A sham-controlled evaluation of pulmonary vein isolation in atrial fibrillation

This thesis presents the results of the first randomised, sham-controlled trial of pulmonary vein isolation for the treatment of symptomatic atrial fibrillation (AF). Despite catheter ablation being widely used and endorsed by international guidelines, there are concerns that pulmonary vein isolation may have a profound placebo effect. Its efficacy has not previously been tested against a placebo procedure. In a dual centre, double-blind design, patients with symptomatic paroxysmal or persistent AF were randomised to undergo either cryoablation or a sham procedure. The study assessed changes in AF burden using continuous rhythm monitoring, symptoms and quality of life. The results showed a significant reduction in AF burden with improvements seen in symptoms and quality of life metrics providing strong evidence that pulmonary vein isolation delivers genuine symptomatic improvement with no placebo effect. The thesis also explores the relationship between AF burden and quality of life, showing a strong association between symptom improvement and AF burden reduction. These findings highlight the value of combining objective and patient-reported outcomes in future research. In summary, pulmonary vein isolation resulted in a statistically significant and clinically important decrease in AF burden with substantial improvements in symptoms and quality of life when compared to a sham procedure.