Cardiovascular effects of dobutamine in severe congestive heart failure.

The effects of continuous infusion of dobutamine 5 to 15 microgram/Kg./min. were studied in 17 patients using right heart catheterizations, echocardiography, and/or the Systolic Time Intervals. HR increase was dose-related, but insignificant (p less than 0.05) rate increase was obtained at infusion rates below 15 microgram/Kg.)min. C.O. increased from 2.9 +/- 0.7 to 5.0 +/- 1.2 liters/min. (p less than 0.001), and the stroke volume from 30 +/- 6 to 49 +/- 14 ml./min. (p less than 0.005). The mean BP did not change, P.A.W.P. decreased from 30 +/- 7 to 20 +/- 8 mm. Hg (p less than 0.001) and R.A.P. from 20.0 to 12.0 mm. Hg (p less than 0.005). The P.E.P.I. decreased from 160.93 +/- 54.91 to 133.4 +/- 28.7 msec. (p less than 0.050). Echo-determined mean VCf increased from 0.387 +/- 0.14 to 0.537 +/- 0.13 cm. (p less than 0.010), diastolic diameter did not change significantly, but the end systolic diameter decreased from 6.020 +/- 0.69 to 5.750 +/- 0.70 cm. (p less than 0.025). During a mean infusion period of 75 hours, the only side effects noted were transient nausea and/or vomiting at 15 microgram/Kg./min. dose range in two patients, and multifocal P.V.C.'s following 68 hours of infusion in another patient. It is concluded that in the dose range of 5 to 15 microgram/Kg./min., dobutamine is well tolerated and is a very potent inotropic agent with only minor effects on the heart rate and blood pressure.