Absent ventricular tachycardia detection in a biventricular implantable cardioverter-defibrillator due to intradevice interaction with a rate smoothing pacing algorithm.

A biventricular implantable cardioverter-defibrillator failed to detect monomorphic ventricular tachycardia (VT) with a cycle length that was within the programmed VT detection zone. VT beats were undetected because they fell within the atrial-paced ventricular blanking period while a rate smoothing pacing algorithm was turned on. This problem can occur with slow VT, a short AV delay, and a low upper tracking rate without any device interaction warning. This intradevice interaction can lead to untreated episodes of VT and result in recurrent episodes of heart failure and even death in patients with reduced left ventricular function and chronic heart failure.