From the Guidelines
Apical ST depression is a specific electrocardiogram (ECG) finding that may indicate left ventricular hypertrophy (LVH) or myocardial ischemia, and its management should focus on treating the underlying condition rather than the ECG finding itself. This finding is often associated with conditions that cause LVH, such as hypertension, aortic stenosis, or hypertrophic cardiomyopathy, and may be seen as a secondary repolarization abnormality resulting from increased muscle mass 1. The ST depression occurs in the apical leads (typically V5 and V6) of an ECG and is sometimes called the "strain pattern". It's essential to distinguish this finding from ST depression caused by myocardial ischemia, as the treatment approaches differ significantly.
Some key points to consider when evaluating apical ST depression include:
- The ECG is crucial not only for diagnosis but also for prognostic assessment, and patients with ST-segment depression have a higher risk for subsequent cardiac events compared to those with isolated T-wave inversion 1.
- Significant Q waves, consistent with previous myocardial infarction, are highly suggestive of the presence of significant coronary atherosclerosis, but do not necessarily imply current instability 1.
- ST-segment shift and T wave changes are the most reliable electrocardiographic indicators of unstable coronary disease, and ST-segment depression >1 mm in two or more contiguous leads is highly suggestive of unstable angina 1.
- A completely normal ECG in patients presenting with suspicious symptoms does not exclude the possibility of an acute coronary syndrome, and around 5% of patients with normal electrocardiograms who were discharged from the emergency department were ultimately found to have either an acute myocardial infarction or unstable angina 1.
If apical ST depression is found on an ECG, further cardiac evaluation, including echocardiography, may be warranted to confirm LVH and determine its underlying cause. The management typically focuses on treating the underlying condition causing the LVH rather than the ECG finding itself. It is also important to consider alternative causes of ST-segment and T-wave changes, such as pericarditis, pulmonary embolism, or cardiomyopathy, and to establish multilead ST-segment monitoring to detect or rule out ST-segment changes during recurrent episodes of chest pain or in silent ischemia 1.
From the Research
Apical ST Segment Depression
- Apical ST segment depression refers to a specific pattern of ST segment depression observed in the apical leads (typically leads V5 and V6) of an electrocardiogram (ECG) [ 2 ].
- This pattern of ST segment depression is often associated with myocardial ischemia, particularly in patients with significant coronary artery disease [ 3, 4 ].
- However, the localization of coronary artery disease based on exercise-induced ST segment depression, including apical ST segment depression, is not always reliable [ 5 ].
- Studies have shown that ST segment depression in inferior leads, including apical leads, can be a diagnostic sign of coronary artery disease, although it may have a higher false-positive rate [ 2 ].
- Other ECG manifestations of myocardial ischemia, including ST segment elevation, alternans, intraventricular conduction abnormalities, and U-wave inversion, can also be observed in patients with coronary artery disease [ 6 ].