Effects of growth hormone on exercise capacity and cardiopulmonary performance in patients with chronic heart failure.
BACKGROUND
Because GH exerted beneficial effects in various experimental models of heart failure, we investigated the effects of GH on physical exercise capacity and cardiopulmonary performance in patients with dilated cardiomyopathy and chronic heart failure (CHF).


METHODS
Twenty-two patients with CHF (New York Heart Association functional class II-III) underwent spirometry and a symptom-limited, cardiopulmonary exercise testing before and after 3 months of GH (n = 11; seven males; seven idiopathic; 57 +/- 11 yr; 4 IU sc every other day) or placebo (n = 11; eight males; six idiopathic; 54 +/- 10 yr) administration, in a randomized, double-blind trial. Background CHF therapy remained unchanged.


RESULTS
GH, but not placebo, increased IGF-I serum concentration (from 144 +/- 35 to 293 +/- 58 ng/ml; P < 0.005) and improved New York Heart Association functional class (from 2.4 +/- 0.5 to 1.8 +/- 0.4; P < 0.005), exercise duration (from 831 +/- 273 to 925 +/- 266 sec; P < 0.005), peak power output (from 245 +/- 127 to 280 +/- 132 W; P < 0.05), peak minute ventilation (from 52.5 +/- 16.1 to 61.3 +/- 17.3 liters/min; P < 0.05), peak oxygen consumption (from 19.8 +/- 5.6 to 25.1 +/- 5.6 ml/kg.min; P < 0.005), and anaerobic threshold (from 14.9 +/- 4.8 to 20.0 +/- 4.5 ml/kg.min; P < 0.005) without affecting lung function parameters. Furthermore, the slope of the relationship between minute ventilation and pulmonary carbon dioxide production (ventilatory efficiency) decreased from 34.7 +/- 5.1 to 31.7 +/- 5.3 (P < 0.005), whereas the slope of the relation between percent predicted heart rate reserve used and percent observed metabolic reserve used (chronotropic index) rose from 0.57 +/- 0.20 to 0.69 +/- 0.18 (P < 0.005).


CONCLUSIONS
Given the predictive value of physical exercise capacity and cardiopulmonary performance in CHF progression, these data provide additional insights into the mechanisms by which GH may potentially benefit CHF patients.
Fazio
Serafino
S
Department of Internal Medicine, Cardiovascular and Immunological Sciences, University Federico II School of Medicine, 80131 Naples, Italy. fazio@unina.it
Palmieri
Emiliano A
EA
Affuso
Flora
F
Cittadini
Antonio
A
Castellano
Graziella
G
Russo
Teresa
T
Ruvolo
Antonio
A
Napoli
Raffaele
R
Saccà
Luigi
L
D015308:Anaerobic Threshold / Q000187:drug effects; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy / Q000503:physiopathology; D002319:Cardiovascular System / Q000187:drug effects*; D002908:Chronic Disease; D004311:Double-Blind Method; D004452:Echocardiography; D017079:Exercise Tolerance / Q000187:drug effects*; D005260:Female; D013006:Growth Hormone / Q000627:therapeutic use*; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology*; D006334:Heart Function Tests / Q000187:drug effects; D006801:Humans; D008168:Lung / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D012129:Respiratory Function Tests; D014797:Vital Capacity
D013006:Growth Hormone