Early stage acromegalic cardiomyopathy: a model for LV hypertrophy and increased contractility without an increase in loading

Purpose: In patients with acromegaly, due to chronic GH and IGF-I excess a specific cardiomyopathy, associated with myocardial hypertrophy and diastolic dysfunction, develops. The first stage of acromegalic cardiomyopathy is characterized by a visually hyperkinetic LV but normal ejection fraction (EF). We sought to analyze whether this was associated with signs of increased contractility in acromegaly patients. Methods: 32 patients with acromegaly (49.5± 10.6 years) and normal EF were compared to 26 healthy sex and age matched normals. Patients in both groups underwent a complete echocardiographic exam. LV mass was calculated and indexed by body surface area to obtain the LV mass index (LVMI). The outflow velocity time integral (VTI) and ejection time (ET) were measured from PW Doppler traces of transaortic flow. ET was indexed by heart cycle duration (R-R) to obtain the relative ET duration (ET/R-R). Results: Acromegaly: mean disease duration was 6.6± 6.0 years, LVMI=93.9± 25.3 g/m² , VTI = 23.4± 5.2 cm, ET/R-R = 0.35± 0.04 s. A correlation was found between LVMI and ET/R-R (R=0.34 ; p=0.07) and LVMI and VTI (R=0.58 ; p= 0.002). These correlations are presented in Fig 1 (right). Normals: LVMI=86.5± 15.7 g/m² , VTI = 24.4± 3.4 cm, ET/R-R = 0.35± 0.04 s. No correlation between LVMI and ET/R-R nor LVMI and VTI was found (Fig 1, left). Conclusion: A significantly higher degree of LVH was found in acromegaly patients compared to normals. This was associated with an increase in outflow together with a shorter relative ejection time suggesting the presence of increased contractility in the acromegalic hearts. Thus acromegalic heart disease, at an early stage, might be considered as a model of a hypertrophic and hypercontractile LV without an additional increase in afterload.