Electrocardiogram # 7
Nine year old boy with prolonged PR interval (First degree atrioventricular AV block)
Prolonged PR interval also known as first degree atrioventricular (AV) block.
This may be a normal variant in children
It is a minor criterion in the diagnosis of Acute Rheumatic fever
First degree atrioventricular block occurs when conduction through the atrioventricular node is slowed. This results in longer time for the electrical activity to travel from the sinoatrial node through the AV node to the ventricles. This is indicated on the electrocardiogram as an increase in the PR interval