Question

During acute myocardial infarction which of the following changes occurs in the ECG?
(a) Flattened T wave
(b) Depressed ST segment
(c) Elevated ST segment
(d) Increased length of the PR interval

Answer 1

Hint: An electrocardiogram ECG is a graphical representation of the electrical activity that occurs during a cardiac cycle in the heart and is measured by a machine known as an electrocardiograph. An ECG is similar for different individuals so any change from the general graph would mean that the person is suffering from some sort of cardiac abnormality.

Complete Step by Step Answer:
Myocardial infarction is the medical term used to refer to a heart attack. A heart attack is defined as the blockage of coronary arteries that supply blood to the muscles of the heart. This may lead to the death of the muscles of the heart due to an inadequate supply of oxygen and nutrients. During such a condition when the heart is under stress, there is a change in the electrocardiogram. We see an elevation in the ST segment of ECG because of the improper functioning of the heart.

So, the correct option is ‘Elevated ST segment’.

Additional information: Let us study in detail all the segments of an ECG.
P segment: It represents the depolarization of atria which results in their contraction.
QRS segment: It represents the depolarization of ventricles which results in their contraction as well.
T segment: It represents the repolarization of ventricles by which they return back to normal.
- As elevated ST is a characteristic feature of acute myocardial infarction, it is also known as ST elevated myocardial infarction (STEMI).
- ST is a phase marked by the ending of S and the beginning of the T wave.
- We can figure out the heart rate of an individual by counting the number of QRS complexes for a given time period.

Note:
- Acute chest pain when enough oxygen is not reaching the muscles of the heart is known as angina pectoris.
- Heart failure is when the heart is not pumping enough blood to meet the needs of the body and one of the first symptoms is congestions of the lungs.
- Heart failure should not be confused with cardiac arrest when the heart stops beating or heart attack when the heart muscle is damaged by the inadequate blood supply.