Prognostic Value of Noninvasively Obtained Left Ventricular Contractile Reserve in Patients With Severe Heart Failure

Objectives. The present study sought to evaluate the prognostic value of contractile reserve measured noninvasively during dobutamine infusion in patients with severe heart failure. Background. In patients with severe heart failure there is great need for objective criteri to define candidates for heart transplantation or intensive medical treatment. Cardiac pumping performance reserve has been shown to have excellent prognostic value in patients with cardiogenic shock. Methods. Cardiac peak power, an afterload-independent contractility index, was measured noninvasively at rest and at peak dobutamine inotropic stimulation. Contractile reserve was defined as the difference between maximal cardiac power at peak dobutamine dose and baseline value. Maximal cardiac power was calculated from the maximal product of validated central arterial pressure and aortic flow. Results. Results were obtained from 52 subjects (42 patients, 10 control subjects). Twenty-two patients were in New York Heart Association functional classes III and IV. Of nine patients with contractile reserve <1.5 W/ml, eight died during the 3-year follow-up period. In contrast, all survivors had contractile reserve>1.5 W/ml. Using multiple logistic regression analysis, contractile reserve was shown to be the only predictor of survival. Conclusions. Contractile reserve measured noninvasively during dobutamine infusion is valuable prognostic indicator in patients with severe heart failure, with added value to ejection fraction.