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Can right ventricular pacing be useful in the assessment of cavo-tricuspid isthumus block?

Miracapillo G, Costoli A, Addonisio L, Breschi M, Severi S - Indian Pacing Electrophysiol J (2008)

Bottom Line: CTI block was confirmed by analyzing local electrograms on the line of block and circumannular activation during CS and RV pacing.Before ablation, during RV stimulation, the collision front of circumannular activation shifted counterclockwise in contrast with the pattern observed during CS pacing.After ablation, circumannular activation was similar during CS and RV pacing, showing fully descending lateral right atrium activation, even if double potentials registered on the ablation line were less widely split during RV pacing than CS pacing (111+/-26 ms vs 128+/-30 , p=0.0001).

View Article: PubMed Central - PubMed

Affiliation: Division of Cardiology, Misericordia Hospital, Grosseto, Italy. g.miracapillo@usl9.toscana.it

ABSTRACT

Background: Cavo-tricuspid isthmus (CTI) block is currently assessed by coronary sinus (CS) pacing or low lateral and septal atrial pacing. Occasionally, CS catheterization through the femoral route can be difficult to perform or right atrial pacing can be problematic because of catheter instability or saturation of the atrial electrograms recorded near the catheter.

Objectives: Our aim was to evaluate the feasibility of assessing cavo-tricuspid isthmus block by means of right ventricular (RV) pacing in patients with ventriculo-atrial conduction, comparing it with CS pacing.

Methods: Circumannular activation was analyzed during CS and RV pacing in consecutive patients in sinus rhythm undergoing CTI ablation for typical atrial flutter. Patients without ventriculo-atrial conduction were excluded from the study. The linear lesion was created during RV pacing and split atrial signals on the ablation line were analyzed. CTI block was confirmed by analyzing local electrograms on the line of block and circumannular activation during CS and RV pacing.

Results: Out of 31 patients, 20 displayed ventriculo-atrial conduction (64%) and were included in the study. Before ablation, during RV stimulation, the collision front of circumannular activation shifted counterclockwise in contrast with the pattern observed during CS pacing. After ablation, circumannular activation was similar during CS and RV pacing, showing fully descending lateral right atrium activation, even if double potentials registered on the ablation line were less widely split during RV pacing than CS pacing (111+/-26 ms vs 128+/-30 , p=0.0001).

Conclusions: In patients with ventriculo-atrial conduction, tricuspid annulus activation during CS and RV pacing is similar, before and after CTI ablation. The occurrence of split atrial electrograms separated by an isoelectric interval registered on the line of block can be detected during CS or RV pacing. In patients with difficult CS catheterization via the femoral vein, before trying the subclavian or internal jugular route, if retrograde ventriculo-atrial conduction is present, RV pacing can be an easy trick to assess isthmus block.

No MeSH data available.


Related in: MedlinePlus

Patient 9: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. During RV pacing, the achievement of a complete CTI block, as evidenced by the changing of the TA activation potentials (arrows) with a clear change in the polarity  of the atrial electrograms from TA1-2 to TA5-6, correlated with a sudden increase (a sort of "isthmic jump") in the distance between the two atrial components induced by retrograde VA conduction and recorded on the ablation catheter during RF delivery. (CS1-4: coronary sinus; TA1-20: tricuspidal annulus; Abl d: ablator distal poles, evidencing the splitting of the double potentials s-s', RVA: right ventricular apex).
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Figure 3: Patient 9: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. During RV pacing, the achievement of a complete CTI block, as evidenced by the changing of the TA activation potentials (arrows) with a clear change in the polarity of the atrial electrograms from TA1-2 to TA5-6, correlated with a sudden increase (a sort of "isthmic jump") in the distance between the two atrial components induced by retrograde VA conduction and recorded on the ablation catheter during RF delivery. (CS1-4: coronary sinus; TA1-20: tricuspidal annulus; Abl d: ablator distal poles, evidencing the splitting of the double potentials s-s', RVA: right ventricular apex).

Mentions: Out of 31 consecutive patients who underwent CTI RF ablation, 20 (males 80%, mean age 72±7 years, height 171±5 cm, weight 77±12 Kg) displayed VA conduction (64%) and were included in the study. No patients evidenced accessory pathways, nor had a permanent pacemaker. At the beginning of the procedure, 11 patients were in sinus rhythm, whereas 9 had typical AFl, with a mean cycle length of 222 ± 22 ms (range 181-250). In all patients with AFl at the beginning of the procedure, atrial potentials recorded on the CTI coincided with the plateau between F waves on the surface electrocardiogram, and the entrainment technique showed that the CTI was the critical zone of the re-entry circuit. In all of these patients, the arrhythmia was interrupted by RF delivery, but only in one of them complete CTI block was present when sinus rhythm was restored; in all the others, further RF pulses were necessary to eliminate conduction gaps. In all patients in sinus rhythm, including those in AFl whose sinus rhythm had been restored during the ablation procedure without achieving a complete CTI block, RF pulses were delivered during RV pacing, and electrograms were monitored to detect splitting of double potentials recorded on the ablation line after the ventricular signals. In all patients, the achievement of a complete CTI block (subsequently verified by CS pacing) correlated with a sudden increase in the distance between the two atrial components induced by retrograde VA conduction and recorded on the ablation catheter during RF delivery (Figure 3). Thus, once complete CTI block had been achieved, a corridor of split atrial potentials was present all along the ablation line during RV pacing, after the ventricular electrograms. Comparison of atrial potentials recorded on the ablation line during RV and CS pacing revealed that double potentials were more widely split during CS pacing than during RV pacing (128±30 ms vs. 111±26 ms, p=0.0001). A mean of 12 RF pulses (range 4-30) were delivered. All patients were successfully ablated and no complications occurred.


