RV Function in Dilated Cardiomyopathy
What is the prognostic role of right ventricular (RV) function in dilated cardiomyopathy (DCM)?
The study cohort was comprised of 512 patients with DCM (46 years of age [36-55 years of age], left ventricular [LV] ejection fraction 32% [25%-41%]) with a potential follow-up of ≥72 months and available data at baseline and at least one prespecified follow-up evaluation (i.e., 6, 24, 48, or 72 months). The study authors defined RV dysfunction as RV fractional area change <35% at two-dimensional echocardiography. The composite of death or heart transplantation was the primary outcome measure. Logistic regression was used to investigate whether early RV improvement was associated with subsequent LV reverse remodeling (LVRR).
The study authors found that 20% (n = 103) had RV dysfunction. The RV function normalized at a median time of 6 months in 86% of these patients (n = 89) or 17% of the whole cohort, whereas 9% (n = 38 of remaining 409 patients) or 7% of the whole cohort had new-onset RV dysfunction. The investigators found that subsequent LVRR was significantly associated with normalization of RV function at a median time of 24 months (odds ratio, 2.49; 95% confidence interval [CI], 1.17-5.3; p = 0.018). Interestingly, the rate of left bundle branch block was lower in patients with RV dysfunction (23% vs. 34%; p = 0.003). RV dysfunction was independently associated with the primary outcome measure of composite of death or heart transplantation on baseline multivariate analysis (hazard ratio, 1.71; 95% CI, 1.02-2.85; p = 0.0413). RV function remained an independent predictor in the time-dependent model (hazard ratio, 2.83; 95% CI, 1.57-5.11; p = 0.0006).
The authors concluded that RV function needs to be assessed regularly in DCM patients to better prognosticate such patients.
This is an important study because it suggests that improvement of RV function precedes LVRR, and therefore, is a good prognostic predictor. The findings of this study suggest that serial follow-up evaluation of RV function allows better prognostication of patients with DCM. It would be interesting to know whether sleep apnea was a confounder in the prediction of improvement in RV function.
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