Supraventricular Tachyarrhythmias
Supraventricular tachycardia Supraventricular tachycardia (SVT) is a rhythm disturbance with a rate greater than 100 that requires tissue from above the His-Purkinje system to perpetuate. SVT can be regular (e.g.,…
Cardiac Pacing and Pacemaker Rhythms
Pacemaker rhythms Cardiac pacing systems are described by a three- or four-letter code. The first letter indicates the chamber in which pacing stimuli are delivered (atrium, A; ventricle, V; or…
Implantable Cardioverter Defibrillators
Implantable cardioverter defibrillators An implantable cardioverter defibrillator (ICD) is a device that is placed subcutaneously or submuscularly, with leads that are positioned within the heart (or, more recently, subcutaneously). In…
Drug Effects and Electrolyte Disorders
Antiarrhythmic drugs By several mechanisms, some drugs, particularly antiarrhythmic drugs, can cause serious rhythm disturbances in susceptible individuals. This is termed proarrhythmia . Proarrhythmia encompasses an extensive list of arrhythmia…
Ventricular Tachyarrhythmias
Nonsustained ventricular tachycardia Description Ventricular tachycardia (VT) is defined as three or more consecutive ventricular beats occurring at a rate of 100 beats or more per minute. Nonsustained ventricular tachycardia…
Ectopic Complexes and Rhythms
Premature atrial complexes Description Premature atrial complexes (PACs) are supraventricular ectopic depolarizations originating in or near the atria or in the pulmonary veins that supersede activation from the sinus node….
Bradyarrhythmias—Conduction System Abnormalities
Atrioventricular conduction abnormalities Atrioventricular (AV) block occurs when an atrial impulse either is not conducted to the ventricle or is conducted with delay. This assumes that the impulse occurs at…
Athletes and Arrhythmias
Athletes with arrhythmias constitute a potentially high-risk group that may need special attention and evaluation in addition to care that might be required for nonathletes, especially if these athletes have…
Management of Arrhythmias in Pregnancy
During pregnancy, preexisting arrhythmias may or may not increase. Hemodynamic changes, particularly during the third trimester, may predispose to some arrhythmias. Palpitations due to higher plasma volumes or ectopy are…
Treatment of Arrhythmias
Pharmacologic therapy for clinical arrhythmias Antiarrhythmic Agents Adenosine Adenosine is an intravenous (IV) purinergic blocker that inhibits sinus node and atrioventricular (AV) node automaticity and conduction, similar to high parasympathetic…
