Evaluation of New Non-Pharmacological Therapies for Symptomatic Atrial Fibrillation With Special Emphasis on the Maze Procedure

University dissertation from Uppsala : Acta Universitatis Upsaliensis

Abstract: Atrial fibrillation is a common disease. With pharmacological therapy most patients with atrial fibrillation have moderate or little symptoms, but a number of patients have severely symptomatic disease. This study evaluates two new non-pharmacological therapies for atrial fibrillation, the Maze procedure and atrial overdrive pacing.In the patients planned for Maze surgery the quality of life, assessed with the SF-36 questionnaire, was very low before the operation. The quality of life was markedly improved 6 and 12 months after the Maze operation, and was comparable to values of the general Swedish population.In the patients with sinus rhythm before surgery, the atrial size and transport function was assessed with echocardiography, and the autonomic balance was assessed with heart rate variability (HRV). The sizes of both atria were reduced and the transmitral early filling / atrial filling (E/A) ratio was increased at 6 months after the operation compared to before. A progressive increase of the E/A ratio was seen during the 24 months follow-up period, indicating a progressive decline of the left atrial transport function.All components of HRV, including the parameters expressing sympathetic and parasympathetic modulation, were markedly decreased early after the Maze procedure compared to before. Late after the operation all components of HRV were still markedly depressed. This is interpreted as a partial autonomic denervation of the heartSingle-site right atrial overdrive pacing with two different levels of overdriving was compared with no pacing in patients with paroxysmal atrial fibrillation in a cross-over study. Overdrive pacing reduced the median number of episodes of atrial fibrillation with 50% compared to no pacing. There was no difference between medium rate overdrive pacing and high rate overdrive pacing.