efficiency study evaluating the use of pvac catheter technology for performing ablation in pts with atrial fibrillation

Conditions: Atrial Fibrillation

Summary: atrial fibrillation (af) is the most common arrhythmia affecting the canadian population. af is associated with increased risk of stroke,hf, and even mortality. af can cause debilitating symptoms, adversely affect patient's (pt's) quality of life and functional status. hence a strategy of sinus rhythm (sr) may be pursued over a strategy of allowing af to persist. percutaneous catheter ablation is an effective alternative to antiarrhythmic drugs (aad) for maintaining sr. the success rate of pv isolation off aad is about 80-90% in pt's with paf, but repeat procedures are required in up to 40% of pt's. after one ablation, the success rate may only be 50-70% off drugs.current standard ablation procedures for pv antral isolation employ mapping systems which reconstructions of the la and pv anatomy are created. visualization may be supplemented by integration of ct/ mri images and/or intracardiac echocardiography. robotic navigation has been employed to assist in ablation. based on single point unipolar radiofrequency (rf) ablation catheter where lesions are created point-by-point around the pvs to obtain electrical isolation.this results in lengthy complex, costly procedures,often more than 4 hours, which requires high degree of operator skill.creation of contiguous, transmural lesions is challenging with standard single-point rf. a novel multipolar catheter ablation system has been evaluated for achieving pv isolation (pvac catheter, medtronic inc.) an over-the-wire circular mapping/ablation catheter can be advanced into the pv antrum, and multiple lesions around the circumference of the catheter can be delivered simultaneously using duty-cycled unipolar and bipolar rf energy. early reports, the system can achieve complete pv isolation with reduced fluoroscopy and procedural times using lower powers to achieve more reliable lesion sets.long-term efficacy also seems comparable to standard rf ablation.this novel technology has potential to broaden the application of af ablation, making procedures less time-consuming, less complex without compromising procedural efficacy. published data pvac technology outcomes are limited to studies with small sample sizes of 12-102 pt's. data has been restricted to a small number of european centers performing moderate numbers of pvac procedures. there is no prospective, multicenter data. little is known about the efficiency of pvac procedures, allowing for an assessment of cost-effectiveness in using this technology.

this is a multicenter, open label, prospective, cohort study. patients undergoing ablation with pvac technology in up to 15 centers across canada will be enrolled, ablated, and followed for one year post-ablation. both primary and secondary objectives of the study will be determined from this cohort of patients. comparisons to the traditional ablation methods will be made by collecting data from a prospective group of control subjects who are undergoing af ablation with traditional ablation technology at the same centers by the same operators. control patients will be enrolled in a 1:2 ratio compared to the pvac cohort. while the final ratio of control to pvac patients must be 1:2 by study end for each operator, the ratio may vary while the study is conducted to allow some flexibility in patient recruitment. however, the absolute difference between \[# of pvac patients\] and 2x\[# control patients\] should not exceed 5 at any given time for any operator in any study center

Eligibility criteria:
inclusion criteria: * patients aged 18 years or greater. * patients undergoing first-time catheter ablation for af. * patients with paroxysmal af. paroxysmal af will be defined as self-terminating episodes less than 7 days duration. patients should have had at least 3 episodes of af in a one year period. * patients with symptomatic af that is refractory to at least one antiarrhythmic medication. "symptomatic" patients are those who have been aware of their af anytime within the last 5 years prior to enrollment. symptoms may include, but are not restricted to, palpitations, shortness of breath, chest pain, fatigue, or any combination of the above. * at least one episode of af must have been documented by ecg, holter, loop recorder, telemetry, or transtelephonic monitoring within 24 months of enrollment in the study. * patients must be able and willing to provide written informed consent to participate in the clinical study. exclusion criteria: * patients with persistent af (defined as an episode of af lasting \>7 days). * patients with af felt to be secondary to an obvious reversible cause. * patients with contraindications to systemic anticoagulation with heparin or warfarin or a direct thrombin inhibitor. * patients who have previously undergone af ablation. * patients with left atrial size \>/= 55 mm (2d echocardiography, parasternal long axis view). * patients who are or may potentially be pregnant.

Keywords: radiofrequency ablation atrial fibrillation pvac