Transcript Long QT Syndrome

LONG QT
SYNDROME
Katie DePlatchett, M.D.
AM Report
April 7, 2010
LONG QT SYNDROME
(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
LONG QT SYNDROME
(LQTS)
 Disease
of the ion channels
 Prolongation of the action
potential
 Early after depolarization*
 Increased sympathetic activity
 Imbalance in sympathetic
innervation of heart
ACTION POTENTIAL
ACQUIRED
 Metabolic
(HypoK, HypoMg, HypoCal,
Anorexia, Hypothyroidism)
 Medications
Antiarrhythmics (sotalol, amiodarone, etc)
Antibiotics (Macrolides, Fluoroquinolones)
Psychotropic (Haldol, TCAs, Thioridazine)
SSRIs, Risperidone, Methadone,
Droperidol, protease inhibitors
ACQUIRED
 Myocardial
Ischemia or Infarction
 Intracranial disease
 Hypothermia
 HIV
CONGENITAL
 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
TREATMENT
 Primary
Prevention
Beta blockers
 Avoidance of strenuous activity/sports
 Left cardiac sympathetic denervation

 Secondary
Prevention
Beta blockers
 ICD
 Avoidance of QT prolonging agents

BACK 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
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
