Activation pattern within Koch's triangle during sinus rhythm in patients with and without atrioventricular nodal reentrant tachycardia

BackgroundSeveral studies have visualized the slow pathway during sinus rhythm using high-density mapping of Koch's triangle (KT) in patients with atrioventricular nodal reentrant tachycardia (AVNRT). However, it is unclear whether the slow pathway can be visualized in all people. Therefore, we evaluated the activation pattern within KT during sinus rhythm in patients with and without AVNRT.MethodsHigh-density mapping using the Advisor HD Grid mapping catheter (Abbott) within KT during sinus rhythm was created in 10 patients with slow-fast AVNRT and 30 patients without AVNRT.ResultsIn 8 (80%) patients with AVNRT, the activation pattern pivoting around a block line (BL) within KT was observed. In 12 (40%) patients without AVNRT, similar activation pattern pivoting around BL was observed, but jump was observed in 11 (92%) of these patients. In all patients, the activation pattern pivoting around BL was observed in 17 (85%) of 20 patients with jump, but only 3 (15%) of 20 patients without jump (p < 0.0001). During jump, there was a long period of no potential from the last atrial potential within KT to the His bundle potential, suggesting the slow pathway conduction through the rightward inferior extension that cannot be visualized. A linear ablation between the pivot point and the septal tricuspid annulus was successful for slow-fast AVNRT.ConclusionAlthough the slow pathway could not be visualized using high-density mapping during sinus rhythm, the activation pattern pivoting around BL within KT was observed in most patients with the dual pathway physiology, with or without AVNRT.