What causes the reduction of heart rate after GP ablation during AF ablation?

The reduction of heart rate following GP (ganglionated plexus) ablation during atrial fibrillation (AF) is primarily attributed to enhanced vagal tone. The vagus nerve plays a significant role in autonomic control of the heart, and when vagal tone is increased, it leads to a decrease in heart rate.

During GP ablation, the procedure targets specific nerve clusters that modulate heart rhythm and influence the autonomic nervous system. By inhibiting the sympathetic outflow and enhancing the parasympathetic (vagal) influences on the heart, the overall effect is a lowered heart rate.

This enhanced vagal tone counteracts the effects of sympathetic stimulation, which typically increases heart rate, allowing the heart to slow down, particularly after the chaotic electrical activity of atrial fibrillation has been disrupted by the ablation. The relationship between vagal stimulation and heart rate is well established, as increased vagal activity results in reduced conduction velocity through the AV node and a slower heart rate.