Abstract 2846: Deceleration Capacity Measured 6 Weeks Post Myocardial Infarction is Associated With ICD Treatable Arrhythmias
Background: Deceleration Capacity (DC), a marker of cardiac autonomic tone, is associated with all cause mortality in post acute myocardial infarction (AMI) patients. Stratifying patients at risk of sudden cardiac death using DC at 6 weeks post AMI has not been studied in patients with reduced left ventricular ejection fraction (LVEF≤0.40).
Methods: A total of 5869 consecutive patients were screened in 10 European centers, and 312 patients (age 65±11 years) with a mean LVEF of 31±6% were included in the CARISMA study. DC was derived using standard methods from 227 patients with analyzable 24hr holters acquired 6 weeks from the index MI. The primary endpoint (PE) was ECG-documented ventricular fibrillation or symptomatic sustained ventricular tachycardia (>30 sec) adjudicated as ‘most probably treatable by an ICD’ according to the consensus of the 5-member committee blinded to outcome. Secondary endpoints included all-cause mortality (ACM) and cardiac death (CD).
Results: During a mean 1.85 year follow up and among the 227 patients studied, there were 17 PE, 19 ACM and 12 CD. DC at 6 weeks post AMI was significantly associated with the PE (Hazard Ratio [HR] = 0.91 [0.84 – 0.99] p=0.02), and ACM (HR=0.89 [0.82– 0.96] p=0.0048) but not CD (HR=0.91 [0.79 –1.05] p=0.1952). Figure⇓ shows Kaplan-Meier estimates of survival free of the PE stratified using conventional DC cutoff values. DC ≤4.5ms identified 65% of patients who developed VT/VF with 96% negative predictive and 15% positive predictive values.
Conclusion: Deceleration capacity measured 6 weeks post AMI in patients with LVEF≤0.40 is a strong risk marker for ventricular tachyarrhythmias and may guide clinicians towards ICD therapy.