Systematic reassessment of right ventricular systolic function in patients with dilated cardiomyopathy added prognostic value to baseline evaluation, according to research published in JACC: Cardiovascular Imaging.
Marco Merlo, MD, of the Cardiovascular Department at the University of Trieste in Italy, and colleagues investigated the relationship between right ventricular systolic function and progression of dilated cardiomyopathy in 512 patients (median age: 46 years; left ventricular ejection fraction [LVEF]: 32%) from 1993 to 2008. Right ventricular dysfunction was defined as right ventricular fractional area change <35% and evaluated by 2D-echocardiography.
The primary outcome measure was a composite of death or heart transplantation. Pump failure death or heart transplantation compared with a composite of sudden cardiac death and malignant ventricular arrhythmias were considered secondary outcomes in a competing risks analysis.
Upon first evaluation, 103 patients had right ventricular dysfunction (20% of the total population). These patients had a more advanced New York Heart Association class, poorer LV systolic function, and a more pronounced hemodynamic impairment compared to patients with preserved right ventricular function.
Researchers pointed out that the left bundle branch block rate was actually lower in patients with right ventricular dysfunction (23% vs 34%; P=.003). “In our opinion, this suggests that worse right ventricular function might be mostly the expression of hemodynamic impairment, rather than of extensive biventricular structural damage.”
Furthermore, they noted, “Longitudinal trends of RV [right ventricular] dysfunction presented 2 distinct patterns: 89/103 patients with baseline dysfunction (86%; 17% of the overall cohort) normalized RVF in the short-term (median time of 6 months—interquartile range: 5-7 months), whereas 38/409 patients with preserved RVF at enrollment (9%; 7% of the total population), RV function deteriorated at a later follow-up (median time of 36 months—interquartile range: 24-48 months).”
Older age, longer duration of disease, and a lower LVEF, together with right ventricular dysfunction, were considered independent prognostic predictors (hazard ratio [hazard ratio]: 1.71; 95% confidence interval [CI]: 1.02-2.85; P=.0413). In a time-dependent Cox model, the reassessment of right ventricular systolic function maintained an independent predictive value (HR: 2.83; 95% CI: 1.57-5.11; P=.0006).
Impaired right ventricular function was mainly due to pump failure death or heart transplantation, especially when the impairment was newly onset (baseline P<.001; follow-up P<.0001). This was not related to major ventricular arrhythmic events, except in the very long-term (baseline P=.618; follow-up P=.07).
“Notably, we demonstrated for the first time the strong independent prognostic impact of serial RVF reassessment over time,” researchers concluded. “This emphasizes the importance of a comprehensive echocardiographic evaluation, which should always include a careful assessment of both the right and left chambers at baseline and systematically during the follow-up, in order to improve the accuracy of clinical management and risk stratification of DCM [dilated cardiomyopathy] patients.”
In addition, specific genetic mutations may help pinpoint different phenotypes that affect the right ventricle in dilated cardiomyopathy, but this will require further research.
Merlo M, Gobbo M, Stolfo D, et al. The prognostic impact of the evolution of right ventricular function in idiopathic dilated cardiomyopathy. JACC Cardiovasc Imag. 2016. doi: 10.1016/j.jcmg.2016.01.027.