Atrial diagnostics in a tiered therapy implantable defibrillator.

Dual chamber sensing has been proposed in implantable defibrillators as an additional diagnostic modality for enhanced differentiation of ventricular and supraventricular tachycardias. A patient with different rates of wide QRS complex tachycardias is described in whom a tiered therapy implantable defibrillator with atrial sensing capability was implanted. Atrial diagnostic data in this patient enabled definitive diagnosis of his ventricular tachycardias and guided management decisions of his arrhythmia.