Acute Myocardial Infarction
The Common Vein Copyright 2008
Myocardial infarction is a circulatory disorder of the heart caused by acute coronary occlusion usually by thrombus or by a ruptured plaque that secondarily accumulates platelet thrombi, and results in necrosis and myocardial injury. It is clinically characterized by presence of symptoms of acute myocardial ischemia (ischemic chest pain or chest pain equivalent as dyspnea, diaphoresis, lightheadedness, palpitations).
The diagnosis is confirmed by characteristic ECG changes and biochemical markers of myocardial necrosis as reflected by typical rise and fall of cardiac enzymes: troponin I or T, CK-MB and is classified as ST elevation (STEMI)or non ST elevation myocardial infarction (NSTEMI) based on the EKG
The pathological diagnosis of myocardial infarction requires evidence of myocyte cell death (i.e. necrosis of the myocardium) as a consequence of prolonged ischemia.(Luepker)
Treatment depends on the type of infarction (STEMI vs NSTEMI, but attempts are usually made to lyse thrombus and open the vessels by angioplasty or stenting in a timely manner in order to salvage myocardium at risk.
CT scan of a 67 year old female with anca vasculitis shows regions of dystrophic calcification in the lateral aspect of the right lower lobe (white arrow, a and b) )with focal nodular parenchymal consolidation, that likely reflects a site of prior small vessel infarct. Dystrophic calcification in the LV myocardium (blue arrows c) and a suggestion of fatty dysplasia in the left ventricular apex red arrow d) suggest changes from small vessel infarct. Ashley Davidoff MD
- Luepker RV, Apple Fs et al: Case definitions for acute coronary disease in epidemiology and clinical research studies. Circulation 108:2543, 2003