From the Guidelines
The apical four-chamber view on transthoracic echocardiography (TTE) is crucial for assessing left anterior descending (LAD) myocardial infarction by evaluating wall motion abnormalities in the anterior septum and apex, with key measurements including regional wall motion scoring, left ventricular ejection fraction calculation, and assessment of apical thinning or aneurysm formation, as recommended by the American Society of Echocardiography and the European Association of Cardiovascular Imaging 1. To assess LAD myocardial infarction, the following measurements are taken from the TTE apical four-chamber view:
- Regional wall motion scoring of the apical and mid-anterior septal segments (using a 1-4 scale where 1 is normal and 4 is dyskinetic)
- Left ventricular ejection fraction calculation
- Assessment of apical thinning or aneurysm formation
- Tissue Doppler imaging of the septal and apical segments to quantify myocardial velocities
- Strain and strain rate imaging to detect subtle contractility abnormalities
- Mitral regurgitation severity assessment, as it may result from papillary muscle dysfunction These measurements are valuable because LAD occlusion typically affects the anterior interventricular septum and apex, regions well visualized in the apical four-chamber view, allowing for early detection of abnormalities and prompt intervention to determine prognosis following myocardial infarction 1. It is essential to note that the apical four-chamber view provides a comprehensive assessment of the left ventricle, including the anterior septum and apex, which are commonly affected in LAD myocardial infarction, and that the use of TTE is recommended for assessing left atrial size, as it allows for dedicated acquisitions of the left atrium from the apical approach, ensuring optimal LA volume measurements 1.
From the Research
Measurements from the TTE Apical Four Chamber View
To assess LAD myocardial infarction, the following measurements can be taken from the TTE apical four chamber view:
- Left ventricular ejection fraction (LVEF) 2, 3, 4, 5
- Left ventricular end-diastolic and end-systolic volumes 6
- Segmental longitudinal strain (LS) assessment with the use of acoustic marker tracking 6
- Diastolic and systolic volumes 5
Key Findings
- LVEF is a strong predictor of prognosis after acute myocardial infarction 3, 4
- LAD-related infarcts show a lower residual LVEF compared to non-LAD-related infarcts for a similar amount of myocardial necrosis 3
- LS patterns in the apical segments of the left ventricle can differentiate between Takotsubo syndrome and acute coronary syndrome 6
- ACE inhibition has a beneficial effect on left ventricular remodelling in patients with myocardial infarction and left ventricular dysfunction 5