Prevention of heart rhythm disorder (atrial fibrillation) after open heart surgery by combining pacing therapy with anti-arrhythmic drugs.

Postoperative atrial fibrillation (POAF) is an important complication of cardiothoracic surgery. Pharmacological strategies can diminish, but not prevent POAF, therefore other than pharmacological treatments need to be developed in order to reduce the incidence of POAF. (part I)

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia in adults with growing socio-economic burden. Although a significant progress has been made in understanding the pathophysiology of this arrhythmia, treatment of AF patients is still far from satisfactory. The success rate of electric cardioversion is still limited and anti-arrhythmic drugs are unable to prevent recurrences of AF. Prevention of thromboembolic events still requires anticoagulation therapy with all the associated risks. Ablation techniques vary in their efficacy to cure persistent AF. Only a better understanding of this disease can lead to a better treatment. (part II)

Objectives

To determine the add-on value of bi-atrial pacing in combination with standardised Sotalol treatment for the prevention of postoperative atrial fibrillation (POAF).
To study the development of the electropathological substrate (the conduction pattern of fibrillating waves in fibrillating atria) in atrial fibrillation in humans.

Study design

This is an open prospective randomised trial, comparing two treatment strategies (with or without bi-atrial pacing) for postoperative AF on a long-term basis, using trans-telephonic electrocardiographic monitoring until 4 weeks after surgery. Epicardial mapping will be conducted in patients in the non-pacing group and in patients with concomitant AF.

Population

All will-competent patients who are undergoing primary cardiac surgery (valve surgery or coronary artery bypass grafting) will be enrolled. Patients who already underwent heart surgery (reoperation) will not qualify for participation in this study.

Intervention

Bi-atrial pacing for 72 hours postoperatively in the pacing group.
(Peroperative high density mapping of the right and left atrium with a 64 and 256 channel electrode.)

Primary study parameters/ primary outcome

To determine the difference in incidence of POAF between the pacing and the non pacing group

To define an 'AF-score' in epicardial mapping patients using the parameters derived from wave analysis correlated to the clinical characteristics of the patients and tissue parameters. This is more an outcome parameter than an endpoint.

Secondary study parameters/ outcome

Analysis of preoperative echocardiographic findings: left ventricle function, atrial size, valve defects.

Microscopic and biochemical research of the atrial biopsies: quantification of fibrosis and hypertrophy.

Biomarkers and genetic markers for atrial fibrillation.

Quantification of postoperative AF for each patient based on daily printouts of telemetry and analysis of Vitaphone data.
Clinical parameters (age, hemodynamics, relevant medical history, etc.

Patient burden/ risks

Peroperative high density mapping of left and right atrium will take place in the mapping group. Postoperative biatrial pacing will take place for 72 hours in the pacing group. In the mapping group there will be a preoperative echocardiography if

-if no echocardiography has been made

-if atrial data can not be obtained out of previous echocardiographies

and 3 additional blood withdrawals (24,5cc each time).

There will be a 4 weeks postoperative follow-up using an event loop recorder (Vitaphone). After 4 weeks patients will be seen again and the Vitaphone will be stopped. Based on their heart rhythm, patients can be invited to come back in one year for another week of Vitaphone.
Their will be no risk of thromboembolic event during induction of acute AF as the patients will be heparinised. Mapping will take place before cardiopulmonary bypass and will not affect the aortic clamp time. There will be a prolonged anaesthesia time in the mapping group.

Combination of biatrial pacing and class III anti-arhythmic drug Sotalol will significantly reduce incidence, frequency and duration of postoperative atrial fibrillation.

6 weeks of postoperative rhythm monitoring using a transtelephonic loop-event-recorder (Vitaphone).

Postoperative pacing in combination with Sotalol treatment

Electrophysiological mapping studies