Anterior myocardial infarction electrocardiograms, or ECGs, may contain convex patterns reminiscent of a row of tombstones, or simply exhibit particular J point, T-wave or ST-segment patterns that may be accompanied by inchoate tombstone forms with lateral and septal aspects, explains Healio. Where the tombstone forms are present, ST elevations reach heights of between 4 millimeters and 6 millimeters.Continue Reading
The ECG changes that accompany acute infarction include inverted T-waves, elevation and depression of the ST segment, variations in the QRS complex, and cresting of the T waves, behavior alternately known as hyperacute T-wave change, reports the American Heart Association. Several factors cause these patterns. For instance, voltage gradients at the boundary separating ischemic and nonischemic sections of the myocardium precipitate ST-segment variations, while changes in the QRS complex come from variations in electrical activation within the infarcted area.
When the ST segment peaks, the change is known as the ST-segment elevation myocardial infarction, or STEMI, notes the American Heart Association. In contrast, ST segment patterns that exhibit ST segment inversion, minimal ST segment elevation, T-wave inversion or unusual ST-segment elevations in less than two adjacent leads are known as non-STEMI, or NSTEMI.
Correct interpretation of these patterns is extremely important as ECGs form the most important first-line tools in the diagnosis of myocardial infarction and ischemia, according to the American Heart Association. Subsequent tests and therapeutic interventions depend on the initial interpretation of these tests.Learn more about Cardiac Health