Early STEMIs may be preceded by peaked T waves. Other ECG abnormalities relating to complications of acute myocardial infarctions may also be evident, such as atrial or ventricular fibrillation. Imaging
Noninvasive imaging plays an important role in the diagnosis and characterisation of myocardial infarction. Tests such as chest X-rays can be used to explore and exclude alternate causes of a persons symptoms. Echocardiography may assist in modifying clinical suspicion of ongoing myocardial infarction in patients that cant be ruled out or ruled in following initial ECG and Troponin testing. Myocardial perfusion imaging has no role in the acute diagnostic algorithm, however it can confirm a clinical suspicion of Chronic Coronary Syndrome when the patients history, physical examination (including cardiac examination) ECG, and cardiac biomarkers suggest coronary artery disease.Echocardiography, an ultrasound scan of the heart, is able to visualize the heart, its size, shape, and any abnormal motion of the heart walls as they beat that may indicate a myocardial infarction. The flow of blood can be imaged, and contrast dyes may be given to improve image. Other scans using radioactive contrast include SPECT CT-scans using thallium, sestamibi (MIBI scans) or tetrofosmin; or a PET scan using Fludeoxyglucose or rubidium-82. These nuclear medicine scans can visualize the perfusion of heart muscle.
An ECG, which is a recording of the hearts electrical activity, may confirm an ST elevation MI (STEMI), if ST elevation is present. Commonly used blood tests include troponin and less often creatine kinase MB.Treatment of an MI is time-critical. Aspirin is an appropriate immediate treatment for a suspected MI. Nitroglycerin or opioids may be used to help with chest pain; however, they do not improve overall outcomes. Supplemental oxygen is recommended in those with low oxygen levels or shortness of breath. In a STEMI, treatments attempt to restore blood flow to the heart and include percutaneous coronary intervention (PCI), where the arteries are pushed open and may be stented, or thrombolysis, where the blockage is removed using medications. People who have a non-ST elevation myocardial infarction (NSTEMI) are often managed with the blood thinner heparin, with the additional use of PCI in those at high risk. In people with blockages of multiple coronary arteries and diabetes, coronary artery bypass surgery (CABG) may be recommended rather than angioplasty. After an MI, lifestyle modifications, along with long-term treatment with aspirin, beta blockers and statins, are typically recommended.Worldwide, about 15.9 million myocardial infarctions occurred in 2015. More than 3 million people had an ST elevation MI, and more than 4 million had an NSTEMI. STEMIs occur about twice as often in men as women. About one million people have an MI each year in the United States. In the developed world, the risk of death in those who have had an STEMI is about 10%.