Implications of 2:1 atrioventricular block during typical atrioventricular nodal reentrant tachycardia (original) (raw)
2007, Journal of Interventional Cardiac Electrophysiology
Objective The effects of 2:1 AV block (AVB) on AV nodal reentrant tachycardia (AVNRT) remain to be elucidated. This study was performed to localize the site of 2:1 AVB and elucidate the effects of 2:1 AVB on typical AVNRT. Methods The His bundle (HB) electrograms during typical AVNRT with 2:1 AV block were reviewed in 24 patients. It was hypothesized that if 2:1 AVB at the HB or below changed tachycardia cycle length (TCL), the lower turnaround point of the reentrant circuit (RC) might be located within the HB and parts of the HB might be involved in the RC. Results A HB potential was absent in blocked beats during 2:1 AVB in four patients (supra-Hisian block), and the maximal amplitude of the HB potential in blocked beats was the same as that in conducted beats in four patients (infra-Hisian block), and was significantly smaller than that in conducted beats (0.1±0.1 versus 0.5±0.2 mV, P<0.05) in 16 patients (intra-Hisian block). Eight patients (33%) with intra-Hisian block had a nearly identical prolongation of the H-A and A-A intervals in blocked beats (12±3 and 13±2 ms, respectively) with unchanged A-H intervals, while the remaining 16 patients (67%) exhibited invariable A-A and/or H-A intervals. Conclusion The site of 2:1 AVB during typical AVNRT was estimated to be at the HB or below in 83% of the cases. Two-to-one intra-Hisian block transiently prolonged TCL, possibly indicating involvement of the proximal HB in the RC in one-third of typical the AVNRT cases with 2:1 AVB.
Sign up to get access to over 50M papers
Related papers
Effects of right bundle branch block during atrioventricular nodal reentrant tachycardia
International Journal of Cardiology, 2005
Background: The significant role of bundle branch block during atrioventricular nodal reentrant tachycardia (AVNRT) is not clear. The purposes of this study were to study the effects of complete right bundle branch block (RBBB) on electrophysiological parameters during AVNRT and to define the significance of complete RBBB during AVNRT. Methods and results: According to characteristics of electrocardiogram during sinus rhythm and AVNRT, 50 patients who underwent catheter ablation for slow-fast AVNRT were divided into three groups. Group I included 20 patients who had narrow QRS (V110 ms) during sinus rhythm and AVNRT. Group II included 18 patients who had persistent RBBB (z120 ms) during sinus rhythm and AVNRT. Group III included 12 patients who had narrow QRS during sinus rhythm, but they had narrow QRS and transient RBBB during AVNRT. The atrio-His (AH) interval (296F60 vs. 288F75 ms), His-ventricular (HV) interval (36F11 vs. 35F11 ms), His-atrial (HA) interval (72F24 vs. 71F28 ms), VA HRA interval (defined as the interval between the onset of ventricular depolarization and the onset of atrial activity of right high atrium; 34F24 vs. 37F25 ms), VA CSO interval (defined as the interval between the onset of ventricular depolarization and the onset of atrial activity of coronary sinus ostium; 13F28 vs. 26F23 ms) and tachycardia cycle length (TCL; 368F67 vs. 359F73 ms) during AVNRT were similar between group I and group II (all PN0.05). In group III, the AH interval (255F81 vs. 246F83 ms), HV interval (44F5 vs. 42F11 ms), HA interval (66F19 vs. 70F15 ms), VA HRA interval (27F15 vs. 29F16 ms), VA CSO interval (23F25 vs. 21F25 ms) and TCL (322F76 vs. 316F77 ms) were not significantly different between AVNRT with narrow QRS and those with transient RBBB (all PN0.05). Conclusions: Persistent RBBB and transient RBBB have no significant effects on the electrophysiological parameters during AVNRT. These findings suggest that RBBB might not influence the conduction of lower common pathway or the circuit of AVNRT.
Paradoxical Shortening of the Second PR Interval During 3:2 Atrioventricular Nodal Block
Journal of Cardiovascular Electrophysiology, 1996
Paradoxical Shortening in Second‐Degree AV Block. A patient with 3:2 second‐degree AV block after acute inferior wall myocardial infarction showed consistent PR interval shortening on the second conducted beat in each periodicity. Intracardiac electrophysiologic evaluation revealed that the site of block was nodal. A typical Wenckebach pattern with prolongation of the AH interval was noted. The shorter PR resulted from a paradoxical shortening of the HV interval in the second beat, most likely due to supernormal conduction in the setting of concomitant trifascicular disease.
Diagnostic Approach to Narrow Complex Tachycardia with VA Block
Pacing and Clinical Electrophysiology, 1997
HAMDAN, M.H., ET AL.: Diagnostic Approach to Narrow Complex Tachycardia with VA Block. Narrow complex tachycardia with VA block is rare. The differential diagnosis usually con. 'iists of (1) junctional tachycardia (JT) with retrograde block: (2) A V nodal reentrant tachycardia (A VNRT) with proximal common pathway block; and finally (3) nodofascicular tachycardia using the His-Purkinje system for antegrade conduction and a nodofascicular pathway for retrograde conduction. Analysis of tachycardia onset and termination, the effect of bundle branch block on tachycardia cycle length, and the response to atrial and ventricular premature depolarization must be carefully done. Making the correct diagnosis is crucial as the success rate in eliminating the tachycardia will depend on tachycardia mechanism. (PACE 1997: 20[Pt. I]:2984~2988)
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.