Coronary adrenergic hyperreactivity in patients with syndrome X and abnormal electrocardiogram at rest.
Syndrome X is characterized by an abnormal vasomotility of coronary microvessels. It is unknown whether the presence of an ischemic-like pattern in the electrocardiogram at rest (T-wave inversion) reflects a more severe vasomotion disturbance. Changes in coronary sinus flow (thermodilution) and epicardial vessel diameter (quantitative angiography) during adrenergic activation were measured with a standard cold pressor test in patients with syndrome X whose electrocardiogram at rest was normal (group 1: 17 patients) or showed stable, symmetrically inverted T waves (group 2: 22 patients). Cold pressor test increased mean blood pressure and rate-pressure product to a similar extent in both groups, increased coronary sinus flow in group 1 (88 +/- 29 to 119 +/- 36 ml/min; p less than 0.05) and not in group 2 (109 +/- 37 vs 104 +/- 36 ml/min; p = not significant), and decreased coronary resistance in group 1 (1.38 +/- 0.42 to 1.19 +/- 0.38 mm Hg/ml/min; p less than 0.05) and augmented it in group 2 (1.06 +/- 0.32 to 1.28 +/- 0.43 mm Hg/ml/min; p less than 0.02). During cold stimulus, the proximal and middle segments of epicardial arteries showed negligible changes in their lumen, whereas the distal segment dilated in group 1 (1.81 +/- 0.27 to 2.01 +/- 0.32 mm; p less than 0.05) and constricted in group 2 (1.82 +/- 0.12 to 1.62 +/- 0.20 mm; p less than 0.05). Differences in coronary hemodynamic and angiographic responses between the groups were statistically significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Montorsi
P
P
Instituto di Cardiologia, University of Milan, Italy.
Fabbiocchi
F
F
Loaldi
A
A
Annoni
L
L
Polese
A
A
De Cesare
N
N
Guazzi
M D
MD
D000320:Adrenergic Fibers / Q000187:drug effects / Q000502:physiology; D000787:Angina Pectoris / Q000473:pathology / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003080:Cold Temperature; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D003331:Coronary Vessels / Q000294:innervation* / Q000473:pathology; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000494:pharmacology; D013577:Syndrome; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D014666:Vasomotor System / Q000187:drug effects / Q000503:physiopathology*
D011433:Propranolol