Question

Describe the in-depth pathophysiology of a STEMI including all cellular changes.

Answer 1

Pathophysiology of STEMI

ST elevation myocardial infarction refers to the process by which areas of myocardial cells in the heart are permanently destroyed.Unstable angina ,NSTEMI and Acute MI are considered are happening in the same causes but at different intensity and cell infarction level.

MI is usually caused by reduced blood flow in coronary artery due to atherosclerosis and occlusion of an artery be an embolus or thrombus.Other causes of MI include vasospasm of a coronary artery,decrease myocardial oxygen supply (egs. acute blood loss ,anemia or low blood pressure) or from a increased myocardial oxygen demand (eg from tachycardia,thyrotoxicosis)

As the myocardial cells get deprived of oxygen from the above mentioned reasons,it develops the ischemia of the cells then to cellular injury and over time ,the persistent lack of oxygen results in infarction or death of cells where the specific coronary artery is supplied. MI results in the disruption of normal cardiac myocyte membrane integrity. This results in the release of intracellular components into the extracellular space, biological active structural proteins such as cardiac troponins.Based on the main coronary blood vessel behind the STEMI it will cause infarction and cell death of large area of myocardium thus affecting the cardiac output and results in cardiogenic shock and rhythm disturbances and even to cardiac arrest.

Ischemia will be reflected with st depression or t inversion in ECG further proceed to STEMI as infarction happen.The area of involvement make the terms as Anterior STEMI,Posterior STEMI,Inferior STEMI etc.