Shock efficacy comparable between subcutaneous, transvenous ICDs
Among patients who received implantable cardioverter defibrillator therapy, the subcutaneous or transvenous approaches demonstrated similar shock efficacy, according to data from the PRAETORIAN trial.
The findings were presented at the American Heart Association Scientific Sessions and published simultaneously in Circulation.
As previously reported by Healio, the international, randomized PRAETORIAN trial found that the subcutaneous ICD (S-ICD; Emblem S-ICD System, Boston Scientific) was noninferior to the transvenous ICD (TV-ICD) in inappropriate shocks and complications.
In the present prespecified secondary analysis, Reinoud E. Knops, MD, PhD, cardiac electrophysiologist at Academic Medical Center in Amsterdam, and colleagues examined appropriate therapy — defined as therapy for ventricular arrhythmias — and whether antitachycardia pacing (ATP) decreased the number of appropriate shocks. They classified arrhythmia episodes as discrete and storm ( 3 episodes within 24 hours).
Overall, the study included 849 patients at 39 centers. Patients had an indication for ICD therapy and were treated with either an S-ICD (n = 426) or TV-ICD (n = 423).
During a median follow-up of 52 months, a similar rate of patients received appropriate therapy (48-month Kaplan-Meier estimates: S-ICD, 19.4% vs. TV-ICD, 17.5%; P = .45), while patients in the subcutaneous ICD arm had a higher rate of receiving at least one shock (48-month Kaplan-Meier estimates: 19.2% vs. 11.5%; P = .02), according to the results.
In all, 254 total shocks were reported in the subcutaneous group compared with 228 in the transvenous group (P = .68).
Researchers found a similar shock efficacy between both arms (S-ICD, 93.8% vs. TV-ICD, 91.6%; P = .40), and that the first ATP attempt terminated 46% of all monomorphic ventricular tachycardias, but accelerated the arrhythmia in 9.4% of episodes.
In other data, 13 electrical storms were reported among 10 patients in the S-ICD group compared with 19 electrical storms among 18 patients in the TV-ICD group. For those who received appropriate therapy, there was an almost two-fold increase in the relative risk of electrical storms in the TV-ICD group compared with the S-ICD group (RR = 1.98; 95% CI, 0.98-4.04; P = .05).
“Shock efficacy is not statistically different between the S-ICD and TV-ICD, and the decision for either device should be made in a shared decision-making process between patient and physician,” Knops and colleagues concluded. “Physicians are recommended to observe the efficacy of ATP in the individual patient. When ATP is repeatedly unsuccessful in terminating ventricular arrhythmias, we recommend to limit programming to a single ATP attempt.”
Reference:
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Knops RE, et al. FS.05. Featured Science - Advances in EP: Leaks, Pacing and Persistence. Presented at: American Heart Association Scientific Sessions; Nov. 13-15, 2021 (virtual meeting).