What is the mechanism of ST elevation?
ST elevation on an electrocardiogram is a hallmark of acute transmural ischemia. However, the underlying mechanism remains unclear. We hypothesized that high ischemic sensitivities of epicardial adenosine triphosphate-sensitive potassium (IKATP) and sodium (INa) currents play key roles in the genesis of ST elevation.
What causes elevation of ST segment?
To summarize, non-ischemic causes of ST-segment elevation include left ventricular hypertrophy, pericarditis, ventricular-paced rhythms, hypothermia, hyperkalemia and other electrolyte imbalances, and left ventricular aneurysm.
How long does ST segment remain elevated?
The ST segment elevation associated with an inferior myocardial infarction may take up to two weeks to resolve. ST segment elevation associated with anterior myocardial infarction may persist for even longer, and if a left ventricular aneurysm develops it may persist indefinitely.
What is the pathophysiology of STEMI?
Pathophysiology. STEMI is caused by acute, total occlusion of an epicardial coronary artery, most often due to atherosclerotic plaque rupture/erosion and subsequent thrombus formation.
Why does the ST segment rise in MI?
An acute ST-elevation myocardial infarction occurs due to occlusion of one or more coronary arteries, causing transmural myocardial ischemia which in turn results in myocardial injury or necrosis.
How is ST elevation and depression measured?
The transition from ST segment to T-wave is smooth, and not abrupt. ST segment deviation (elevation, depression) is measured as the height difference (in millimeters) between the J point and the baseline (the PR segment). ST segment deviation occurs in a wide range of conditions, particularly acute myocardial ischemia.
How long can you have ST elevation?
S-T segment elevation was present on admission in 18 of 23 patients (78 per cent) with acute anterior myocardial infarction and persisted in 13 after 1 week and in 9 of 14 (64 percent) during a follow-up period of 1 to 6 months.
What happens during ST segment?
The ST segment reflects the midportion, or phase 2, of repolarization during little change in electrical potential. It is usually isoelectric. Ischemia causes a loss of intracellular potassium, resulting in a current of injury. With subendocardial injury, the ST segment is depressed in the surface leads.
What is ST segment elevation myocardial infarction?
ST-segment elevation myocardial infarction (STEMI) is the most acute manifestation of coronary artery disease and is associated with great morbidity and mortality. A complete thrombotic occlusion developing from an atherosclerotic plaque in an epicardial coronary vessel is the cause of STEMI in the majority of cases.