What are the implications and management of ST elevation in lead V1 (electrocardiogram lead) post-percutaneous coronary intervention (PCI) to the right coronary artery (RCA)?

ST Elevation in Lead V1 Post-PCI to RCA: Immediate Evaluation for Stent Thrombosis or Coronary Dissection

ST elevation in lead V1 following PCI to the RCA represents a potential acute complication requiring immediate coronary angiography to evaluate for stent thrombosis, coronary dissection, or right ventricular infarction from proximal RCA involvement. 1, 2

Immediate Assessment and Triage

Obtain a 12-lead ECG immediately to characterize the pattern and extent of ST elevation, specifically looking for:

• ST elevation in right-sided chest leads (V3R, V4R) which indicates proximal RCA occlusion with right ventricular involvement 3
• ST elevation pattern in inferior leads (II, III, aVF) with greater elevation in lead III than lead II, confirming RCA territory 3
• ST depression in leads I and aVL, which typically accompanies RCA occlusion 3

Assess for hemodynamic instability immediately, as right ventricular infarction from proximal RCA involvement carries high risk of cardiogenic shock requiring mechanical circulatory support 4. Check for hypotension, elevated jugular venous pressure, and clear lung fields (the classic triad of RV infarction). 4

Differential Diagnosis and Mechanism

The most critical diagnoses to exclude are:

• Acute stent thrombosis - occurs in 2.8-3.6% of STEMI patients post-PCI and can present within hours of the procedure 1. This case from the European Heart Journal demonstrates stent thrombosis occurring 39 hours post-PCI after interruption of dual antiplatelet therapy 1
• Coronary artery dissection - can occur at the stent edge causing acute vessel occlusion, as documented in a case of RCA dissection 2 hours post-stent implantation 2
• Right ventricular infarction - from proximal RCA occlusion affecting RV marginal branches 4

Immediate Management Algorithm

Step 1: Stabilization (First 5-10 Minutes)

• Continue dual antiplatelet therapy - aspirin 162-325 mg (if not already given) and ensure P2Y12 inhibitor loading dose was administered 1
• Avoid nitrates and preload-reducing agents if RV infarction is suspected, as these can precipitate profound hypotension 4
• Administer IV fluids cautiously if hypotension is present with suspected RV involvement 4
• Initiate continuous ECG monitoring for life-threatening arrhythmias including ventricular tachycardia/fibrillation 5

Step 2: Urgent Coronary Angiography (Within 60 Minutes)

Transfer immediately to the catheterization laboratory for repeat angiography - this is a Class I indication for patients with evidence of failed reperfusion or reocclusion post-PCI 1. The 2013 ACC/AHA guidelines specifically recommend immediate angiography for cardiogenic shock or acute severe heart failure irrespective of time delay 1.

Do not wait for biomarker results - the clinical presentation and ECG findings are sufficient to proceed with urgent catheterization 1

Step 3: Interventional Strategy

Based on angiographic findings:

• If stent thrombosis is confirmed: Perform thrombus aspiration, assess for adequate stent expansion, and consider additional stent placement if dissection or geographic miss is identified 1
• If coronary dissection is present: May require additional stenting or use of specialized techniques like the "rescue STAR" technique for distal dissections 2
• Ensure TIMI 3 flow is achieved - anything less than TIMI 3 flow is associated with worse outcomes 6

Step 4: Anticoagulation Management

Continue unfractionated heparin or bivalirudin during the repeat procedure 1. The 2013 ACC/AHA guidelines recommend:

• UFH bolus during PCI with activated clotting time monitoring 1
• Consider GP IIb/IIIa inhibitors (abciximab, eptifibatide, or tirofiban) if high thrombus burden is present, though this increases bleeding risk 1

Step 5: Post-Procedure Monitoring

• Mandatory dual antiplatelet therapy for minimum 1 year with either clopidogrel 75 mg daily, prasugrel 10 mg daily, or ticagrelor 90 mg twice daily 1
• Never interrupt antiplatelet therapy in the first 30 days post-stent placement due to extremely high risk of stent thrombosis 1
• Echocardiography within 24-48 hours to assess for RV dysfunction, LV thrombus formation (1.5% incidence in STEMI patients), and overall ventricular function 7

Critical Pitfalls to Avoid

Do not attribute ST elevation to "normal post-PCI changes" - any new or recurrent ST elevation post-PCI should be considered acute vessel occlusion until proven otherwise 1, 2

Do not discontinue antiplatelet therapy for bleeding concerns without cardiology consultation - the case from the European Heart Journal demonstrates how interruption of DAPT led to fatal stent thrombosis with ventricular tachycardia and third-degree AV block 1

Do not give nitrates empirically - if RV infarction is present, nitrates can cause catastrophic hypotension requiring mechanical circulatory support 4

Do not delay angiography for "conservative management" - the REACT trial showed rescue PCI reduced reinfarction from 10.7% to 6.1% and heart failure from 17.8% to 12.7% compared to conservative therapy 1

Special Considerations for RCA Territory

Left coronary dominance patients (7% of population) have worse outcomes with lower LVEF and higher rates of TIMI ≤2 flow, requiring preparation for no-reflow phenomenon and potential mechanical circulatory support 6

Right ventricular infarction from proximal RCA occlusion may require percutaneous RV assist device if refractory cardiogenic shock develops despite IABP and maximal pressors 4