Clinical ECG Interpretation
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Introduction to ECG Interpretation6 Chapters
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Cardiac electrophysiology and ECG interpretation
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Cardiac electrophysiology: Action potential, automaticity and vectors
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The ECG leads: Electrodes, limb leads, chest (precordial) leads and the 12-Lead ECG
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The Cabrera format of the 12-lead ECG & lead –aVR instead of aVR
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ECG interpretation: Characteristics of the normal ECG (P-wave, QRS complex, ST segment, T-wave)
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How to interpret the ECG: A systematic approach
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Cardiac electrophysiology and ECG interpretation
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Arrhythmias and arrhythmology24 Chapters
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Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry)
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Aberrant ventricular conduction (aberrancy, aberration)
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Premature ventricular contractions (premature ventricular complex, premature ventricular beats)
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Premature atrial contraction (premature atrial beat / complex): ECG & clinical implications
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Sinus rhythm: physiology, ECG criteria & clinical implications
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Sinus arrhythmia (respiratory sinus arrhythmia)
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Sinus bradycardia: definitions, ECG, causes and management
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Chronotropic incompetence (inability to increase heart rate)
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Sinoatrial arrest & sinoatrial pause (sinus pause / arrest)
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Sinoatrial block (SA block): ECG criteria, causes and clinical features
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Sinus node dysfunction (SND) and sick sinus syndrome (SSS)
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Sinus tachycardia & Inappropriate sinus tachycardia
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Atrial fibrillation: ECG, classification, causes, risk factors & management
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Atrial flutter: classification, causes, ECG diagnosis & management
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Ectopic atrial rhythm (EAT), atrial tachycardia (AT) & multifocal atrial tachycardia (MAT)
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Atrioventricular nodal reentry tachycardia (AVNRT): ECG features & management
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Pre-excitation, Atrioventricular Reentrant (Reentry) Tachycardia (AVRT), Wolff-Parkinson-White (WPW) syndrome
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Junctional rhythm (escape rhythm) and junctional tachycardia
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Ventricular rhythm and accelerated ventricular rhythm (idioventricular rhythm)
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Ventricular tachycardia (VT): ECG criteria, causes, classification, treatment
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Long QT (QTc) interval, long QT syndrome (LQTS) & torsades de pointes
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Ventricular fibrillation, pulseless electrical activity and sudden cardiac arrest
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Pacemaker mediated tachycardia (PMT): ECG and management
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Diagnosis and management of narrow and wide complex tachycardia
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Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry)
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Myocardial Ischemia & Infarction22 Chapters
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Introduction to Coronary Artery Disease (Ischemic Heart Disease) & Use of ECG
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Classification of Acute Coronary Syndromes (ACS) & Acute Myocardial Infarction (AMI)
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Clinical application of ECG in chest pain & acute myocardial infarction
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Diagnostic Criteria for Acute Myocardial Infarction: Cardiac troponins, ECG & Symptoms
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Cardiac troponin I (TnI) and T (TnT): Interpretation and evaluation in acute coronary syndromes
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Myocardial Ischemia & infarction: Reactions, ECG Changes & Symptoms
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The left ventricle in myocardial ischemia and infarction
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Factors that modify the natural course in acute myocardial infarction (AMI)
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ECG in myocardial ischemia: ischemic changes in the ST segment & T-wave
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ST segment depression in myocardial ischemia and differential diagnoses
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ST segment elevation in acute myocardial ischemia and differential diagnoses
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ST elevation myocardial infarction (STEMI) without ST elevations on 12-lead ECG
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T-waves in ischemia: hyperacute, inverted (negative), Wellen's sign & de Winter's sign
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ECG signs of myocardial infarction: pathological Q-waves & pathological R-waves
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Other ECG changes in ischemia and infarction
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Supraventricular and intraventricular conduction defects in myocardial ischemia and infarction
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ECG localization of myocardial infarction / ischemia and coronary artery occlusion (culprit)
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The ECG in assessment of myocardial reperfusion
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Approach to patients with chest pain: differential diagnoses, management & ECG
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Stable Coronary Artery Disease (Angina Pectoris): Diagnosis, Evaluation, Management
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NSTEMI (Non ST Elevation Myocardial Infarction) & Unstable Angina: Diagnosis, Criteria, ECG, Management
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STEMI (ST Elevation Myocardial Infarction): diagnosis, criteria, ECG & management
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Introduction to Coronary Artery Disease (Ischemic Heart Disease) & Use of ECG
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Conduction Defects11 Chapters
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Overview of atrioventricular (AV) blocks
