Severe Brady arrhythmia and Hypertension Following Dipyridamole Ingestion

We report an episode of severe bradycardia and hypotension following the administration of 400 mg oral dipyridamole in preparation for thallium-201 imaging in 2 patients. The severe effects in both were reversed with aminophylline infusion. Subsequent cardiac catheterization of 1 patient revealed occlusion of the right artery and 80% stenosis of the left main coronary artery. The response to dipyridamole by both patients suggests that careful monitoring should be performed when evaluating patients with a high pretest suspicion of multivessel coronary artery disease