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The ECG
ELECTROCARDIOGRAM
Cont:
An electrocardiogram — also called ECG Or EKG
INDICATION FOR USE
Noninvasive – Used to diagnose many common heart problems.
A health care provider might use an electrocardiogram to determine or detect the
following:
 Irregular heart rhythms (arrhythmias)
 If blocked or narrowed arteries in the heart (coronary artery disease) are causing
chest pain or a heart attack
 Whether you have had a previous heart attack
 How well certain heart disease treatments, such as a pacemaker, are working
Signs and symptoms
• Patients may need ECG if they have the following symptoms
• Chest pain
• Dizziness, lightheadedness or confusion
• Heart palpitations
• Rapid pulse
• Shortness of breath
• Weakness, fatigue or a decline in ability to exercise

Cont:
If symptoms come and go, they may not be detected during a standard ECG
recording.
A health care provider might recommend remote or continuous ECG monitoring .
Types
 Holter monitor. A Holter monitor is a small, wearable device that records a
continuous ECG, usually for 24 to 48 hours.
 Event monitor. This portable device is similar to a Holter monitor, but it records
only at certain times for a few minutes at a time.
 Can be worn longer than a Holter monitor, typically 30 days.
 Patient can push a button when they feel symptoms.
 Some devices automatically record when an irregular rhythm is detected.

Application
 During an ECG, up to 12 sensors (electrodes) are attached to the chest and limbs
 The electrodes are sticky patches with wires that connect to a monitor.
 They record the electrical signals that make the heart beat.
 A computer records the information and displays it as waves on a monitor or on
paper.
 Patient can breathe during the test, but will need to lie still.
 Keep the patient warm and ready to lie still.
 Moving, talking or shivering may interfere with the test results.
 A standard ECG takes a few minutes.
RESULTS OF ECG
ECG results can give a health care provider details about the following:
Heart rate.
 Usually, heart rate can be measured by checking the pulse.
 An ECG may be helpful if the pulse is difficult to feel or too fast or too irregular to
count accurately.
 An ECG can help identify an unusually fast heart rate (tachycardia) or an
unusually slow heart rate (bradycardia).
Heart rhythm.
 An ECG can detect irregular heartbeats (arrhythmias).
 An arrhythmia may occur when any part of the heart's electrical system doesn't
work properly.
Cont:
 Heart attack.
 An ECG can show evidence of a previous heart attack or one that's currently
happening.
 The patterns on the ECG may help determine which part of the heart has been
damaged, as well as the extent of the damage.
 Blood and oxygen supply to the heart.
 An ECG done while having symptoms can help health care provider determine
whether reduced blood flow to the heart muscle is causing the chest pain.
 Heart structure changes.
 An ECG can provide clues about an enlarged heart, heart defects and other heart
problems.
Application
 Ask the patient to undress down to the waist and lie down
 Remove excess hair where necessary
 Attach limb leads (anywhere on the limb)
 Attach the chest leads
o V1 and V2: either side of the sternum on the fourth rib (count down from the sternal angle, the second rib
insertion)
o V4: on the apex of the heart (feel for it)
o V3: halfway between V2 and V4
o V5 and V6: horizontally laterally from V4 (not up towards the axilla)
 Ask the patient to relax
 Press record

Cont:
Limb leads
 Three bipolar leads and three unipolar leads are obtained from three electrodes attached to
the left arm, the right arm, and the left leg, respectively.
 (An electrode is also attached to the right leg, but this is an earth electrode.)
 The bipolar limb leads reflect the potential difference between two of the three limb
electrodes:
 lead I: right arm–left arm
 lead II: right arm–left leg
 lead III: left leg–left arm

Cont:
 The unipolar leads reflect the potential difference between one of the three limb electrodes
and an estimate of zero potential – derived from the remaining two limb electrodes.
 These leads are known as augmented leads.
 The augmented leads and their respective limb electrodes are:
 aVR lead: right arm
 aVL lead: left arm
 aVF lead: left leg

Chest leads
 Another six electrodes, placed in standard positions on the chest wall, give rise to a further
six unipolar leads – the chest leads (also known as precordial leads), V1–V6.
 The potential difference of a chest lead is recorded between the relevant chest electrode and
an estimate of zero potential – derived from the average potential recorded from the three limb
leads.

Electrical Activity
Cont:
 P wave
 The P wave is a small deflection wave that represents atrial depolarization.
 PR interval
 The PR interval is the time between the first deflection of the P wave and the first deflection of
the QRS complex.
 QRS wave complex
 The three waves of the QRS complex represent ventricular depolarization.
 Note: the most confusing aspects of ECG reading is the labeling of these waves.
 The rule is: if the wave immediately after the P wave is an upward deflection, it is an R wave; if
it is a downward deflection, it is a Q wave:
Cont:
Small Q waves correspond to depolarization of the interventricular septum.
Q waves can also relate to breathing and are generally small and thin.
They can also signal an old myocardial infarction (in which case they are big and wide)
 the R wave reflects depolarization of the main mass of the ventricles –hence it is the largest
wave
 the S wave signifies the final depolarization of the ventricles, at the base of the heart

Cont:
 ST segment
 The ST segment, which is also known as the ST interval, is the time between the end of the
QRS complex and the start of the T wave.
 It reflects the period of zero potential between ventricular depolarization and repolarization.
 T wave
 T waves represent ventricular repolarization (atrial repolarization is obscured by the large
QRS complex).

