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Title: Interventional electrophysiology in advanced heart disease atrial fibrillation and heart failure
Author: Jones, David Gareth
ISNI:       0000 0004 2735 4108
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2013
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The optimal therapy for atrial fibrillation (AF) associated with heart failure (HF) is unclear. Drug-based rhythm control has not proved clinically beneficial. Catheter ablation-based rhythm control improves cardiac function in HF patients, but impact on physiological performance has not been formally evaluated in a randomised trial. A randomised trial was designed and conducted, comparing catheter ablation with rate control in adults with symptomatic heart failure, radionuclide left ventricular ejection fraction (EF) ≤35%, and persistent AF. The primary outcome was change in peak oxygen consumption (VO2) at cardiopulmonary exercise test. Secondary endpoints included change in quality of life (Minnesota), 6-minute walk, BNP, and EF. Patients were followed-up for 12 months, and results analysed by intention-to-treat. 52 patients (63±9y, EF 24±8%, VO2 17.3±5.1ml/kg/min) were randomised, 26 to each arm. In the ablation arm, at 12 month follow up, 88% maintained SR, with a single procedure success of 69%. In the rate control arm, rate criteria were achieved in 96% at 12 months. At 12 months, peak VO2 had increased by 2.13 (95%CI -0.1 to 4.36) ml/kg/min in the ablation arm, compared with a decrease (-0.94ml/kg/min, 95%CI -2.21 to 0.32) under rate control: mean benefit of ablation +3.07ml/kg/min, 95% CI 0.56-5.59, p=0.018. The change appeared progressive, with a difference of only 0.79ml/kg/min at 3 months (95% CI -1.01 to 2.60, p=0.38). Compared with rate control, ablation reduced 12-month Minnesota score (p=0.019) and BNP (p=0.045), and showed trends toward increased 6 min walk distance (p=0.095) and EF (p=0.055). LA size fell significantly after ablation (p=0.001). Catheter ablation of persistent AF in patients with HF, with the ablation strategy achieving sinus rhythm in the majority, improves prognostically important objective cardiopulmonary exercise performance, symptoms and neurohormonal status. The effects are clear at 1 year but less distinct earlier, suggesting a period of cardiac remodelling and recovery.
Supervisor: Wong, Tom ; Markides, Vias ; Collins, Peter Sponsor: St. Jude Medical, Inc.
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral