Suspected donor-vessel ischemia in a collateral-dependent right coronary artery occlusion presenting as a de Winter-like pattern with inferior ST-segment elevation: a case report

The de Winter electrocardiographic pattern is a recognized equivalent of ST-segment elevation myocardial infarction and is most commonly associated with acute left anterior descending artery ischemia. Its coexistence with overt ST-segment elevation in another territory is uncommon and may create uncertainty in culprit-vessel identification. In patients with multivessel coronary disease and collateral-dependent myocardium, acute compromise of a donor coronary circulation may produce simultaneous but apparently discordant ECG manifestations. A 48-year-old man presented with worsening chest pain. The initial ECG showed a de Winter-like anterior morphology, characterized by upsloping J-point ST-segment depression followed by tall, symmetric T waves in leads V2-V4, together with ST-segment elevation in leads III and aVF. Urgent coronary angiography was delayed for approximately 4 h because the patient initially declined the procedure; aspirin, ticagrelor, and heparin were administered during this interval. At angiography, the left coronary circulation retained TIMI grade 3 antegrade flow but contained a critical proximal-to-mid left anterior descending artery lesion and severe distal left circumflex artery stenosis. The mid right coronary artery was completely occluded, with a blunt proximal stump and Rentrop grade 2 left-to-right collateral filling, strongly favoring a pre-existing RCA occlusion with chronic characteristics. Because the right coronary lesion was considered unlikely to be the acute culprit, emergency percutaneous coronary intervention was directed to the left anterior descending and distal left circumflex arteries. Inferior ST-segment elevation decreased markedly but incompletely after left coronary revascularization, with residual elevation most evident in lead III. The right coronary occlusion was successfully treated during a staged procedure 4 days later, after which the residual inferior ST-segment elevation decreased further. De Winter-like anterior morphology and inferior ST-segment elevation may coexist when inferior myocardial perfusion depends on left-to-right collateral flow to a right coronary artery occlusion with features strongly favoring chronicity. This case raises the possibility of a dynamic donor-system ischemia mechanism as an explanation for the apparently discordant ECG findings. De Winter-like anterior morphology should not be disregarded solely because overt ST-segment elevation is present elsewhere. In this setting, the ST-elevation territory may not identify the vessel requiring first-pass reperfusion; ECG morphology should be integrated with angiographic chronicity features and collateral anatomy.