Download Spatial relation of the right coronary artery to the cavotricuspid

Spatial relation of the right coronary artery to the
cavotricuspid isthmus and the impact on radiofrequency
catheter ablation of common-type atrial flutter
HANNO U KLEMM Heart Center Dortmund
TIM F WEBER University Medical Center Heidelberg
CHRISTIN JOHNSEN University Heart Center Hamburg
PHILIPP G C BEGEMANN University Medical Center Hamburg
THOMAS MEINERTZ University Heart Center Hamburg
RODOLFO VENTURA Electrophysiology Bremen, Bremen, Germany
Rationale for the study
Why should the right coronary artery (RCA) influence
cavotricuspid isthmus (CTI) ablation?
1. The RCA is in close proximity to the CTI. Anatomic studies
report a distance of approximately 5mm whereas RFlesions penetrate up to 8mm.
2. Isthmus anatomy is highly variable.
3. There are cases of CTI that are resistant to block.
4. At out center higher incidence of failure to block with cryoablation (unreported data).
5. There are few case reports of RCA injury due to ablation.
Cavotricuspid Isthmus Anatomy
Cabrera et al. J Cardiovasc Electrophysiol 2005
Study design
60 patients scheduled for ablation of paroxysmal or persistant AF underwent
cardiac CT for image integration.
The CT protocoll was modified to visualize the right atrium in addition to the
left atrium and coronary arteries.
In 6 patients CT quality was poor due to atrial fibrillation at the time of the CT
study.
Irrigated tip (3.5mm tip, Thermocool, Biosense) CTI ablation was performed
using a step-up protocoll starting at 30W with increments of 5W.
The course of the RCA was tagged at the Ensite Verismo Workstation and
segmentation data were exported for further analysis.
Anatomical variations of the CTI were evaluated using multiplanar
reconstructions of the CT-scans (Merge eFilm).
Invasive follow-up was available for 34 patients who required ablation for
recurrence of atrial fibrillation.
Gaps were detected and reablation performed if necessary
Variations of RCA Anatomy
Ensite Verismo® segmentation of CT model
Possible confounders
What about pouch-like recesses and prominent
Eustachian valves?
Both, pouch-like recesses and prominent Eustachian valves, have
been found to complicate CTI ablation.
(Heidbüchel et al. Circulation 2001; Da Costa et al. Circulation 2004)
Acute CTI-block, however, was achieved in almost all patients.
There are few data on invasive follow-up and late conduction
recurrence.
Variations of CTI Anatomy
straight
pouch
concave
Eust. v.
Threedimensional CTI Model
CTI spatial relation with RCA
septal
inferior
anterior
p*
26 ±8
28 ±8
33 ±9
<0.01
Mean RCA distance from
CTI (mm)
7.3 ±3.3
5.3 ±2.5
5.7 ±2.3
<0.01
Mean RCA distance from
TV (mm)
5.2 ±4.4
5.4 ±4.5
5.8 ±4.6
0.78
Mean Isthmus length
(mm)
Ablation Results I
Ablation Results II
Ablation Results III
Ablation Results IV
7
6
5
4
3
2
1
0
ventricular
central
Gap
RCA at Gap
caval
Conclusion
The proximity of the right coronary artery to the cavotricuspid
isthmus results in a protective (cooling) effect with the requirement
of higher ablation power for closer distances.
Anatomical variations with the RCA leaving the AV-groove towards
the atrial aspect might be responsible for myocardial strands
surviving RF ablation giving rise to late conduction recurrence.