Effects of atrial pacing and dipyridamole administration on coronary hemodynamics of collateralized myocardial regions in stable angina pectoris.
Great cardiac vein blood flow by thermodilution and great cardiac vein oxygen saturation were measured in 14 patients with stable exertional angina and an angiographic pattern of complete occlusion of the proximal left anterior descending artery retrogradely filled by collateral vessels supplying still viable myocardium. Measurements were obtained under control conditions, at peak atrial pacing and after dipyridamole administration (0.56 mg/kg intravenously over 4 minutes). Both stress tests induced ischemic electrocardiographic changes in all patients, but dipyridamole administration resulted in greater ST-segment depression in 11 patients (1.6 +/- 0.5 vs 2.4 +/- 1.6 mm, p less than 0.05) and transient ST-segment elevation in 3 patients. Dipyridamole provoked ischemia at a lower value of rate-pressure product (145.3 +/- 30.6 vs 202.9 +/- 36.6 beats/min . mm Hg . 10(-2), p less than 0.0005) and anterior region myocardial oxygen consumption (9.32 +/- 4.76 vs 11.39 +/- 3.91 ml/min, p less than 0.05), despite a greater increase in great cardiac vein flow (139.4 +/- 45 vs 93 +/- 27.4 ml/min, p less than 0.0025) and a greater decrease in the calculated index of anterior region coronary resistance (0.87 +/- 0.27 vs 1.46 +/- 0.43 mm Hg/ml/min, p less than 0.0005). Moreover, great cardiac vein oxygen saturation increased more significantly during dipyridamole-induced ischemia than at peak pacing (63 +/- 12 vs 35 +/- 8%, p less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)
De Servi
S
S
Divisione di Cardiologia, Policlinico San Matteo, Istituto di Ricovero e Cura a Carattere Scientifico, Pavia, Italy.
Ferrario
M
M
Ghio
S
S
Angoli
L
L
Bramucci
E
E
Ardissino
D
D
Specchia
G
G
D000787:Angina Pectoris / Q000175:diagnosis* / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial; D003097:Collateral Circulation / Q000502:physiology; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000175:diagnosis / Q000503:physiopathology; D004176:Dipyridamole; D004562:Electrocardiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D013815:Thermodilution
D004176:Dipyridamole