Congratulations to Drs. Jeffrey Karp and Arthur Moss regarding the publication of their article "Dental treatment of patients with long QT syndrome" (
JADA 2006;137:630–7
). This article provided an in-depth report about long QT syndrome, or LQTS. However, there are several assumptions within the article that are not supported by evidence-based criteria, and several conclusions that may be problematic with respect to dental care.
At present, there are a considerable number of questions within the medical community concerning the etiology, epidemiology and medical management of patients with regard to LQTS.1 For example, although such drugs as amiodarone tend to produce significant bradycardia and QT lengthening, they appear to have a proclivity for reducing torsadogenic activity.2 In a review of the English-language case reports, there is only one case report with clinical dental implications that may be related to LQTS.3 That particular case involved a partial glossectomy, and was probably more surgical than dental. At present, there are insufficient data to formulate a risk:benefit assessment related to LQTS and dentistry, and a total lack of available guidelines.
There is no argument that patients with American Society of Anesthesiologists (ASA) 4 classifications should be treated in a hospital. However, the issues related to the diagnosis of LQTS are more in line with a physician’s medical history work-up, or a preoperative anesthesia work-up, compared with the medical work-up administered by the vast majority of dentists. It is my opinion that it is not necessary or advantageous to refer every patient with a history of routine syncope for a complete cardiovascular work-up, and I believe that these patients’ internists would have much the same opinion.
Certainly, particular drug interactions have been implicated with regard to dental therapeutics as morbidity and mortality factors related to the torsades de pointes arrhythmia. Therefore, such drugs as terfenadine, erythromycin, theophylline and ketoconazole are implicated as problematic with respect to inducing torsades de pointes arrhythmia, when combined with one another or at toxic dosage levels.4
Furthermore, epinephrine infusions in concentrations relevant to dental therapy are currently utilized with respect to the diagnosis of LQTS, but epinephrine has not been implicated clinically as problematic. On the contrary, epinephrine within local anesthetic formulations in connection with using two to three cartridges appears to be safe and effective for medically complex patients with cardiac disease.5
As the authors stated, one of the purposes of their article was to catalyze the publication of clinical practice guidelines for treating such patients. The authors are to be commended for bringing this topic up for debate. But it is my opinion that there is no evidence at present that patients with LQTS have any increased risk from routine dental therapy, other than the avoidance of known drug-drug interactions.
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