Decrescendo atrioventricular node conduction can result in ventricular rate faster than atrial rate during atrial tachycardia: implantable cardioverter-defibrillator electrogram analysis.

摘要

Discrimination of supraventricular tachycardia (SVT) from ventricular tachycardia (VT) in a dual-chamber implantable cardioverter-defibrillator (ICD) can sometimes prove challenging for both device and physician. During 1:1 tachycardias, subtleties of the atrioventricular (AV) relationship can suggest a diagnosis of SVT or VT. The AV relationship tends to be most revealing at tachycardia onset, at spontaneous tachycardia termination, and during ventricular anti-tachycardia pacing (ATP). The possibility of a double tachycardia (i.e., simultaneous atrial and ventricular arrhythmias) is always present and may confound rhythm interpretation. When the ventricular rate exceeds the atrial rate, the diagnosis of VT is generally thought to be secure. We present an example of atrial tachycardia where, transiently, sequential V-V intervals are each shorter than the associated A-A intervals. AV node conduction behavior likely explains how this example initially seems to defy one of the fundamental principles of rhythm discrimination