Clinical Research
Heart Rhythm Disorder
Effects of Stepwise Ablation of Chronic Atrial Fibrillation on Atrial Electrical and Mechanical Properties

https://doi.org/10.1016/j.jacc.2006.11.033Get rights and content
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Objectives

This study sought to evaluate the effects of stepwise catheter ablation of chronic atrial fibrillation (AF) on atrial electrical and mechanical properties.

Background

Although stepwise catheter ablation of chronic AF is associated with acute arrhythmia termination and a favorable clinical outcome, atrial tissue damage following the procedure has not been evaluated.

Methods

Forty patients who had previously undergone catheter ablation of chronic AF were studied. In the index procedure, termination of AF was achieved by catheter ablation alone in 36 of 40 patients (90%). Electroanatomical mapping was performed in sinus rhythm ≥1 month after the index procedure, during which the surface area of scar (bipolar voltage of <0.05 mV), low-voltage tissue (<0.5 mV), and atrial propagation were evaluated. Left atrial (LA) mechanical function was assessed by transthoracic echocardiography.

Results

Electroanatomical mapping showed areas of scar and low-voltage accounting for 31% ± 12% and 32% ± 17% of the total LA surface area respectively, with the ablated pulmonary vein region accounting for 20% ± 4% of the LA surface area. The area of scar outside the pulmonary vein region represented 14% ± 12% of the LA surface area using the initial randomized ablation strategy, and 6% ± 8% (p = 0.02) using a specific ablation strategy. Atrial conduction was diversely affected by ablation with a wide range of LA conduction times observed (range 100 to 360 ms). The LA contraction was shown in all patients by the presence of late diastolic mitral flow (37 ± 15 cm/s) and a mean LA active emptying fraction of 18 ± 11%. At 9 ± 5 months of follow-up, 39 patients (98%) were in sinus rhythm.

Conclusions

Stepwise ablation achieving sinus rhythm in patients with chronic AF has a significant impact on LA electrical activity but is associated with recovery of LA function.

Abbreviations and Acronyms

AF
atrial fibrillation
AT
atrial tachycardia
CS
coronary sinus
LA
left atrium
LAA
left atrial appendage
LV
left ventricle
PV
pulmonary vein
RA
right atrium
SVC
superior vena cava

Cited by (0)

1

Dr. O’Neill is supported by a British Heart Foundation International Fellowship.

2

Dr. Jonsson is supported by the Swedish Society of Cardiology.

3

Dr. Rostock is supported by the German Cardiac Society.

4

Dr. Rotter is supported by the Swiss National Foundation for Scientific Research, Bern, Switzerland.

5

Dr. Sanders is supported by the Neil Hamilton Fairley Fellowship from the National Health and Medical Research Council of Australia and the Ralph Reader Fellowship from the National Heart Foundation of Australia.

6

Drs. Jaïs, Sanders, and Haïssaguerre have served on the advisory boards of and have received lecture fees from Biosense-Webster and Bard Electrophysiology.

7

Drs. Hocini and Rotter have received lecture fees from Biosense-Webster.