From the Guidelines
An anteroseptal infarct of indeterminate age on an ECG is typically characterized by Q waves in leads V1-V4, which are pathological when they exceed 0.04 seconds in duration and/or have a depth greater than 25% of the following R wave amplitude, as indicated in the ESC guidelines for the management of acute myocardial infarction 1. The ECG findings for an anteroseptal infarct may also include persistent ST segment elevation, T wave inversions, or poor R wave progression in leads V1-V4. The term "age indeterminate" signifies that the timing of the infarct cannot be determined from the ECG alone, as the changes have evolved beyond the acute phase but remain as permanent scarring. These findings suggest that the patient has had a myocardial infarction affecting the anteroseptal wall of the left ventricle at some point in the past, caused by occlusion of the left anterior descending coronary artery, as discussed in the context of STEMI diagnosis and management 1. Key considerations for diagnosis and management include:
- Timely ECG interpretation to detect life-threatening arrhythmias and allow prompt defibrillation if indicated
- Awareness of atypical presentations of STEMI, which may delay diagnosis and treatment
- The importance of liberal access to acute angiography for early diagnosis and improved outcomes in high-risk groups
- Further cardiac evaluation with echocardiography and possibly cardiac stress testing to assess functional impact and guide management.
From the Research
ECG Findings for Anteroseptal Infarct
- The ECG definition of anteroseptal myocardial infarction is a Q wave or QS wave > 0.03 second in leads V1 to V3, with or without involvement of lead V4 2
- Q-waves were present in precordial leads V(1)-V(2) in some patients, V(1)-V(3) in others, and V(1)-V(4) in the remaining patients 3
- The ECG pattern traditionally termed anteroseptal AMI should be called an anteroapical AMI; the term anteroseptal AMI should be defined as extensive anterior wall AMI associated with diffuse ST changes involving the anterior, lateral, and occasionally, inferior leads 2
Anatomic Location of Myocardial Injury
- Neither angiographic nor echocardiographic data support the notion of an isolated anteroseptal myocardial infarction 3
- Left anterior descending artery involvement appears more often to be midsegment and postseptal 3
- The apex is always and principally affected in anteroseptal myocardial infarction 3, 2
Clinical Implications
- The term anteroseptal myocardial infarction is a misnomer and the V(1) to V(2)-V(4) Q-wave pattern should be considered to indicate a predominantly apical, and generally limited, myocardial infarction 3
- Aspirin therapy is commonly used in the management of cardiovascular disease, including myocardial infarction, but its use requires careful consideration of benefits and risks 4, 5, 6