Back to the Case
While the patient had no genetic testing for LQTS, evaluation of previous ECGs demonstrated a prolonged QT interval. The hip fracture repair was considered an urgent procedure, which precluded the ability to undertake genetic testing and consideration for device implantation. The only medication that was known to increase the risk for dysrhythmias in this patient was his diuretic, with the attendant risk of electrolyte abnormalities.
Thus, the patient’s hydrochlorothiazide was discontinued and his pre-existing atenolol continued. The patient’s electrolytes and minerals were monitored closely, and magnesium was administered on the day of surgery. Anesthesia was made aware of the prolonged QT interval, such that they were able to minimize the risk for and anticipate the treatment of dysrhythmias. The patient tolerated the surgery and post-operative period without complication and was scheduled for an outpatient workup and management for his prolonged QT interval.
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Bottom Line
Long QT syndrome is frequently genetic in origin, but it can be caused by certain medications and perturbations of electrolytes. Beta blockers are the first-line therapy for the majority of LQTS cases, along with discontinuation of drugs that might induce or aggravate the QT prolongation.
Patients who have had cardiac arrest or who remain symptomatic despite beta-blocker therapy should have an ICD implanted.
In the perioperative period, patients’ electrolytes should be monitored and kept within normal limits. If the patient is on a beta blocker, it should be continued, and the anesthesiologist should be made aware of the diagnosis so that the anesthethic plan can be optimized to prevent arrhythmic complications. TH
Dr. Kamali is a medical resident at the University of Colorado Denver. Dr. Stickrath is a hospitalist at the Veterans Affairs Medical Center in Denver and an instructor of medicine at UC Denver. Dr. Prochazka is director of ambulatory care at the Denver VA and professor of medicine at UC Denver. Dr. Varosy is director of cardiac electrophysiology at the Denver VA and assistant professor of medicine at UC Denver.
References
- Kao LW, Furbee BR. Drug-induced q-T prolongation. Med Clin North Am. 2005;89(6):1125-1144.
- Marchlinski F. Chapter 226, The Tachyarrhythmias; Harrison’s Principles of Internal Medicine, 17e. Available at: www.accessmedicine.com/resourceTOC .aspx?resourceID=4. Accessed Nov. 21, 2009.
- Zareba W, Cygankiewicz I. Long QT syndrome and short QT syndrome. Prog Cardiovasc Dis. 2008; 51(3):264-278.
- Booker PD, Whyte SD, Ladusans EJ. Long QT syndrome and anaesthesia. Br J Anaesth. 2003;90(3):349-366.
- Khan IA. Long QT syndrome: diagnosis and management. Am Heart J. 2002;143(1):7-14.
- Morita H, Wu J, Zipes DP. The QT syndromes: long and short. Lancet. 2008;372(9640):750-763.
- Schwartz PJ, Moss AJ, Vincent GM, Crampton RS. Diagnostic criteria for the long QT syndrome. An update. Circulation. 1993;88(2):782-784.
- Kapa S, Tester DJ, Salisbury BA, et al. Genetic testing for long-QT syndrome: distinguishing pathogenic mutations from benign variants. Circulation. 2009;120(18):1752-1760.
- Modell SM, Lehmann MH. The long QT syndrome family of cardiac ion channelopathies: a HuGE review. Genet Med. 2006;8(3):143-155.
- Kies SJ, Pabelick CM, Hurley HA, White RD, Ackerman MJ. Anesthesia for patients with congenital long QT syndrome. Anesthesiology. 2005;102(1):204-210.
- Wisely NA, Shipton EA. Long QT syndrome and anaesthesia. Eur J Anaesthesiol. 2002;19(12):853-859.