Temporary atrial pacing in the prevention of postoperative atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). Since its prevention with prophylactic drug therapy has limited success, alternative approaches are desirable. This study examined the efficacy of atrial or biatrial pacing, compared with no pacing, on the incidence of AF after isolated CABG. METHODS: From August 2002 to September 2004, 240 patients underwent CABG. After surgery, right and left atrial epicardial pacing wires were implanted for 72 hours of temporary pacing. Patients were randomly assigned to one of three groups: no pacing (control group), right atrial (RA), and biatrial (BiA) pacing. Cardiac rhythm was monitored continuously during intensive care, or daily on the ward. The primary endpoints of this study were an episode of AF occurring up to 72 hours after CABG and the risk factors correlated with this event. RESULTS: Atrial and BiA pacing significantly lowered the incidence (1.25% vs 25%, P = 0.001) of AF episodes, and were both correlated (odd ratio 0.038; 95% confidence interval 0.005-0.29) with a decrease in rates of postoperative AF. Multivariable analysis identified older age (odd ratio 1.074; 95% confidence interval 1.024-1.12) and no pacing as independent risk factors of postoperative AF. CONCLUSIONS: Temporary right atrial or biatrial pacing after CABG significantly decreased the postoperative incidence of AF. Multivariable analysis identified older age and no pacing as predictors of AF occurrence.

Effects of hypertonic saline-dextran solution in cardiac valve surgery with cardiopulmonary bypass.

BACKGROUND: Hypertonic saline-dextran (HSD) solution may be beneficial in patients undergoing coronary artery surgery with cardiopulmonary bypass. Valvular dysfunction is associated with high pulmonary wedge pressure, pulmonary hypertension, and ventricular dysfunction. Fluid overload or transient left ventricular failure may occur with HSD infusion in such patients. This study evaluates the cardiorespiratory effects and tolerance of HSD solution infusion in patients undergoing cardiac valve surgery. METHODS: This prospective, randomized, double-blind study compared clinical, laboratory, hemodynamic, and respiratory measurements, and fluid balance in 50 patients over a 48-hour period after cardiopulmonary bypass for cardiac valve surgery. Twenty-five patients received 4 mL/kg of HSD during 20 minutes before cardiopulmonary bypass (HSD group). The control group received the same volume of Ringer's solution (Ringer group). RESULTS: Hospital mortality was zero. The HSD patients had a near zero fluid balance (6.5 +/- 13.5 mL/Kg/48 hours), and the control patients had a positive balance (91.0 +/- 33.7 mL/Kg/48 hours). Hemoglobin was similar in both groups, but more blood transfusions were necessary in the Ringer group (1.21 +/- 1.28 vs 0.48 +/- 0.59 units per patients). The HSD solution induced a higher cardiac index and left ventricular systolic work index postoperatively, and a lower systemic vascular resistance index until 6, 24, and 48 hours. Right ventricular systolic work index increased and pulmonary vascular resistance index decreased after HSD infusion. A better Pao(2)/Fio(2) relation was observed at 1 and 6 hours postoperatively in the HSD group and was associated with a shorter extubation time (432.0 +/- 123.6 vs 520.8 +/- 130.2 minutes). Increased oxygen delivery index occurred in the HSD group. The HSD infusion was well tolerated as none of the patients experienced fluid overload or had left ventricular failure develop. No other complication attributable to the use of HSD solution was observed. CONCLUSIONS: The HSD solution infusion in patients during cardiac valve surgery with cardiopulmonary bypass was well tolerated. Hemodynamic and respiratory functions improved and fluid balance was near zero during the first 48 hours as compared with a large positive balance in the control group. We conclude that HSD infusion is advantageous for patients undergoing cardiac valve surgery.