What is the Difference Between Sinus Arrest and Sinus Block?

Sinus arrest and sinus block are two conditions related to the dysfunction of the sinoatrial (SA) node, which is responsible for generating electrical impulses in the heart. They are characterized by the following differences:

Sinus Arrest:

• Occurs when the SA node ceases to generate electrical impulses for more than two P-P intervals.
• Results in a pause in the electrical activity of the heart.
• Caused by various pathological conditions that stop the generation of impulses by the SA node.
• In an EKG, the R-R interval measurement is greater than plus or minus 2 small boxes.

Sinus Block:

• Occurs when the transmission of impulses from the SA node to the atria is blocked.
• Does not result in a complete pause in the electrical activity of the heart, but rather a defect in the transmission of impulses.
• Caused by defects in the transmission of impulses generated by the SA node.
• In an EKG, the R-R interval measurement is within plus or minus 2 small boxes.

Both sinus arrest and sinus block can lead to an abnormal cardiac rhythm, and they may be accompanied by symptoms such as bradycardia, fatigue, and faintness.

Comparative Table: Sinus Arrest vs Sinus Block

Here is a table comparing the differences between sinus arrest and sinus block:

Both sinus arrest and sinus block are characterized by a sudden pause in the sinus rhythm, but the main difference lies in the pathology: sinus arrest is due to the cessation of the firing of the SA node, while sinus block is due to the blockage of the electrical impulses.