Elsevier

Heart Rhythm

Volume 11, Issue 6, June 2014, Pages 984-991
Heart Rhythm

Comparison of lesion formation between contact force-guided and non-guided circumferential pulmonary vein isolation: A prospective, randomized study

https://doi.org/10.1016/j.hrthm.2014.03.019Get rights and content

Background

Contact force (CF) monitoring could be useful in accomplishing circumferential pulmonary vein (PV) isolation (CPVI) for atrial fibrillation (AF).

Objective

The purpose of this study was to compare procedure parameters and outcomes between CF-guided and non-guided CPVI.

Methods

Thirty-eight consecutive AF patients (mean age 60 ± 11 years, 28 paroxysmal AF) undergoing CPVI were randomized to non–CF-guided (n = 19) and CF-guided (n = 19) groups. CPVI was performed with the ThermoCool SmartTouch catheter in both groups. The end-point was bidirectional block between the left atrium (LA) and PV. In the CF group, CF was kept between 10 and 20 g during CPVI, whereas in the non-CF group, all CF information was blanked. Radiofrequency energy at 30 W in the anterior and 25 W in the posterior LA wall was applied for 20–25 seconds at each point.

Results

CPVI was successfully accomplished without any major complications in both groups. Mean CF in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g, respectively, for left-side CPVI, and 9.8 ± 6.6 g and 12.1 ± 4.8 g, respectively, for right-side CPVI (both P <.001). The procedure and fluoroscopy times for CPVI in the non-CF and CF groups were 96 ± 39 minutes and 59 ± 16 minutes, respectively (P <.001), and 22 ± 63 seconds and 9 ± 20 seconds (P = NS), respectively. Total number of residual conduction gaps was 6.3 ± 3.0 in the non-CF group and 2.8 ± 1.9 in the CF group (P <.001). During 6-month follow-up, 84.2% of patients in the non-CF group and 94.7% in the CF group were free from any atrial tachyarrhythmias (P = .34).

Conclusion

CF-guided CPVI is effective in reducing procedure time and additional touch-up ablation and may improve long-term outcome.

Introduction

The efficacy and safety of radiofrequency (RF) catheter ablation of atrial fibrillation (AF) has been established,1 and the 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation recommended ablation as a Class I indication for drug-refractory, symptomatic paroxysmal AF when it is performed by an electrophysiologist who has received appropriate training and is performing the procedure in an experienced center.2 This statement indicated pulmonary vein (PV) isolation as an essential procedure for AF ablation irrespective of the type of AF. The most important and urgent issue in AF ablation is the relatively high recurrence rate after ablation. It has been demonstrated that recurrence of AF after ablation is associated with resumption of conduction between the left atrium (LA) and previously isolated PV.3, 4, 5 Thus, incomplete PV isolation by ablation is responsible for AF recurrence, which indicates the necessity of achieving complete and permanent PV isolation with the use of different technologies other than conventional RF ablation strategies.

One such technology recently developed is a catheter system that can monitor the real-time contact force (CF) of the catheter tip to the endocardial wall during ablation. A recent experimental study revealed that CF is a major determinant of RF lesion size, and CF monitoring may optimize RF power and application time to maximize lesion formation and avoid steam pop and thrombus during ablation.6 Excessive CF has been shown to increase the risk of cardiac perforation.7 A recent clinical study showed that CF during AF ablation correlates with clinical outcome, and arrhythmia control is best achieved by applying an average CF >20 g, whereas clinical failure is universally noted with an average CF <10 g.8 Thus, CF monitoring during ablation is expected to facilitate effectively and safely the procedure of circumferential pulmonary vein isolation (CPVI) for AF.9 To evaluate its advantage prospectively and quantitatively, we randomly assigned AF patients to CF-guided and non-guided CPVI and compared the procedure parameters and outcomes between the 2 groups.

Section snippets

Study population

The study protocol was approved by the Ethics Committee of our institution, and written informed consent was obtained from all patients before the study.

Thirty-eight consecutive patients undergoing CPVI for AF were randomly assigned to non–CF-guided group (non-CF group, n = 19) or CF-guided ablation group (CF group, n = 19). There were 29 men and 9 women (mean age 60 ± 11 years). Twenty-eight patients had paroxysmal AF, and the other 10 had nonparoxysmal AF. The absence of thrombus in the LA

Patient characteristics and results of ablation

Patient characteristics at baseline are given in Table 1 for non-CF and CF groups. Age, prevalence of paroxysmal AF, CHADS2 score, left ventricular ejection fraction, and LA diameter were not different between the 2 groups. All PVs were successfully isolated by CPVI in all of the study patients. There were no major complications during and after CPVI in both groups.

CF during CPVI

Mean CFs during left-side CPVI in the non-CF and CF groups were 5.9 ± 4.5 g and 11.1 ± 4.3 g (P <.001), respectively, and those

Major findings

To evaluate quantitatively the usefulness of CF monitoring in CPVI, we conducted a prospective study in which AF patients undergoing CPVI were randomly assigned to either CF-guided or non-guided ablation, and procedure parameters and outcomes were compared between the 2 groups. The results showed that the procedure time in the CF group was significantly shorter than that in the non-CF group. Mean CF for the whole CPVI was significantly greater in the CF group than in the non-CF group, mainly as

Conclusion

CF-guided CPVI is effective in reducing the procedure time and additional touch-up ablation, and may improve long-term clinical outcome.

References (12)

  • V.Y. Reddy et al.

    The relationship between contact force and clinical outcome during radiofrequency catheter ablation of atrial fibrillation in the TOCCATA study

    Heart Rhythm

    (2012)
  • K.H. Kuck et al.

    A novel radiofrequency ablation catheter using contact force sensing: Toccata study

    Heart Rhythm

    (2012)
  • R. Parkash et al.

    Approach to the catheter ablation technique of paroxysmal and persistent atrial fibrillation: a meta-analysis of the randomized controlled trials

    J Cardiovasc Electrophysiol

    (2011)
  • H. Calkins et al.

    2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design

    Europace

    (2012)
  • R. Cappato et al.

    Prospective assessment of late conduction recurrence across radiofrequency lesions producing electrical disconnection at the pulmonary vein ostium in patients with atrial fibrillation

    Circulation

    (2003)
  • K. Nanthakumar et al.

    Resumption of electrical conduction in previously isolated pulmonary veins: rationale for a different strategy?

    Circulation

    (2004)
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Drs. Okumura and Kimura have received speaker honoraria from Johnson & Johnson K.K. Drs. S. Sasaki and Itoh have received research grant support from Johnson & Johnson K.K. and Medtronic Japan Co. Ltd.

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