The loss of circadian heart rate variations in patients undergoing mitral valve replacement and Corridor procedure - comparison to heart transplant patients

We have presently demonstrated that when added to mitral valve replacement (MVR) the corridor procedure is 75% efficient in restoring and maintaining sinus rhythm in patients with chronic atrial fibrillation (AF), caused by r heumatic mitral valve disease, (follow up 13.9 months). In the same patient population, we observed that the typical day-night cycle heart rate (HR) v ariations were lost and our present study concentrates on this subject. Hea rt rate variability analysis based on 24-h Holter ECG recording (StrataScan 563 DelMar Avionics) or hospital discharge (12th-14th postoperative days) was performed in 3 patient groups: Group I: Patients with a Corridor proced ure added to MVR (12 pts, m/f 10/2, mean age 47.3 +/- 7.5 yr); Group II (co ntrol): with patients MVR performed through the left atrial approach, witho ut additional antiarrhythmic procedures (10 pts, m/f 3/7 mean age 51.5 +/- 6.7 yr), and Group III: heart transplant recipients (5 pts, mean age 46.4 /- 11.22 yr). We analyzed the hourly heart rate over 24-h period divided in to three 8-h segments (07-14 h: 15-22 h and 23-06 h). Statistical compariso n of mean hourly heart rate values was made between the three time periods of Holter monitoring. The Corridor procedure performed with mitral valve re placement resulted in conversion of sinus rhythm in 75% of patients (Group I), but postoperative heart rate variability analyses based on Holter monit oring disclosed that the mean heart rate was not statistically significantl y difficult between the three 8-h segments of the day-night (P > 0.05). The same results were found in the group of patients after heart transplant (P > 0.05). The same results were found in the group of patients after heart transplant (P > 0.05). In the second group (classical MVR), statistically s ignificant differences in mean HR variation existed between the three 8-h i ntervals (P < 0.05), and although atrial fibrillation occurred postoperativ ely physiologic circadian heart rate variations were preserved. With the Corridor procedure, both atria were surgically and electrically is olated and chronotropic function of the ventricles was restored by creating a small strip of atrial tissue with isolated sinus node and atrio-ventricu lar node, connected to the ventricles, This technique produced heart denerv ation nervous system influence, producing the loss of circadian HR variatio ns, similar to the transplanted heart. (C) 2001 The International Society f or Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights re served.