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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 17: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. Once the CTI has been definitely blocked, a completely descending wave front along the lateral right atrium is observed during both CS (left side panel) and RV (right side panel) pacing (TA 1-20: tricuspidal annulus; CS 9-10: coronary sinus; RV: right ventricle). Time between split atrial potentials along the ablation line after the creation of isthmus block was measured and analyzed during both CS and RV pacing (s and s').
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Figure 2: Patient 17: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. Once the CTI has been definitely blocked, a completely descending wave front along the lateral right atrium is observed during both CS (left side panel) and RV (right side panel) pacing (TA 1-20: tricuspidal annulus; CS 9-10: coronary sinus; RV: right ventricle). Time between split atrial potentials along the ablation line after the creation of isthmus block was measured and analyzed during both CS and RV pacing (s and s').

Mentions: When patients were in sinus rhythm, the procedure was performed while pacing from the RV apex at a cycle length adapted to the individual retrograde conduction properties, 600 ms if possible, at twice the diastolic threshold. The ablation catheter was initially positioned, during sinus rhythm, close to the TA where a large ventricular potential and a small atrial electrogram were recorded (A/V ratio approximately 0.1). RV pacing was then started and the catheter was progressively drawn back in a posteroseptal direction under fluoroscopic guidance, with sequential stops between each RF delivery up to the edge of the IVC. At each step, the modifications of atrial potentials related to VA conduction were observed in order to control the progression of the ablation line. The endpoint of the procedure was the achievement of a complete clockwise isthmus block. In the first instance, this endpoint was evaluated on the basis of evidence of a sudden increase in the distance between split, reduced-amplitude atrial potentials separated by an isoelectric interval registered after the ventricular electrogram during RV pacing in the corridor between the TA and the IVC edge. The presence of sites of recording of single atrial potentials after the ventricular electrograms, or fragmented atrial potentials without an isoelectric interval between them, suggested the presence of conduction gaps. Complete block was then validated by analyzing local electrograms registered on the line of block and circumannular activation on the duo-decapolar catheter during low lateral RA and CS pacing. This activation model was then compared with the circumannular activation registered when pacing was performed from the RV (Figure 2). The time between split atrial potentials along the ablation line after the creation of isthmus block was measured and analyzed during both CS and RV pacing. The persistence of isthmus block was assessed 20 minutes after the last RF pulse in order to exclude the early recovery of CTI conduction. Continuous variables are reported as mean value ± standard deviation and analyzed by means of two-tailed paired Student t test. Discrete variables are reported as percentages. A p value <0.05 was considered statistically significant. Statistical analysis was made by means of the SPSS statistical software package (version 12.0, SPSS Inc., Chicago, Illinois, USA).


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 17: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. Once the CTI has been definitely blocked, a completely descending wave front along the lateral right atrium is observed during both CS (left side panel) and RV (right side panel) pacing (TA 1-20: tricuspidal annulus; CS 9-10: coronary sinus; RV: right ventricle). Time between split atrial potentials along the ablation line after the creation of isthmus block was measured and analyzed during both CS and RV pacing (s and s').
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Patient 17: electrogram tracings and fluoroscopic image in the left anterior oblique 45º projection. Once the CTI has been definitely blocked, a completely descending wave front along the lateral right atrium is observed during both CS (left side panel) and RV (right side panel) pacing (TA 1-20: tricuspidal annulus; CS 9-10: coronary sinus; RV: right ventricle). Time between split atrial potentials along the ablation line after the creation of isthmus block was measured and analyzed during both CS and RV pacing (s and s').
Mentions: When patients were in sinus rhythm, the procedure was performed while pacing from the RV apex at a cycle length adapted to the individual retrograde conduction properties, 600 ms if possible, at twice the diastolic threshold. The ablation catheter was initially positioned, during sinus rhythm, close to the TA where a large ventricular potential and a small atrial electrogram were recorded (A/V ratio approximately 0.1). RV pacing was then started and the catheter was progressively drawn back in a posteroseptal direction under fluoroscopic guidance, with sequential stops between each RF delivery up to the edge of the IVC. At each step, the modifications of atrial potentials related to VA conduction were observed in order to control the progression of the ablation line. The endpoint of the procedure was the achievement of a complete clockwise isthmus block. In the first instance, this endpoint was evaluated on the basis of evidence of a sudden increase in the distance between split, reduced-amplitude atrial potentials separated by an isoelectric interval registered after the ventricular electrogram during RV pacing in the corridor between the TA and the IVC edge. The presence of sites of recording of single atrial potentials after the ventricular electrograms, or fragmented atrial potentials without an isoelectric interval between them, suggested the presence of conduction gaps. Complete block was then validated by analyzing local electrograms registered on the line of block and circumannular activation on the duo-decapolar catheter during low lateral RA and CS pacing. This activation model was then compared with the circumannular activation registered when pacing was performed from the RV (Figure 2). The time between split atrial potentials along the ablation line after the creation of isthmus block was measured and analyzed during both CS and RV pacing. The persistence of isthmus block was assessed 20 minutes after the last RF pulse in order to exclude the early recovery of CTI conduction. Continuous variables are reported as mean value ± standard deviation and analyzed by means of two-tailed paired Student t test. Discrete variables are reported as percentages. A p value <0.05 was considered statistically significant. Statistical analysis was made by means of the SPSS statistical software package (version 12.0, SPSS Inc., Chicago, Illinois, USA).

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