Can right ventricular pacing be useful in the assessment of cavo-tricuspid isthumus block?

Miracapillo G, Costoli A, Addonisio L, Breschi M, Severi S - Indian Pacing Electrophysiol J (2008)

Patient 9: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. During RV pacing, the achievement of a complete CTI block, as evidenced by the changing of the TA activation potentials (arrows) with a clear change in the polarity  of the atrial electrograms from TA1-2 to TA5-6, correlated with a sudden increase (a sort of "isthmic jump") in the distance between the two atrial components induced by retrograde VA conduction and recorded on the ablation catheter during RF delivery. (CS1-4: coronary sinus; TA1-20: tricuspidal annulus; Abl d: ablator distal poles, evidencing the splitting of the double potentials s-s', RVA: right ventricular apex).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2572027&req=5

Figure 3: Patient 9: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. During RV pacing, the achievement of a complete CTI block, as evidenced by the changing of the TA activation potentials (arrows) with a clear change in the polarity of the atrial electrograms from TA1-2 to TA5-6, correlated with a sudden increase (a sort of "isthmic jump") in the distance between the two atrial components induced by retrograde VA conduction and recorded on the ablation catheter during RF delivery. (CS1-4: coronary sinus; TA1-20: tricuspidal annulus; Abl d: ablator distal poles, evidencing the splitting of the double potentials s-s', RVA: right ventricular apex).
Mentions: Out of 31 consecutive patients who underwent CTI RF ablation, 20 (males 80%, mean age 72±7 years, height 171±5 cm, weight 77±12 Kg) displayed VA conduction (64%) and were included in the study. No patients evidenced accessory pathways, nor had a permanent pacemaker. At the beginning of the procedure, 11 patients were in sinus rhythm, whereas 9 had typical AFl, with a mean cycle length of 222 ± 22 ms (range 181-250). In all patients with AFl at the beginning of the procedure, atrial potentials recorded on the CTI coincided with the plateau between F waves on the surface electrocardiogram, and the entrainment technique showed that the CTI was the critical zone of the re-entry circuit. In all of these patients, the arrhythmia was interrupted by RF delivery, but only in one of them complete CTI block was present when sinus rhythm was restored; in all the others, further RF pulses were necessary to eliminate conduction gaps. In all patients in sinus rhythm, including those in AFl whose sinus rhythm had been restored during the ablation procedure without achieving a complete CTI block, RF pulses were delivered during RV pacing, and electrograms were monitored to detect splitting of double potentials recorded on the ablation line after the ventricular signals. In all patients, the achievement of a complete CTI block (subsequently verified by CS pacing) correlated with a sudden increase in the distance between the two atrial components induced by retrograde VA conduction and recorded on the ablation catheter during RF delivery (Figure 3). Thus, once complete CTI block had been achieved, a corridor of split atrial potentials was present all along the ablation line during RV pacing, after the ventricular electrograms. Comparison of atrial potentials recorded on the ablation line during RV and CS pacing revealed that double potentials were more widely split during CS pacing than during RV pacing (128±30 ms vs. 111±26 ms, p=0.0001). A mean of 12 RF pulses (range 4-30) were delivered. All patients were successfully ablated and no complications occurred.

Bottom Line: CTI block was confirmed by analyzing local electrograms on the line of block and circumannular activation during CS and RV pacing.Before ablation, during RV stimulation, the collision front of circumannular activation shifted counterclockwise in contrast with the pattern observed during CS pacing.After ablation, circumannular activation was similar during CS and RV pacing, showing fully descending lateral right atrium activation, even if double potentials registered on the ablation line were less widely split during RV pacing than CS pacing (111+/-26 ms vs 128+/-30 , p=0.0001).

View Article: PubMed Central - PubMed

Affiliation: Division of Cardiology, Misericordia Hospital, Grosseto, Italy. g.miracapillo@usl9.toscana.it

ABSTRACT

Background: Cavo-tricuspid isthmus (CTI) block is currently assessed by coronary sinus (CS) pacing or low lateral and septal atrial pacing. Occasionally, CS catheterization through the femoral route can be difficult to perform or right atrial pacing can be problematic because of catheter instability or saturation of the atrial electrograms recorded near the catheter.

Objectives: Our aim was to evaluate the feasibility of assessing cavo-tricuspid isthmus block by means of right ventricular (RV) pacing in patients with ventriculo-atrial conduction, comparing it with CS pacing.

Methods: Circumannular activation was analyzed during CS and RV pacing in consecutive patients in sinus rhythm undergoing CTI ablation for typical atrial flutter. Patients without ventriculo-atrial conduction were excluded from the study. The linear lesion was created during RV pacing and split atrial signals on the ablation line were analyzed. CTI block was confirmed by analyzing local electrograms on the line of block and circumannular activation during CS and RV pacing.

Results: Out of 31 patients, 20 displayed ventriculo-atrial conduction (64%) and were included in the study. Before ablation, during RV stimulation, the collision front of circumannular activation shifted counterclockwise in contrast with the pattern observed during CS pacing. After ablation, circumannular activation was similar during CS and RV pacing, showing fully descending lateral right atrium activation, even if double potentials registered on the ablation line were less widely split during RV pacing than CS pacing (111+/-26 ms vs 128+/-30 , p=0.0001).

Conclusions: In patients with ventriculo-atrial conduction, tricuspid annulus activation during CS and RV pacing is similar, before and after CTI ablation. The occurrence of split atrial electrograms separated by an isoelectric interval registered on the line of block can be detected during CS or RV pacing. In patients with difficult CS catheterization via the femoral vein, before trying the subclavian or internal jugular route, if retrograde ventriculo-atrial conduction is present, RV pacing can be an easy trick to assess isthmus block.

No MeSH data available.


Related in: MedlinePlus