Intraoperative defibrillation threshold testing during implantable cardioverter-defibrillator insertion: do we really need it?
BACKGROUND
The assessment of defibrillation efficacy using a safety margin of 10 J has long been the standard of care for insertion of implantable cardioverter-defibrillator (ICD), but physicians are concerned about complications related to induction test. Therefore, the need for testing has been recently questioned. The aim of our study was to assess the impact of defibrillation threshold (DFT) testing of ICD on the efficacy of ICD therapy.


METHODS
We analyzed data obtained from follow-up visits of 122 consecutive patients who underwent ICD implantation at our institute from April 1996 to June 2008, with (n = 42) or without (n = 80) DFT testing. Patients in the DFT group were less likely to be men (83.3% vs 96.3%, P < .031) than those in the non-DFT group. Conversely, the 2 groups were similar in age, left ventricular ejection fraction at baseline, functional class, and underlying cardiovascular disease. Results during a 12-month follow-up, 13 (31.0%) and 30 (37.5%) ventricular tachyarrhythmic episodes were recorded in the DFT and non-DFT groups, respectively (P = .472). Antitachycardia pacing (ATP) terminated most of episodes, reducing the need of defibrillation at 7.7% in the DFT group and 3.3% in the non-DFT group (P = .533). Similar percentages of inappropriate ATP interventions (7.1% vs 3.8%, P = .413) and shock deliveries (2.4% vs 5.0%, P = .659) were recorded between DFT and non-DFT groups.


CONCLUSIONS
At 1-year follow-up, the performance of DFT testing does not seem to add any significant efficacy advantage in patients undergoing ICD implantation. Prospective randomized trials and long-term follow-up are warranted to clarify whether routine DFT testing may be safely abandoned leading to a revision of current guidelines.
Calvi
Valeria
V
Electrophysiology Unit, Cardiology Department, Ferrarotto Hospital, University of Catania, Catania, Italy. valcalvi@unict.it
Dugo
Daniela
D
Capodanno
Davide
D
Arancio
Rocco
R
Di Grazia
Angelo
A
Liotta
Claudio
C
Puzzangara
Euglena
E
Ragusa
Antonio
A
Arestia
Alberto
A
Tamburino
Corrado
C
D000368:Aged; D002304:Cardiac Pacing, Artificial; D009202:Cardiomyopathies / Q000628:therapy*; D015331:Cohort Studies; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004869:Equipment Safety; D005500:Follow-Up Studies; D006334:Heart Function Tests; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D012684:Sensory Thresholds; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome; D019564:Unnecessary Procedures; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000628:therapy*