An electrocardiogram (ECG) is a routine and painless test that records the heart’s electrical activity. When an ECG indicates a “septal infarct,” it points to specific damage within a particular area of the heart. This article aims to clarify what a septal infarct means and how it is identified through an ECG.
Understanding the Heart’s Septum and Infarction
The heart is a powerful muscle divided into four chambers, with a crucial muscular wall separating the two lower chambers, the ventricles. This wall is called the interventricular septum. It plays a significant role in the heart’s pumping function by ensuring blood flows in the correct direction and contributes to the structural integrity of the heart. The septum also contains parts of the heart’s electrical conduction system, which coordinates muscle contractions.
The term “infarction” refers to tissue death that occurs due to a sudden lack of blood supply. This typically happens when an artery supplying blood to a particular tissue becomes blocked. In the context of the heart, this event is commonly known as a heart attack or myocardial infarction. A septal infarct, therefore, means that a section of this dividing wall of the heart has experienced tissue death.
How ECG Detects Heart Damage
An ECG works by measuring the electrical signals generated by the heart as it beats. Electrodes are placed on the skin to pick up these electrical impulses. These signals are then translated into wave patterns, providing a visual representation of the heart’s electrical activity.
Healthy heart muscle produces predictable electrical patterns. However, when heart tissue is damaged, such as during an infarct, it either produces no electrical activity or abnormal signals. These changes create distinct alterations in the ECG tracing, allowing medical professionals to identify damage, its location, and whether it is a recent or older event.
Identifying a Septal Infarct on ECG
A septal infarct is often identified on an ECG by specific changes in the electrical patterns, particularly the presence of what are known as pathological Q waves. A Q wave is a downward deflection that occurs early in the QRS complex, which represents the electrical activity associated with ventricular contraction. While small Q waves can be a normal finding in some ECG leads, pathological Q waves are typically wider and deeper, indicating that the heart muscle in that area has died and is electrically silent.
For a septal infarct, these pathological Q waves are most often seen in specific ECG leads, particularly V1, V2, and sometimes V3 and V4. These leads are positioned on the chest and monitor the septal and anterior regions of the heart. The appearance of these characteristic Q waves in these specific leads suggests that the septal heart muscle has undergone tissue death, usually due to a past blockage in its blood supply.
Causes and Clinical Importance
The primary cause of a septal infarct is a blockage in one of the coronary arteries supplying the septum. This blockage often occurs in the left anterior descending (LAD) artery, or its septal branches. This frequently stems from coronary artery disease, where fatty deposits (plaque) build up, narrowing and hardening the arteries.
A septal infarct signifies a past myocardial infarction (heart attack) in this heart area. This finding can indicate reduced heart function, an increased risk for future cardiac events, or potential heart rhythm abnormalities. It requires careful evaluation and ongoing medical management to improve health outcomes.