Right ventricular systolic function as a predictor of appropriate ICD therapy.

BACKGROUND

Recent studies have shown that right ventricular dysfunction is associated with a significantly increased risk of sudden cardiac death. The purpose of this study was to evaluate the association of the right ventricular fractional area change (RVFAC) and appropriate implantable cardioverter-defibrillator (ICD) therapy to determine the cutoff value of the RVFAC.

METHODS

Consecutive patients who underwent initial ICD implantations except those with hypertrophic cardiomyopathy, Brugada syndrome, and long QT syndrome were retrospectively enrolled. The primary endpoint was defined as any appropriate ICD therapy. The right ventricular dimensions and function on transthoracic echocardiography were measured for analysis.

RESULTS

In total, 172 patients (60.3 ± 13.6 years, 131 males) were enrolled. Ninety patients received an ICD as a secondary prophylaxis. The mean LV ejection fraction and RVFAC were 38.3 ± 14.3% and 35.8 ± 8.8%, respectively. Regarding appropriate ICD therapy events, the best cutoff value of the RVFAC was 34.8%, while 74 patients had an RVFAC < 34.8%. Regarding the primary endpoint, the hazard ratio of a low RVFAC was 2.73 (95% CI 1.46-5.12, P < 0.01). In the multivariate analysis, a low RVFAC was an independent predictor of appropriate ICD therapy (HR: 3.40, 95% CI 1.74-6.64, P < 0.01). The secondary prophylactic cohort with a low RVFAC had the highest incidence of appropriate ICD therapy. Among the patients with RV dysfunction, the RVFAC normalized in 39% of patients during follow-up. This recovered RVFAC group had a significantly lower incidence of appropriate ICD therapy than the unrecovered RVFAC group (P = 0.043).

CONCLUSION

A low RVFAC might be associated with increased appropriate ICD therapy.