Question

of the types of damage resulting from a myocardial infarction, which is most likely to cause the greatest increase in the q - t interval?

multiple choice

infarction in the av node

left bundle branch block

infarction affecting the sa node

tachycardia

ectopic focus

Explanation:

The Q - T interval represents the time from the start of ventricular depolarization to the end of ventricular repolarization. Left bundle branch block can significantly prolong the Q - T interval as it delays the electrical conduction in the left ventricle, affecting the overall time of ventricular electrical activity. Infarction in the AV node mainly affects the conduction between atria and ventricles, not as directly related to Q - T interval prolongation. Infarction of the SA node affects the heart's pace - making function rather than Q - T interval. Tachycardia shortens the Q - T interval. Ectopic focus is related to abnormal heart rhythms rather than Q - T interval increase.

Answer:

Left bundle branch block