Atrial fibrillation (AF) is an irregular heart rhythm that occurs in 30% to 40% of patients following heart surgery. This irregular heart rhythm, although often self-limiting, can be cause for concern. AF is associated with a two-fold increase in patient complications and mortality after heart surgery. During AF, the heart muscle does not contract properly causing the blood flow through the heart to slow down potentially forming clots. A clot may then enter the blood stream and be carried to the brain, possibly causing a stroke. Patients in persistent AF require blood thinners to prevent strokes, and this carries its own bleeding risks especially in elderly patients.

Patients in AF after heart surgery spend twice as many days in the intensive care unit and 3 to 4 more days in the hospital, hence the impact on hospital resources is quite significant. Various medications are used to prevent AF after heart surgery but they are unable to completely prevent this complication and the medications have associated side effects. In an effort to optimize the care of heart surgery patients, strategies set on eliminating the onset of AF after surgery, as opposed to trying to control AF with less than effective medications, is a necessity.

We are proposing a study to determine if isolating the misfiring areas that cause AF at the time of bypass surgery in high-risk patients will decrease the occurrence of AF following heart surgery. Consenting patients will be randomized to one of two groups. Group 1 will undergo bypass surgery plus the additional procedure of pulmonary vein isolation and Group 2 will undergo bypass surgery only, without the additional procedure. Four staff cardiac surgeons at the London Health Sciences Centre will perform all surgeries. Patients will be seen postoperatively every six months and will be followed for a two-year period. The occurrence of AF will be recorded as well as other complications and lengths of hospital stay. We predict that the group with the additional pulmonary vein isolation procedure to prevent AF will have a much lower occurrence of this complication. If this is found to be beneficial, this will significantly decrease the complications and mortality associated with heart surgery. This will have a profound effect in the delivery of care to patients with coronary artery disease and other forms of heart disease.