Beta blockers improve survival and reduce morbidity of patients with chronic heart failure. Stringent dosing guidelines calling for a 1-hour observation period after initiation or up-titration of beta-blocker therapy might limit the use of beta blockers and increase the expense involved. This study was conducted to determine the usefulness of this observation period. Data were collected from 130 in-clinic postdosing observation periods for 34 stable chronic heart failure patients started on carvedilol. The mean left ventricular ejection fraction was 0.22±0.09, and the mean functional class was 2.5±0.6. No patient had greater than first-degree heart block. Carvedilol was started at 3.125 or 6.25 mg b.i.d., and the dose was doubled every 1-3 weeks. All patients were observed for 1-2 hours after initiation or dosage increase, and blood pressure and heart rate were measured hourly. The maximal daily dose was 50±31 mg. In none of the observation periods was there a decrease in the dose of beta blockers administered in the clinic. The predosing mean blood pressure was 110±15/71±10 mm Hg, and the mean heart rate was 78±13 bpm; the 1-hour postdosing mean blood pressure was 101±14/67±10 mm Hg (p is less than 0.001), and the heart rate was 78±13 bpm. The dose was decreased in six patients and medication was discontinued in three, all consequent to symptoms reported several days after dosage increase. Beta blockers can be safely initiated and up-titrated at home in properly selected and evaluated stable patients with chronic heart failure and severe left ventricular dysfunction resulting in mild or moderate impairment of functional capacity. (c)2001 by CHF, Inc.