Key result
High ECG burden is linked to ~3.6-fold higher odds of appropriate ICD therapy, improving prediction beyond LVEF.
Why the study?
ICD selection based on LVEF may miss at-risk patients with LVEF > 35%, raising the question of whether a simple ECG burden adds discriminatory power beyond clinical factors and LVEF.
Does a high ECG abnormality burden predict appropriate ICD therapy beyond clinical factors and LVEF in ICD recipients?
Does a high ECG abnormality burden predict appropriate ICD therapy beyond clinical factors and LVEF in ICD recipients?
A simple cumulative ECG abnormality burden score modestly improves the prediction of appropriate ICD therapy beyond standard clinical factors and LVEF.
May refine ICD risk stratification beyond LVEF with ECG burden score; extends current models but remains hypothesis-generating pending validation.
Selection for implantable cardioverter-defibrillator (ICD) therapy based on left ventricular ejection fraction (LVEF) may miss at-risk patients with LVEF > 35%. We tested whether a simple electrocardiogram (ECG) burden adds discriminatory power for appropriate ICD therapy beyond clinical factors and LVEF. Single-center retrospective cohort of 236 ICD recipients. Six routinely reported ECG abnormalities (heart rate > 75 bpm; QRS duration > 110 ms; obtuse QRS–T angle; delayed transition zone; prolonged QTc; prolonged Tp–Te) were prespecified, summed to form an ECG burden (0–6), and categorized as 0–1, 2–3, or ≥ 4 abnormalities. Logistic regression estimated odds ratios (OR) with 95% CIs for appropriate ICD therapy. Multivariable models included LVEF category (≤ 35% vs > 35%), ischemic vs non-ischemic cardiomyopathy, ICD indication (secondary vs primary prevention), and ECG burden category. Discrimination of the clinical + LVEF model with and without ECG burden was assessed using the AUC (C-statistic) and the DeLong test. Mean age was 62.1 ± 16.2 years; 71% were male; 61% had ischemic cardiomyopathy; 72% underwent primary-prevention ICD implantation; and mean follow-up was 7.6 ± 2.9 years. Appropriate ICD therapy was delivered to 26/236 (11.0%) patients. A high ECG burden (≥ 4 abnormalities) was associated with appropriate ICD therapy after adjustment (OR 3.6, 95% CI 1.8–7.2; p < 0.001). Adding ECG burden to a clinical + LVEF model modestly improved discrimination in this cohort, with the AUC (C-statistic) from 0.67 to 0.72 (DeLong p = 0.01). Kaplan–Meier curves showed graded separation across ECG-burden categories (log-rank p < 0.001). Among patients with LVEF > 35%, therapy was observed more frequently in the high-burden group than in the low-burden group. In this single-center retrospective cohort of ICD recipients, a higher ECG abnormality burden was associated with a higher risk of appropriate ICD therapy and modestly improved discrimination when added to a clinical + LVEF model. These findings are hypothesis-generating and warrant prospective, multicenter external validation using standardized ECG measurements before any clinical application.
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Almegbel et al. (2026) studied this question. High ECG burden (≥4 abnormalities) increased the odds of appropriate ICD therapy by 3.6-fold and improved risk prediction beyond LVEF with AUC rising from 0.67 to 0.72 (p=0.01).
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