coronary steal phenomenon
Paradoxical reduction in blood flow to ischemic myocardium during vasodilation due to preferential flow to non-ischemic regions.
Full Definition
Coronary steal phenomenon occurs when pharmacological vasodilation paradoxically reduces blood flow to areas of myocardium supplied by stenotic coronary arteries while increasing flow to regions with normal coronary circulation. This mechanism involves differential vasodilatory responses where normal coronary vessels dilate significantly in response to vasodilators like adenosine or dipyridamole, while vessels distal to significant stenoses have limited vasodilatory reserve. The resulting preferential flow redistribution can worsen ischemia in territories supplied by diseased vessels. Coronary steal is the physiological basis for pharmacological stress testing and can occasionally cause clinical symptoms during stress imaging procedures. Understanding this phenomenon is crucial for interpreting stress test results and managing patients during provocative testing.
Usage
Usage note: Use 'phenomenon' in formal writing; 'steal' alone is acceptable in informal clinical contexts.
In Context
- "Coronary steal phenomenon was observed during adenosine stress testing, causing chest pain and ST-depression." — Stress test report
- "The pharmacological stress protocol was terminated early due to symptomatic coronary steal." — Nuclear cardiology procedure note