1. Catheter ablation as a treatment of atrioventricular block
Stephen Tuohy, MD, Walid Saliba, MD, FHRS, Manjunath Pai, MD, Patrick Tchou, MD 
Heart Rhythm 
Volume 15, Issue 1, Pages (January 2018)
DOI: /j.hrthm
Copyright © 2017 Heart Rhythm Society Terms and Conditions

2. Heart Rhythm 2018 15, 90-96DOI: (10.1016/j.hrthm.2017.08.015)
Copyright © 2017 Heart Rhythm Society Terms and Conditions

3. Figure 1
Holter monitor strips of symptomatic events. A: Sinus rhythm with AV block in a pattern of quadrigeminy. There are only minimal changes in PR intervals and sinus rates preceding and following the blocked beats. B: Premature junctional beats following each conducted sinus beat. At the end of each premature QRS, one can appreciate the following sinus beat (arrow) occurring on time that blocks due to interference from the junctional beat. C: Sinus rhythm with 2:1 AV conduction. This panel is similar to panel B except the JPB could have blocked in the anterograde direction as well. D: Same 2:1 AV conduction during the first half of the rhythm strip and premature atrial beats with a superior axis presumably coming from the JPBs that only conducted in the retrograde fashion (arrows). E: Interpolated narrow QRS premature beats (asterisks) that do not interfere with the following sinus beats (arrows) but do prolong their PR intervals. These JPBs do not appear to have any retrograde atrial activation and are JPBs that only conducted down the normal conduction system. F: Sinus rhythm with a premature junctional beat that shows both retrograde conduction to the atrium (arrow) and anterograde conduction to the ventricle (asterisk). The patient feels palpitations with all of these events but gets lightheaded when 2:1 AV conduction occurs that suddenly drops her ventricular rate. All rhythm strips were recorded at 25 mm/s or 200 ms per large division. JPB = junctional premature beat.
Heart Rhythm  , 90-96DOI: ( /j.hrthm )
Copyright © 2017 Heart Rhythm Society Terms and Conditions

4. Figure 2
Intracardiac tracing showing spontaneous JPBs and blocked sinus beat. A: Sinus beat followed by a JPB. Note that the premature beat is not preceded by any premature atrial depolarization but only by a His-bundle electrogram. The atrial activation following the premature beat is sinus in origin, as attested by the P-wave morphology and atrial activation sequence. His-bundle activation of the sinus beat and the premature beat have the same anterograde activation sequence. B: The AV blocked sinus beat is not preceded by any notable His depolarization. JPB = junctional premature beat.
Heart Rhythm  , 90-96DOI: ( /j.hrthm )
Copyright © 2017 Heart Rhythm Society Terms and Conditions

5. Figure 3
Anatomic map of the site of successful ablation. Anatomic map (Biosense CARTO 3) of the septal tricuspid annular region on the ventricular side in the right anterior oblique (RAO) view. A shadow of the His-bundle catheter is shown. Sites where His-bundle recordings were noted are marked with yellow dots. Several ablation lesions delivered just superior to the His on the ventricular side near the tricuspid annulus did not change the AV conduction pattern. Ablation lesions were then delivered inferior to the His, again on the ventricular side of the annulus, starting inferiorly at the level of the coronary sinus and then incrementing superiorly toward the His-bundle area. Dark maroon dots above the His bundle and at the lower end of the figure show where radiofrequency applications did not terminate junctional premature beats or AV block of sinus beats. The blue dot represents the site of first ablation lesion that resulted in 1:1 AV conduction of sinus beats. Additional lesions were then delivered in the same area represented by the pink dots at up to 40 W.
Heart Rhythm  , 90-96DOI: ( /j.hrthm )
Copyright © 2017 Heart Rhythm Society Terms and Conditions

6. Figure 4
Onset of first RF energy delivery at the successful site. The patient was experiencing bigeminal retrogradely conducted junctional premature beats at the time of RF onset (at beginning of panel). ECG lead aVF is gained up to show the retrograde P waves of the premature beats. RF energy was started at 15 W. At 10 seconds into delivery, the power was increased to 20 W. At 12 seconds, 1:1 AV conduction of sinus beats commenced. The power was then ramped up to 25 W at 17 seconds and continued for a total of 25 seconds of delivery. RF = radiofrequency.
Heart Rhythm  , 90-96DOI: ( /j.hrthm )
Copyright © 2017 Heart Rhythm Society Terms and Conditions

7. Figure 5
Location of the concealed ventricular nodal tract. Based on the site of successful ablation, the ventricular nodal tract likely connects from the base of the ventricular septum just below the His bundle across the tricuspid annulus into the distal AV node. The tricuspid valve leaflet in this figure is cut away to show the ventricular portion of the pathway. AVN = atrioventricular node; CS = coronary sinus; CT = crista terminalis; FO = fossa ovalis; RV = right ventricle; TV = tricuspid valve.
Heart Rhythm  , 90-96DOI: ( /j.hrthm )
Copyright © 2017 Heart Rhythm Society Terms and Conditions