Influence of spinal anesthesia on corrected QT interval.
OBJECTIVE
Prolongation of the QT interval may result in grave cardiac arrhythmias, polymorphic ventricular tachycardia ("torsades de pointes"), and ventricular fibrillation. We assessed the influence of spinal anesthesia on the QTc interval and the potential arrhythmogenicity of this method of anesthesia.


METHODS
Assessment was performed in 20 male unpremedicated patients, I or II American Society of Anesthesiologists physical status, who underwent spinal anesthesia for elective surgical procedures. Values of the QTc interval, heart rate, and arterial pressure were measured before spinal anesthesia as well as after 1, 3, 5, and 15 minutes of adequate blockade.


RESULTS
Statistically significant lengthening of the QTc interval (compared with initial values) was observed in the first minute after blockade and in subsequent measurements. No differences were observed between mean values of the QTc interval after the onset of blockade. No significant changes in heart rate were noted. From the third minute on, significant decreases of the systolic, diastolic, and mean arterial blood pressure were observed as compared with baseline. These decreases in systolic, diastolic, and mean arterial blood pressure persisted for the entire study duration. No one patient developed clinically important cardiac arrhythmias.


CONCLUSIONS
Spinal anesthesia provokes significant QTc interval prolongation in patients without cardiovascular disorders.
Owczuk
Radoslaw
R
Department of Anaesthesiology and Intensive Therapy, Medical University of Gdansk, Debinki 7 str., 80-211 Gdansk, Poland. r.owczuk@amg.gda.pl
Sawicka
Wioletta
W
Wujtewicz
Magdalena A
MA
Kawecka
Aleksandra
A
Lasek
Jerzy
J
Wujtewicz
Maria
M
D000328:Adult; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000627:therapeutic use*; D003971:Diastole / Q000187:drug effects; D004562:Electrocardiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D013599:Systole / Q000187:drug effects; D013997:Time Factors; D016276:Ventricular Function / Q000187:drug effects
D000779:Anesthetics, Local; D002045:Bupivacaine