Impact of routine right parasternal electrocardiographic screening in assessing eligibility for subcutaneous implantable cardioverter‐defibrillator

INTRODUCTION: Between 7% and 15% of patients with an indication for an implantable cardioverter-defibrillator (ICD) are not eligible for implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD) on the basis of the result of the conventional left parasternal electrocardiographic screening (LPES). Our objective was to determine the impact of systematically performing right parasternal electrocardiographic screening (RPES) in addition to conventional LPES, in terms of increasing both the total percentage of potentially eligible patients for S-ICD implantation and the number of suitable vectors per patient. METHODS AND RESULTS: Consecutive patients from the outpatient device clinic who already had an implanted ICD, and no requirement for pacing were enrolled. Conventional left parasternal electrode position and right parasternal electrode positions were used. The automatic screening tool was used to analyze the recordings. Screenings were performed in the supine and standing positions. Overall, 209 patients were included. The mean age was 63.4 ± 13 years, 59.8% had ischemic heart disease, mean QRS duration was 100 ± 31 ms, and 69.9% had a primary prevention ICD indication. Based on conventional isolated LPES, 12.9% of patients were not eligible for S-ICD compared with 11.5% based on RPES alone (P = .664). Considering LPES and RPES together, only 7.2% of patients were not eligible for S-ICD (P < .001). Moreover, the number of patients with more than one suitable vector increased from 66.5% with isolated LPES to 82.3% (23.7% absolute increase [P < .001]). CONCLUSION: Adding an automated RPES to the conventional automated LPES increased patient eligibility for the S-ICD significantly. Moreover, combined screening increased the number of suitable vectors per eligible patient.