Cardiac Infarction is injury of the heart muscle caused by a lack of blood supply. Symptoms include chest pain, palpitations, sweating and shortness of breath.
Acute Myocardial Infarction is a term used to describe heart muscle injury due to a lack of blood supply. This is characterised by a rise and fall of cardiac troponin values coupled with at least one of the following: symptoms of myocardial ischaemia; new ischaemic ECG changes; development of pathological Q waves on ECG; imaging evidence of loss of viable myocardium; or coronary thrombus.
At initial assessment of the patient, the information available is most often limited to history, examination and ECG. Therefore recognising abnormal ECG findings is important in the diagnosis and treatment of Acute Myocardial Infarction, as a diagnosis of such is made on the basis of ECG Changes and a rise and fall of cardiac troponin.
Most commonly, changes in the ST Segment are the first abnormality to be detected, and these are followed by changes in T waves, with later development of Q waves in some cases. New left bundle branch block may also indicate Acute Myocardial Infarction. Myocardial Infarction causes a loss of function of heart muscle cells. This can lead to complications including heart failure, heart rhythm abnormalities and rupture of the heart muscle.
In ST elevation Myocardial Infarction rapid treatment, ideally with primary angioplasty to open the coronary artery, leads to a reduction in myocardial damage and improved survival. The sooner this is performed the better the outcome. In acute coronary syndromes generally, early treatment with medical therapy reduces coronary thrombus and myocardial ischaemia. For high risk non-ST segment elevation Myocardial Infarction, in-patient coronary intervention also improves prognosis but is less time-critical than for ST elevation Myocardial Infarction.
Therefore, abnormal ECG findings should be acted on, leading to further investigations, such as baseline tests and referral to the appropriate medical expert, so as to prevent some of the potential long-term consequences of Cardiac Infarction.