Right vs. left ventricular contractile reserve in one-year prognosis of patients with idiopathic dilated cardiomyopathy: assessment by dobutamine stress echocardiography.

Aim: To determine prognostic implications of the assessment of right (RV) vs. left ventricular (LV) contractile reserve with dobutamine echocardiography in patients with idiopathic dilated cardiomyopathy.

Methods And Results: Forty-eight consecutive patients (41 male, NYHA class III/IV 13 patients, LV ejection fraction 19+/-8%) were subjected to dobutamine stress echocardiography in incremental stages lasting 5 min each. Contractile reserve was defined as the difference between the values of LV ejection fraction and RV fractional area change obtained at peak dobutamine dose and the baseline values. Patients were followed for one year after enrollment for combined end-point of cardiac death, partial left ventriculectomy and hospitalization for congestive heart failure. During the follow-up 15/48 patients reached combined end-point. Patients who reached end-point had lower RV and LV contractile reserves (14+/-5 vs. 8+/-6%, p=0.0014, and 9+/-5 vs. 3+/-2%, p<0.001, respectively). Kaplan-Meier curves demonstrated that both LV and RV contractile reserves can identify patients with dismal prognosis (log rank=17.02 and log rank=14.66, respectively, p<0.001 for both). Multivariate analysis identified dobutamine induced change in LV functional reserve as the only independent predictor of combined end-point (beta=-0.63, p=0.0035).

Conclusion: Both RV and LV contractile reserves can be used for prognostic stratification in patients with idiopathic dilated cardiomyopathy. It appears that dobutamine induced change in LV functional reserve may better identify patients with dismal prognosis.