Asystole during dipyridamole infusion in patients without coronary artery disease or beta-blocker therapy

Oral Dipyridamole-Associated Circulatory Collapse

Extended-release dipyridamole plus aspirin is widely used for secondary prevention of ischemic stroke, although the molecular pharmacodynamics of dipyridamole are not completely determined. Adverse effects of fixed-dose combination of aspirin and dipyridamole include headache, bleeding, and gastrointestinal events. Previously, intravenous infusion of dipyridamole in cardiac stress testing has been associated with cardiogenic shock and pulmonary edema. Herein, we report a case study of a 72-year-old man, presented with a transient ischemic attack who suffered a circulatory collapse after an oral dose of 200 mg extended-release dipyridamole. The possible molecular mechanisms of dipyridamole on the cardiovascular system are reviewed. This is the first case report of a circulatory collapse induced by an oral intake of dipyridamole.

Surviving a stressful MIBI scan

Dipyridamole/technetium sestamibi scans (more commonly known as MIBI scans, an acronym for methoxyisobutyl isonitrile) are used commonly for the diagnosis and risk stratification of coronary artery disease. Adverse events from MIBI scans are extremely rare. We present the case of a 64-year-old man who was successfully resuscitated after two asystolic episodes following dipyridamole infusion for a MIBI scan. The second asystolic episode occurred in the emergency department 40 minutes after the patient had been transferred from the Cardiac Stress Test Laboratory. To our knowledge, there are no previous reports of patients having two discrete asystolic episodes or an asystolic episode as delayed as we report after a MIBI scan. Our case illustrates why emergency physicians should be aware of the potential for asystole following MIBI scanning and why aminophylline, the antidote for dipyridamole, should be readily available in emergency departments that could see patients after pharmacologic stress testing. Patients who become asystolic following dipyridamole infusion likely require prolonged cardiac monitoring, given the potential for further episodes after periods of hemodynamic stability.

Reversible severe lower limb pain during a dipyridamole sestamibi myocardial perfusion study: a case report

A 68-year-old woman reported acute severe pain in both lower limbs during a dipyridamole sestamibi myocardial perfusion scan. The pain was rapidly relieved by the administration of intravenous aminophylline. A review of the literature on the adverse effects of dipyridamole did not include this symptom.