In a normal heart, the sinoatrial (SA) node triggers the
electrical impulse, causing the upper chambers (atria) to contract. The signal
travels through the atrioventricular (AV) node to the atrioventricular bundle,
which divides into the Purkinje fibers that carry the signal and cause the
lower chambers (ventricles) to contract. The electrocardiogram (EKG, ECG)
tracing shows this normal electrical
In atrial fibrillation, erratic electrical impulses can cause the upper chambers of the heart (atria) to
fibrillate, or quiver, resulting in an irregular and frequently rapid heart
rate. The irregular, sawtooth pattern in the electrocardiogram (EKG, ECG)
tracing shows these erratic impulses.
For this nonsurgical procedure called catheter ablation, thin tubes called catheters are inserted into a vein, typically in the groin or neck, and threaded through the vein into the heart.
A small puncture in the tissue that divides
the right and left chambers (septum) allows the catheter to pass into the left
An electrode at the tip of the catheter sends out
radiofrequency energy, creating heat that destroys (ablates) the tissue that is
causing atrial fibrillation. In this image, the heat is destroying tissue at
the base of the pulmonary vein. (The pulmonary veins bring blood back from the
lungs to the heart.)
Catheter ablation creates scar tissue that prevents impulses
from leaving the pulmonary veins or eliminates the impulses
December 14, 2012
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & John M. Miller, MD, FACC - Cardiology, Electrophysiology
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