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Illustration of ST segment elevation and depression The normal ST segment has a slight upward concavity. Flat, downsloping, or depressed ST segments may indicate coronary ischemia. ST elevation may indicate transmural myocardial infarction. An elevation of >1mm and longer than 80 milliseconds following the J-point.
ST segment depression and T-wave changes may be seen in patients with unstable angina; Depressed but upsloping ST segment generally rules out ischemia as a cause. Also, it can be a normal variant or artifacts, such as: Pseudo-ST-depression, which is a wandering baseline due to poor skin contact of the electrode [3]
12-lead electrocardiogram showing ST-segment elevation (orange) in I, aVL and V1–V5 with reciprocal changes (blue) in the inferior leads, indicative of an anterior wall myocardial infarction. When there is a blockage of the coronary artery , there will be lack of oxygen supply to all three layers of cardiac muscle (transmural ischemia).
Plaques in the walls of the coronary arteries can rupture, resulting in occlusion of the artery and deprivation of blood flow and oxygen to the heart muscle, resulting in cardiac cell death. [9] This is known as myocardial infarction. [9] A heart attack can cause arrhythmias, as well as permanent damage to the heart muscle. [25]
Patients with heart tumours usually have non-specific symptoms, such as dyspnea (in particular, shortness of breath when lying down), thoracoabdominal pain (pain in the general area around the heart), fatigue, hemoptysis, nausea and vomiting, fever, weight loss, and night sweats.
Diagnosis is based on an ECG showing ST-segment depression at the J-point of 1 to 3 mm in leads V1 to V6, with tall and symmetrical T waves. [1] The ST-segment is upsloping and there is also often ST-segment elevation of 0.5 to 2 mm in lead aVR. [1] [2] The QRS complex is either normal or slightly wide. [1]
Over time, however, as the heart undergoes ongoing remodeling, it becomes less elliptical and more spherical. Ventricular mass and volume increase, which together adversely affect cardiac function. Eventually, diastolic function, or the heart's ability to relax between contractions may become impaired, further causing decline. [7]
ST segments remains neutral in this syndrome. Those who were treated without angiography will develop anterior wall myocardial infarction in a mean period of 9 days. [4] An episode of chest pain in Wellens' syndrome is associated with ST elevation or depression and later progressed to T wave abnormality after chest pain subsided.