Evaluation of a Dual Chamber Implantable Cardioverter Defibrillator for the Treatment of Atrial and Ventricular Arrhythmias

Abstract

Eighty-nine patients with a documented history of atrial tachyarrhythmias or fibrillation (AF) received a cardioverter defibrillator designed to selectively differentiate and treat atrial and ventricular arrhythmias. Twenty-two patients received a coronary sinus lead and, therefore, could use a separate shock vector for selective treatment of atrial tachyarrhythmias/AF. The device is designed to treat tachyarrhythmias with antitachycardia pacing (ATP) and/or shock therapy using an atrial and/or a ventricular shock vector. Patients underwent induction and shock termination of atrial or dual tachyarrhythmias (AF/VF) to verify proper device function and to measure the arrhythmia detection time with enhancements and preventive algorithms programmed On and Off, respectively. Detection time for 329 VF inductions was 2.41 +/- 0.64 seconds with enhancements On and 2.29 +/- 0.47 with enhancements Off (NS). At implant or predischarge, 283 AF and/or AF/VF (121 atrial and 162 atrial/ventricular fibrillation) were induced. Shock conversion efficacy was 89.8% with AF conversion energies ranging from 0.9 to 27 J. Thirteen of the 23 patients had atrial shock conversions using the separate shock vector with an average conversion energy of 1.9 +/- 1.4 J. (range 0.5-5 J). During follow-up the efficacy of ATP on atrial tachyarrhythmias was 59% and the efficacy of delivered shocks on AF was 85%. This new dual chamber cardioverter defibrillator appropriately detected and classified atrial arrhythmias, and shock therapy for AF was highly effective. The detection algorithm differentiated atrial tachyarrhythmia/AF and did not delay VF detection. The separate shock vector converted induced AF with energies ranging from 0.6 to 5 J.

Atrial Fibrillation in Patients with a Dual Defibrillator: Characteristics of Spontaneous and Induced Episodes and Effect of Ventricular Tachyarrhythmia Induction

“…Dual‐chamber ICDs offer the possibility of monitoring, discriminating, and selectively treating both atrial and ventricular tachyarrhythmias. This has further increased interest in the characteristics of AF in this setting and in the complex interaction between atrial and ventricular tachyarrhythmias 12–19 …”

How, Why, and When May Atrial Defibrillation Find a Specific Role in Implantable Devices? A Clinical Viewpoint

“…The second approach allows very low energies (no more than 3 or 4 J) to be used for conversion of AF. Devices of this type have been extensively evaluated (Table I) in patients with both atrial and ventricular tachyarrhythmias, and have also been implanted in a few selected “AF‐only” patients 21–23,26–41 …”

“…The results of the main studies on efficacy of the three possible electrical therapies that can be delivered by dual‐chamber defibrillators for conversion of AF can be seen in Table I 22,30,31,33–37 . Painless therapies included ATP (with a reported efficacy of 30–66% for regular atrial tachyarrhythmias and of 0–7% for AF) and 50‐Hz burst (with a reported efficacy of 12–44% for regular atrial tachyarrhythmias and of 11–30% for AF).…”

Comparison of Induced and Spontaneous Atrial Tachyarrhythmias in Patients with a History of Spontaneous Atrial Tachyarrhythmias

“…The availability of dual‐chamber implantable cardioverter defibrillators (ICDs) may represent a potential side‐effect‐free alternative for the management of atrial tachyarrhythmias for some patients. These devices have the option to selectively detect, differentiate and treat atrial, and ventricular tachyarrhythmias 2 . It has also been shown that they have the ability to pace terminate approximately 50% of documented spontaneous atrial episodes as well as reducing the incidence of inappropriate shock therapy, both of which may improve quality of life.…”

“…It has also been shown that they have the ability to pace terminate approximately 50% of documented spontaneous atrial episodes as well as reducing the incidence of inappropriate shock therapy, both of which may improve quality of life. Presently, however, it is difficult to predict which patients would benefit from atrial antitachycardia pacing (AATP) 2–6 . Gillis et al reported that termination of AT/AF by AATP was dependent upon arrhythmia cycle length (CL) with arrhythmias of ≥220 msec having increased odds of termination 7 .…”