Do current dual chamber cardioverter defibrillators have advantages over conventional single chamber cardioverter defibrillators in reducing inappropriate therapies? A randomized, prospective study.
BACKGROUND
Supraventricular tachyarrhythmias are the main cause of inappropriate therapies in patients with conventional single chamber implantable cardioverter defibrillators (VVI-ICD). It was anticipated that dual chamber cardioverter defibrillators (DDD-ICD), with their capacity to analyze atrial and ventricular rhythm, could substantially reduce inappropriate therapies.


RESULTS
Our prospective study included 92 patients (87 men; mean age 61 +/- 12.7 years) who were randomly assigned to a VVI-ICD (45 patients) or a DDD-ICD (47 patients). Both groups were followed for 7.5 +/- 3.5 and 7.6 +/- 4.1 months, respectively. During the follow-up period, overall 725 ventricular tachycardia (VT)/ventricular fibrillation (VF) episodes were recorded in 45 (49%) of 92 patients. Of these episodes, 404 (56%) occurred in the VVI-ICD group and 321 (44%) episodes occurred in the DDD-ICD group. Twenty-three (51%) patients in the VVI-ICD group and 22 (47%) patients in the DDD-ICD group (P = 0.8) developed VT/VF. Overall, 73 (10%) of 725 treated episodes were inappropriate in 6 (13%) patients in the VVI group and in 10 (21%) patients in the DDD-ICD group (P = 0.2). There were 22 (31%) inappropriately treated episodes in the VVI-ICD group and 51 (69%) in the DDD-ICD group. Thirty-two of the 51 inappropriate episodes in the DDD-ICD patients resulted from intermittent atrial sensing problems that led to failure of the respective dual chamber algorithms. Nonfatal complications occurred in 6 (13%) patients in the VVI-ICD group and in 3 (6%) patients in the DDD-ICD group (P = 0.7).


CONCLUSIONS
We conclude that the implanted DDD-ICD and conventional VVI-ICD are equally safe and effective for therapy of life-threatening ventricular tachyarrhythmias. Although DDD-ICDs allow better rhythm classification, the applied detection algorithms do not offer benefits in avoiding inappropriate therapies during supraventricular tachyarrhythmias.
Deutsches Herzzentrum München and I. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
I
I
Deisenhofer
C
C
Kolb
G
G
Ndrepepa
J
J
Schreieck
M
M
Karch
S
S
Schmieder
B
B
Zrenner
C
C
Schmitt
D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy*; D017147:Defibrillators, Implantable / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies