ARRHYTHMIAS 101

Arrhythmia is the abnormal rhythm of the heart that can be classified as tachyarrhythmia (abnormally fast) or bradyarrhythmia (abnormally slow heart beat rate). Tachycardia can be diagnosed by checking the QRS complex and atrial activity and depending upon their origin, these can be classified as supraventricular or ventricular tachycardias. Tachycardia involving atria includes sinus tachycardia, atrial tachycardia, multifocal atrial tachycardia (MAT), atrial flutter and atrial fibrillation and those involving AV node are junctional tachycardia, AV nodal reentrant tachycardia (AVNRT) and AV reentrant tachycardia (AVRT). Tachyarrhythmias that originate in the ventricles include ventricular tachycardia (VT), torsades de pointes and ventricular fibrillation (VF). Bradyarrhythmia is a heart rate of < 60 beats/min that can be identified by examining the P wave. It can be due to sinus bradycardia and junctional rhythm, second-degree heart block or complete heart block. P wave also helps in defining the degree of heart block. Pacer spikes should be considered while defining the type of arrhythmia. Sinus tachycardia with a paced ventricular rhythm can easily be mistaken for a wide complex tachycardia if these spikes are unnoticed at the beginning of QRS complex. Origin, causative factors and management of different arrhythmias as per the guidelines of American Heart Association (AHA) are discussed. The manual also include the diagnoses of paced rhythm and rarely occurring arrhythmias.