Related Experiment Video
Updated: Mar 9, 2026
Testing the Efficacy of Pharmacological Agents in a Pericardial Target Delivery Model in the Swine
Published on: July 7, 2016
Effectiveness of subcutaneous implantable cardioverter-defibrillator testing in patients with hypertrophic
Niccoló Maurizi1, Ilaria Tanini2, Iacopo Olivotto2
1Referral Center for Cardiomyopathies, Univ Hosp of Careggi, Florence, Italy; Fondazione ARCARD, Florence, Italy.
Insights
Subcutaneous implantable cardioverter-defibrillators (S-ICDs) effectively terminate ventricular fibrillation in most hypertrophic cardiomyopathy patients. Severe obesity was the only factor linked to initial S-ICD shock failure.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Subcutaneous implantable cardioverter-defibrillators (S-ICDs) offer a promising approach for hypertrophic cardiomyopathy (HCM) patients at risk of sudden cardiac death (SCD).
- The efficacy of S-ICDs in terminating ventricular arrhythmias within the HCM population remains under investigation.
Purpose of the Study:
- To evaluate the effectiveness of S-ICD in terminating induced ventricular arrhythmias in HCM patients.
- To identify predictors of S-ICD conversion failure in this cohort.
Main Methods:
- Prospective enrollment of consecutive HCM patients undergoing S-ICD implantation.
- Induction of ventricular fibrillation (VF) or sustained ventricular tachycardia (VT) via programmer, with up to two shock attempts.
- Analysis of clinical and instrumental parameters to determine factors associated with conversion failure.
Main Results:
- Fifty HCM patients were evaluated; 82% experienced inducible VF episodes.
- The S-ICD successfully cardioverted 98% of induced VF/VT episodes at 65J.
- One patient with severe obesity (BMI 36) experienced initial 65J failure, but was successfully converted with an 80J reversed polarity shock.
Conclusions:
- Acute testing demonstrates S-ICD effectiveness in recognizing and terminating VT/VF in HCM patients.
- Extreme left ventricular hypertrophy (LVH) did not impede S-ICD performance.
- Severe obesity emerged as a potential factor contributing to initial S-ICD shock failure at 65J.
Background:
Subcutaneous ICD (S-ICD) is a promising option for Hypertrophic Cardiomyopathy (HCM) patients at risk of Sudden Cardiac Death (SCD). However, its effectiveness in terminating ventricular arrhythmias in HCM is yet unresolved.
Methods:
Consecutive HCM patients referred for S-ICD implantation were prospectively enrolled. Patients underwent one or two attempts of VF induction by the programmer. Successful conversion was defined as any 65J shock that terminated VF (not requiring rescue shocks). Clinical and instrumental parameters were analyzed to study predictors of conversion failure.
Results:
Fifty HCM patients (34 males, 40±16years) with a mean BMI of 25.2±4.4kg/m2 were evaluated. Mean ESC SCD risk of was 6.5±3.9% and maximal LV wall thickness (LVMWT) was 26±6mm. In 2/50 patients no arrhythmias were inducible, while in 7 (14%) only sustained ventricular tachycardia was induced and cardioverted. In the remaining 41 (82%) patients, 73 VF episodes were induced (1 episode in 14 and >1 in 27 patients). Of these, 4 (6%) spontaneously converted. In 68/69 (98%) the S-ICD successfully cardioverted, but failed in 1 (2%) patient, who needed rescue defibrillation. This patient was severely obese (BMI 36) and LVMWT of 25mm. VF was re-induced and successfully converted by the 80J reversed polarity S-ICD.
Conclusions:
Acute DT at 65J at the implant showed the effectiveness of S-ICD in the recognition and termination of VT/VF in all HCM patients except one. Extreme LVH did not affect the performance of the device, whereas severe obesity was likely responsible for the single 65J failure.
More Related Videos
12:45Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
16:40A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Related Concept Videos
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
01:29Cardiomyopathy V: Interprofessional Care
01:30Cardiomyopathy II: Dilated Cardiomyopathy
01:30Dysrhythmias V: Evaluating Dysrhythmias