Limits...
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 12: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. In patients in sinus rhythm, when the line of block is not created, on pacing from CS (left side panel) and RV (right side), using the same catheter set-up (above), TA activation is similar, except for the counterclockwise shifting of the collision front (from TA 7-8 during CS pacing to TA 5-6 during RV pacing). The 'difference of circumannular activation time' was defined as the time from proximal pole to collision point (b) minus the time from distal pole to collision point (a) recorded  by the duo-decapolar catheter. These values were measured during RV and CS pacing at the same cycle length and compared. (TA 1-20: tricuspidal annulus; CS 1-4: coronary sinus; RV: right ventricle).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2572027&req=5

Figure 1: Patient 12: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. In patients in sinus rhythm, when the line of block is not created, on pacing from CS (left side panel) and RV (right side), using the same catheter set-up (above), TA activation is similar, except for the counterclockwise shifting of the collision front (from TA 7-8 during CS pacing to TA 5-6 during RV pacing). The 'difference of circumannular activation time' was defined as the time from proximal pole to collision point (b) minus the time from distal pole to collision point (a) recorded by the duo-decapolar catheter. These values were measured during RV and CS pacing at the same cycle length and compared. (TA 1-20: tricuspidal annulus; CS 1-4: coronary sinus; RV: right ventricle).

Mentions: Consecutive patients undergoing CTI RF ablation of typical AFl were proposed for inclusion in the study. All patients gave written informed consent. Electrophysiological study was performed by using 3 catheters inserted via the right and left femoral or left subclavian veins: a quadripolar diagnostic catheter in the RV apex (Explorer ST, Boston Scientific EPT, Boston, MA, USA), a decapolar in the CS (Marinr CS, Medtronic, Minneapolis, MN, USA) and a duo-decapolar around the TA (Stablemapr, Medtronic, Minneapolis, MN, USA, or Halo XP, Biosense Webster, Diamond Bar, CA, USA). An 8 mm tip ablation catheter (Blazer XP large standard curve, Boston Scientific EPT, Boston, MA, USA) was inserted into the right atrium (RA) from the right femoral vein. In those patients who were in AFl, isthmus dependence was assessed by the entrainment technique before beginning the ablation procedure. In patients in sinus rhythm at the beginning of the study and in those in AFl whose sinus rhythm was restored during RF delivery, circumannular activation was registered during proximal CS and RV pacing. Efforts were made to pace the left atrium as nearer as possible to the CS ostium, consistently with pacing threshold and catheter stability and avoiding left ventricular pacing. When the line of block had not yet been created, the 'difference of circumannular activation time' was defined as the time from proximal pole to collision point minus the time from distal pole to collision point, recorded on the duo-decapolar catheter during RV and CS pacing at the same cycle length (Figure 1). Patients with no evidence of retrograde VA conduction were excluded from the study. The presence of accessory pathways was another criterion of exclusion from the study. In the absence of isthmus block, the linear RF lesion was created during RV pacing, on observing real-time signals from the ablator only. Simultaneous blinded recordings of TA and CS signals were observed off-line once the CTI was deemed to be blocked.


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 12: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. In patients in sinus rhythm, when the line of block is not created, on pacing from CS (left side panel) and RV (right side), using the same catheter set-up (above), TA activation is similar, except for the counterclockwise shifting of the collision front (from TA 7-8 during CS pacing to TA 5-6 during RV pacing). The 'difference of circumannular activation time' was defined as the time from proximal pole to collision point (b) minus the time from distal pole to collision point (a) recorded  by the duo-decapolar catheter. These values were measured during RV and CS pacing at the same cycle length and compared. (TA 1-20: tricuspidal annulus; CS 1-4: coronary sinus; RV: right ventricle).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Patient 12: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. In patients in sinus rhythm, when the line of block is not created, on pacing from CS (left side panel) and RV (right side), using the same catheter set-up (above), TA activation is similar, except for the counterclockwise shifting of the collision front (from TA 7-8 during CS pacing to TA 5-6 during RV pacing). The 'difference of circumannular activation time' was defined as the time from proximal pole to collision point (b) minus the time from distal pole to collision point (a) recorded by the duo-decapolar catheter. These values were measured during RV and CS pacing at the same cycle length and compared. (TA 1-20: tricuspidal annulus; CS 1-4: coronary sinus; RV: right ventricle).
Mentions: Consecutive patients undergoing CTI RF ablation of typical AFl were proposed for inclusion in the study. All patients gave written informed consent. Electrophysiological study was performed by using 3 catheters inserted via the right and left femoral or left subclavian veins: a quadripolar diagnostic catheter in the RV apex (Explorer ST, Boston Scientific EPT, Boston, MA, USA), a decapolar in the CS (Marinr CS, Medtronic, Minneapolis, MN, USA) and a duo-decapolar around the TA (Stablemapr, Medtronic, Minneapolis, MN, USA, or Halo XP, Biosense Webster, Diamond Bar, CA, USA). An 8 mm tip ablation catheter (Blazer XP large standard curve, Boston Scientific EPT, Boston, MA, USA) was inserted into the right atrium (RA) from the right femoral vein. In those patients who were in AFl, isthmus dependence was assessed by the entrainment technique before beginning the ablation procedure. In patients in sinus rhythm at the beginning of the study and in those in AFl whose sinus rhythm was restored during RF delivery, circumannular activation was registered during proximal CS and RV pacing. Efforts were made to pace the left atrium as nearer as possible to the CS ostium, consistently with pacing threshold and catheter stability and avoiding left ventricular pacing. When the line of block had not yet been created, the 'difference of circumannular activation time' was defined as the time from proximal pole to collision point minus the time from distal pole to collision point, recorded on the duo-decapolar catheter during RV and CS pacing at the same cycle length (Figure 1). Patients with no evidence of retrograde VA conduction were excluded from the study. The presence of accessory pathways was another criterion of exclusion from the study. In the absence of isthmus block, the linear RF lesion was created during RV pacing, on observing real-time signals from the ablator only. Simultaneous blinded recordings of TA and CS signals were observed off-line once the CTI was deemed to be blocked.

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