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First-degree AV block (AV block I, AV block 1)
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Second-degree AV block: Mobitz type 1 (Wenckebach) & Mobitz type 2 block
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Third-degree AV block (3rd degree AV block, AV block 3, AV block III)
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Management and treatment of AV block (atrioventricular blocks)
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Intraventricular conduction delay: bundle branch blocks & fascicular blocks
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Right bundle branch block (RBBB): ECG, criteria, definitions, causes & treatment
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Left bundle branch block (LBBB): ECG criteria, causes, management
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Left bundle branch block (LBBB) in acute myocardial infarction: the Sgarbossa criteria
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Fascicular block (hemiblock): Left anterior & left posterior fascicular block
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Nonspecific intraventricular conduction delay (defect)
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Overview of atrioventricular (AV) blocks
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Cardiac Hypertrophy & Enlargement5 Chapters
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Atrial and ventricular enlargement: hypertrophy and dilatation on ECG
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ECG in left ventricular hypertrophy (LVH): criteria and implications
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Right ventricular hypertrophy (RVH): ECG criteria & clinical characteristics
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Biventricular hypertrophy ECG and clinical characteristics
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Left atrial enlargement (P mitrale) & right atrial enlargement (P pulmonale) on ECG
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Atrial and ventricular enlargement: hypertrophy and dilatation on ECG
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Drugs & Electrolyte Imbalance3 Chapters
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Genetics, Syndromes & Miscellaneous7 Chapters
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ECG J wave syndromes: hypothermia, early repolarization, hypercalcemia & Brugada syndrome
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Brugada syndrome: ECG, clinical features and management
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Early repolarization pattern on ECG (early repolarization syndrome)
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Takotsubo cardiomyopathy (broken heart syndrome, stress induced cardiomyopathy)
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Pericarditis, myocarditis & perimyocarditis: ECG, criteria & treatment
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Eletrical alternans: the ECG in pericardial effusion & cardiac tamponade
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Long QT Syndrome (LQTS)
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ECG J wave syndromes: hypothermia, early repolarization, hypercalcemia & Brugada syndrome
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Exercise Stress Testing (Exercise ECG)6 Chapters
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Introduction to exercise stress testing (treadmill test, exercise ECG)
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Indications, Contraindications, and Preparations for Exercise Stress Testing
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Exercise stress test (exercise ECG): protocols, evaluation & termination
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Exercise stress testing in special patient populations
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Exercise physiology: from normal response to myocardial ischemia & chest pain
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Evaluation of exercise stress test: ECG, symptoms, blood pressure, heart rate, performance
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Introduction to exercise stress testing (treadmill test, exercise ECG)
Eletrical alternans: the ECG in pericardial effusion & cardiac tamponade
Eletrical alternans: an ECG sign of pericardial effusion and cardiac tamponade
The pericardial space (cavity) always contains a small amount of serous fluid which acts as a lubricant that prevents friction during ventricular contraction and relaxation. Pericardial effusion is the presence of an abnormal amount of fluid in the pericardial space. It can be caused by numerous local and systemic disorders. Accumulation of fluid in the pericardial space may lead to increased intrapericardial pressure, which in turn affects ventricular relaxation (and thus ventricular filling). This may even lead to compression of the ventricles during diastole; cardiac tamponade occurs if excess pericardial fluid causes hemodynamic effects. Electrical alternans – i.e the beat-to-beat variation i electrical amplitude – is the ECG hallmark of cardiac tamponade.
Chapter content
ToggleCauses of pericardial effusion and cardiac tamponade
- The most common cause of pericardial effusion is infections, such as viral, bacterial, and tuberculous infections.
- Post-pericardiotomy syndrome.
- Acute transmural myocardial infarction.
- Rupture of the free ventricular wall.
- Neoplasms (particularly breast and lung cancer).
- Inflammatory conditions, such as rheumatoid arthritis, systemic lupus erythematosus, scleroderma, and rheumatic fever.
- Aortic dissection rupturing into the pericardium.
- Idiopathic pericardial effusion.
- Renal failure, hypothyroidism, and hypercholesterolemia.
- Dressler syndrome.
- Iatrogenic damage to the pericardium.
- Irradiation.
- Trauma.
The most common cause of pericardial effusion is pericarditis. Because it is difficult to determine if there is also myocarditis (which is frequent), it is common to use the term perimyocarditis.
Hemodynamic effects of pericardial effusion and cardiac tamponade
Intrapericardial pressure increases as fluid accumulates in the pericardial space. Intrapericardial pressure may reach the point where the ventricles and atria can no longer relax normally, and the ventricles may even be compressed during diastole. This causes adverse hemodynamic effects, and the condition is classified as cardiac tamponade. The classical signs of cardiac tamponade are hypotension, muffled heart sounds and jugular venous distention. Other frequent symptoms are pulsus paradoxus, pericardial friction sounds, tachycardia, tachypnea, weakened peripheral pulses, edema, cyanosis. Cardiac tamponade is seen in Video 1.
ECG changes caused by pericardial effusion and cardiac tamponade
Small amounts of pericardial effusion may not cause any ECG changes. Significant pericardial effusion may bring about the following ECG changes.:
- Low voltage: large amounts of pericardial effusion will diminish the QRS amplitudes.
- Electrical alternans: The amplitude of the QRS complexes vary from one beat to another (in the same lead). This is due to the swinging back and forth of the heart in the pericardial space. Note that tachycardia, pulmonary embolism and ischemia may also cause electrical alternans.
- PQ segment depression.
- Sinus tachycardia.
Refer to Figure 1.