One more question about halothane?

Question

do you know how halothane directly depresses the sinoatrial node of the heart and therefore heart rate/rhythm?

Answer 1

Halothane sensitizes the heart to catecholamines, increasing the chance of arrhythmias.

When we used it, clinically we'd see a LOT of junctional rhythms and extrasystoles.  It was almost unusual to see a normal P wave.

Thank God for sevoflurane!

Answer 2

Halothane alters cell membrane sodium-calcium exchange along with intracellular calcium utilization, thereby altering the action potential.  Slight action potential differences can affect the rate of contraction.