Atrial Arrhythmias

Snapshot

A 66-year-old man presents to the emergency deparment with palpitations and lightheadedness. The patient has been experiencing these symptoms for the past few days. He reports mild chest discomfort. Medical history is significant for hypertension, type 2 diabetes mellitus, and rheumatic heart disease. An electrocardiogram is immediately performed, which demonstrates a narrow QRS complex tachyarrhythmia that is irregularly irregular. (Atrial fibrillation)

Introduction

Aberrant rhythms can occur anywhere along the cardiac conduction system (SA node to a single cardiomyocyte)these aberrant rhythm can originate from theatrium (thus a supraventricular arrhythmia)ventriclesEtiologythere are a number of causes and they include
myocardial infarctioncardiac scarring can interrupt the cardiac conduction systematrial stretch
alters the cardiac conduction system (e.g., significant mitral stenosis)reentrant circuitaccessory pathway (e.g., atrioventricular re-entry tachycardia) normal atrioventricular node (e.g., atrioventricular nodal reentrant tachycardia)Symptomsasymptomaticpalpitationlight headednesssyncope sudden cardiac death

Type	Electrocardiogram Findings	Treatment	Comments
Atrial fibrillation	A tachyarrhythmia that is irregularly irregular rhythm and has absent P-waves	*Stable patientsrate controle.g.,* β-blockers and non-dihydropyridine calcium channel blockers rhythm controle.g., amiodaroneUnstable patientssynchronized cardioversionAnticoagulationoptions includeaspirinwarfarinnew oral anticoagulant (NOAC)e.g., dabigatran**	*Most common type of atrial arrhythmiaA dilated left atrium can result in atrial fibrillatione.g.,* mitral stenosisCan result in a thromboembolic event (e.g., stroke) The ventricular rate is determined by the AV node refractory period Often originates in the pulmonary veins**
Atrial flutter	A tachyarrhythmia with a “sawtooth” appearance	Stable patientstreat similarly as atrial fibrillationUnstable patientssynchronized cardioversion	Definitive treatment is with catheter ablationCaused by a re-entrant circuit in the right atrium
Sick sinus syndrome	A bradyarrhythmia with episodes of tachycardia	acute patients assess for reversible causes such as medications (calcium channel blockers, digoxin, lithium)chronic patientsanticoagulationpacemaker placement

Useful Links

Information

Socials