Coronary Sinus Activation Pattern in Patients with Atrioventricular Nodal Reentrant Tachycardia

Patterns of left atrial (far-field signals) or coronary sinus (CS) muscle (near-field) have been defined in CS recordings. The purpose of this study was to define the activation patterns from the coronary sinus in patients with anterior and posterior type of atrioventricular nodal reentrant tachycardia (AVNRT) circuits. Methods and Results: This retrospective study involved a total of 149 patients with 155 episodes of AVNRT which were divided into 3 patterns. In the anterior pattern (123 tachycardias), the atrial deflection from the His bundle electrogram preceded that from the proximal CS electrogram. In the posterior pattern (23 tachycardias), the proximal CS electrogram (CSp) was recorded earlier than the His bundle atrial electrogram. In the left atrial pattern (9 tachycardias), activation of distal CS sites preceded both proximal CS and atrial activation from the His bundle electrogram. A decapolar catheter with a 5-mm interelectrode distance was used for CS recording. The CS electrograms were analyzed to determine the total signal duration as well as the duration of the initial component. An initial slow wave was defined as a duration exceeding 10 ms. 1) The duration of the initial component in patients with the anterior pattern was longer than in those with the posterior pattern in CSp (7.3 ± 3.1 ms vs. 4.5 ± 2.0 ms), CS7-8 (7.4 ± 2.9 ms vs. 3.8 ± 1.5 ms), CS5-6 (7.3 ms ± 3.3 ms vs. 4.4 ms ± 2.5 ms) and CS3-4 (6.7 ms ± 2.4 ms vs. 4.5 ms ± 2.0 ms) (p < 0.01). 2) Similarly the total electrogram duration in the CS was longer in patients with an anterior compared to a posterior pattern in CSp (38.3 ms ± 10.1 ms vs. 26.8 ± 6.1 ms), CS7-8 (31.8 ms ±6.6 ms vs. 27.2 ms ± 6.0 ms), CS5-6 (31.3 ms ± 6.8 ms vs. 26.5 ms ± 4.9 ms), and CS3-4 (30.0 ms ± 6.3 ms vs. 25.0 ms ± 5.1 ms) (p < 0.01). 3) The percentage of tachycardias showing an initial slow wave followed by rapid activation was higher for anterior pattern patients compared with posterior pattern patients in CSp (62% vs. 13%), CS7-8 (79% vs. 4%), CS5-6 (72% vs. 4%), CS3-4 (54% vs. 9%) and distal CS (47% vs. 0%) (p < 0.01). Conclusions: The pattern of an initial slow wave followed by a rapid wave in the CS was characteristic of an anterior AVNRT circuit and is explained by the initial involvement of far field left atrial components. In contrast, the predominant early rapid waves in the posterior AVNRT circuit are compatible with early CS activation from the right atrium

His-Purkinje system-related incessant ventricular tachycardia arising from the left coronary cusp

We describe the case of a 23-year-old woman who had His-Purkinje system-related incessant ventricular tachycardia with a narrow QRS configuration. The ventricular tachycardia was ablated successfully in the left coronary cusp where the earliest endocardial activation had been recorded. We hypothesize that a remnant of the subaortic conducting tissue was the source of the ventricular arrhythmias