Fig. 5.

Functional conduction block (induced by flecainide) in the murine left atrium. A Characteristic activation spread across the left atrium under control conditions, taking approximately 15 ms to traverse the whole tissue when paced at 100 ms CL. B Disrupted activation wave propagation across the same left atrium following 15 min of 1 μM flecainide infusion. A clearly defined region of functional conduction block develops and is outlined in black. An alternative route of conduction (black arrow) is required and this causes a substantial increase in activation time (25 ms). Both images acquired at 1 kHz sampling.