What are the implications and management of a significant R wave in leads II, III, and AVF (atrioventricular fascicle) on an electrocardiogram (ECG)?

From the Guidelines

A significant R wave in leads II, III, and aVF on an ECG is indicative of inferior wall myocardial hypertrophy or previous inferior wall myocardial infarction, and management should focus on identifying the underlying cause through additional testing and initiating standard post-MI therapy if necessary. The presence of a significant R wave in these leads suggests increased muscle mass or paradoxical depolarization patterns from scarred tissue after infarction in the inferior wall of the heart, which is typically supplied by the right coronary artery 1.

Key Considerations

• The ECG findings should be interpreted in the context of the patient's clinical presentation and medical history, as the ECG alone may not be sufficient to diagnose acute myocardial ischemia or infarction 1.
• Additional testing, including echocardiography, cardiac stress testing, and possibly coronary angiography, may be necessary to determine the underlying cause of the ECG findings and to guide management decisions.
• For patients with evidence of previous myocardial infarction, standard post-MI therapy should be initiated, including aspirin, a beta-blocker, an ACE inhibitor, and a statin, to reduce morbidity and mortality 1.
• If left ventricular hypertrophy is the cause of the ECG findings, treatment should address underlying conditions like hypertension with appropriate antihypertensives targeting a blood pressure below 130/80 mmHg.

Management and Follow-up

• Regular cardiac follow-up every 3-6 months is essential, with repeat ECGs to monitor for changes and to assess the effectiveness of treatment.
• The use of right-sided chest leads, such as V4R, may be helpful in diagnosing right ventricular involvement in the setting of an inferior wall infarction and in making the distinction between RCA and LCx occlusion 1.
• The joint task force of the AHA and the American College of Cardiology recommends that right-sided chest leads be recorded in all patients presenting with ECG evidence of acute inferior wall ischemia/infarction 1.

From the Research

Implications of a Significant R Wave in Leads II, III, and AVF

• A significant R wave in leads II, III, and AVF on an electrocardiogram (ECG) can be an indicator of various cardiac conditions, including myocardial ischemia or infarction 2.
• The increase in R wave amplitude in these leads may be associated with the expansion of the left ventricular cavity during ischemia and/or alterations in conduction that are intrinsic to the myocardium 2.
• However, a significant R wave in these leads is not necessarily a manifestation of clinical disease, as it may be due to a changed position of the electric axis of the heart 3.

Management of a Significant R Wave in Leads II, III, and AVF

• The management of a significant R wave in leads II, III, and AVF depends on the underlying cause of the ECG finding.
• If the ECG finding is associated with symptoms of acute coronary syndrome (ACS), such as chest pain or pressure, further evaluation should be performed, including troponin testing and echocardiography or coronary angiography if necessary 4, 5.
• The diagnosis of ACS is typically made based on a combination of clinical presentation, ECG findings, and troponin levels, with a troponin level greater than the 99th percentile of the upper reference limit being consistent with ACS 4, 6.
• In patients with a significant R wave in leads II, III, and AVF, but without symptoms of ACS, further evaluation may still be necessary to rule out underlying cardiac disease, such as coronary artery disease (CAD) 4, 3.

Diagnostic Evaluation

• The diagnostic evaluation of a significant R wave in leads II, III, and AVF may include:

• ECG: to evaluate for signs of ischemia or infarction, such as ST-segment elevation or depression, or Q waves 2, 3.
• Troponin testing: to evaluate for cardiac damage or injury, with a troponin level greater than the 99th percentile of the upper reference limit being consistent with ACS 4, 6.
• Echocardiography or coronary angiography: to evaluate for underlying cardiac disease, such as CAD or myocardial infarction 4, 5.
• Vectorcardiographic examination and mapping of electric potentials of the heart on the body surface: to provide more detailed and spatial visualization of the electric field of the heart 3.