Blood pressure-independent cardiac hypertrophy in acromegalic patients

Objective Acromegaly is frequently associated with an increase in left vent ricular mass, even in the absence of systemic hypertension. Pathological st udies on acromegalic hearts have shown an extensive interstitial fibrosis, suggesting the existence of a specific acromegalic cardiomyopathy, The aim of this study was to assess left ventricular wall structure in acromegaly b y ultrasonic tissue characterization. Design and methods We studied 10 untreated acromegalic patients and 10 age- matched healthy control subjects. The echo patterns of two-dimensional long -axis end-diastolic echocardiograms were assessed by colour-scale analysis of the interventricular septum, with estimates of the mean colour scale val ue, the broad band (Bb) and the derived collagen volume fraction (dCVF). We also measured electrocardiographic QT interval dispersion (QTd) as a marke r of dyshomogeneous ventricular repolarization. Results Seven patients had left ventricular hypertrophy according to the se x-independent criteria; of these, two had arterial hypertension. None of ou r patients had echocardiographic evidence of diastolic or systolic dysfunct ion. All patients showed significantly increased myocardial echoreflectivit y (Bb = 106.4 +/- 12.1 versus 79.3 +/- 6.5; dCVF% = 2.78 +/- 0.53 versus 1. 58 +/- 0.29; P < 0.0001) and QTd (66 +/- 13 ms versus 54 +/- 8 ms, P < 0.05 ). A significant correlation was found between dCVF and the duration of acr omegaly (r = 0.80; P= 0.005). Conclusions Left ventricular remodelling observed in acromegaly is not rela ted to the presence of arterial hypertension; we hypothesize that the incre ased echoreflectivity and QTd are long-term consequences of cardiac hypertr ophy and prolonged exposure to high levels of growth hormone and insulin-li ke growth factor-I. (C) Lippincott Williams & Wilkins.