What is the pathophysiology of ST elevation myocardial infarction?
Usually STEMI is characterized by MI induced by de-stabilization of an atherosclerotic plaque that triggers intra-luminal thrombosis leading to reduced blood flow to the myocardium, myocardial ischemia, and cardiomyocyte necrosis. The manifestation of MI may occur repeatedly and also in more than one coronary artery.
Why does infarction cause ST elevation?
ST segment elevation occurs because when the ventricle is at rest and therefore repolarized, the depolarized ischemic region generates electrical currents that are traveling away from the recording electrode; therefore, the baseline voltage prior to the QRS complex is depressed (red line before R wave).
Why is ST segment high 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.
Is ST segment elevation life threatening?
ST-segment elevation is an abnormality detected on the 12-lead ECG. It is a profoundly life-threatening medical emergency and usually associated with a disease process called atherosclerosis (coronary artery disease).
What happens during ST segment?
The ST segment is an interval between ventricular depolarization and ventricular repolarization. It is identified as the end of the QRS complex to the beginning of the T wave. The end of the T wave to the beginning of the P wave is described as the TP segment, which is the zero potential or isoelectric point.
Why does pericarditis cause ST elevation?
The source of this ST elevation is thought to be local inflammatory changes in the epicardium underlying the inflamed pericardium. The current from this area of ST elevation must return to some unaffected region of the heart and this should be associated with a region of ST depression.
What does ST elevation indicate?
ST elevation refers to a finding on an electrocardiogram wherein the trace in the ST segment is abnormally high above the baseline.
Can ST elevation be normal?
As age progresses, the prevalence of elevation of the ST segment declined[8]. Thus, most men have elevation of the ST segment greater than 0.1 mV in the precordial leads. Therefore, elevation of the ST segment should be regarded as a normal finding and is often termed “male pattern”.
What does an ST elevation indicate?
ST-segment elevation myocardial infarction (STEMI) is the term cardiologists use to describe a classic heart attack. It is one type of myocardial infarction in which a part of the heart muscle (myocardium) has died due to the obstruction of blood supply to the area.
What is considered ST elevation?
An ST elevation is considered significant if the vertical distance inside the ECG trace and the baseline at a point 0.04 seconds after the J-point is at least 0.1 mV (usually representing 1 mm or 1 small square) in a limb lead or 0.2 mV (2 mm or 2 small squares) in a precordial lead.