PMC5420031_01
A: Schematic representation of the activation of the left atrium (LA) via the Bachmann bundle (BB). B: Corresponding 12-lead electrocardiogram with prolonged atrioventricular node (AV) (270 ms). C: During sinus rhythm after electrical cardioversion, the first atrial activation was recorded in coronary sinus (CS) distal (CS 1-2); map 1/2 was located in LA. MA = mitral annulus; SN = sinus node; TA = tricuspid annulus.
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AV conduction (P-Q 280 ms) (Figure 1A-C). A circumferential pulmonary vein (PV) ablation was delivered until complete PV isolation. A voltage map showed low-voltage signals in the septum, roof, and posterior walls; thus additional ablation lines and substrate modification were made in these regions.
A: Schematic representation of sinus rhythm with Bachmann bundle (BB) block and a junctional escape rhythm conducted to the left atrium (LA). B: LA voltage map generated by Carto-3 in right anterior oblique view; red and rose dots represent the ablation points. C: Corresponding electrocardiogram shows a junctional escape rhythm and a sinus rhythm (blue arrows) dissociated; below the coronary sinus (CS) catheter recorded a junctional escape rhythm with 1:1 retrograde conduction to LA while Map 1-2, placed in right atrium (RA), recorded the sinus rhythm. In the transparent orange box, signal recorded from a catheter in RA; in the transparent red box, signal recorded from CS in LA. AV = atrioventricular node; MA = mitral annulus; SN = sinus node; TA = tricuspid annulus.
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AVNRT (cycle length 580 ms, VA <70 ms, dual AV node conduction, ventricular pacing at a cycle length 20 ms shorter than supraventricular tachycardia with a V-A-V response, postpacing interval-tachycardia cycle length >114 ms) was induced. After radiofrequency delivery in the anterosuperior septum (BB area, close to the right superior PV) (Figure 2B), sinus rhythm was recorded in the RA but not conducted to the LA and ventricular activation was induced by junctional rhythm (40-50 min) with 1:1 retrograde conduction to the LA (Figure 2) or by AVNRT (Figure 3). AV node arose, we also observed an asystole, coexisting with sinus rhythm. At the end of the procedure, we recorded, with the ablation catheter placed in the RA, sinus signals dissociated from the left side (Figure 2).
A: Schematic representation of sinus rhythm with Bachmann bundle (BB) block and atrioventricular nodal reentrant tachycardia (AVNRT). B: Coronary sinus (CS) catheter recorded typical AVNRT dissociated from the sinus signal recorded from the right atrium (RA), placed in RA. C,D: Pacing from RA (C) and CS 1/2 (D) shows an RA-left atrium dissociation. AV = atrioventricular node; MA = mitral annulus; SN = sinus node; TA = tricuspid annulus.
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AVNRT (cycle length 580 ms, VA <70 ms, dual AV node conduction, ventricular pacing at a cycle length 20 ms shorter than supraventricular tachycardia with a V-A-V response, postpacing interval-tachycardia cycle length >114 ms) was induced. After radiofrequency delivery in the anterosuperior septum (BB area, close to the right superior PV) (Figure 2B), sinus rhythm was recorded in the RA but not conducted to the LA and ventricular activation was induced by junctional rhythm (40-50 min) with 1:1 retrograde conduction to the LA (Figure 2) or by AVNRT (Figure 3). By pacing from the ablation catheter, located not only in the triangle of Koch but in different regions of the RA, the stimuli were not able to capture the atrium in the CS, determining RA-LA dissociation (Figure 3C and D).