What Is a Septal Infarct on an ECG?
A septal infarct is damage to the heart’s dividing muscular wall, the septum, often caused by reduced blood flow after a heart attack. An electrocardiogram (ECG) is a common diagnostic tool used to detect such damage by measuring the heart’s electrical activity. Identifying a septal infarct on an ECG is an important step in understanding the extent of heart injury.
Understanding the Heart’s Septum
The heart’s septum is a muscular wall that separates the heart’s left and right sides. This wall ensures that oxygen-rich blood from the left side does not mix with oxygen-poor blood from the right side. The septum is comprised of two main parts: the interatrial septum, separating the upper chambers (atria), and the interventricular septum, dividing the lower chambers (ventricles).
The interventricular septum is particularly thick and plays a significant role in the heart’s pumping action. It contains specialized conducting nerve fibers that help coordinate the muscular contractions of the ventricles. This coordinated contraction is necessary for efficient blood circulation throughout the body. Damage to this structure can therefore affect the heart’s ability to pump blood effectively.
What is a Septal Infarct?
Heart muscle tissue within the septum dies due to a prolonged lack of oxygen supply, a process known as necrosis. This tissue death is a consequence of a heart attack. When blood flow to the septal region becomes severely blocked or restricted, the affected cells are deprived of oxygen and nutrients.
The loss of viable heart muscle tissue in the septum can impair the heart’s overall function. Since the septum contributes to the coordinated contraction of the ventricles, damage here can lead to reduced pumping efficiency. The extent of the impact depends on the size and location of the damaged area within the septum.
ECG Findings in Septal Infarct
When a septal infarct occurs, the damaged heart muscle no longer conducts electrical impulses normally, leading to specific changes on the ECG tracing. These changes help healthcare providers identify the presence of the infarct.
A common finding in septal infarcts is the appearance of pathological Q waves in specific ECG leads. These are observed in leads V1 and V2, and sometimes V3, which are positioned over the chest to view the septal region of the heart. Pathological Q waves indicate that an area of heart muscle has died and is electrically silent. Their presence or abnormal depth and width in V1-V3 are significant indicators of a septal infarct. Acute septal infarctions may also present with ST-segment elevations in leads V1 and V2, reflecting ongoing muscle injury.
Causes, Risk Factors, and Next Steps
The primary cause of a septal infarct is a severe reduction or blockage of blood supply to the septum. This often results from coronary artery disease, where plaque buildup narrows the arteries. A blood clot forming on this plaque can completely obstruct blood flow, leading to a heart attack. The left anterior descending artery and its septal branches are the main vessels supplying blood to the interventricular septum, making blockages in this artery a common cause of septal infarcts.
Several factors increase an individual’s risk of developing a septal infarct:
- High blood pressure
- Elevated cholesterol levels
- Diabetes
- Smoking
- Advanced age
- Family history of heart disease
- Obesity
Upon diagnosis of a septal infarct, immediate medical attention is necessary. Treatment often involves reperfusion strategies, such as percutaneous coronary intervention (PCI), to restore blood flow to the affected area quickly. Medications like antiplatelet therapy, statins, ACE inhibitors, and beta-blockers are prescribed to manage the condition and prevent future cardiac events. Lifestyle modifications, including regular exercise, a heart-healthy diet, and quitting smoking, are also recommended for long-term heart health and recovery.