Long QT syndrome is an inherited condition that is characterised by delayed repolarization of the ventricles, which increases the risk of ventricular tachyarrhythmias, leading to syncope, cardiac arrest, or sudden death. It can be diagnosed incidentally on an EKG, following…

Sick sinus syndrome is characterized by abnormal sinus node functioning with resultant bradycardia and cardiac insufficiency. It can be caused by many factors, both intrinsic and extrinsic Causes of sick sinus syndrome Classification Causes Intrinsic Idiopathic degenerative fibrosis (most common),…

Atrial Fibrillation Atrial fibrillation is a chaotic irregular atrial rhythm, with an atrial electrical activity of about 300 – 600 bpm, resulting in an irregularly irregular ventricular rate. It peaks at 70+ years, and affects men slightly more than women.…

Sinus tachycardia is HR > 100 bpm with a normal sinus rhythm. Patients are usually asymptomatic, and it is inconsequential. Sinus tachycardia is prevented in patients with coronary artery disease by using beta-blockers.

Supraventricular tachycardia includes arrhythmias that originate from supraventricular tissue or involve supraventricular tissue through a reentrant circuit. Definition of terms Term Definition Paroxysmal supraventricular tachycardia (PSVT) A sudden, intermittent episode of SVT. It may be self-limited – lasting minutes to…

Wolff-Parkinson-White (WPW) syndrome is caused by a congenital accessory conducting pathway between the atria and ventricles (bundle of Kent), which leads to an atrioventricular re-entry tachycardia (AVRT). It can degenerate rapidly into ventricular fibrillation since the accessory pathway does not…

Ventricular tachycardia is caused by a re-entrant circuit that is limited to the ventricles. This is a medical emergency since it can degenerate into ventricular fibrillation. Classification Classification Description Monomorphic ventricular tachycardia Uniform QRS complexes – usually due to reentry…

Torsades de pointes is a polymorphic ventricular tachycardia with a characteristic “twisting” (oscillating QRS amplitude). It is commonly caused by hypomagnesemia.

Tachyarrhythmias are arrhythmias with HR > 100 bpm. Symptoms occur because the heart beats too fast to allow it to fill during diastole. Narrow QRS Complex Tachyarrhythmias Arrhythmia EKG First-line treatment (stable) Sinus tachycardia Sinus rhythm with bradycardia Non necessary…