| Abstract: | Propranolol (P) .13 mg./kg. was given to seven patients with mitral valve obstruction the changes in resting and exercise hemodynamics were followed by means of combined right and left heart catheterization. Changes were variable. At rest there was a decrease in heart rate of 10 beats/min. with no consistent change in stroke volume, cardiac output, left ventricular systolic (LVS) or left atrial (LA) pressure after P. Mean left ventricular end-diastolic (LVED) pressure was increased 3 mm., mean pulmonary artery (PA) pressure was increased 4 mm., and mean mitral valve gradient was reduced 3 mm. Hg by P. During exercise, mean LVS pressure was decreased 31 mm., mean LVED pressure increased 3 mm., mean LA pressure decreased 3 mm., and mean mitral valve gradient was reduced 5 mm. Hg after P. Mean exercise PA pressure was unchanged, cardiac output was reduced 0.9 1./min., and mean heart rate was reduced 37 beats/min., while stroke volume increased 3 ml./beat after P. Exercise pulmonary vascular resistance was increased from 6.1 to 8.2 units by P. Despite a slower heart rate, the diastolic filling period was not increased. P has no place in the treatment of the majority of patients with mitral stenosis because it further reduces cardiac performance below normal. |
