What are the expected ECG changes post Percutaneous Coronary Intervention (PCI) for a lateral wall Myocardial Infarction (MI)?

Expected ECG Changes Post-PCI for Lateral Wall MI

After successful percutaneous coronary intervention (PCI) for a lateral wall myocardial infarction (MI), ECG monitoring should be continued for at least 12-24 hours to observe for resolution of ST-segment elevations and possible development of Q waves in the lateral leads (I, aVL, V6). 1

Typical ECG Findings Post-PCI for Lateral Wall MI

• Resolution of ST-segment elevations in the lateral leads (I, aVL, V6) is expected within hours after successful reperfusion 1
• Possible development of Q waves in lateral leads, which may persist even after successful reperfusion 2
• T-wave inversions may develop in the affected leads as part of the evolutionary changes of MI 2
• Possible persistent ST changes that gradually normalize over 12-24 hours 1

Monitoring Recommendations

• Arrhythmia monitoring should be initiated immediately on presentation with MI and continue uninterrupted for ≥12 to 24 hours after reperfusion 1
• Ischemia monitoring may be considered on admission, continuing uninterrupted for ≥12 to 24 hours after reperfusion 1
• The duration of monitoring may be shorter or longer depending on how quickly the patient was revascularized, cardiac biomarker levels, and clinical condition 1

Important Considerations for Lateral Wall MI ECGs

• Lateral wall MIs can sometimes be "electrocardiographically silent" with minimal ST changes 2
• In purely lateral/posterolateral infarcts, only about half of patients show ST elevations, and these may appear in either lateral or inferior leads 2
• Post-PCI ECG changes should be compared with the pre-PCI ECG to assess for resolution of ischemic changes 1

Potential Post-PCI Complications to Monitor

• Ventricular arrhythmias occur in approximately 5% of STEMI patients undergoing PCI, with 60-64% occurring within the first 24 hours 1
• Recurrent ischemia may manifest as recurrent ST-segment elevations, indicating possible reocclusion or infarct extension 1
• Lack of ST-segment resolution despite angiographically successful PCI may indicate poor myocardial perfusion and is associated with worse outcomes 1

Clinical Implications

• Persistent or recurrent ST-segment elevations after PCI warrant immediate attention as they may indicate unsuccessful reperfusion or reocclusion 1
• The absence of ST-segment changes on continuous monitoring after successful PCI has been suggested as a criterion for low risk and potential early hospital discharge 1
• Patients with suboptimal PCI results should be monitored more intensively for at least 24 hours 1

Common Pitfalls in ECG Interpretation Post-PCI

• Failing to recognize that lateral wall MI may not always show classic ST elevations in lateral leads 2
• Misinterpreting persistent ST elevations as normal when they may indicate incomplete reperfusion 1
• Overlooking subtle ST changes in lateral leads that may indicate residual ischemia or extension of infarction 2
• Not considering that post-PCI ECG changes should be interpreted in conjunction with clinical symptoms and cardiac biomarkers 1