Normal ECG
Heart Rate
 Identify the QRS complex (this is generally the biggest wave); count the number of large
squares between one QRS wave and the next; divide 300 by this number to determine the rate
Cont:
Number of large squares between QRS complexes Heart rate (bpm)
5 60
4 75
3 100
2 150
Heart Rhythm
 P waves are the key to determining whether a patient is in sinus rhythm or not.
 If P waves are not clearly visible in the chest leads, look for them in the other leads.
 The presence of P waves immediately before every QRS complex indicates sinus rhythm.
 If there are no P waves, note whether the QRS complexes are wide or narrow, regular or
irregular.

No P waves and irregular narrow QRS
Complexes
 This is the hallmark of atrial fibrillation.
 Sometimes the baseline appears "noisy" and sometimes it appears entirely flat.
 However, if there are no P waves and the QRS complexes appear at randomly irregular
intervals, the diagnosis is atrial fibrillation.

Atrial Fibrillation
Sawtooth P waves
 A sawtooth waveform signifies atrial flutter .
 The number of atrial contractions to one ventricular contraction should be specified.

Atrial Flutter
ST Segment Changes
 The ST segment extends from the end of the S wave to the start of the T wave.
 It should be flat or slightly upsloping and level with the baseline.
 Elevation of more than two small squares in the chest leads or one small square in the limb
leads, combined with a characteristic history, indicates the possibility of MI
 ST depression is diagnostic of ischemia .
 It is worth noting that although ST elevation can localize the lesion (eg, anterior MI,
inferior MI), ST depression cannot.
 Concave upwards ST elevation in all 12 leads is diagnostic of pericarditis.

T waves
 In a normal ECG, T waves are upright in every lead except aVR.
 T-wave inversion can represent current ischemia or previous infarction .
 In combination with LVH and ST depression, it can represent "strain". This form of LVH
carries a poor prognosis.

T Wave Inversion
QT
 Long QT syndrome may also be drug-induced.
 Once this occurs, the responsible drug needs to be discontinued.
Question
 A Nurse is caring for a patient with Atrial Fibrillation, in addition to
antidysrhythmic, what other medication does the nurse administer?
 a. Heparin
 b. Atropin
 c. Amoxicillin
 d. Magnesium sulphate

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ICU - The ECG - ELECTROCARDIOGRAM.pptx

