The electrocardiogram (ECG) is an essential diagnostic test for patients with possible or established myocardial ischemia, injury, or infarction. Abnormalities are manifest in the ST-segment, T wave, and QRS complex.
Keeping this in view, how is ischemia detected on ECG?
T wave inversion may be considered to be evidence of myocardial ischaemia if:
- At least 1 mm deep.
- Present in ≥ 2 continuous leads that have dominant R waves (R/S ratio > 1)
- Dynamic — not present on old ECG or changing over time.
Keeping this in consideration, should I worry about abnormal ECG?
An abnormal ECG can mean many things. Sometimes an ECG abnormality is a normal variation of a heart’s rhythm, which does not affect your health. Other times, an abnormal ECG can signal a medical emergency, such as a myocardial infarction /heart attack or a dangerous arrhythmia.
What ECG changes indicate myocardial injury?
ECG Signs of Myocardial Infarction
ECG changes of infarction include ST elevation (indicating injury), Q waves (indicating necrosis), and T-wave inversion (indicating ischemia and evolution of the infarction). These changes are called the indicative changes of infarction and occur in leads facing the damaged tissue.
What is the difference between ischemia and infarction on ECG?
A zone of ischemia typically produces ST segment depression. A zone of injury produces ST segment elevation. A zone of infarction produces a large Q wave in the QRS complex.