Growth Hormone, Acromegaly, and Heart Failure: An Intricate Triangulation

Luigi Saccà, Raffaele Napoli, Antonio Cittadini

Disclosures

Clin Endocrinol. 2003;59(6) 

In This Article

The Heart in Longstanding Acromegaly

Acromegalic heart disease, in its end-stage, is a congestive heart failure syndrome, resistant to conventional therapy and, in many respects, resembling dilated cardiomyopathy (Saccà et al., 1994). The heart is enlarged because of increased myocardial mass and marked ventricular cavity dilation. Histological examination shows extensive replacement fibrosis, consequent to cardiomyocyte necrosis, and signs of myocarditis with lymphomononuclear cell infiltrates (Lie & Grossman, 1980). In a recent study of endomyocardial biopsies from acromegalic patients, an eight-fold increase in the content of connective tissue was reported (Frustaci et al., 1999). Interestingly, the degree of fibrosis was strongly correlated with the duration of acromegaly. The study also provided evidence that programmed cell death of both myocytes and interstitial cells occurs in the acromegalic heart.

Even in the intermediate stage of acromegaly (after ~5 years of active disease) one can demonstrate the presence of heart dysfunction that occurs predominantly at expense of diastole, because of impaired ventricular relaxation (Fazio et al., 1994). Diastolic dysfunction, in turn, impairs systolic function, particularly during physical exercise, when the normal ventricular filling is crucial to sustain the enhanced pump activity of the heart. The overall picture is one of diastolic heart failure, analogous to that occurring in other conditions associated with ventricular hypertrophy. It must be stressed, however, that in acromegaly the heart shows diastolic dysfunction even when the disease has not yet been complicated by other events, such as hypertension, diabetes, and coronary artery disease (Fazio et al., 1994).

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