Intravenous Beta-blockade for Improvement of Autonomic Activity
Status:
Completed
Trial end date:
2009-11-01
Target enrollment:
Participant gender:
Summary
Chronic beta-adrenoceptor blockade is known to improve outcome of high risk patients whereas
amelioration of autonomic activity was demonstrated to be a major cause of outcome
improvement. Therefore, perioperative beta-adrenoceptor blockade is recommended in patients
with Revised Cardiac Risk Index score of three or greater. The investigators hypothesise that
preoperative intravenous beta-adrenoceptor blockade for treatment of hypertension and/or
tachycardia improves autonomic activity reflected by increase of Total Power of Heart Rate
Variability.
Material and Methods: After IRB approval 20 patients scheduled for elective cardiac surgery
were included into the study. Routine medication was continued throughout the study as
recommended by the guidelines. HRV (TP and Low to High Frequency ratio (LF/HF) reflecting
sympathetic to parasympathetic balance) was analysed prior to induction of general anesthesia
and beta-adrenoceptor blockade in all patients (Baseline). Patients were assigned by their
baseline hemodynamics. Patients with hypertension (systolic blood pressure > 140mmHg or
diastolic blood pressure > 90mmHg) or tachycardia (heart rate > 80bpm) were assigned to group
BETA-BLOCK. In this group metoprolol-boli (2mg) were administered intravenously in stepwise
manner until hemodynamic values decreased to normal. Total dosage was recorded. After
normalisation of hemodynamics, second HRV analysis was performed (Intervention). Normotensive
and normocardic patients were assigned to group CONTROL. No intervention was performed.
Statistics: Mann Whitney U test for comparison between groups and between events Baseline and
Intervention within group BETA-BLOCK, p<0.05.
Details
Lead Sponsor:
University Hospital Schleswig-Holstein University of Schleswig-Holstein