Arrhythmias and arrhythmology
- Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry)This section introduces the most common arrhythmias encountered in clinical practice, beginning with a discussion of the underlying mechanisms of cardiac…
- Aberrant ventricular conduction (aberrancy, aberration)Aberrant conduction is not a mechanism of arrhythmia; it is a ventricular conduction disturbance. It is discussed in this chapter because the phenomenon is…
- Premature ventricular contractions (premature ventricular complex, premature ventricular beats)Premature ventricular complexes are also referred to as premature ventricular beats, premature ventricular contractions or just ventricular…
- Premature atrial contraction (premature atrial beat / complex): ECG and clinical implicationsA premature atrial contraction is produced by an impulse discharged from an ectopic focus located anywhere in the atria. In most cases, the premature atrial…
- Sinus rhythm: physiology, ECG criteria & clinical implicationsA rhythm is defined as three consecutive heartbeats with identical waveforms on the ECG. The similarity of the waveforms indicates that the origin of the…
- Sinus arrhythmia (respiratory sinus arrhythmia)Sinus arrhythmia and respiratory sinus arrhythmia both refer to the same phenomenon. Sinus arrhythmia fulfill all criteria for sinus rhythm except from the…
- Sinus bradycardia: definitions, ECG, causes and managementSinus bradycardia fulfills the criteria for sinus rhythm but the heart rate is slower than 50 beats per minute. ECG criteria follow:
- Chronotropic incompetence (inability to increase heart rate)Chronotropic incompetence is an independent predictor of overall and cardiovascular mortality. The condition is very common among individuals with heart…
- Sinoatrial arrest & sinoatrial pause (sinus pause / arrest)A sinoatrial arrest occurs when the sinoatrial node does not discharge an impulse for ≥2 seconds. Failure to discharge an impulse within <2 seconds is…
- Sinoatrial block (SA block): ECG criteria, causes and clinical featuresSinoatrial SA block implies that the impulses discharged in the sinoatrial node are either not conducted to the atria or are so with a delay. This manifests…
- Sinus node dysfunction (SND) and sick sinus syndrome (SSS)Sinus node dysfunction is an umbrella term for conditions that either affect the automaticity of the sinoatrial node or block the impulse from reaching the…
- Sinus tachycardia & Inappropriate sinus tachycardiaSinus tachycardia is the most common tachyarrhythmia tachycardia. Sinus tachycardia is the result of an increased rate of depolarization i.e increased…
- Atrial fibrillation: ECG, classification, causes, risk factors & managementAtrial fibrillation is the most common abnormal tachyarrhythmia only sinus tachycardia is…
- Atrial flutter: classification, causes, ECG criteria and managementAtrial flutter is the second most common pathological tachyarrhythmia. Only atrial fibrillation is more common.…
- Ectopic atrial rhythm (EAT), atrial tachycardia (AT) & multifocal atrial tachycardia (MAT)Ectopic atrial tachycardia EAT, or atrial tachycardia arises when an ectopic focus within the atria generates electrical impulses at a rate exceeding that…
- Atrioventricular nodal reentry tachycardia (AVNRT): ECG features & managementAtrioventricular nodal reentrant tachycardia AVNRT is a common tachyarrhythmia observed across all age groups, from children to the elderly, and frequently…
- Pre-excitation, Atrioventricular Reentrant (Reentry) Tachycardia (AVRT), Wolff-Parkinson-White (WPW) syndromeThe atrioventricular node and bundle of His are normally the only communication between the atria and the ventricles. The atrial impulse must pass through…
- Junctional rhythm (escape rhythm) and junctional tachycardiaIn this article, you will learn about rhythms arising in, or near, the atrioventricular AV node. The most common rhythm arising in the AV node is…
- Ventricular rhythm and accelerated ventricular rhythm (idioventricular rhythm)This article provides an overview of ventricular rhythm and accelerated ventricular rhythm, the latter also known as idioventricular rhythm. Recognizing…
- Ventricular tachycardia (VT): ECG criteria, causes, classification, treatmentThis chapter deals with ventricular tachycardia from a clinical perspective, with emphasis on ECG diagnosis, definitions, management, and clinical…
- Long QT (QTc) interval, long QT syndrome (LQTS) & torsades de pointesThe QT interval is the time interval from the beginning of the QRS complex to the end of the T-wave. This interval represents the total time taken to…
- Ventricular fibrillation, pulseless electrical activity and sudden cardiac arrestThis chapter will focus on ventricular fibrillation and pulseless electrical activity PEA. These are highly lethal arrhythmias that lead to death if…
- Pacemaker-mediated tachycardia (PMT): ECG and managementPacemaker-mediated tachycardia may arise if the pacemaker records a rapid atrial rate e.g. during a supraventricular tachycardia and stimulates the…
- Diagnosis and management of supraventricular and ventricular tachyarrhythmias: Narrow complex tachycardia & wide complex tachycardiaAll clinically significant supraventricular and ventricular tachyarrhythmias have been reviewed in previous sections. However, given that each arrhythmia…
How to interpret the ECG: A systematic approach
The ECG must always be interpreted systematically. Failure to perform a systematic interpretation of the ECG may be detrimental. The interpretation…
Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry)
This section introduces the most common arrhythmias encountered in clinical practice, beginning with a discussion of the underlying mechanisms of cardiac…