Aims: Dobutamine stress echocardiography (DSE) is widely used to evaluate myocardial contractile reserve in patients with heart failure (HF). The aim of the study was to assess the relationship between the tissue Doppler (TD) mitral annulus systolic velocity (Sm) change during DSE, contractile reserve, and aerobic exercise capacity in HF patients.
Methods and results: Sixty-four HF patients (age 67 ± 9 years, 58% with an ischaemic aetiology, and a mean value of the ejection fraction 29 ± 7%) underwent high-dose DSE. The mean value of the TD mitral annulus septal-lateral Sm change was analysed at rest and at peak DSE. All patients underwent also the cardiopulmonary exercise test. With a receiver operating characteristic analysis, a value of 2.02 cm/s obtained as a stress-rest difference in a mean value of the peak systolic velocity of the mitral annulus (Sm) was the best value for diagnosing the myocardial contractile reserve [area under the curve 0.69 (95% CI 0.56-0.80), sensitivity 69% (95% CI 54-81), specificity 80% (95% CI 45-97)]. The patient population was divided into two groups: with rest-stress Sm change during DSE ≤ 2.02 cm/s and with rest-stress Sm change >2.02 cm/s. Patients with Sm rest-stress >2.02 change during DSE, compared with patients with rest-stress change ≤2.02, showed a lower incidence of severe diastolic dysfunction at rest (16 vs. 46%, P= 0.039) and lower E/Ea values (11 ± 5 vs. 15 ± 6, P = 0.005), similar ejection fraction at rest but higher ejection fraction at peak DSE (53 ± 14 vs. 41 ± 12%, P = 0.001), better myocardial contractile reserve assessed by a pressure-volume relationship (1.89 ± 2.01 vs. 0.58 ± 1.38 mmHg/mL/m(2), P = 0.004), with a lower end-systolic volume (-46 ± 20 vs. -24 ± 19%, P< 0.001), a higher increase in the ejection fraction (23 ± 10 vs. 12 ± 10%, P = 0.001) during DSE, and better peak oxygen consumption (16 ± 4 vs. 13 ± 2 mL/kg/min, P = 0.01).
Conclusion: In patients with HF, the rest-stress variation of mitral annulus systolic velocities during DSE predicts the presence of myocardial contractile reserve and exercise tolerance.