1. L ONG QT SYNDROME Katie DePlatchett, M.D. AM Report April 7, 2010

2. L ONG QT S YNDROME (LQTS) QT interval = beginning of the QRS to the end of the T wave duration of activation and recovery of the ventricular myocardium. Bazett formula: QT/ square root of RR > 440 msecs in men > 460 msecs in women

3. L ONG QT S YNDROME (LQTS) Disease of the ion channels Prolongation of the action potential Early after depolarization* Increased sympathetic activity Imbalance in sympathetic innervation of heart

4. A CTION P OTENTIAL

5. A CQUIRED Metabolic (HypoK, HypoMg, HypoCal, Anorexia, Hypothyroidism) Medications Antiarrhythmics (sotalol, amiodarone, etc) Antibiotics (Macrolides, Fluoroquinolones) Psychotropic (Haldol, TCAs, Thioridazine) SSRIs, Risperidone, Methadone, Droperidol, protease inhibitors

6. A CQUIRED Myocardial Ischemia or Infarction Intracranial disease Hypothermia HIV

7. C ONGENITAL h/o syncope, family h/o SCD, deafness 7 genetic defects Important for identifying arrhythmia triggers LQT1 = exercise-related LQT2 = auditory stimuli LQT3 = at rest or sleep; no benefit from BB Most cases discovered after syncope or arrest

8. T REATMENT Primary Prevention Beta blockers Avoidance of strenuous activity/sports Left cardiac sympathetic denervation Secondary Prevention Beta blockers ICD Avoidance of QT prolonging agents

9. B ACK TO OUR PATIENT … Discharge with life vest & beta blocker Repeat Echocardiogrm = normal EF Genetic testing: LQT1 + LQT9 mutations LQT1 = EXERCISE RELATED!!! No more novice marathon training. s/p ICD placement No Family History of SCD

11. REFERENCES Schwartz, PJ. The long QT syndrome. Curr Probl Cardiol 1997; 22:297. Zipes, DP, et al. ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias & Prevention of SCD. J. Am Coll Cardiol 2006; 48; 1064. Priori, SG, et al. Association of long QT syndrome loci and cardiac events among patients treated with beta-blockers. JAMA 2004; 292;1341. UpToDate