Right-Sided ECG Lead Placement for Right Ventricular Myocardial Infarction
Place leads V3R and V4R on the right anterior chest wall in mirror-image positions to the standard left precordial leads, with V4R positioned at the 5th intercostal space at the right midclavicular line—this is the most critical lead for detecting right ventricular infarction. 1, 2
Specific Lead Positioning
V4R (Most Important):
- Position at the 5th intercostal space at the right midclavicular line 2
- This is the single most valuable right-sided lead for diagnosing right ventricular involvement 1
V3R:
- Position between V2R and V4R on the right anterior chest 2
- Provides additional diagnostic information but V4R remains the priority 1
Additional Right-Sided Leads (Optional):
- V1R and V2R: Note that standard V1 is equivalent to V2R, and standard V2 is equivalent to V1R 1
- V5R and V6R: Can complete the right-sided array if comprehensive assessment is needed 2
Critical Timing Consideration
Record V3R and V4R immediately—within minutes of patient presentation—because ST elevation in right-sided leads disappears much faster than ST elevation in inferior leads. 1, 2 This is the most common pitfall leading to missed diagnoses of right ventricular infarction. The window of opportunity may be only hours, whereas inferior ST elevation persists for days. 1
When to Obtain Right-Sided Leads
Obtain right-sided leads V3R and V4R in ALL patients with ST elevation >0.1 mV in leads II, III, and aVF (inferior MI pattern). 1, 2 This is a joint recommendation from the American Heart Association and American College of Cardiology. 1, 2
The rationale is straightforward:
- Proximal right coronary artery occlusion causes both inferior and right ventricular infarction 1, 3
- Right ventricular involvement has major therapeutic implications (avoid nitrates and diuretics, give IV fluids) 2
- V4R distinguishes proximal vs. distal RCA occlusion and RCA vs. left circumflex occlusion 1, 2
Diagnostic Criteria
ST elevation ≥0.1 mV (1 mm) in V3R or V4R indicates right ventricular infarction with moderate sensitivity and high specificity. 2 This finding often appears in conjunction with ST elevation in V1 as well. 1
Practical Implementation
Modern ECG machines should be programmed to automatically suggest recording V3R and V4R when inferior ST elevation is detected, and should have labeling mechanisms for these leads. 1, 2 If your machine lacks this feature, manually place the electrodes and clearly label the tracings as V3R and V4R to avoid confusion.
Clinical Impact on Management
The presence of right ventricular infarction (detected by V4R) fundamentally changes management:
- Identifies patients at higher risk for in-hospital complications 1
- Guides fluid resuscitation strategies (these patients are preload-dependent) 2
- Helps predict underlying coronary anatomy and extent of myocardial damage 1, 4
Common Pitfalls to Avoid
Do not rely solely on V1 for right ventricular assessment—while V1 may show ST elevation in right ventricular infarction, it lacks the sensitivity and specificity of V4R. 1, 2, 5
Do not delay obtaining right-sided leads—the diagnostic window closes rapidly, often within hours of symptom onset. 1, 2
Do not skip right-sided leads in inferior MI—even if the patient appears stable, right ventricular involvement has prognostic significance and alters treatment algorithms. 1, 2