Effects of metoprolol in chagasic patients with severe congestive heart failure.
BACKGROUND
Beta-blockers are the most effective and promising treatment for congestive heart failure secondary to left ventricular dysfunction and sympathetic activation.


METHODS
Since chagasic patients with severe congestive heart failure have left ventricular systolic dysfunction and neurohormonal activation, we administered metoprolol to nine chagasic patients who were in severe congestive heart failure. Metoprolol (5 mg p.o. daily) was uptitrated on a weekly basis.


RESULTS
Patients were receiving digitalis, diuretics and angiotensin converting enzyme inhibitors and had left ventricular dilatation (6.77+/-0.89 cm), depressed ejection fraction (0.20+/-0.06), low systolic blood pressure (93+/-11 mm Hg), sinus tachycardia (115+/-17 beats/min) and sympathetic activation 400+/-246 pg/ml). One patient was in New York Heart Association Functional class III and eight patients were in functional class IV. At the end of the fifth week of treatment (metoprolol 25 mg), seven patients were in functional class III and two were in functional class II. Heart rate decreased to 85+/-15 beats/min (P<0.05) and the systolic blood pressure increased to 108+/-18 mm Hg (P<0.01). There were no significant changes in left ventricular ejection fraction. By the end of the tenth week of treatment (metoprolol 50 mg), four patients were now in functional class I and five were in functional class II. Left ventricular ejection fraction increased to 0.27+/-0.05 (P<0.01) and the left ventricular systolic diameter decreased from 6.38+/-0.90 at baseline to 5.89+/-0.59 and 5.76+/-0.96 after 25 and 50 mg of metoprolol treatment, respectively (P<0.04). Plasma norepinephrine decreased non-significantly to 288+/-91 pg/ml.


CONCLUSIONS
Beta-blockers improve the clinical status and the left ventricular function of chagasic patients with severe congestive heart failure.
Dávila
Diego F
DF
Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Universidad de Los Andes, Apartado Postal 590, Mérida, Venezuela. diegod@ing.ula.ve
Angel
Francisco
F
Arata de Bellabarba
Gabriela
G
Donis
Jose H
JH
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000704:Analysis of Variance; D002598:Chagas Cardiomyopathy / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000209:etiology; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D018487:Ventricular Dysfunction, Left / Q000188:drug therapy* / Q000209:etiology
D000319:Adrenergic beta-Antagonists; D008790:Metoprolol; D009638:Norepinephrine