Inappropriate Therapy and Shock Rates Between the Subcutaneous and Transvenous Implantable Cardiac Defibrillator: A Secondary Analysis of the PRAETORIAN Trial
Authors: Olde Nordkamp Louise R.A. , Pepplinkhuizen Shari , Ghani Abdul , Boersma Lucas V.A. , Kuschyk Juergen , El-Chami Mikhael F. , Behr Elijah R. , Brouwer Tom F. , Kääb Stefan , Mittal Suneet , Quast Anne-Floor B.E. , van der Stuijt Willeke , Smeding Lonneke , de Veld Jolien A. , Tijssen Jan G.P. , Bijsterveld Nick R. , Richter Sergio , Brouwer Marc A. , de Groot Joris R. , Kooiman Kirsten M. , Lambiase Pier D. , Neuzil Petr , Vernooy Kevin , Alings Marco , Betts Timothy R. , Bracke Frank A.L.E. , Burke Martin C. , de Jong Jonas S.S.G. , Wright David J. , Jansen Ward P.J. , Whinnett Zachary I. , Nordbeck Peter , Knaut Michael , Philbert Berit T. , van Opstal Jurren M. , Chicos Alexandru B. , Allaart Cornelis P. , Borger van der Burg Alida E. , Dizon Jose M. , Miller Marc A. , Nemirovsky Dmitry , Surber Ralf , Upadhyay Gaurav A. , Weiss Raul , de Weger Anouk , Wilde Arthur A.M. , Knops Reinoud E. ,   on behalf of the PRAETORIAN Investigators
Published: December 2024

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.