Intracoronary ECG May Reveal Dynamic Changes in Tissue-Level Reperfusion During Primary PCI

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  Visual Summary. IC-ECG During Sequential Steps of Primary PCI Demonstrating Dynamic ST-Segment Changes Despite Angiographically Successful Reperfusion (Top Row) Sustained ST-segment resolution may reflect stable tissue-level reperfusion, whereas (Bottom Row) re-emergence of ST-segment elevation after stent deployment may indicate evolving microvascular injury or distal embolization, findings that correspond to differences in infarct characteristics on cardiac magnetic resonance. IC-ECG = intracoronary electrocardiogram; PCI = percutaneous coronary intervention.

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  Figure 1. Dynamic Changes in IC-ECG During Individual Steps of Primary PCI Two patients (Top and Bottom Rows) with anterior myocardial infarction due to proximal left anterior descending artery occlusion (A and G). Although postintervention TIMI flow grade 3 flow was achieved in both cases (B and H), the patient in the top row shows baseline ST-segment elevation (C), a limited reduction after balloon dilatation (D), and re-emergence of ST-segment elevation after stent implantation on intracoronary ECG (E). In contrast, the patient in the botton row demonstrates sustained ST-segment resolution on IC-ECG throughout the intervention (I to K). Corresponding CMR late gadolinium enhancement short-axis images reveal a larger infarct size with severe microvascular obstruction in the patient at the top (F), with limited infarct in the patient at the bottom (L). CMR = cardiac magnetic resonance; ECG = electrocardiogram; IC = intracoronary; PCI = percutaneous coronary intervention.