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. Author manuscript; available in PMC: 2010 Sep 30.
Published in final edited form as: Circulation. 2007 Nov 12;116(22):2535–2543. doi: 10.1161/CIRCULATIONAHA.107.696583

Figure 5.

Figure 5

Effects of procainamide in class III mutant hearts. vECG and activation maps before (A and C) and after (B and D) treatment with procainamide. In this particular heart, procainamide blocked conduction over the bypass tract, shifting conduction to the AV node pathway. E, From the posterior aspect of a control heart, the atria (RA) and coronary sinus (CS) were clearly visible. F, In the class III mutant heart shown in A through D, a connection (indicated by white arrows) was visible between the coronary sinus region and the ventricle. The remaining 5 class III mutant hearts showed no response to procainamide treatment. G and H, Representative vECGs of a nonresponsive class III mutant before (G) and after (H) a high dose (160 μg/mL) of procainamide. Impulse propagation continued through the accessory conduction pathway. P indicates atrial depolarization; QRS, ventricular depolarization; LV, left ventricle; RV, right ventricle; and A, Apex.