title: Short atrioventricular delay dual-chamber pacing early after coronary artery bypass grafting in patients with poor left ventricular function.
abstract: OBJECTIVE
  To investigate the effect of short atrioventricular (AV) delay dual-chamber pacing on mean arterial pressure (MAP) and stroke volume index (SVI) in patients with poor left ventricular (LV) function after cardiac surgery.
  
  
  METHODS
  A prospective study.
  
  
  METHODS
  A university hospital, single-center study.
  
  
  METHODS
  The study group consisted of 20 patients aged 63 +/- 9 years with a left ventricular ejection fraction (LVEF) less than 30%. The control group consisted of 20 patients aged 61 +/- 10 years, with an LVEF greater than 50%.
  
  
  METHODS
  Immediately after routine coronary artery bypass grafting (CABG) the AV delay was shortened from 160 to 40 milliseconds in atrial-paced (DDD) mode and from 100 to 40 milliseconds in atrial-sensed ventricular stimulation (VDD) mode. MAP was on-line monitored and SVI was calculated by thermodilution. In one patient with an LVEF of 18% (case study), transmitral flow velocity and LV isovolumetric relaxation time were assessed using Doppler echocardiography during VDD pacing at 40-, 80-, and 120-millisecond AV delay.
  
  
  RESULTS
  Short-AV delay DDD pacing decreased MAP in the control group (84.3 +/- 9 v 75.7 +/- 9 mmHg; p < 0.05) and SVI in both groups (study group, 35.9 +/- 7 v 31.7 +/- 7 mL/m2; control group, 35.3 +/- 6 v 31.0 +/- 6 mL/m2; p < 0.05). Shortening the AV delay had no influence on MAP and SVI during VDD pacing. During the echocardiographic case study, AV delay shortening distinctly modified ventricular filling patterns. Optimal LV filling and transmitral flow were achieved with an intermediate AV delay of 80 milliseconds.
  
  
  CONCLUSIONS
  Dual-chamber pacing with nonphysiologic short AV delay failed to improve acute hemodynamics in patients with poor LV function after CABG. Short AV delay VDD pacing was superior to DDD pacing in both normal and impaired LV function. The use of Doppler echocardiography enabled optimization of the AV delay on the basis of LV filling patterns.
authors.affiliation: Department of Cardiothoracic Surgery and Anesthesiology, University of Regensburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Liebold
authors.forename: G
authors.initials: G
authors.lastname: Rödig
authors.forename: J
authors.initials: J
authors.lastname: Merk
authors.forename: D E
authors.initials: DE
authors.lastname: Birnbaum
mesh_terms: D001783:Blood Flow Velocity; D001794:Blood Pressure; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D015150:Echocardiography, Doppler; D005260:Female; D006327:Heart Block / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D011446:Prospective Studies; D013318:Stroke Volume; D013815:Thermodilution; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*