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Updated: May 4, 2026
A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Inappropriate Therapy and Shock Rates Between the Subcutaneous and Transvenous Implantable Cardiac Defibrillator: A
Louise R A Olde Nordkamp1, Shari Pepplinkhuizen1, Abdul Ghani2
1Department of Cardiology, Amsterdam UMC Location University of Amsterdam, Heart Center, Amsterdam Cardiovascular Sciences Heart failure and Arrhythmias, the Netherlands (L.R.A.O.N., S.P., L.V.A.B., T.F.B., A.-F.B.E.Q., W.v.d.S., L.S., J.A.d.V., J.G.P.T., N.R.B., J.R.d.G., K.M.K., A.d.W., A.A.M.W., R.E.K.).
Background:
Inappropriate therapy (IAT) is an undesirable side effect of implantable cardiac defibrillator (ICD) therapy. Early studies with the subcutaneous ICD (S-ICD) showed relatively high inappropriate shock (IAS) rates. The PRAETORIAN (Prospective Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) trial demonstrated that the S-ICD is noninferior to the transvenous ICD (TV-ICD) with regard to the combined end point of IAS and complications. This secondary analyses evaluates all IAT in the PRAETORIAN trial.
Methods:
This international, multicenter trial randomized 849 patients with an indication for ICD therapy between S-ICD (n=426) and TV-ICD therapy (n=423). ICD programming was mandated by protocol. All analysis were performed in the modified intention-to-treat population.
Results:
In both groups 42 patients experienced IAT (48-month Kaplan-Meier estimated cumulative incidence, 9.9% and 10.1%, respectively; hazard ratio (HR), 0.99 [95% CI, 0.65-1.52]; P=0.97). There was no significant difference in patients experiencing IAS between both groups (P=0.14). In the S-ICD group, 81 IAT episodes with 124 IAS and 1 inappropriate antitachycardia pacing occurred versus 89 IAT episodes with 130 IAS and 124 inappropriate antitachycardia pacing in the TV-ICD group. IAT episodes were most frequently caused by supraventricular tachycardias in the TV-ICD group (n=83/89) versus cardiac oversensing in the S-ICD group (n=40/81). In the TV-ICD group, a baseline heart rate >80 bpm (HR, 1.99 [95% CI, 1.05-3.76]; P=0.03), a history of atrial fibrillation (HR, 2.66 [95% CI, 1.41-5.02]; P=0.003), and smoking (HR, 2.46 [95% CI, 1.31-4.09]; P=0.005) were independent predictors for IAT. A QRS duration >120 ms was an independent predictor for IAT caused by cardiac oversensing in the S-ICD group (HR, 3.13 [95% CI, 1.34-7.31]; P=0.008). Post-IAS interventions significantly reduced IAS recurrence in both groups (P=0.046).
Conclusions:
There was no significant difference in IAT and IAS rates between the S-ICD and TV-ICD in a conventional ICD population, but causes and predictors for IAT differed between the devices. After the first IAS, an intervention significantly reduced the recurrence rate of IAS.
Registration:
URL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.
