From the Guidelines
Right-sided heart involvement in a myocardial infarction (MI) is primarily detected on a 12-lead ECG through ST-segment elevation in the right precordial leads, particularly lead V4R, with a sensitivity and specificity of approximately 90% for right ventricular infarction, as indicated by ST elevation ≥1 mm in lead V4R 1.
Key ECG Changes
- ST elevation in leads II, III, and aVF, with ST elevation in lead III greater than lead II, indicating inferior wall MI that commonly accompanies right ventricular involvement
- ST depression in leads I and aVL
- Right bundle branch block
- Atrial arrhythmias such as atrial fibrillation
Importance of Right-Sided ECG Leads
The European Society of Cardiology guidelines recommend recording right precordial leads (V3R and V4R) in patients with inferior MI to identify concomitant right ventricular infarction 1. This is crucial because right ventricular infarction requires specific management considerations, including careful fluid administration, avoidance of preload-reducing medications, and maintenance of adequate right ventricular filling pressures to prevent hemodynamic compromise.
Clinical Context
Recognizing these ECG patterns is essential in the clinical context, as right ventricular infarction can lead to significant morbidity and mortality if not managed properly. The American College of Cardiology/American Heart Association guidelines recommend obtaining right-sided ECG leads in patients with inferior STEMI to screen for ST elevation suggestive of right ventricular infarction 1.
Management Considerations
The management of right ventricular infarction involves careful consideration of fluid administration, avoidance of preload-reducing medications, and maintenance of adequate right ventricular filling pressures to prevent hemodynamic compromise, as recommended by the European Society of Cardiology guidelines 1.
From the Research
ECG Changes Indicative of Right-Sided Heart Involvement in MI
The 12-lead electrocardiogram (ECG) is a crucial diagnostic tool for detecting myocardial infarction (MI), including right-sided heart involvement. Several studies have investigated the ECG changes that indicate right ventricular infarction.
- ST-segment elevation in right precordial leads is a reliable indicator of right ventricular infarction 2
- The presence of ST-segment elevation in lead III > lead II and ST-segment depression in lead I > lead aVL can indicate right coronary artery (RCA) involvement and right ventricular MI (RVMI) 3
- The finding of ST elevation in V1 but no ST elevation in V2 on admission ECG can also indicate RVMI 3
- Continuous ST-segment monitoring with 12-lead ECG can aid in the early detection of ongoing right ventricular ischemia and improve risk stratification in patients with chest pain and ECG nondiagnostic of acute MI 4
Diagnostic Criteria for Right Ventricular Infarction
The diagnostic criteria for right ventricular infarction include:
- ST-segment elevation in right precordial leads
- ST-segment elevation in lead III > lead II
- ST-segment depression in lead I > lead aVL
- ST elevation in V1 but no ST elevation in V2
- Presence of Q waves in lead III > lead II
These criteria can aid in the prompt institution of appropriate treatment and improve outcomes for patients with right ventricular infarction 2, 3