Arrhythmias & electrophysiologyCohort study
Combined Analysis of Cardiac Repolarization Entropy and Magnetic Resonance Imaging Enhances Risk Stratification of Patients Receiving a Primary-Prevention Implantable Cardioverter-defibrillator (ICD)
- Prospective Observational Study
- consecutive patients
Authors' conclusion
EntropyXQT and CMR gray zone mass complement each other and conventional risk factors, improving risk stratification for appropriate ICD shock and mortality, and together may enhance the selection of primary prevention ICD recipients. (Prospective Observational Study of the ICD in Sudden Cardiac Death Prevention (PROSe-ICD; NCT00733590).
Study context
- Population
- Patients with a left ventricular ejection fraction ≤35% in sinus rhythm receiving a primary prevention ICD
- Participants
- 230 consecutive patients
- Exposure
- EntropyXQT and CMR gray zone mass added to a model composed of conventional clinical predictors, left ventricular end-systolic volume (LVESV) and prescribed diuretics
- Outcome
- ICD shock for VT
- Follow-up
- 6.1 ± 3.3 years
Main finding
As reported in the abstract
- EntropyXQT
- adjusted hazard ratio (per SD change) 1.8 (95% CI 1.4–2.3)
- CMR gray zone mass
- adjusted hazard ratio (per SD change) 1.5 (95% CI 1.2–1.8)
- Patients who received appropriate ICD shocks
- 62 patients (27%)
Observational data: associations, not effects.
Secondary outcomes
Model discrimination (Harrell's C-statistic)
- Harrell's C-statistic improved with EntropyXQT and CMR gray zone mass, from
- 0.59
- Harrell's C-statistic improved to
- 0.73
Predictor strength over time
- EntropyXQT was the strongest predictor in years 1-3, whereas CMR and LVESV were stronger in years >3
Secondary endpoints (all-cause events, including mortality)
- EntropyXQT independently predicted the secondary endpoints
Original publication
Combined Analysis of Cardiac Repolarization Entropy and Magnetic Resonance Imaging Enhances Risk Stratification of Patients Receiving a Primary-Prevention ICD. JACC Clin Electrophysiol. Published 14 March 2026. doi:10.1016/j.jacep.2026.01.051
Summarised from the published abstract; every number is checked against it