Obesity cardiomyopathy: pathophysiology and evolution of the clinical syndrome.

Obesity produces an increase in total blood volume and cardiac output because of the high metabolic activity of excessive fat. In moderate to severe cases of obesity, this may lead to left ventricular dilation, increased left ventricular wall stress, compensatory (eccentric) left ventricular hypertrophy, and left ventricular diastolic dysfunction. Left ventricular systolic dysfunction may occur if wall stress remains high because of inadequate hypertrophy. Right ventricular structure and function may be similarly affected by the aforementioned morphologic and hemodynamic alterations and by pulmonary hypertension related to the sleep apnea/ obesity hypoventilation syndrome. The term obesity cardiomyopathy is applied when these cardiac structural and hemodynamic changes result in congestive heart failure. Obesity cardiomyopathy typically occurs in persons with severe and long-standing obesity. The predominant causes of death in those with obesity cardiomyopathy are progressive congestive heart failure and sudden cardiac death.