVE DURATION : 0.08 sec ( 0.12 sec)
 P-R INTERVAL : 0.12 to 0.20 sec
 QRS VOLTAGE : 0.04 to 0.12 sec
 QRS DURATION : 1.8 mV
 ST SEGMENT : iso - electric
 T WAVE VOLTAGE : 0.4 mV
 T WAVE DURATION : 0.27 sec
 Q WAVE VOLTAGE : 1 Mv 7/15/2017
3:36 AM
60

61.  Q. What is atrial rate ??
 ANS. DISTANCE BETWEEN P-P. ( P-P interval.)
 5 MV = PEDIA ( 5MM PER SECOND )
 25 MV = ADULT ( 25 MM PER SECOND )
 50 MV = ADULT ( 50 MM PER SECOND )
 V1 / V2 = VENTRICULAR SEPTUM.
 V3 / V4 = VENTRICLE
 V5 / V6 = LATERAL VENTRICLE
 S WAVE V1 V6 ( SMALL )
 R WAVE V1 V6 ( LARGE ) .
7/15/2017
3:36 AM
61

62. ABNORMAL ECG
 P WAVE : atrial depolerization ( atrial contraction ) ---best seen in lead 2. ----in all leads
upward except avR.
Height : 0.3 Mv , duration : 0.12 sec.
ABNORMALITY :
1. Absent – atrial fibrillation
SA node block
hyperkalemia
2. Wide & notched --- P-MITRALE – left atrial enlargement.
3.. Tall & peaked-----P- PULMONALY – right atrial enlargement.
4. Inverted in lead I ---dextrocardia.
7/15/2017
3:36 AM
62

63. 7/15/2017
3:36 AM
63
 QRS COMPLEX :
 1. Q WAVE : ---negative deflection.
it donates depolerization of the ventricular septum from left to right.
 2. R WAVE – positive deflection – depolerization of ventricle .
Antero septal portion, followed by the major ventricular muscle mass,
 3. S WAVE : negative deflection : negative deflection
posterobasal part of left ventricular, pulmonary conus and the uppermost
part of the intraventricular septum.
 4. R’ WAVE : R’ wave ---second positive wave of QRS COMPLEX.
 5. S’ WAVE : S’ wave –second negative deflection of QRS COMPLEX.

64. 7/15/2017
3:36 AM
64

65. 7/15/2017
3:36 AM
65
 ABNORMALITY OF QRS COMPLEX :
 Low voltage high voltage
 QRS complex : < 5 , small square.
 Cause : pericardial effusion left right
 emphysema
 thick chest wall. S– v1 , R – v6 v1 --- R > 7
small square.
more than 35 small square

66. AXIS DEVIATION
LEFT AXIS DEVIATION
 Prominent R wave in lead 1.
 Prominent s wave in lead 3.
 CAUSE : left ventricular hypertrophy
 LBBB
 during expiration
 high diaphragm – ascites
 - obesity
 - pregnancy.
RIGHT AXIS DEVIATION
 Prominent S wave in lead 1.
 Prominent R wave in lead 3.
 CAUSES :
 Right ventricular hypertrophy
 RBBB
 during inspiration.
7/15/2017
3:36 AM
66

67. 7/15/2017
3:36 AM
67
 T WAVE : ventricular repolarization.
 normally, upright -----except in lead 3, avF , v1 & v2
 ABNORMALITY : 1. inverted T WAVE : myocardial ischemia.
 2. flat : in thick chest – walled individuals.
 U WAVE : represent slow repolarization of the purkinjie fibres, papillary- muscle or ventricular
septum.
 PR INTERVAL : measured from the beginning of the P wave to the beginning of QRS complex.
Represent time interval between atrial and ventricular depolerization.
Hence, include the time taken for atrial depoerization, atrial repolarization , and delay of
excitation in the AV node.
Normal PR interval : 0.12 to 0.20 seconds.
ABNORMALITY : PR interval : increased : rheumatic fever , IHD , digitalis and quinine therapy.
decreased : WPW syndrome , AV nodal rhythm.

68. 7/15/2017
3:36 AM
68

69. 7/15/2017
3:36 AM
69
 QT INTERVAL :
 represents the duration of ventricular systole and is measured from the beigining
 Of Q wave to the end of the T wave.
 It varies with heart rate.
 QT interval corrected for the heart rate is called QT- C interval.
 Normally, QT-C interval does not exceed 0.44 second.
 Qtc = QT interval / R-R interval.
 ABNORMALITY : INCREASED – 1. acute rheumatic carditis
2. myocarditis
3. hypokalemia.
4. hypocalcaemia.
DECREASED : - 1. hyperkalaemia
2. following digitalis & phenytoin sodium therapy.

70. 7/15/2017
3:36 AM
70
 QRS INTERVAL : time taken for ventricular repolerization.
 Measured from beginning of the Q WAVE to the end of the S WAVE.
 Normal QRS interval is 0.1 second.
 ABNORMALITY : > 0.1 sec indicate bundle branch block OR intraventicular conduction defect.
 BUNDLE BRANCH BLOCK ( BBB ) :
 Definition : bundle branch block OR delay in conduction to the right OR left main branch of
the BUNDLE OF HIS.
 HOW DIAGNOSE ? ECG :
1. An abnormality prolonged QRS interval of 0.1 second.
2. More due to delay in and an abnormal spread of excitation through the ventricles.
3. VAT is prolonged.
4. ST Segment is depressed and T WAVE are inverted.

71. 7/15/2017
3:36 AM
71

72. BBB
RBBB
 There is right axis deviation .
 rsR’ pattern in QRS complex in lead v1 &
v2.
 CAUSES : 1. in a normal person young
people without any cardiac lesion.
 2. coronary artery disease.
 3. myocarditis.
 4.acute pulmonary embolism.
 5. HTN.
LBBB
 there is usually left axis deviation and rsR’
pattern of QRS complex in leads v5 & v6.
 CAUSES : 1.coronary heart disease
 2. cardiomyopathy
 3. heart failure
 4. aortic valve disease
 5. HTN
 6. quinidine.
7/15/2017
3:36 AM
72

73. 7/15/2017
3:36 AM
73

74. 7/15/2017
3:36 AM
74

75. 7/15/2017
3:36 AM
75
 ST SEGMENT :
 Measured from the ST junction to the beginning of the T- wave.
 It is usually ISO – ELECTRIC but may be slightly depressed ( 0.5 mm ) OR
 elevated ( 0.2 mm ) in precordial leads.
 Represent the time between ventricular depolerization and repolerization.
 ST segment must not deviate more than 1 mm above OR below iso- electric line in any lead.
 ABNORMALITY : RAISED : 1. acute MI
2. prinzmetal vasospastic angina.
3. ventricular aneurysm.
4. pericarditis
5. early repolerization.
DEPRESSED : 1. acute subendocardial ischemia / infract.
2. digitalis effect and toxicity
3. L.V. hypertrophy and strain.

76. 7/15/2017
3:36 AM
76

77. 7/15/2017
3:36 AM
77Thank you