title: Cardiac output is not affected during intraoperative testing of the automatic implantable cardioverter defibrillator.
abstract: BACKGROUND
  Perioperative mortality of patients undergoing implantation of automatic implantable cardioverter defibrillators (ICDs) has been reduced dramatically following the availability of transvenous-subcutaneous defibrillation leads. However, patients with severely reduced left ventricular function show a substantial rate of nonsudden cardiac mortality within the first year. Whether repeated intraoperative inductions of ventricular tachycardia/fibrillation (VT/VF) during implantation lead to hemodynamic deterioration and thus might contribute to development of end-stage heart failure in these patients is unknown. The purpose of the present study was to determine cardiac output and hemodynamic performance during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction.
  
  
  RESULTS
  In 11 patients with a left ventricular ejection fraction (EF) < or = 0.35, cardiac output was measured automatically with a combined continuous cardiac output/mixed venous oxygen saturation pulmonary artery catheter system. ICD implantation was performed during standardized general anesthesia. In the 11 patients (EF = 27 +/- 2% [mean +/- SEM]) a total of 95 episodes of VT/VF followed by defibrillation were induced (episodes per patient = 9 +/- 1; range 6 to 11). Cardiac index was 2.2 +/- 0.2 L.min-1.m-2 after induction of anesthesia (before start of surgery), and 1.9 +/- 0.1 L.min-1.m-2 immediately before first induction of VT/VF. After the last episode of VT/VF, cardiac index was 2.1 +/- 0.2 L.min-1.m-2. Cardiac index measured 1, 2, and 3 minutes after induction of VT/VF was not significantly different when compared to the preinduction value during any episode of VT/VF induction. Similarly, stroke volume index was 39 +/- 5 mL.m-2 immediately before first induction of VT/VF and 36 +/- 3 mL.m-2 after the last episode of VT/VF (NS). At the end of surgery, hemodynamic parameters did not exhibit any significant difference when compared to the data obtained before start of ICD implantation and testing.
  
  
  CONCLUSIONS
  Extensive defibrillation tests during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction are not associated with acute deterioration of cardiac performance.
authors.affiliation: Klinik und Poliklinik für Anästhesiologie und operative Intensivmedizin, Münster, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Meyer
authors.forename: T
authors.initials: T
authors.lastname: Möllhoff
authors.forename: T
authors.initials: T
authors.lastname: Seifert
authors.forename: J
authors.initials: J
authors.lastname: Brunn
authors.forename: J
authors.initials: J
authors.lastname: Rötker
authors.forename: M
authors.initials: M
authors.lastname: Block
authors.forename: T
authors.initials: T
authors.lastname: Prien
mesh_terms: D002302:Cardiac Output; D017147:Defibrillators, Implantable; D006321:Heart / Q000503:physiopathology; D006334:Heart Function Tests; D006439:Hemodynamics; D006801:Humans; D007432:Intraoperative Period; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000601:surgery*