What is the most common cause of inferior wall myocardial infarction?

Inferior wall myocardial infarction is most commonly caused by occlusion of the right coronary artery. This anatomical relationship is primarily due to the supply of blood to the inferior wall of the heart, which is mostly provided by the right coronary artery in the majority of individuals, especially in those with a right-dominant coronary circulation. When the right coronary artery becomes occluded, the blood flow to the inferior wall is compromised, resulting in myocardial ischemia and potential infarction.

Understanding the coronary anatomy is crucial in this context. The right coronary artery supplies the right atrium and right ventricle and, in most people, the inferior portion of the left ventricle via its posterior descending branch. This makes it a key player in inferior wall ischemia.

In contrast, while the circumflex artery can also supply the inferior wall in individuals with a left-dominant coronary system, it is less commonly responsible for inferior wall infarctions compared to the right coronary artery. The left anterior descending artery predominantly supplies the anterior portion of the heart and hence is typically associated with anterior wall infarctions. The left main coronary artery occlusion is a more critical condition that can lead to extensive myocardial damage but does not exclusively cause inferior wall infarctions.