Immediate Medication Management for RSR Pattern in V2
Critical ECG Interpretation
An RSR' pattern in V2 represents incomplete or complete right bundle branch block (RBBB), NOT an acute STEMI pattern requiring immediate reperfusion therapy. 1 However, RBBB can obscure ST-segment analysis and may indicate underlying acute coronary syndrome requiring immediate medical management. 1
Immediate Assessment Required
Before initiating medication, rapidly determine:
- Obtain 12-lead ECG within 10 minutes to assess for ST-segment elevation in other leads, ST-depression, or T-wave changes that indicate ischemia 1
- Check for symptoms: Active chest pain, dyspnea, diaphoresis, or hemodynamic instability 1
- Assess vital signs: Blood pressure, heart rate, oxygen saturation 2
- Draw cardiac troponin immediately (do not delay treatment pending results if high clinical suspicion) 1, 3
Immediate Medication Protocol
If RBBB with Evidence of Acute Ischemia (chest pain + ST changes in other leads):
Antiplatelet Therapy:
- Aspirin 162-325 mg chewed immediately (non-enteric formulation) 1, 3, 4
- Ticagrelor 180 mg loading dose (preferred) or clopidogrel 300-600 mg 3, 4
Anticoagulation:
- Unfractionated heparin: 60-70 units/kg IV bolus (maximum 5,000 units), followed by 12-15 units/kg/hour infusion targeting aPTT 50-70 seconds 3, 4
- Alternative: Enoxaparin (low-molecular-weight heparin) per institutional protocol 3
Anti-ischemic Therapy:
- Metoprolol 25-50 mg orally (or 5 mg IV every 2 minutes up to 15 mg total if hemodynamically stable) targeting heart rate 50-60 bpm 1, 4, 5
- Contraindications: Systolic BP <100 mmHg, heart rate <50 bpm, heart failure, or severe COPD 5
Symptom Relief:
- Morphine 2-4 mg IV titrated for pain relief (use cautiously as may mask symptoms) 1
- Oxygen only if SaO2 <95%, breathlessness, or acute heart failure 1
If RBBB WITHOUT Clear Ischemic Changes:
Still initiate antiplatelet and anticoagulation therapy if:
- Active chest pain with high clinical suspicion for ACS 3, 2
- RBBB patients have 64% increased odds of in-hospital death when presenting with MI 1
- RBBB obscures ST-segment analysis, making ECG less reliable—treat based on clinical presentation 1
Critical Management Pitfalls
- Do NOT withhold reperfusion therapy or aggressive medical management based solely on RBBB pattern—these patients are undertreated and have worse outcomes 1
- RBBB patients receive aspirin, heparin, and beta-blockers at significantly lower rates (32% vs 65.5% fibrinolysis rate compared to non-BBB patients) despite higher mortality 1
- Serial troponin measurements at 3-6 hours are required if initial troponin negative but clinical suspicion remains 3, 2
- Continuous cardiac monitoring is mandatory—RBBB patients are at higher risk for complete heart block and ventricular arrhythmias 1
Disposition and Next Steps
- Immediate cardiology consultation for risk stratification and potential early invasive strategy 3, 4
- Repeat ECG at 15-30 minute intervals during first hour if symptoms persist or recur 1
- Consider right-sided leads (V3R-V4R) if inferior changes present to assess for right ventricular infarction 1, 4
- Admit to monitored bed (CCU or step-down unit) for serial troponins and continuous telemetry 1, 2