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Updated: May 20, 2026
A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
A randomized-controlled pilot study comparing ICD implantation with and without intraoperative defibrillation testing
Jeff S Healey1, Lorne J Gula, David H Birnie
1Population Health Research Institute, Barton St. East, Hamilton, Ontario, Canada. Jeff.Healey@phri.ca
Insights
Defibrillation testing (DT) during implantable cardioverter defibrillator (ICD) implantation is controversial. This trial found DT was safe, with no increase in complications, but a nonsignificant trend towards higher mortality or heart failure hospitalization.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- The necessity of defibrillation testing (DT) during implantable cardioverter defibrillator (ICD) implantation remains debated.
- A growing number of ICD implants are performed without DT, influenced by the lack of randomized trial data.
Purpose of the Study:
- To investigate the safety and efficacy of performing ICD implantation with versus without defibrillation testing (DT).
Main Methods:
- A substudy of the Resynchronization for Ambulatory Heart Failure Trial randomized patients to ICD implantation with or without DT.
- Patient characteristics, perioperative outcomes, and a composite of heart failure hospitalization or all-cause mortality were assessed.
Main Results:
- All patients undergoing DT achieved successful testing, with minimal need for system modification.
- No significant differences were observed in perioperative complications, including stroke, myocardial infarction, or heart failure.
- The length of hospital stay was similar between groups.
- A nonsignificant trend towards increased risk of death or heart failure hospitalization was noted in the DT group (19% vs. 10%).
Conclusions:
- Defibrillation testing during ICD implantation is associated with a low rate of perioperative complications and adverse events.
- While this trial did not demonstrate a significant increase in adverse outcomes with DT, a trend towards higher mortality or heart failure hospitalization warrants consideration.
Introduction:
The need to perform defibrillation testing (DT) at the time of implantable cardioverter defibrillator (ICD) insertion is controversial. In the absence of randomized trials, some regions now perform more than half of ICD implants without DT.
Methods:
During the last year of enrolment in the Resynchronization for Ambulatory Heart Failure Trial, a substudy randomized patients to ICD implantation with versus without DT.
Results:
Among 252 patients screened, 145 were enrolled; 75 randomized to DT and 70 to no DT. Patients were similar in terms of age (65.9 ± 9.3 years vs 67.9 ± 8.9 years); LVEF (24.7 ± 4.6% vs 23.6 ± 4.6%), QRS width (154.8 ± 23.5 vs 155.8 ± 23.6 ms), and history of atrial fibrillation (5% vs 6%). All 68 patients in the DT arm tested according to the protocol achieved a successful DT (≤25 J); 96% without requiring any system modification. No patient experienced perioperative stroke, myocardial infarction, heart failure (HF), intubation or unplanned ICU stay. The length of hospital stay was not prolonged in the DT group: 20.2 ± 26.3 hours versus 21.3 ± 23.0 hours, P = 0.79. One patient in the DT arm had a failed appropriate shock and no patient suffered an arrhythmic death. The composite of HF hospitalization or all-cause mortality occurred in 10% of patients in the no-DT arm and 19% of patients in the DT arm (HR = 0.53, 95% CI: 0.21-1.31, P = 0.14).
Conclusions:
In this randomized trial, perioperative complications, failed appropriate shocks, and arrhythmic death were all uncommon regardless of DT. There was a nonsignificant increase in the risk of death or HF hospitalization with DT.
