Alterations of Left Ventricular Myocardial Characteristics Associated With Obesity

Abstract

Background-Obesity is associated with heart failure, but an effect of weight, independent of comorbidities, on cardiac structure and function is not well established. We sought whether body mass index (BMI) and insulin levels were associated with subclinical myocardial disturbances. Methods and Results-Transthoracic echocardiography, myocardial Doppler-derived systolic (sm) and early diastolic velocity (em), strain and strain rate imaging and tissue characterization with cyclic variation (CVIB), and calibrated integrated backscatter (cIB) were obtained in 109 overweight or obese subjects and 33 referents (BMI Ͻ25 kg/m 2 ). BMI correlated with left ventricular (LV) mass and wall thickness (PϽ0.001). Severely obese subjects (BMI Ͼ35) had reduced LV systolic and diastolic function and increased myocardial reflectivity compared with referents, evidenced by lower average long-axis strain, sm, cIB, lower CVIB, and reduced em, whereas LV ejection fraction remained normal. Differences in regional or global strain, sm, and em were identified between the severely obese (BMI Ͼ35) and the referent patients (PϽ0.001). Similar but lesser degrees of reduced function by sm, em, and basal septal strain and increased reflectivity by cIB were present in overweight (BMI, 25 to 29.9) and mildly obese (BMI, 30 to 35) groups (PϽ0.05). Although tissue Doppler measures were not associated with duration of obesity, they did correlate with fasting insulin levels and reduced exercise capacity. BMI was independently related to average LV strain (␤ϭ0.40, Pϭ0.02), sm (␤ϭϪ0.36, Pϭ0.002), and em (␤ϭϪ0.41, PϽ0.001). Conclusions-Overweight subjects without overt heart disease have subclinical changes of LV structure and function even after adjustment for mean arterial pressure, age, gender, and LV mass.

Clinical Phenotypes in Heart Failure With Preserved Ejection Fraction

“…An elevated body mass index (BMI; kg/m 2 ) is a recognized risk factor for new‐onset HFrEF and HFpEF 108, 109, 110, 111. Obesity has been associated with LVH and incipient LV dysfunction 112, 113.…”

Dynamic Relation of Changes in Weight and Indices of Fat Distribution With Cardiac Structure and Function: The Dallas Heart Study

“…Previous studies have primarily examined the cross‐sectional relationship between measures of adiposity and cardiac morphology 2, 5, 16, 17. These static measurements do not permit evaluation of the dynamic impact of body mass and fat distribution changes on alterations in cardiac structure and function over time, which may be critical determinants for HF risk.…”

Cardiovascular consequences of obesity and targets for treatment

“…There is evidence that excess body weight itself, independent of other known cardiovascular risk factors and independent of atherosclerosis and myocardial infarction impairs both diastolic and systolic function [48,49] Indeed, the risk of developing clinical heart failure is estimated to increase by 5% −7% for every 1 kg/m 2 BMI increase and is thought to contribute to 11-15% of all heart failure cases [3]. Consistent with this there are several studies using loaddependent measures demonstrating the detrimental effects of excess body weight on diastolic function as measured using traditional echocardiographic Doppler imaging [50][51][52][53].…”

“…There is an increase in load through an increase in plasma and blood volume via activation of the renin-angiotensin-aldosterone system [10]. Pathologic and calibrated integrated backscatter studies also suggest that there are textural alterations in the myocardium that may affect the viscoelastic properties of the myocardium, which may be load-independent [49]. Lastly, alterations in myocardial metabolism may also play a role in the development of cardiac dysfunction.…”