Introduction: Patients with severe GH deficiency (GHD) suffer with a reduced quality of life in addition to diverse changes in cardiac size and performance. So far, the cardiac reserve ability to maintain the circulation during peak exercise has not been measured. We tested the hypothesis that patients with severe GHD have reduced cardiac reserve function compared with healthy controls and that this could explain, in part, their reduced quality of life.
Aims: Eighteen patients with severe GHD and an assessment of GHD in adults (AGHDA) score > or =11 (mean 20.0, range 12-25) were studied and compared with 18 age-, sex- and body mass index-matched healthy controls. Peak cardiac power and cardiorespiratory fitness were investigated using noninvasive haemodynamic measurements during maximal cardiopulmonary exercise testing.
Results: Compared with matched controls, the cardiac power of GHD patients during exercise to volitional exhaustion was significantly reduced by 15% (mean +/- SD 4.4 +/- 1.0 W vs. 5.2 +/- 1.0 W, P = 0.02). Patients with GHD also had lower cardiac chronotropic reserve (peak heart rate 154 +/- 21/min vs. 174 +/- 11/min, P = 0.001) and a lower cardiac pressure-generating capacity (systolic blood pressure 160 +/- 25 mmHg vs. 200 +/- 15 mmHg, P < 0.0001). We found no correlation between any measure of peak cardiac power or function and the AGHDA score.
Conclusion: Using this robust noninvasive method of assessing functional cardiac pumping capacity, we have for the first time shown that, while patients with severe GHD have a significantly impaired cardiac functional reserve associated with chronotropic incompetence and impaired pressure-generating capacity, this does not correlate with their reduced quality of life assessed using the current standard AGHDA score.