Device programming
The ventricular fibrillation (VF) zone detected ventricular events
faster than 185-200 beats/min and initial therapy was ≥30 joules
(maximum energy of the device). The ventricular tachycardia (VT) zone
detected ventricular events faster than 150-170 beats/min, and 3
sequences of ATP were initially attempted. If the arrhythmia continued,
the first shock ranged from 10-20 joules and subsequent shocks with
maximal energy were delivered until its termination. In cases of
patients with documented slow VT, a detection zone lower than 150
beats/min was sometimes programmed. The device-related detection
algorithms, such as dual chamber sensing, and the stability and
sudden-onset criteria were usually employed for the discrimination of
supraventricular tachycardia 10. The morphology-based
algorithm for detecting ventricular tachycardia was used as a nominal
setting 11. The ICD devices were manufactured by
Boston Scientific (Marlborough, Massachusetts, USA), Medtronic
(Minneapolis, Minnesota, USA), or Abbott/St. Jude Medical (Lake Bluff,
Illinois, USA).