What clinical and electrocardiographic signs are expected after coronary reperfusion (e.g., percutaneous coronary intervention or surgical grafting), and how should they be monitored and managed?

Reperfusion Symptoms and Signs After Coronary Revascularization

Expected Electrocardiographic Changes

After successful coronary reperfusion, ST-segment resolution within hours is the primary expected ECG finding, with 70% of patients showing ST-segment normalization and 60% developing terminal T-wave inversions. 1

Immediate Post-Reperfusion ECG Patterns

• ST-segment normalization occurs in 70% of patients following successful reperfusion of the infarct-related artery 1
• Transient ST-segment elevation increase occurs in 30% of patients during the reperfusion process itself, more commonly with thrombolytic therapy than with primary PCI 1
• Terminal T-wave inversion develops in 60% of patients as an early sign of successful reperfusion 1
• Only 11% of patients show no ST-segment changes after reperfusion, which may indicate unsuccessful reperfusion or poor myocardial perfusion 1

Time Course of ECG Resolution

• Resolution of ST-segment elevations should occur within hours after successful PCI for lateral wall MI 2
• Persistent ST changes may gradually normalize over 12-24 hours following reperfusion 2
• Lack of ST-segment resolution despite angiographically successful PCI indicates poor myocardial perfusion and is associated with worse outcomes, warranting additional evaluation 3, 2

Expected Arrhythmias After Reperfusion

Reperfusion arrhythmias are common, with accelerated idioventricular rhythm occurring in 51% of patients and increased ventricular premature complexes in 42%. 1

Specific Arrhythmia Patterns

• Accelerated idioventricular rhythm occurs in 51% of patients during or immediately after reperfusion 1
• Increased ventricular premature complexes occur in 42% of patients following successful reperfusion 1
• Nonsustained ventricular tachycardia occurs in 7% of patients after reperfusion 1
• Bradycardia develops in 18% of patients during the reperfusion period 1

High-Risk Ventricular Arrhythmias

• Malignant ventricular arrhythmias (VT/VF) occur in approximately 5% of STEMI patients undergoing primary PCI 3
• 60-64% of ventricular arrhythmias occur within the first 24 hours after PCI, with 90-92% occurring within 48 hours 3
• Patients with elevated initial troponin values are more likely to experience malignant reperfusion arrhythmias after primary PCI 3

Monitoring Requirements

All patients receiving reperfusion therapy must undergo uninterrupted ECG monitoring for a minimum of 24 hours, including during intra-hospital transport, due to the risk of malignant reperfusion arrhythmias. 3

Arrhythmia Monitoring Duration

• Minimum 24 hours of continuous monitoring for uncomplicated acute MI after successful reperfusion 3
• Monitoring should continue for 24 hours after complications resolve in patients with ongoing ischemia, heart failure, cardiogenic shock, or arrhythmias requiring intervention 3
• Extended monitoring up to 72 hours is appropriate for patients with complicated courses, comorbidities, or advanced age 3

Ischemia Monitoring Duration

• ST-segment monitoring for ≥12 to 24 hours after reperfusion is reasonable (Class IIb recommendation) 3
• Duration may be shorter or longer depending on how quickly revascularization was achieved, cardiac biomarker levels, and clinical condition 3
• Ischemia monitoring should not be discontinued in patients with recurrent ischemic signs or symptoms 3

Post-Cardiac Surgery Monitoring

• Minimum 48-72 hours of continuous ECG monitoring after uncomplicated coronary artery bypass surgery 3
• Monitoring until hospital discharge for patients at high risk for postoperative atrial fibrillation (advanced age, history of atrial fibrillation, valvular disease, preoperative β-blocker withdrawal) 3
• Atrial fibrillation occurs in 32% after CABG alone, 64% after combined CABG and mitral valve replacement, and 49% after combined CABG and aortic valve replacement 3
• Peak incidence of postoperative atrial fibrillation is on postoperative days 2-4 3

Clinical Signs of Successful vs. Unsuccessful Reperfusion

Persistent or recurrent ST-segment elevations after PCI indicate possible reocclusion or infarct extension and require immediate attention. 3, 2

Indicators of Successful Reperfusion

• Resolution of chest pain or anginal equivalent symptoms within hours of reperfusion 3
• ST-segment normalization on continuous monitoring suggests successful myocardial perfusion 2, 1
• Absence of recurrent ischemic changes for 24 hours indicates low risk 3

Warning Signs of Unsuccessful Reperfusion

• Persistent ST-segment elevations despite angiographically successful PCI indicate poor myocardial perfusion and worse outcomes 3, 2
• Recurrent ST-segment elevations suggest possible reocclusion or infarction extension 3, 2
• Development of acute heart failure or cardiogenic shock requires extended monitoring beyond 24 hours 3

Common Pitfalls to Avoid

• Do not misinterpret persistent ST elevations as normal evolutionary changes when they may indicate incomplete reperfusion requiring immediate intervention 2
• Do not discontinue monitoring prematurely in patients with suboptimal PCI results, as they require at least 24 hours of intensive monitoring 2
• Do not ignore asymptomatic ST-segment shifts in alert patients during the active recovery phase, as they may represent position changes, activity, or axis shifts rather than true ischemia, but warrant clinical correlation 3
• Do not fail to recognize that atrial fibrillation with rapid ventricular response (>150 bpm) may be misdiagnosed as paroxysmal supraventricular tachycardia when R-R interval variability is less noticeable 3
• Do not overlook that 14% of patients develop atrial fibrillation within 2 weeks after hospital discharge, with 69% of episodes being asymptomatic 3

Management Algorithm

Immediate Post-PCI (0-24 hours)

• Initiate continuous ECG monitoring immediately and continue uninterrupted for minimum 24 hours 3
• Compare post-PCI ECG with pre-PCI ECG to assess for resolution of ischemic changes 2
• Monitor for reperfusion arrhythmias (accelerated idioventricular rhythm, increased PVCs, nonsustained VT, bradycardia) 1
• Assess for ST-segment resolution within hours; lack of resolution warrants additional evaluation 3, 2, 1

Extended Monitoring (24-72 hours)

• Continue monitoring for 24 hours after complications resolve in patients with ongoing ischemia, heart failure, shock, or arrhythmias requiring intervention 3
• Extend monitoring to 48-72 hours for complicated courses, comorbidities, or advanced age 3
• Monitor post-CABG patients for minimum 48-72 hours, with particular attention to atrial fibrillation on postoperative days 2-4 3

Reassessment

• Reassess need for monitoring every 24 hours based on clinical and diagnostic findings, response to therapy, and absence of major complications 3
• Reapply ischemia monitoring in previously stable patients who develop recurrent signs or symptoms of ischemia 3