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Non pressure overload LV hypertrophy in acromegaly leads to increased contractility and cardiac output whereas hypertensive hypertrophy does not

Background: Due to chronic GH and IGF-I excess, a specific cardiomyopathy associated with ventricular hypertrophy and diastolic dysfunction develops in patients with acromegaly. The first stage of acromegalic cardiomyopathy is characterized by a visually hyperkinetic left ventricle (LV) but normal ejection fraction (EF) and may be difficult to discern from LV remodelling taking place in arterial hypertension. We sought to analyze the potential difference in LV contractility among these two patient groups with a similar grade of hypertrophic remodelling. Methods: 37 patients with acromegaly (50.1 ± 10.5 years, 20 female/17 male) and normal EF were compared to 15 patients with arterial hypertension (52.7±16.6 years, 7 female/8 male, normal EF). 32 healthy sex- and age matched volunteers served as a control group. Patients in all three 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 left ventricular outflow. ET was indexed by heart cycle duration (R-R) to obtain the relative ET duration (ET/R-R). Aortic root size (Ao), LV stroke volume (SV) and cardiac output (CO) were calculated as previously described. Results: Acromegaly: mean disease duration was 6.5±6.0 years, LVMI=95±24 g/m², SV = 158±60 mL, Ao = 3.4±0.5 cm, ET/R-R = 0.33±0.03 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). Hypertension group: LVMI=93±13 g/m², SV = 87±16 mL, Ao = 3.1±0.2 cm, ET/R-R = 0.36±0.03 s. Control group: LVMI = 77±12 g/m², SV = 84±20 mL, Ao = 2.8±0.4 cm. ET/R-R = 0.34±0.04 s. No correlation between LVMI and ET/R-R nor LVMI and VTI was found in the hypertensive or control group. Conclusion: A comparable degree of LVH was found in acromegaly and the hypertensive group, both significantly higher compared to normals. Unlike in hypertension, in the acromegalic hearts this was associated with an increase in outflow together with a shorter relative ejection time suggesting the presence of increased contractility. Additionally, the aortic diameter was increased both in acromegaly and hypertension, although significantly higher in acromegaly. Thus, unlike hypertensive heart disease, acromegalic heart disease at an early stage is associated with a hypertrophic and hypercontractile LV without an additional increase in afterload, leading to a higher grade of aortic dilatation.

Acromegaly; Left ventricular hypertrophy; Doppler echocardiography; Hypertensive heart disease; Cardiac output

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