Improvement of left ventricular function by lifestyle intervention in obesity: contributions of weight loss and reduced insulin resistance

Abstract

Aims/hypothesis Weight excess and insulin resistance mediate the link between obesity and left ventricular dysfunction. We investigated the effect and mechanisms of lifestyle modification on left ventricular function changes in obese patients. Methods Reduction of body weight and insulin resistance was sought using a behavioural intervention programme including dietary restrictions and exercise training in 261 patients (age 45±13 years) with BMI ≥30 kg/m 2 , no history of cardiac disease and a normal stress echocardiogram. Each patient underwent echocardiographic measurement of myocardial deformation and velocity at baseline and at 6 month follow-up. Results Improvements in left ventricular systolic and diastolic function were demonstrated only in patients with significant reduction of weight and/or insulin resistance. Left ventricular improvement was less frequent in patients with diabetes than in those without (52% vs 82% for strain, 50% vs 81% for strain rate and 59% vs 80% for peak early diastolic myocardial velocity). The independent predictors of improved left ventricular systolic function (increase in strain) were: weight reduction (β=0.14, p<0.05), decrease in the HOMA insulin resistance index (β=0.20, p<0.005) and absence of diabetes (β=0.18, p<0.02). A decrease in HbA 1c also predicted improvement of left ventricular diastolic function (β=0.26, p<0.001). There was a parallel increment in exercise capacity with intervention and increase in strain was independently correlated with increase in Á VO 2 (β=0.13, p<0.04). Conclusions/interpretation Effective lifestyle modifications in obese patients improve left ventricular systolic and diastolic function, but appear less effective with coexisting diabetes. The reversal of left ventricular function abnormalities is associated with reduction of both weight and insulin resistance, and is accompanied by an increase in cardiorespiratory fitness.

Cardiac dysfunction in type II diabetes: a bittersweet, weighty problem, or both?

“…We did not have a group of patients who achieved weight loss without any reduction in HbA1c levels to examine the independent contribution of weight loss alone without improved glycaemic control on LV function. However, as the study by Kosmala et al has shown [32], improvement in LV function with weight loss alone (their patients did not have significant reduction in HbA1c with behavioural intervention) was less frequently observed in patients with diabetes. We did not evaluate changes in insulin resistance in our patients.…”

“…In a study of 261 patients with BMI ≥ 30 kg/m 2 who undertook a behavioural intervention programme including dietary restriction and exercise training, independent predictors of improvement in LV function were weight reduction, improvement in insulin resistance and absence of diabetes [32]. There was no significant reduction in HbA1c levels with intervention in either the adherent group or in the non-adherent group; therefore, the effects of improved glycaemic control on LV function was not examined.…”

Cardiometabolic Syndrome and Increased Risk of Heart Failure

“…Notably, the respective study designs for exercise in obese type-2 diabetics have maintained the traditional low-fat/high-carbohydrate nutrition [87,88]. Their ambiguous outcome fits the results of the low-fat vs. GL restriction dietary arm in spite of moderate aerobic training as discussed above [30••].…”

Cardiovascular Effects of Weight Loss

“…Intentional weight loss in subjects who achieve reductions of 5% to 10% body weight using combinations of behavioral weight loss, dietary, and exercise interventions have shown significant reductions in LV hypertrophy, characterized by decreases in LV mass and wall thickness [17, 33•, 58, 65, 66]. Similarly, weight loss significantly improves LV systolic and diastolic function in obese subjects [17,65,67,68]. Improvements in LV diastolic and systolic function are characterized by echocardiographic load-independent indices of systolic and diastolic myocardial velocities at the mitral annulus and transmitral flow velocities, measures that demonstrate improved LV relaxation and decreased LV filling pressures.…”

“…Improvements in LV diastolic and systolic function are characterized by echocardiographic load-independent indices of systolic and diastolic myocardial velocities at the mitral annulus and transmitral flow velocities, measures that demonstrate improved LV relaxation and decreased LV filling pressures. In a study of 261 obese subjects with no CHD enrolled in a lifestyle intervention with dietary restrictions and exercise for 6 months, there were significant improvements in LV systolic and diastolic function and peak ventilatory exercise capacity among those who achieved 5% weight loss and a 20% decrease in the homeostasis model assessment of insulin resistance (HOMA) index [68]. These improvements in LV function were less predictable in T2DM, suggesting that insulin resistance and T2DM may have independent deleterious effects on LV dysfunction.…”