What is an Inferior Wall Myocardial Infarction?

An inferior wall myocardial infarction refers to a type of heart attack that occurs in the lower section of the heart muscle. The heart is anatomically divided into several regions, including the anterior (front), lateral (side), posterior (back), and inferior (bottom) walls. In most cases, approximately 80% of the blood supply to the inferior wall comes from the right coronary artery, while 20–30% is supplied by the left circumflex coronary artery. When an electrocardiogram (ECG) indicates an inferior wall myocardial infarction, there is about an 80% chance that the issue originates in the right coronary artery.

Complications Related to the Right Coronary Artery

Besides supplying blood to the inferior wall of the heart, the right coronary artery also provides blood to critical electrical components of the heart, such as the sinoatrial (SA) node and the atrioventricular (AV) node. If the right coronary artery becomes blocked during an inferior wall myocardial infarction, these nodes may suffer from reduced blood flow, leading to a range of cardiac rhythm disturbances.

Impact on Heart Rhythm

One of the common complications of inferior wall heart attacks is bradycardia, or an abnormally slow heart rate. In more severe cases, patients may develop atrioventricular (AV) conduction block, where the electrical signals between the upper and lower chambers of the heart are impaired. This condition can progress from first-degree AV block to more severe forms, such as second-degree and eventually third-degree AV block, where communication between the atria and ventricles is completely lost.

In some instances, this disruption in heart rhythm can lead to sudden cardiac arrest. In such emergencies, immediate intervention with a temporary pacemaker is often required to stabilize the patient. Fortunately, once blood flow is restored, many patients do not require a permanent pacemaker, as the conduction system often recovers function over time.