Heart Block
A heart block, also known as atrioventricular (AV) block, is a type of arrhythmia. That occurs when the electrical signals that regulate the heartbeat are partially or completely disrupted as they move from the upper chambers (atria) to the lower chambers (ventricles) of the heart. This interruption can cause the heart to beat too slowly (bradycardia), irregularly, or stop entirely for brief periods. This can range in severity from mild and asymptomatic to life-threatening. Furthermore, it requires timely diagnosis and management to prevent complications.
Electrical impulses in the heart originate from the sinoatrial (SA) node and pass through the atria to the atrioventricular (AV) node before travelling to the ventricles. In a heart block, this conduction pathway is impaired. There are three degrees of this:
In first-degree H-B, the heart slows the electrical signals, but they still reach the ventricles. This type is usually benign and often does not cause symptoms.
In second-degree H-B, the heart blocks some signals, causing dropped heartbeats. This may cause symptoms such as dizziness or fatigue.
Third-degree (complete) H-B: No electrical signals reach the ventricles. The atria and ventricles beat independently, which can lead to a dangerously slow heart rate and requires immediate medical intervention.
Heart Block
Heart block can be congenital (present at birth) or acquired due to various factors, including ageing, heart disease, surgical complications, or the use of certain medications. While some mild forms may not require treatment, more advanced cases often necessitate a pacemaker to maintain a safe and regular heart rhythm.
Symptoms depend on the severity of the block and may include fatigue, dizziness, fainting, shortness of breath, or chest pain. Doctors may only discover heart block during routine electrocardiogram (ECG) testing in some individuals.