  • 2. Cont: An electrocardiogram — also called ECG Or EKG INDICATION FOR USE Noninvasive – Used to diagnose many common heart problems. A health care provider might use an electrocardiogram to determine or detect the following:  Irregular heart rhythms (arrhythmias)  If blocked or narrowed arteries in the heart (coronary artery disease) are causing chest pain or a heart attack  Whether you have had a previous heart attack  How well certain heart disease treatments, such as a pacemaker, are working
  • 3. Signs and symptoms • Patients may need ECG if they have the following symptoms • Chest pain • Dizziness, lightheadedness or confusion • Heart palpitations • Rapid pulse • Shortness of breath • Weakness, fatigue or a decline in ability to exercise 
  • 4. Cont: If symptoms come and go, they may not be detected during a standard ECG recording. A health care provider might recommend remote or continuous ECG monitoring .
  • 5. Types  Holter monitor. A Holter monitor is a small, wearable device that records a continuous ECG, usually for 24 to 48 hours.  Event monitor. This portable device is similar to a Holter monitor, but it records only at certain times for a few minutes at a time.  Can be worn longer than a Holter monitor, typically 30 days.  Patient can push a button when they feel symptoms.  Some devices automatically record when an irregular rhythm is detected. 
  • 6.
  • 7. Application  During an ECG, up to 12 sensors (electrodes) are attached to the chest and limbs  The electrodes are sticky patches with wires that connect to a monitor.  They record the electrical signals that make the heart beat.  A computer records the information and displays it as waves on a monitor or on paper.  Patient can breathe during the test, but will need to lie still.  Keep the patient warm and ready to lie still.  Moving, talking or shivering may interfere with the test results.  A standard ECG takes a few minutes.
  • 8. RESULTS OF ECG ECG results can give a health care provider details about the following: Heart rate.  Usually, heart rate can be measured by checking the pulse.  An ECG may be helpful if the pulse is difficult to feel or too fast or too irregular to count accurately.  An ECG can help identify an unusually fast heart rate (tachycardia) or an unusually slow heart rate (bradycardia). Heart rhythm.  An ECG can detect irregular heartbeats (arrhythmias).  An arrhythmia may occur when any part of the heart's electrical system doesn't work properly.
  • 9. Cont:  Heart attack.  An ECG can show evidence of a previous heart attack or one that's currently happening.  The patterns on the ECG may help determine which part of the heart has been damaged, as well as the extent of the damage.  Blood and oxygen supply to the heart.  An ECG done while having symptoms can help health care provider determine whether reduced blood flow to the heart muscle is causing the chest pain.  Heart structure changes.  An ECG can provide clues about an enlarged heart, heart defects and other heart problems.
  • 10. Application  Ask the patient to undress down to the waist and lie down  Remove excess hair where necessary  Attach limb leads (anywhere on the limb)  Attach the chest leads o V1 and V2: either side of the sternum on the fourth rib (count down from the sternal angle, the second rib insertion) o V4: on the apex of the heart (feel for it) o V3: halfway between V2 and V4 o V5 and V6: horizontally laterally from V4 (not up towards the axilla)  Ask the patient to relax  Press record 
  • 11. Cont:
  • 12. Limb leads  Three bipolar leads and three unipolar leads are obtained from three electrodes attached to the left arm, the right arm, and the left leg, respectively.  (An electrode is also attached to the right leg, but this is an earth electrode.)  The bipolar limb leads reflect the potential difference between two of the three limb electrodes:  lead I: right arm–left arm  lead II: right arm–left leg  lead III: left leg–left arm 
  • 13. Cont:  The unipolar leads reflect the potential difference between one of the three limb electrodes and an estimate of zero potential – derived from the remaining two limb electrodes.  These leads are known as augmented leads.  The augmented leads and their respective limb electrodes are:  aVR lead: right arm  aVL lead: left arm  aVF lead: left leg 
  • 14. Chest leads  Another six electrodes, placed in standard positions on the chest wall, give rise to a further six unipolar leads – the chest leads (also known as precordial leads), V1–V6.  The potential difference of a chest lead is recorded between the relevant chest electrode and an estimate of zero potential – derived from the average potential recorded from the three limb leads. 
  • 16. Cont:  P wave  The P wave is a small deflection wave that represents atrial depolarization.  PR interval  The PR interval is the time between the first deflection of the P wave and the first deflection of the QRS complex.  QRS wave complex  The three waves of the QRS complex represent ventricular depolarization.  Note: the most confusing aspects of ECG reading is the labeling of these waves.  The rule is: if the wave immediately after the P wave is an upward deflection, it is an R wave; if it is a downward deflection, it is a Q wave:
  • 17. Cont: Small Q waves correspond to depolarization of the interventricular septum. Q waves can also relate to breathing and are generally small and thin. They can also signal an old myocardial infarction (in which case they are big and wide)  the R wave reflects depolarization of the main mass of the ventricles –hence it is the largest wave  the S wave signifies the final depolarization of the ventricles, at the base of the heart 
  • 18. Cont:  ST segment  The ST segment, which is also known as the ST interval, is the time between the end of the QRS complex and the start of the T wave.  It reflects the period of zero potential between ventricular depolarization and repolarization.  T wave  T waves represent ventricular repolarization (atrial repolarization is obscured by the large QRS complex). 
  • 20. Heart Rate  Identify the QRS complex (this is generally the biggest wave); count the number of large squares between one QRS wave and the next; divide 300 by this number to determine the rate
  • 21. Cont: Number of large squares between QRS complexes Heart rate (bpm) 5 60 4 75 3 100 2 150
  • 22. Heart Rhythm  P waves are the key to determining whether a patient is in sinus rhythm or not.  If P waves are not clearly visible in the chest leads, look for them in the other leads.  The presence of P waves immediately before every QRS complex indicates sinus rhythm.  If there are no P waves, note whether the QRS complexes are wide or narrow, regular or irregular. 
  • 23. No P waves and irregular narrow QRS Complexes  This is the hallmark of atrial fibrillation.  Sometimes the baseline appears "noisy" and sometimes it appears entirely flat.  However, if there are no P waves and the QRS complexes appear at randomly irregular intervals, the diagnosis is atrial fibrillation. 
  • 25. Sawtooth P waves  A sawtooth waveform signifies atrial flutter .  The number of atrial contractions to one ventricular contraction should be specified. 
  • 27. ST Segment Changes  The ST segment extends from the end of the S wave to the start of the T wave.  It should be flat or slightly upsloping and level with the baseline.  Elevation of more than two small squares in the chest leads or one small square in the limb leads, combined with a characteristic history, indicates the possibility of MI  ST depression is diagnostic of ischemia .  It is worth noting that although ST elevation can localize the lesion (eg, anterior MI, inferior MI), ST depression cannot.  Concave upwards ST elevation in all 12 leads is diagnostic of pericarditis. 
  • 28. T waves  In a normal ECG, T waves are upright in every lead except aVR.  T-wave inversion can represent current ischemia or previous infarction .  In combination with LVH and ST depression, it can represent "strain". This form of LVH carries a poor prognosis. 
  • 30. QT  Long QT syndrome may also be drug-induced.  Once this occurs, the responsible drug needs to be discontinued.
  • 31. Question  A Nurse is caring for a patient with Atrial Fibrillation, in addition to antidysrhythmic, what other medication does the nurse administer?  a. Heparin  b. Atropin  c. Amoxicillin  d. Magnesium sulphate