左脚ブロックペーシング患者における心筋梗塞

A pacing rhythm can delay the diagnosis of acute myocardial infarction.

A patient with chest pain and left bundle branch pacing (LBBP) was admitted to the emergency department. His subsequent electrocardiogram did not show dynamic ST-segment changes but a decrease in QRS amplitude in the anterior wall. Emergency angiography showed total occlusion of the proximal left anterior descending artery.

This case highlights that in patients with chest pain and LBBP: 1) dynamic ST-segment changes may be absent even in the setting of total coronary occlusion; 2) dynamic QRS amplitude reduction can be a critical sign of ongoing myocardial ischemia and infarction; and 3) emergency angiography is warranted when angina cannot be relieved despite drug therapy, even if ST-T changes are absent.

In patients with chest pain and LBBP, a dynamic decrease in QRS amplitude should be considered as significant as ST-segment deviation. Emergency coronary angiography is crucial for timely intervention, especially when patients' symptoms persist.