Figure 6.
Chronic amiodarone prevents the development of late phase 3 early afterdepolarizations (EADs) and triggers activity in a pulmonary vein (PV) sleeve preparation. A: PV sleeve preparation from untreated dog: acetylcholine (ACh) and high calcium combined markedly shorten action potential (AP) during fast pacing (basic cycle length, BCL = 200 ms) and induce late phase 3 EAD (middle panel) and triggered activity (lower panel) upon return to a BCL of 2,000 ms. B: PV sleeve from chronic amiodarone-treated dog. ACh and high extracellular calcium do not shorten AP at fast rates and fail to induce late phase 3 EAD and triggered activity.