title: Effects of anesthetic induction in patients with diastolic dysfunction.
abstract: OBJECTIVE
  To evaluate the effects of anesthetic induction on bi-ventricular function in patients with known preoperative left ventricular (LV) diastolic dysfunction undergoing coronary artery bypass grafting surgery (CABG).
  
  
  METHODS
  Fifty patients with diastolic dysfunction undergoing CABG were studied. Preoperative transthoracic echocardiographic (TTE) examination was performed on the day before surgery and transesophageal echocardiography (TEE) assessment was undertaken after induction of anesthesia with sufentanil, midazolam, isoflurane, and pancuronium. Mean arterial pressure (MAP) and heart rate (HR) were recorded. The diameters of the left atrium (LA) and right atrium (RA) and right ventricular (RV) end-diastolic area (EDA), end-systolic area (ESA) and fractional area change (FAC) were obtained from the apical 4-chamber view. The LV EDA, LV ESA and LV FAC were measured from a transgastric midpapillary view. Pulsed wave Doppler of the transmitral flow (TMF) and transtricuspid flow (TTF), pulmonary venous flow (PVF) and hepatic venous flow (HVF) were measured. Mitral (Em, Am) and tricuspid (Et, At) annulus velocities were assessed by tissue Doppler imaging (TDI). Assessment of diastolic dysfunction was graded from normal to severe using a validated score.
  
  
  RESULTS
  Following induction of anesthesia, HR decreased (66 +/- 12 vs 55 +/- 9 beats.min(-1), P < 0.0001) while MAP remained unchanged (86.1 +/- 9.0 vs 85.6 +/- 26.5 mmHg, P = 0.94). The diameters of the LA, RA and RV chambers increased, and these increases were associated with opposite changes in LV dimensions. The RV FAC decreased, but the LV FAC remained unchanged. While most Doppler velocities decreased (P < 0.05), a greater reduction in the atrial components of the TMF, TTF and TDI ratios was observed. The LV diastolic function score improved after induction of anesthesia (100% of patients with a score > or = = 3 pre-induction compared to 58% of patients with a score > or = 3 post-induction; P = 0.0004).
  
  
  CONCLUSIONS
  In patients with left ventricular diastolic dysfunction, cardiac dimensions and bi-ventricular filling patterns are significantly altered after induction of general anesthesia. These changes can be explained to some extent by a reduction in venous return with general anesthesia, reduced atrial contractility, and the effect of positive pressure ventilation. Although the LV diastolic function score improved after induction of anesthesia, it is difficult to dissociate this effect from that of altered loading conditions.
authors.affiliation: Department of Anesthesiology, Montreal Heart Institute and Université de Montréal, 5000 Belanger Street, Montreal, QC, H1T1C8, Canada. pierre.couture@icm-mhi.org
authors.forename: Pierre
authors.initials: P
authors.lastname: Couture
authors.forename: André Y
authors.initials: AY
authors.lastname: Denault
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Shi
authors.forename: Alain
authors.initials: A
authors.lastname: Deschamps
authors.forename: Mariève
authors.initials: M
authors.lastname: Cossette
authors.forename: Michel
authors.initials: M
authors.lastname: Pellerin
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Tardif