Mechanism of isoproterenol-induced angina pectoris in patients with obstructive hypertrophic cardiomyopathy and normal coronary arteries.
In 14 patients with obstructive hypertrophic cardiomyopathy and angiographically normal coronary arteries, 8 with angina (group B) and 6 without (group A), the effects of intravenous isoproterenol, 2 to 4 micrograms/min, followed by intravenous propranolol, 0.2 mg/kg, were studied. An intraventricular systolic gradient less than 50 mm Hg, high-quality echocardiograms and cineangiograms and high-fidelity pressure tracings were selection criteria. Hemodynamic and metabolic variables were assessed during basal conditions, after 5 minutes of isoproterenol infusion or at angina and ST-segment depression, and 5 and 10 minutes after intravenous propranolol infusion. Isoproterenol increased the intraventricular systolic gradient more significantly in group B than in group A (102.4 +/- 8.3 vs 52.2 +/- 8.2, p less than 0.0001). Group B also had higher left ventricular end-diastolic pressure (32.5 +/- 3.9 vs 20.2 +/- 5.7), lower mean arterial pressure (69.7 +/- 3.5 vs 84.7 +/- 4.8) and a smaller increase in coronary sinus flow (176.1 +/- 9.2 vs 261.5 +/- 33.9, all p less than 0.0001), concomitant with lactate release and ST-segment depression. Propranolol promptly reversed hemodynamic and metabolic changes caused by isoproterenol, except for a further coronary sinus flow increase (from 176.1 +/- 9.2 to 219 +/- 14.2 ml/min, p less than 0.001), and heart rate decrease below basal values (57.8 +/- 7.5 vs 79.9 +/- 9.8 beats/min, p less than 0.001) in group B.(ABSTRACT TRUNCATED AT 250 WORDS)
Cuccurullo
F
F
Istituto di Patologia Medica, University of Chieti, Italy.
Mezzetti
A
A
Lapenna
D
D
Tomassetti
V
V
Porreca
E
E
Poggiopollini
G
G
Guglielmi
M D
MD
Mancini
M
M
Marzio
L
L
Lenzi
S
S
D000787:Angina Pectoris / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications*; D003331:Coronary Vessels; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000494:pharmacology; D012016:Reference Values
D011433:Propranolol; D007545:Isoproterenol