From the Guidelines
A posterior EKG is a specialized electrocardiogram that utilizes additional leads V7, V8, and V9 on the patient's back to detect posterior wall myocardial infarctions, which can be missed on a standard 12-lead EKG, as indicated by the 2012 European Heart Journal guidelines 1.
Key Points
- The posterior EKG involves positioning leads V7, V8, and V9 on the patient's back at the same horizontal level as V6 to better visualize the posterior wall of the heart.
- Posterior MIs typically appear as ST depression in leads V1-V3 on a standard EKG, which can be misinterpreted as ischemia rather than infarction.
- The use of additional posterior chest wall leads [V7 –V9 ≥0.05 mV (≥0.1 mV in men, 40 years old)] is recommended to detect ST elevation consistent with infero-basal myocardial infarction, as stated in the 2012 European Heart Journal guidelines 1.
- Early detection of posterior wall infarctions through posterior EKG leads can significantly impact treatment decisions and patient outcomes by ensuring appropriate reperfusion therapy is initiated promptly.
Clinical Application
- When performing a posterior EKG, healthcare providers should place V7 at the posterior axillary line, V8 at the mid-scapular line, and V9 at the paraspinal area.
- This additional view is particularly important when evaluating patients with suspected circumflex artery occlusion or when standard EKG shows ST depression in V1-V3 with clinical symptoms suggesting acute coronary syndrome, as noted in the 2014 Circulation guidelines 1.
- The posterior EKG can help identify patients who require prompt reperfusion therapy, which can improve morbidity, mortality, and quality of life outcomes.
From the Research
Definition of Posterior Electrocardiogram (EKG)
A posterior electrocardiogram (EKG) refers to the use of additional leads, specifically V7, V8, and V9, to detect ischemia or infarction in the posterior wall of the left ventricle 2, 3, 4. These leads are used in conjunction with the standard 12-lead EKG to provide a more comprehensive view of the heart's electrical activity.
Importance of Posterior EKG Leads
The posterior EKG leads are important for detecting acute posterior myocardial infarction, which can be missed on a standard 12-lead EKG 3, 4. Studies have shown that the use of posterior leads can increase the detection of posterior wall ischemia and infarction, and can help identify patients who may benefit from reperfusion therapy 2, 4.
Key Findings
- The use of posterior EKG leads can detect ST elevation in patients with acute posterior myocardial infarction, even when the standard 12-lead EKG is non-diagnostic 3, 4.
- The posterior leads can provide important information about the extent of ischemia or infarction in the posterior wall of the left ventricle 2, 5.
- Synthesized posterior EKG leads can be used to rapidly diagnose acute myocardial infarction, including posterior and right ventricular involvement 6.
Clinical Significance
The use of posterior EKG leads has important clinical implications, including:
- Early detection of acute posterior myocardial infarction, which can improve patient outcomes 2, 3.
- Identification of patients who may benefit from reperfusion therapy, such as thrombolysis or percutaneous coronary intervention 2, 4.
- Improved diagnosis and management of patients with acute chest pain, including those with posterior or right ventricular acute myocardial infarction 6.