Question

A 12-lead ECG is done by the paramedic in the field. What changes would you expect to see if Mr. T. is having an MI? The paramedics note ST-segment elevation in Leads II, III, and aVF. What therapies will be administered in the field? In what area of the heart do changes in these leads indicate damage?

Answer 1

Ans.) The 12 lead ECG is a graphical representation of heart’s activity. ST Segment begins from end of the QRS complex (J point) to the start of the T wave. Elevation of the ST segment may results in complete occlusion of a coronary artery in most patients. This elevation is presumptive evidence for myocardial infarction (MI).

To treat such patients, at first sufficient analgesia with morphine is necessary to alleviate pain. Nitroglycerin should also be given instantaneously, if the patient is not hypotensive, as it reduces myocardial oxygen demand and lessens ischemia, and may rarely abort MI if there is coronary spasm. Emergency revascularization is recommended to some patients.

ST Segment represents a period of diastole for the heart and symbolizes the period from the end of systole to the beginning of repolarization of the ventricles. Thus ventricles of the heart do changes in these leads indicate damage.