Catheter Ablation of Atrioventricular Block

Figures

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  Figure 1. Baseline and Atropine Challenge Electrocardiograms (A) A 12-lead electrocardiogram at baseline with atypical persistent Mobitz type I atrioventricular block and a narrow QRS complex. (B) Response to 2 g intravenous atropine: normal 1:1 atrioventricular conduction is seen. Arrows show conducted P waves, curved red lines indicate PR intervals in conducted beats, and arrowheads point to blocked P waves.

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  Figure 2. Holter Recording Showing High-Degree Atrioventricular Block During Sleep There are up to 4 consecutive blocked P waves resulting in a 4-s pause. A total of 9 pauses lasting >3 s occurred during 24-h Holter monitoring. Sinus slowing is evident at the time of atrioventricular block.

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  Figure 3. Serial Electrocardiograms Obtained During Exercise Treadmill Testing Note the gradual improvement in atrioventricular conduction with 1:1 atrioventricular conduction during stage 3 of the exercise protocol. (A and B) Atypical Mobitz type I atrioventricular block with irregular PR intervals. (C) 1:1 atrioventricular conduction. Note the constant PR intervals. (D) Atypical Mobitz type I atrioventricular block with irregular PR intervals. (E and F) Normal 1:1 atrioventricular conduction with constant PR intervals.

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  Figure 4. Electrophysiological Study Baseline measurements at 100 mm/s paper speed using 3 surface electrocardiographic leads (I, II, and III) and 6 intracardiac electrograms positioned in the His bundle (ABL) and the coronary sinus (CS). The surface electrocardiogram shows atypical Mobitz type I atrioventricular block with irregular PR intervals. The intracardiac electrograms show supra-His block with a progressive increase in the AH interval (interval between the activation potential of the right atrium and the activation potential of the His bundle [H]) until the A potential is not followed by an H potential. Black arrows point to conducted P waves (P), and red lines indicate nonconducted beats. Note the irregular PR intervals before the nonconducted P-wave and prolongation of the PR interval after the blocked beat (from 255 to 333 ms).

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  Figure 5. Simultaneous Surface and Intracardiac EGMs at 100 mm/s Paper Speed With 3 Surface Electrocardiographic Leads (I, II, and III) and 15 Intracardiac EGMs During Atrial Pacing The intracardiac electrograms (EGMs) were recorded in the right atrium (ABL), the coronary sinus (CS), and the left atrium (OPT). (A) Atrial pacing through the coronary sinus catheter at a cycle length of 600 ms resulting in 1:1 atrioventricular conduction with a 271-ms PR interval. (B) Atrial pacing at a cycle length of 500 ms causes a prolongation of the PR interval with continuation of 1:1 atrioventricular conduction. (C) 1:1 atrioventricular conduction with a 351-ms PR interval continued after cessation of pacing.

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  Figure 6. Biatrial Electroanatomic Maps Obtained Using the EnSite Precision Mapping System (Abbott Laboratories, Abbott Park, Illinois) During Cardioneuroablation Ablation points show location of ganglionated plexuses on the basis of fragmented electrograms. The right superior ganglionated plexus (RSGP) is located between the superior vena cava (SVC) and the right superior pulmonary vein (RSPV). The right inferior ganglionated plexus (RIGP) is located between the right pulmonary veins and the right atrium (RA) in the interatrial septum (indicated by a white oval). The posteromedial left ganglionated plexus (PMLGP) is bounded by the posterior wall of the left atrium (LA), the inferior vena cava (IVC), and the coronary sinus (CS) ostium. The left superior ganglionated plexus (LSGP) is located between the left atrial appendage (LAA) and the left superior pulmonary vein (LSPV). The Marshall tract ganglionated plexus (MTGP) is located in the lateral wall of the left atrium. The left inferior ganglionated plexus is located in the posterior wall of the left inferior pulmonary vein (LIPV) (not seen in the anteroposterior view). Intracardiac electrograms are shown at the bottom. Ablation lesions…

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  Figure 7. Biatrial Electroanatomic Maps Obtained Using the EnSite Precision Mapping System (Abbott Laboratories, Abbott Park, Illinois) During Cardioneuroablation (A and B) Electroanatomic maps. The intracardiac electrograms are shown at the bottom. The final PR interval and sinus node cycle length were 198 and 560 ms, respectively. Ablation lesions were tagged according to time as follows: white (<5 s); pink (5 to 15 s); and red (>15 s). PN = phrenic nerve; other abbreviations as in Figure 6.

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  Figure 8. Follow-Up 12-Lead Electrocardiogram Sinus rhythm; heart rate, 100 beats/min; P-wave duration, 120 ms; and PR interval, 200 ms; 1:1 atrioventricular conduction is seen.