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Safety of intravenous dipyridamole for stress testing with thallium imaging
Insights
Intravenous dipyridamole is safe for nonexercise stress testing, causing few serious cardiac or noncardiac side effects. Careful patient selection and monitoring are essential due to potential ischemia.
Area of Science:
- Cardiology
- Nuclear Cardiology
Background:
- Nonexercise stress thallium imaging is a diagnostic tool.
- Intravenous dipyridamole is used to induce pharmacologic stress.
Purpose of the Study:
- To evaluate the safety and side effects of intravenous dipyridamole in nonexercise stress thallium imaging.
Main Methods:
- 293 patients undergoing nonexercise stress thallium imaging with intravenous dipyridamole were monitored.
- Cardiac and noncardiac side effects were recorded.
- Hemodynamic changes (heart rate, blood pressure) were assessed.
Main Results:
- Minor hemodynamic changes observed: mean heart rate increase of 9 bpm, mean systolic blood pressure decrease of 12 mm Hg.
- Common noncardiac side effects: headache (11%), lightheadedness (5%), nausea (4%).
- Cardiac side effects included chest pain (26%), ST-segment depression (20%), and arrhythmias (19%). No deaths or myocardial infarctions occurred.
Conclusions:
- Intravenous dipyridamole is safe for nonexercise stress testing.
- Potential for ischemia necessitates careful patient selection and monitoring.
- Few serious adverse events were reported, with most managed effectively.
Abstract:
Cardiac and noncardiac side effects were studied in 293 consecutive patients referred for nonexercise stress thallium imaging with intravenous dipyridamole. Six minutes after the initiation of infusion, there was a mean 9-beat/min increase in heart rate and a mean 12-mm Hg decrease in systolic blood pressure. The largest increase in heart rate exceeded 20 beats/min in only 13% of patients and the largest decrease in systolic blood pressure exceeded 20 mm Hg in 31%. Noncardiac side effects were headache (11%), lightheadedness or dizziness (5%) and nausea (4%). Only 9 patients required intravenous aminophylline for relief of noncardiac side effects: severe headache in 7 and nausea in 2. Cardiac side effects included chest pain in 76 patients (26%), of whom 70% were given aminophylline for relief of symptoms. Sixty patients (20%) had ischemic ST-segment depression and 56 (19%) had arrhythmias (ventricular in 50 and atrial in 6). There were no deaths, myocardial infarctions or sustained arrhythmias due to dipyridamole administration. Among 62 patients also undergoing cardiac catheterization, side effects except for arrhythmias were unrelated to the number of vessels with coronary artery disease. Intravenous dipyridamole is safe for nonexercise stress testing and has few serious side effects. However, the possibility of ischemia requires careful selection of patients and monitoring of vital signs and the electrocardiogram during the test.