From the Guidelines
Right-sided and posterior 12-lead ECGs should be obtained when specific clinical scenarios suggest the possibility of right ventricular or posterior wall myocardial infarction, as recommended by the 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes 1.
Clinical Scenarios for Right-Sided ECGs
- Obtain right-sided ECGs when there is ST elevation in leads II, III, and aVF (inferior MI), especially when ST elevation in lead III is greater than in lead II, or when a patient with inferior MI presents with hypotension, elevated jugular venous pressure, or clear lungs.
- This is performed by placing the precordial leads (V1-V6) on the right side of the chest in mirror image positions, labeled as V1R-V6R.
Clinical Scenarios for Posterior ECGs
- Obtain posterior ECGs when there is ST depression in leads V1-V3, especially with tall R waves and upright T waves in these leads, or when there is inferior or lateral wall MI.
- Posterior leads are placed at the level of V4-V6 but on the patient's back (V7 at the posterior axillary line, V8 at the scapular line, and V9 at the paraspinal area).
Importance of Specialized ECGs
- These specialized ECGs are crucial because standard 12-lead ECGs may miss right ventricular and posterior wall infarctions, which have important treatment implications, particularly regarding fluid management in right ventricular infarction and the potential need for more aggressive reperfusion strategies, as noted in the ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction 1.
- The use of additional posterior precordial leads can be recommended in settings in which treatment will depend on documentation of ST elevation during infarction or other acute coronary syndrome, as stated in the recommendations for the standardization and interpretation of the electrocardiogram 1.
From the Research
Indications for Right-Sided and Posterior 12-Lead Electrocardiogram
The decision to obtain a right-sided 12-lead electrocardiogram (ECG) or a posterior 12-lead ECG is guided by specific clinical scenarios:
- Patients with suspected acute inferior wall myocardial infarction (IWMI) may benefit from additional leads to detect right ventricular or posterior wall involvement 2, 3.
- The presence of chest pain suggestive of a cardiac origin, particularly when the standard 12-lead ECG is non-diagnostic, may warrant the use of additional leads to improve detection of ischemia or infarction 4, 5.
- The use of right-sided precordial leads (V4R, V5R) and posterior leads (V8, V9) can help identify right ventricular and posterior wall infarctions, which may not be evident on a standard 12-lead ECG 2, 5, 6.
Clinical Scenarios
Some specific clinical scenarios where a right-sided or posterior 12-lead ECG may be indicated include:
- Acute chest pain with suspected posterior or right ventricular myocardial infarction 5, 6.
- Inferior wall myocardial infarction with possible right ventricular or posterior wall involvement 2, 3.
- Patients with low-risk chest pain who require further evaluation to rule out acute coronary syndromes 4.
Diagnostic Utility
The addition of right-sided and posterior leads to the standard 12-lead ECG can provide valuable diagnostic information, including: