Improvement of impaired diastolic left ventricular function after diet-induced weight reduction in severe obesity

Background/objectives: Obesity is independently associated with left ventricular (LV) diastolic dysfunction and altered cardiac morphology. Morbidity and mortality in patients with diastolic dysfunction are similar to values observed in patients with systolic heart failure. We hypothesized that dysfunctional cardiac responses in people with obesity are reversible after weight loss. Thus, we studied the effect of dietary weight reduction on LV diastolic function as well as on cardiac structure using transthoracic echocardiography and tissue Doppler imaging (TDI). Subjects/methods: Thirty-two subjects with obesity underwent a 12-week low-calorie fasting phase of a formula diet. Echocardiographic tissue Doppler indices of diastolic function and measurements of cardiac size were obtained prior to and after the fasting phase. Results: A 12-week diet significantly reduced body mass index from 40.3 +/- 6.6 kg/m(2) to 33.2 +/- 6.1 kg/m(2) (p < 0.01). Weight loss was associated with a significant reduction in blood pressure and heart rate. Echocardiography revealed diastolic dysfunction in subjects with obesity, which was improved by dieting. After weight loss, trans-mitral Doppler echocardiography showed a significant reduction in A-wave velocity, from 65.8 +/- 19.2 cm/s to 57.0 +/- 16.8 cm/s, and an increase in E/A ratio from 1.2 +/- 0.4 to 1.4 +/- 0.5 (p < 0.01). TDI displayed a significantly lower a'-wave velocity (10.3 +/- 2.3 cm/s and 8.9 +/- 1.7 cm/s; p < 0.01). Left atrial and LV dimensions were normal and remained unchanged after weight loss. Conclusion: Obesity is associated with diastolic dysfunction. A 12-week low-calorie diet with successful weight loss can reduce blood pressure and heart rate and partially normalize diastolic dysfunction.