Effects of bamiphylline on exercise testing in patients with syndrome X.
An abnormal stimulation of adenosine A1-receptors has been suggested to play a role in the pathogenesis of both chest pain and ischemia-like electrocardiographic changes in patients with syndrome X and a nonselective adenosine antagonist (theophylline) has been reported to be beneficial in these patients. In this study we investigated the acute effects of bamiphylline, a specific A1-receptor antagonist, in 16 patients with syndrome X (14 women, age 57 +/- 6 years), with both angina and ST-segment depression inducible during exercise testing. All patients underwent two treadmill exercise tests (Bruce modified protocol) on 2 separate days, 5 minutes after the end of randomized intravenous infusion of either placebo (saline solution) or bamiphylline (300 mg). Severity of chest pain was assessed by a 100 mm visual analogic scale. There were no significant differences in resting heart rate and blood pressure after bamiphylline or placebo. Rate-pressure product (20 600 +/- 5000 vs 20 200 +/- 5200 bpm.mmHg), time to 1 mm ST depression (549 +/- 196 vs 581 +/- 201 sec), time to angina (519 +/- 209 vs 571 +/- 196 sec), and exercise duration (717 +/- 134 vs 676 +/- 166 sec) were also not significantly different after bamiphylline or placebo, but there was a mild reduction of the severity of exercise-induced chest pain (30 +/- 22 vs 39 +/- 20 mm, p < 0.05) with the active drug. Thus, in patients with syndrome X, bamiphylline does not improve exercise-induced ST changes, suggesting that A1-receptors are not significantly involved in their appearance. In addition, bamiphylline had little effect on anginal pain, suggesting that this cannot be mediated exclusively by A1-receptor stimulation in these patients.
Lanza
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GA
Istituto di Cardiologia, Università Cattolica del Sacro Cuore, Roma.
Gaspardone
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A
Pasceri
V
V
Perino
M
M
Colonna
G
G
Tomai
F
F
Crea
F
F
Gioffrè
P A
PA
Maseri
A
A
D000787:Angina Pectoris / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D004562:Electrocardiography / Q000187:drug effects; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007262:Infusions, Intravenous; D017566:Microvascular Angina / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D008875:Middle Aged; D010147:Pain Measurement; D058915:Purinergic P1 Receptor Antagonists; D013806:Theophylline / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*
D058915:Purinergic P1 Receptor Antagonists; D014665:Vasodilator Agents; D013806:Theophylline; C006683:bamifylline