Figure 2.

Intracardiac electrograms of com‐F/S‐AVNRT illustrating the unequal response in Patient no 8. (A) The 340‐ms pacing CL (S‐S) is identical during EP from the high right atrium (EP‐HRA) and (B) EP from the proximal coronary sinus (EP‐CS). The 359‐ms HA interval in the first cycle [HA(1)] following EP‐CS is considerably shorter than the 389‐ms HA(1) after EP‐HRA. In contrast, the HA interval in the seecond cycle [HA(2)] after EP‐HRA (313 ms) is nearly identical to the HA(2) after EP‐CS (302 ms). I, II and V₁ = surface electrocardiogram. AVNRT, AVNRT, atrioventricular nodal reentrant tachycardia; HRA, high right atrium; HBE, His bundle electrogram; CS13‐14 to 1‐2 = proximal to distal CS recordings; RVA, right ventricular apex