Effects of metoprolol on rest and exercise cardiac function and plasma catecholamines in chronic congestive heart failure secondary to ischemic or idiopathic cardiomyopathy.
To define the effects of 2 months of metoprolol therapy on cardiac function, aerobic performance and sympathetic nervous system activity, metoprolol (75 to 100 mg/day) was administered to 10 patients with chronic congestive heart failure (CHF). Metoprolol was discontinued in 2 patients because of worsening CHF. In the remaining 8 patients, peak oxygen uptake increased significantly (14.8 +/- 3.0 to 16.1 +/- 2.5 ml/kg/min, p less than 0.05) as did the oxygen pulse (9.0 +/- 2.2 to 12.6 +/- 1.8 ml/beat, p less than 0.02). Resting heart rate (87 +/- 18 to 62 +/- 9 beats/min, p less than 0.05) and peak exercise heart rate (133 +/- 13 to 105 +/- 30 beats/min, p less than 0.02) were both reduced. Mean resting ejection fraction increased from 0.15 +/- 0.06 to 0.25 +/- 0.11 and peak exercise ejection fraction also tended to increase (0.19 +/- 0.11 to 0.28 +/- 0.15, difference not significant). Both resting plasma norepinephrine (613 +/- 706 to 303 +/- 142 pg/ml, p less than 0.05) and epinephrine (71 +/- 50 to 40 +/- 21 pg/ml, p less than 0.05) were reduced. Circulating lymphocyte beta-adrenergic receptor number was unchanged (1,334 +/- 292 to 1,344 +/- 456 receptors/cell, difference not significant). It is concluded that metoprolol therapy is associated with improvements in rest and exercise ventricular performance and maximal aerobic capacity. These improvements are associated with a decline in resting sympathetic nervous system activity.
Nemanich
J W
JW
Department of Medicine, Seattle Veterans Administration Medical Center, Washington.
Veith
R C
RC
Abrass
I B
IB
Stratton
J R
JR
D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000150:complications; D002395:Catecholamines / Q000097:blood*; D002908:Chronic Disease; D003327:Coronary Disease / Q000150:complications; D004837:Epinephrine / Q000097:blood; D005080:Exercise Test; D006321:Heart / Q000503:physiopathology*; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood
D002395:Catecholamines; D008790:Metoprolol; D009638:Norepinephrine; D004837:Epinephrine