Improvement in Hypertrophic Cardiomyopathy After Significant Weight Loss: Case Report

Gabriel I. Uwaifo, MD, Erica M. Fallon, BS, Karim A. Calis, PharMD, MPh, Bart Drinkard, PT, MSPT, CCS, Jennifer R. McDuffie, PhD, Jack A. Yanovski, MD, PhD

Disclosures

South Med J. 2003;96(6) 

In This Article

Discussion

This case suggests that even for patients with FAHCM, which is a primarily genetic disease, weight reduction in the obese adolescent can be associated with profound improvement in cardiac functional indices. The patient's clinical, electrocardiographic, and echocardiographic findings were virtually pathognomonic of familial hypertrophic cardiomyopathy,[10] with features most consistent with the midcavity obstructive variant.[6] There also are reports of a distinct apical variant more common in Japanese patients that bears some similarity to the findings in our index case.[10,11]

Although poorly characterized, there is evidence of a distinct obesity-associated cardiomyopathy characterized by left ventricular restrictive dysfunction that improves after marked weight loss associated with bariatric surgery or other effective weight loss strategies.[2,9,12] Unlike the findings in our patient, however, most reports of this entity suggest that it is associated most typically with eccentric left ventricular hypertrophy and consequent diastolic dysfunction.[12,13,14,15] Obesity-associated cardiomyopathy is described as having a greater effect on the interventricular septum than on the left ventricular apex.[16] Concentric hypertrophy has been observed almost exclusively in the setting of coexisting hypertension.[17] Obesity-associated cardiomyopathy may rarely present as dilated cardiomyopathy with a worse prognosis.[16] Obesity-associated cardiomyopathy could coexist with FAHCM in patients such as ours and thus might explain some of the observed improvements in our patient.[18]

Although the exact pathophysiology of obesity-related cardiomyopathy is unclear, the increased epicardial fat and associated fatty infiltration into myocardial cells often found in these patients suggest the possibility of a "lipotoxic" phenomenon possibly related to excess ceramide production with secondary parenchymal cell apoptosis, as described in other tissues, including the pancreatic cell and muscle.[19]

Our patient had isolated systolic hypertension before weight loss initiation and thus could have had a component of hypertensive heart disease superimposed on FAHCM. Black patients such as ours with hypertension have an even higher prevalence of hypertension-related left ventricular hypertrophy.[20] The recognition of the potential for this coexisting condition in such patients is vital, because left ventricular hypertrophy secondary to hypertension is treatable with antihypertensive medication and/or with weight loss in a patient with comorbid obesity.[21]

Rarely, fatty infiltration of the cardiac myofibers may result in cardiac dysfunction. This condition, called adipositas cordis, most commonly presents as a restrictive or hypertrophic cardiomyopathy with selective interventricular septal thickening, but occasionally it may be associated with dilated cardiomyopathy as well.[22,23,24] Without performing endomyocardial biopsy, making a definitive premortem diagnosis of this entity is impossible.

The marked weight loss that our patient achieved had the expected multisystemic effects reported to be associated with marked weight loss, including significant improvement in both systolic and diastolic blood pressure. Furthermore, pulse pressure, which has been identified as a distinct cardiac risk factor, was significantly reduced,[25] as was the rate pressure product (i.e., an index of sympathetic cardiac activity and a surrogate of myocardial oxygen demand).[26] The cardiac dynamics required to achieve a static estimated ejection fraction changed during the study period, even though the ejection fraction remained similar throughout that time. The heart rate and midventricular peak gradient decreased, as did the left ventricular mass, left ventricular volume, and left ventricular fractional shortening. Consonant with the patient's weight and fat mass losses, his overall cardiac function improved, with maintenance of normal systolic function at a lower myocardial mass, lower myocardial oxygen demand, and more efficient muscle contractility.

Although obesity is common, reports of its association or coexistence with familial hypertrophic cardiomyopathies are scant in the literature. Smahel and Gregor's[27] cohort is probably the largest reported group in which the findings of obesity and increased abdominal girth are mentioned. There is an isolated report in the literature of an obese patient with pickwickian syndrome and hypertrophic cardiomopathy.[28] This paucity of information, however, probably does not mean that the association is uncommon, because the prevalence of obesity is great. The benefits associated with weight loss in our patient suggest that in evaluating patients with this rare familial cardiomyopathy, physicians should not lose sight of this potentially modifiable cardiac risk factor, the amelioration of which can have salutary effects on cardiac structure, physiologic function, and possibly long-term cardiac risk.[18,29]

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