Pulmonary vein isolation using “contact force” ablation: The effect on dormant conduction and long-term freedom from recurrent atrial fibrillation—A prospective study
Introduction
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice and is associated with reductions in quality of life, functional status, cardiac performance, and overall survival.1 Radiofrequency catheter ablation centered on electrical isolation of triggering foci within the pulmonary veins (PVs) through circumferential lesions around PV ostia (pulmonary vein isolation [PVI]) and/or elimination of the arrhythmic substrate has been shown to be a highly effective option for patients with both paroxysmal and persistent AF.2 Unfortunately, despite initial procedural success, up to 20% to 40% of patients will require a second intervention because of arrhythmia recurrence, which most often is due to recovery of conduction between PVs and the left atrium (LA).3, 4, 5, 6, 7, 8
Ablation electrode–tissue contact is an important determinant of lesion size and ultimately of durability. Conventionally, this has been assessed by the operator using a combination of fluoroscopic and electroanatomic imaging of catheter tip motion, tactile feedback, and local electrogram attenuation and impedance reductions during energy delivery. Although widely used, the accuracy of these surrogate measures is poor.9, 10 Contact force sensing is a newly developed technology that allows for real-time estimation of the contact force between the tip of the catheter and the target myocardium, which providing the operator with accurate quantitative assessment of tissue contact.
One such technology is contained in the ThermoCool SmartTouch mapping and ablation catheter (Biosense Webster, Diamond Bar, CA). The force-sensing capability of this catheter is based on the electromagnetic location technology used in the CARTO system (Biosense Webster). Specifically, a precision spring mounted within the tip of the electrode is connected to a transmitter coil, which emits a location reference signal to 3-location sensor coils mounted within the shaft of the catheter. The micromovements of the spring are sampled every 50 ms and calibrated to produce a contact force reading (in grams) based on the known spring characteristics as well as the location information of the sensor. The purpose of this study was to evaluate the effect of a “contact force”–guided approach on the immediate (prevalence of adenosine-induced dormant PV conduction) and long-term outcomes (freedom from recurrence of atrial tachyarrhythmia) compared to standard ablation.
Section snippets
Study population
Seventy-five consecutive patients with highly symptomatic paroxysmal AF refractory to antiarrhythmic drugs referred for catheter ablation at either of the participating centers (Montreal Heart Institute or Florida Hospital Cardiovascular Institute) between August 2011 and October 2012 were prospectively enrolled in this pragmatic parallel cohort study. All patients had structurally normal hearts as assessed by clinical evaluation and cardiac imaging (echocardiography, computed tomography,
Baseline parameters
A total of 75 consecutive patients (58.8 ± 12.0 years; 82% male) were enrolled in the study protocol. Mean AF duration before enrollment was 61.7 ± 66.1 months. Overall, mean LA diameter was 36.9 ± 9.6mm, and left ventricular ejection fraction (LVEF) was 61.1% ± 5.6%. Only 9 patients (12%) had CHADS score >1. Baseline characteristics broken down by study group are given in Table 1. LVEF was significantly higher in the contact force group (P = .012), although no patient had LVEF <50%. There were
Discussion
The study demonstrated the following key findings. In patients with a history of drug-refractory paroxysmal AF undergoing PVI, use of contact force–guided ablation resulted in a significant reduction in the prevalence of dormant conduction unmasked with adenosine provocation and a superior 1-year freedom from recurrent AF/AT/AFL on intense arrhythmia monitoring.
These findings have important clinical implications. Although wide circumferential PVI is an established treatment for patients
Conclusion
Ablation guided by real-time contact force assessment results in a significant reduction in the prevalence of dormant conduction unmasked with adenosine provocation as well as improved long-term freedom from recurrent AF. The utility of this approach needs to be evaluated in a larger-scale, prospective randomized trial.
References (30)
- et al.
Acute treatment of atrial fibrillation: why and when to maintain sinus rhythm
Am J Cardiol
(1998) - et al.
Histopathologic characterization of chronic radiofrequency ablation lesions for pulmonary vein isolation
J Am Coll Cardiol
(2012) - et al.
A novel radiofrequency ablation catheter using contact force sensing: TOCCATA study
Heart Rhythm
(2012) - et al.
The relationship between contact force and clinical outcome during radiofrequency catheter ablation of atrial fibrillation in the TOCCATA study
Heart Rhythm
(2012) - et al.
Contact force sensing technology identifies sites of inadequate contact and reduces acute pulmonary vein reconnection: a prospective case control study
Int J Cardiol
(2013) - et al.
Adenosine following pulmonary vein isolation to target dormant conduction elimination (advice): methods and rationale
Can J Cardiol
(2012) - et al.
Dormant pulmonary vein conduction induced by adenosine in patients with atrial fibrillation who underwent catheter ablation
Am Heart J
(2011) - et al.
Impact of atrial fibrillation on mortality, stroke, and medical costs
Arch Intern Med
(1998) - et al.
Response of atrial fibrillation to pulmonary vein antrum isolation is directly related to resumption and delay of pulmonary vein conduction
Circulation
(2005) - et al.
Recovered pulmonary vein conduction as a dominant factor for recurrent atrial tachyarrhythmias after complete circular isolation of the pulmonary veins: lessons from double lasso technique
Circulation
(2005)
Prospective assessment of late conduction recurrence across radiofrequency lesions producing electrical disconnection at the pulmonary vein ostium in patients with atrial fibrillation
Circulation
Resumption of electrical conduction in previously isolated pulmonary veins: rationale for a different strategy?
Circulation
Efficacy of repeat pulmonary vein isolation procedures in patients with recurrent atrial fibrillation
J Cardiovasc Electrophysiol
Worldwide survey on the methods, efficacy, and safety of catheter ablation for human atrial fibrillation
Circulation
Contact sensing provides a highly accurate means to titrate radiofrequency ablation lesion depth
J Cardiovasc Electrophysiol
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