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Possible role of coronary spasm in acute myocardial infarction precipitated by hyperventilation
Insights
Hyperventilation triggered acute myocardial infarction in a man with nearly normal coronary arteries. Acetylcholine testing revealed significant coronary artery spasm, suggesting underlying endothelial dysfunction.
Area of Science:
- Cardiology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Acute myocardial infarction (AMI) can occur in patients with seemingly normal coronary arteries.
- Endothelial dysfunction plays a critical role in the pathophysiology of coronary artery disease.
- Hyperventilation is a potential trigger for ischemic events.
Observation:
- A 65-year-old male presented with AMI precipitated by hyperventilation.
- Coronary arteriography demonstrated near-normal coronary arteries.
- Intracoronary acetylcholine administration induced significant spasm in the circumflex artery.
Findings:
- The acetylcholine-induced spasm was associated with typical chest pain and electrocardiographic changes (ST-segment elevation/depression).
- This suggests the presence of significant coronary artery spasm despite a normal angiographic appearance.
- The findings point towards possible underlying atherosclerosis with absent or dysfunctional endothelium.
Implications:
- Coronary artery spasm can cause myocardial infarction even with minimal angiographic disease.
- Endothelial dysfunction may be a key factor in such cases.
- Acetylcholine provocation testing is valuable for diagnosing coronary artery spasm in select patients.
Abstract:
Acute myocardial infarction was precipitated by hyperventilation in a 65 year old man. His coronary arteriogram in the chronic phase showed almost normal coronary arteries. Injection of acetylcholine (50 micrograms) into the left coronary artery induced spasm of the circumflex artery with chest pain in association with ST-segment elevation in the inferior leads and ST-segment depression in the precordial leads. In this patient there may have been atherosclerosis of the coronary arteries with absent or dysfunctional endothelium, despite an almost normal angiographic appearance. In the absence of endothelium the response of the smooth muscle to acetylcholine is constriction.