Exercise capacity and cardiac function assessed by tissue Doppler imaging in chronic heart failure

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Abstract
Objective: To examine the relation between longitudinal left ventricular function assessed by tissue Doppler imaging (TDi) and exercise capacity in heart failure. Subjects: 153 patients with chronic heart failure from left ventricular systolic dysfunction (ejection fraction < 45%) and 87 age and sex matched controls. Methods: Echocardiography was used to measure conventional indices of left ventricular systolic function. TDi was used to assess left and right ventricular longitudinal function by measuring mitral and lateral tricuspid annular velocities during the cardiac cycle. Velocities measured at each point were the systolic peak (Sm) and the diastolic troughs (Em and Am), corresponding to passive and active (atrial) left ventricular filling. Each patient also underwent treadmill exercise testing with metabolic gas exchange measurements. Results: Left and right ventricular TDi velocities were greater in controls than in patients. Left ventricular ejection fraction (LVEF) correlated with Sm (r = 0.30, p = 0.0005), but not with Em, Am, or the Em/Am ratio. There were no significant differences between New York Heart Association (NYHA) functional class for any of the TDi variables. Right ventricular indices were not related to exercise capacity. Systolic myocardial motion measured by TDi correlated more closely with peak oxygen consumption (pV˙o2) (r = 0.35, p < 0.0001) than LVEF (r = 0.21, p < 0.02). The Em/Am ratio was not correlated with pV˙o2. In multiple regression, Sm was the only left ventricular TDi variable to predict exercise capacity independently (p < 0.05). Conclusions: Exercise capacity and symptoms are poorly related to conventional measures of cardiac function and more closely correlated with indices of longitudinal left ventricular function as assessed by TDi.

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