Effects of anesthesia on the heart(. Senior author Gideon Koren MD dire...),Health

Senior author Gideon Koren, MD, director of the Cardiovascular Research Center at Rhode Island Hospital and a professor of medicine at the Warren Alpert Medical School of Brown University, says, "We believe the animal model we have created is the first to be able to accurately predict the effects of various anesthetic agents when LQTS is present. Also, our findings indicate that some anesthetic agents can trigger arrhythmias."

The researchers looked at five common anesthetic agents, including isoflurane, thiopental, midazolam, propofol and the veterinary anesthetic ketamine. Varied effects were noted with each anesthetic in the different models. For instance, isoflurane resulted in a prolonged QT interval in LQT2 but not in LQT1 models, whereas thiopental prolonged the QT interval in both LQT1 and LQT2, though the increase was less pronounced in LQT1. Midazolam prolonged the QT duration in both LQT1 and LQT2 but not in controls, while propofol significantly increased the QT interval in both LQT1 and LQT2 models and the control group.

During the monitoring periods under anesthesia, signs of altered repolarization and arrhythmias were noted only in LQT2 models. Multiple premature ventricular contractions, which can have a marked effect in humans, occurred in many LQT2 models under midazolam, ketamine or thiopental. Also noted is that isoflurane and propofol were especially proarrhythmic in LQT2 models and led to sudden cardiac death in a total of three LQT2 out of nine LQT2 models.

Koren concludes, "We anticipate a great deal more in the way of findings from the development of this model. For now, this study should serve as a reminder to anesthesiologists that an ECG prior to surgery must be carefully studied." He adds, "Further, we would recommend that for those individuals whose ECG appears borderline for LQTS, genotyping may be advisable in order to determine if there is a mutation of the LQT1 or LQT2 genes before selecting a
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