Does growth hormone play a role in chronic heart failure?

Experimental and clinical studies have recently demonstrated that the growth hormone-insulin-like growth factor-I (GH-IGF-I) system is involved in the regulation of cardiac structure and function. Patients with acromegaly have an increased propensity of developing cardiovascular complications, such as ventricular hypertrophy with interstitial fibrosis. Conversely, patients with GH deficiency can exhibit ventricular dysfunction, increased vascular thickness, and an increased number of atheromatous plaques.

Decreased heart rate variability in patients with chronic obstructive pulmonary disease.

To evaluate possible autonomic nervous system (ANS) dysfunction in patients with chronic obstructive pulmonary disease (COPD) in the absence of any hypoxic neuronal damage, we studied 31 patients with COPD patients aged 31 to 68 years (55 +/- 10) and 32 age-matched healthy subjects (control). Respiratory function in the patients was as follows: FEV1 = 52 +/- 8 percent; PaO2 = 71 +/- 14 mm Hg; and PaCO2 = 40 +/- 10 mm Hg. The ANS was assessed by heart rate variability (HRV) in the time domain (SD of mean RR interval) and frequency domain (autoregressive spectral analysis recognizing low [LF] and high [HF] frequency components, vagal and sympathetic related, respectively).