Noise from a dysfunctional atrial lead detected as atrial fibrillation by a cardiac implantable electronic device.

A patient with a dual chamber implantable cardioverter-defibrillator developed a defective atrial lead whereupon the generated false atrial signals were repeatedly interpreted as atrial tachycardia/atrial fibrillation (AF) by the atrial upper rate algorithm coupled with rare episodes of noise reversion. This unusual response highlights the limitations of the upper atrial rate triggers of device diagnosis of supraventricular tachyarrhythmias. The converse may occur with a very fine AF or with a very sensitive sensitivity setting (e. g., 0.1 mV) when AF can be detected as noise.