title: Optimized temporary bi-ventricular pacing improves haemodynamic function after on-pump cardiac surgery in patients with severe left ventricular systolic dysfunction: a two-centre randomized control trial.
abstract: OBJECTIVE
  Optimized temporary bi-ventricular (BiV) pacing may benefit heart failure patients after on-pump cardiac surgery compared with conventional dual-chamber right ventricular (RV) pacing. An improvement in haemodynamic function with BiV pacing may reduce the duration of 'Level 3' intensive care.
  
  
  METHODS
  Thirty-eight patients in sinus rhythm, ejection fraction ≤35%, undergoing on-pump surgical revascularization, valve surgery or both were enrolled in this study. Before closing the sternum, temporary epicardial pacing wires were attached to the right atrium, RV outflow tract and basal posterolateral wall of the left ventricle. Patients were randomly assigned to postoperative BiV pacing with the optimization of the atrio- (AV) and inter-ventricular (VV) pacing intervals (Group 1) or conventional dual-chamber right AV pacing (Group 2). The primary end-point was the duration of 'Level 3' intensive care. Secondary end-points included cardiac output which was measured by thermodiluation at admission to the intensive care unit and at 6 and 18 h later, in five different pacing modes.
  
  
  RESULTS
  The duration of 'Level 3' care was similar between groups (40 ± 35 vs 54 ± 63 h; Group 1 vs 2; P = 0.43). Cardiac output was similar in all pacing modes at baseline. At 18 h, cardiac output with BiV pacing (5.8 l/min) was 7% higher than atrial inhibited (5.4 l/min) and 9% higher than dual-chamber RV pacing (5.3 l/min; P = 0.02 and 0.001, respectively). Optimization of the VV interval produced a further 4% increase in cardiac output compared with baseline settings (P = 0.005).
  
  
  CONCLUSIONS
  Postoperative haemodynamic function may be enhanced by temporary BiV pacing of high-risk patients after on-pump cardiac surgery.
authors.affiliation: Wales Heart Research Institute, Cardiff University, Cardiff, UK. russellsj1@cf.ac.uk
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Russell
authors.forename: Christine
authors.initials: C
authors.lastname: Tan
authors.forename: Peter
authors.initials: P
authors.lastname: O'Keefe
authors.forename: Saeed
authors.initials: S
authors.lastname: Ashraf
authors.forename: Afzal
authors.initials: A
authors.lastname: Zaidi
authors.forename: Alan G
authors.initials: AG
authors.lastname: Fraser
authors.forename: Zaheer R
authors.initials: ZR
authors.lastname: Yousef
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002302:Cardiac Output; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D003422:Critical Care / Q000706:statistics & numerical data; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods*; D011183:Postoperative Complications; D016037:Single-Blind Method; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000503:physiopathology
chemical_list: D015415:Biomarkers