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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 26: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. (TA 1-20: tricuspidal annulus; CS 5-10: coronary sinus; RVA: right ventricle apex). In this case, TA activation evidences a clear shift of the collision front from TA 7-8 during CS pacing (left panel) to TA 3-4 during RV pacing (right panel). The fact that the AV node is located more anterior than the CS ostium means that, when pacing is carried out from the RV instead of the CS, TA activation shifts counterclockwise. Because pacing from the RV can make the collision front shift towards the CTI, careful mapping of the inferior lateral atrial wall is mandatory in order to avoid the mistake of regarding an isthmus as blocked when it is not. In this case, as the distal pole (d) of the TA mapping catheter was spaced 18 mm from the tip, the inferior lateral atrial wall was not completely mapped.
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Figure 4: Patient 26: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. (TA 1-20: tricuspidal annulus; CS 5-10: coronary sinus; RVA: right ventricle apex). In this case, TA activation evidences a clear shift of the collision front from TA 7-8 during CS pacing (left panel) to TA 3-4 during RV pacing (right panel). The fact that the AV node is located more anterior than the CS ostium means that, when pacing is carried out from the RV instead of the CS, TA activation shifts counterclockwise. Because pacing from the RV can make the collision front shift towards the CTI, careful mapping of the inferior lateral atrial wall is mandatory in order to avoid the mistake of regarding an isthmus as blocked when it is not. In this case, as the distal pole (d) of the TA mapping catheter was spaced 18 mm from the tip, the inferior lateral atrial wall was not completely mapped.

Mentions: Analysis of circumannular activation on the basis of the potentials recorded by the duo-decapolar catheter revealed a similar configuration during RV and CS pacing in patients without CTI block before the ablation procedure. There are, however, some important differences: during CS pacing, the atrial electrograms precede the ventricular potentials, while during RV pacing they follow; when RV pacing is used to assess CTI permeability, a counterclockwise shift occurs in the collision front of the two vectors of the circumannular activation because the impulse goes back to the atria through the His Bundle and the AV node that is situated in a more superior position than the CS ostium; this means that careful mapping of the lateral side of the ablation line is essential in order to avoid missing the point of the collision front, which is shifted downwards, and therefore to avoid the mistake of regarding as blocked an isthmus that actually is not (Figure 4). Once the line of block is created, TA activation is very similar during CS pacing and RV pacing, displaying fully descending activation of the lateral wall.


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 26: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. (TA 1-20: tricuspidal annulus; CS 5-10: coronary sinus; RVA: right ventricle apex). In this case, TA activation evidences a clear shift of the collision front from TA 7-8 during CS pacing (left panel) to TA 3-4 during RV pacing (right panel). The fact that the AV node is located more anterior than the CS ostium means that, when pacing is carried out from the RV instead of the CS, TA activation shifts counterclockwise. Because pacing from the RV can make the collision front shift towards the CTI, careful mapping of the inferior lateral atrial wall is mandatory in order to avoid the mistake of regarding an isthmus as blocked when it is not. In this case, as the distal pole (d) of the TA mapping catheter was spaced 18 mm from the tip, the inferior lateral atrial wall was not completely mapped.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Patient 26: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. (TA 1-20: tricuspidal annulus; CS 5-10: coronary sinus; RVA: right ventricle apex). In this case, TA activation evidences a clear shift of the collision front from TA 7-8 during CS pacing (left panel) to TA 3-4 during RV pacing (right panel). The fact that the AV node is located more anterior than the CS ostium means that, when pacing is carried out from the RV instead of the CS, TA activation shifts counterclockwise. Because pacing from the RV can make the collision front shift towards the CTI, careful mapping of the inferior lateral atrial wall is mandatory in order to avoid the mistake of regarding an isthmus as blocked when it is not. In this case, as the distal pole (d) of the TA mapping catheter was spaced 18 mm from the tip, the inferior lateral atrial wall was not completely mapped.
Mentions: Analysis of circumannular activation on the basis of the potentials recorded by the duo-decapolar catheter revealed a similar configuration during RV and CS pacing in patients without CTI block before the ablation procedure. There are, however, some important differences: during CS pacing, the atrial electrograms precede the ventricular potentials, while during RV pacing they follow; when RV pacing is used to assess CTI permeability, a counterclockwise shift occurs in the collision front of the two vectors of the circumannular activation because the impulse goes back to the atria through the His Bundle and the AV node that is situated in a more superior position than the CS ostium; this means that careful mapping of the lateral side of the ablation line is essential in order to avoid missing the point of the collision front, which is shifted downwards, and therefore to avoid the mistake of regarding as blocked an isthmus that actually is not (Figure 4). Once the line of block is created, TA activation is very similar during CS pacing and RV pacing, displaying fully descending activation of the lateral wall.

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