3 Most Common Indications for a Pacemaker

To start off, it is important to understand some anatomy of the heart. The SA node is impulse generating tissue that begins the electrical pathway for contraction of the heart muscle. The SA node is the hearts natural pacemaker, meaning it is responsible for the normal rhythm of the heart. The AV node is a group of specialized muscle fibers located in the right atrium that receives a signal from the SA node. The AV node then regulates the impulses sent from the SA node and allows the atria and ventricles to contract in a coordinated fashion sending blood throughout the body.


Three conditions indicated for pacemakers:

1) Symptomatic bradycardia.
By definition, bradycardia is slow heart rate, specifically a resting heart rate less than 60 beats per minute.


It is important to note that some people may be bradycardic and not have any symptoms. This can be a normal variant, especially in athletes and young persons. However, if you start to experience dizziness, weakness, fatigue, confusion, shortness of breath or chest pains, you should report these symptoms to your doctor for possible evaluation.

2) Third Degree Heart Block
Permanent Pacemaker implantation is indicated for third-degree heart block. Third- degree heart block is also referred to as complete heart block. It is a disorder of the cardiac conduction system, specifically in the AV node. Or more simply put, electrical impulses are not making their way through the heart tissue to cause proper muscle response.


3) Second degree heart block
Second degree heart block comes in two types, Type I and Type II. Both are described as a disruption in the impulse traveling from the AV node to the ventricles, but not as severe as third degree.


Second degree type II heart block in an asymptomatic patient is an indication for pacemaker implantation because of the possibility of progressing to a complete heart block.
Indications for permanent pacing in second-degree AV block are as follows: Second degree AV block associated with bradycardia, heart failure, neuromuscular diseases or asystole; Type 2 second degree AV block with wide QRS complexes; Asymptomatic Type 1 second degree AV block with the block at the level of the ventricles.


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