Question

Following a myocardial infarction (MI), patients can develop atrioventricular (AV) block, especially with an MI in which location?

A) Right ventricle
B) Left atrium
C) Left ventricle
D) Inferior wall of the heart
E) Mitral valve

Answer 1

A myocardial infarction in the inferior wall of the heart can disrupt the blood supply to the AV node and lead to an atrioventricular (AV) block due to its anatomical location and blood supply.

Step-by-step explanation:

Patients can develop atrioventricular (AV) block following a myocardial infarction (MI), especially when the MI occurs in the inferior wall of the heart. The inferior part of the heart is usually supplied by the right coronary artery, which may also supply the AV node, particularly in individuals with right-dominant circulation. When an MI affects the inferior wall, it can impair the blood supply to the AV node, possibly leading to an AV block. This blockage can disrupt the electrical signals that normally travel from the atria to the ventricles, potentially causing various degrees of heart block.

Basic cardiac anatomy includes the atrioventricular valves, specifically the tricuspid valve on the right and the mitral or bicuspid valve on the left, separating the corresponding atrium and ventricle. Since the AV node is located in the inferior portion of the right atrium within the atrioventricular septum, problems with blood supply due to an inferior myocardial infarction can more likely cause disturbances in AV conduction.

Answer 2

Patients are more likely to develop AV block following an MI in the inferior wall of the heart, as this is where the AV node receives its blood supply and can get affected.

The correct answer is options D.

Step-by-step explanation:

Following a myocardial infarction (MI), patients can develop atrioventricular (AV) block, especially with an MI in the inferior wall of the heart. The AV node is situated in the inferior portion of the right atrium within the atrioventricular septum. The blood supply to the AV node is often from the right coronary artery. If this area is affected during an MI, it's most likely due to a blockage in the right coronary artery, which can lead to an inferior wall MI and potentially disturb the functionality of the AV node, resulting in various degrees of AV block.