DELAYED IMPROVEMENT IN EXERCISE CAPACITY WITH RESTORATION OF SINOATRIAL NODE RESPONSE IN PATIENTS AFTER COMBINED TREATMENT WITH SURGICAL REPAIR FOR ORGANIC HEART-DISEASE AND THE MAZE PROCEDURE FOR ATRIAL-FIBRILLATION

Background Although the Maze procedure successfully restores sinus rhy thm in patients with heart disease and atrial fibrillation, it is stil l uncertain whether an addition of the Maze procedure in cardiac surge ry is beneficial for exercise performance of the patients after surger y. Methods and Results The Maze procedure was performed in 25 patients (age, 37 to 70 years) during valve surgery (18 patients) or closure o f atrial septal defect (7 patients). A cardiopulmonary exercise test u sing ramp incremental protocol (15 W/min) was performed before and 1 m onth, 6 months, and 1 year after surgery. Sinus conversion was obtaine d in 23 of 25 patients 1 month after surgery. However, sinoatrial (SA) node response to exercise was attenuated by surgery: Mean heart rate (HR) was 83+/-13/min at rest, 94+/-13/min at 60 W, and 107+/-17/min at peak exercise. Peak oxygen uptake (PVO2) was unchanged at this period (before, 17.6+/-4.5 mL . min(-1) . kg(-1); 1 month after, 17.5+/-4.2 mL . min(-1) . kg(-1)). Thereafter, SA node response was restored 6 mo nths after surgery: Mean HR was 84+/-13/min at rest, 104+/-16/min at 6 0 W, and 130+/-20/min at peak exercise (P<.01 versus 1 month). PVO2 wa s also improved at this period (20.7+/-4.0 mL . min(-1) . kg(-1), P<.0 1), The in crease in PVO2 from 1 month to 6 months after surgery was c orrelated with the increase in peak HR (y=0.73+/-3.6, r=.79). There we re no further changes in heart rate response or PVO2 from 6 months to 1 year after surgery. Conclusions Atrial fibrillation was successfully treated by combined treatment with surgical repair for organic heart disease and the Maze procedure. However, SA node response to exercise was attenuated early after surgery. Thus, exercise capacity was improv ed at the late phase after surgery, which was related to the extent of restoration in SA node response.