Anesth Analg 2003;97:301-302
© 2003 International Anesthesia Research Society
LETTERS TO THE EDITOR
Propofol Reduces Idiopathic Prolonged QT Interval and QT Dispersion During Implantation of Cardioverter Defibrillator
D. Michaloudis, MD, and
E. Kanoupakis, MD FESC
Department of Anesthesiology
Department of Cardiology, University Hospital, Iraklion, Crete, Greece
To the Editor:
We have read with interest the recent publication by Weinbroum et al. (1), which demonstrates that halothane, isoflurane, and fentanyl increase the defibrillation energy thresholds, compared with subcutaneous lidocaine plus intermittent small dose IV propofol that minimized these thresholds, during the implantation of cardioverter defibrillator in humans.
However, we would like to draw the authors’ attention to the statement, which refers to our report (2). In their discussion they quote: "Interestingly, although propofol may cause the prolongation of the QT interval during the implantation of an ICD—an event that did not occur in our study—this has not kept the drug from gaining the reputation as being safe for this procedure, even in patients with severe left ventricular dysfunction."
Our report clearly indicates (see Results) that propofol decreases the QT interval and QT dispersion in patients with idiopathic prolonged QT interval and QT dispersion.
Furthermore, we conclude that: "propofol combined with local analgesics may be a safe alternative technique for patients with idiopathic prolonged QT interval and QT dispersion" (2).
Our decision to use midazolam as premedication and propofol for conscious sedation was influenced by our reported results on healthy ASA I-II patients that showed that neither midazolam nor propofol had any significant effect on QTc interval (3).
References
- Weinbroum AA, Glick A, Copperman Y, et al. Halothane, isoflurane, and fentanyl increase the minimally effective defibrillation threshold of an implantable cardioverter defibrillator: first report in humans. Anesth Analg 2002; 95: 1147–53.[Abstract/Free Full Text]
- Michaloudis D, Fraidakis O, Kanoupakis E, et al. Idiopathic prolonged QT interval and QT dispersion: the effects of propofol during implantation of cardioverter-defibrillator. Eur J Anaesth 1999; 16: 842–7.[Web of Science][Medline]
- Michaloudis DG, Kanakoudis FS, Petrou AM, et al. The effects of midazolam or propofol followed by suxamethonium on the QT interval in humans. Eur J Anaesth 1996; 13: 364–8.[Web of Science][Medline]
Response
Avi A. Weinbroum, MD, and
Ron Flaishon, MD
Department of Anesthesia and Critical Care, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
In Response:
We thank Drs. Michaloudis and Kanoupakis for their comments on our manuscript (1). In this study, we had prospectively compared the effects of three general anesthetics and the combination of local anesthesia plus propofol on the minimal energy requirement of an implantable cardioverter defibrillator (ICD) during its insertion. It was not our intention to examine the effect of propofol on the QT interval; rather, we cited the two cases that were reported by Michaloudis et al. (2), in which they demonstrated that the QT interval may be shortened after the administration of propofol. On the basis of the findings they describe in this case report, the differences in the QTc appear not to be of significant value. We believe that their report as well as those of others contribute to the validation of our conclusion that propofol is safe even in patients with severe cardiac dysfunction and electrophysiological disturbances. The results and conclusion of our study, that propofol was a safe and an applicable mode of anesthesia for a group of high-risk patients requiring the implantation of ICD, were the same as theirs (2).
References
- Weinbroum AA, Glick A, Copperman Y, et al. Halothane isoflurane and fentanyl increase the minimally effective defibrillation threshold of an implantable defibrillator: first report in humans. Anesth Analg 2002; 95: 1147–53.
- Michaloudis D, Fraidakis O, Kanoupakis E, et al. Idiopathic prolonged QT interval and QT dispersion: the effect of propofol during implantation of cardioverter-defibrillator. Eur J Anaesth 1999; 16: 842–7.
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