Myocardial fibrosis plus GZF mass predicts sudden death, arrhythmias in CIED recipients

Myocardial fibroses on visual assessment (MFVA) do not include patients at risk of sudden cardiac death (SCD) and ventricular arrhythmias among those with cardiac implantable electronic device (CIED), reports a recent study. However, a quantified gray zone fibrosis (GZF) mass measured with the 5SD method (GZF-5SD), in addition to MFVA, improves predictive value concerning SCD and arrhythmias.

In this prospective study, the authors sought to determine whether the presence of MFVA and GZF mass predicts SCD and ventricular fibrillation/sustained ventricular tachycardia following CIED implantation. They assessed total fibrosis and GZF mass, quantified using cardiovascular magnetic resonance, in relation to SCD and ventricular arrhythmias among 700 CIED recipients (mean age 68.0 years).

Of the patients, 27 (3.85 percent) had an SCD and 121 (17.3 percent) experienced arrhythmias over a median of 6.93 years.

MFVA was highly predictive of SCD (hazard ratio [HR], 26.3, 95 percent confidence interval [CI], 3.7‒3,337; negative predictive value, 100 percent). Competing risk analyses also confirmed the predictive value of MFVA for arrhythmic endpoint (subdistribution HR, 19.9, 95 percent CI, 6.4‒61.9; negative predictive value, 98.6 percent).

A GZF mass >17 g measured with the 5SD method, compared with no MFVA, correlated with the highest SCD risk (HR, 44.6, 95 percent CI, 6.12‒5,685) and the arrhythmic endpoint (subdistribution HR, 30.3, 95 percent CI, 9.6‒95.8). Adding GZF-5SD mass to MFVA resulted in the reclassification of 39 percent for SCD and 50.2 percent for the arrhythmic endpoint.

Left ventricular ejection fraction, on the other hand, was not predictive of either endpoint.