Long QT in post-op patient

Posted By  CCF Cardio MD-SGM on January 30, 1998 at 16:00:02:

In Reply to: Long QT in post-op patient posted by Darlene Long on January 28, 1998 at 12:27:23:

:
  Hello, I am re-posting the following information, in the hope that I might get some insight as to how to proceed with my sons treatment.
  
  I have an 11 yr old male, with previous history of tetralogy of Fallot,
  corrected (age2), who has been discovered on ecg and stress testing, to
  haved a markedly prolonged QTc ranging from 650-700. There is also
  doubling of broad T waves and heavy notching most obvious in the
  precordial leads. He has a past history of syncope with spontaneous
  recovery, and has complained in past of some dizziness and palpitations on exertion. No
  torsade was observed during stress testing. Complicating things is his
  history of severe asthma, which would exclude treatment with beta
  blockers. Q: Could this be in some way related to the operative
  procedure undertaken for his congenital heart defect? (he is left with
   minor pul. regurge of low velocity). A trial of mexilitene proved useless in
  modifying his rythm, and we are left with the option of waiting to see
  if he experiences a cardiac event which we would try and capture on a
  monitor to confirm he is, in fact symptomatic, or trying to pursue more
  aggressive treatment (ICD, or possibly cervical sympathectomy).
  Q: Does the extreme length of his QT interval coupled with the T wave
  doubling and heavy notching indicate a greater degree of risk for
  developing life threatening arrythmia?
  Q: Is it advisable to conduct an epinephrine challenge test to try and
  capture and record an event to confirm that he is symptomatic?
  Currently, we have been told that the risk of invasive treatment
  (ICD, cervical sympathectomy)is greater than his risk of sudden
  cardiac death, and have been advised to wait and watch, making
  use of a cardiotransmitter to record any events in the hope of
  gaining more information.
  The other major question is that if this IS considered to be
  hereditary Long QT (Romano-Ward), why have previous ECGs during
  annual post-op follow-ups not detected it? Up until 3 years ago
  (when the Qtc was described as borderline)QTc measurements were
  WNL, and T wave morphology was normal. Stress ECG testing on
  siblings and parents has been normal.
  And advice, or ideas would be most welcome.
  Darlene Long RN, MHSc.
  Director- Special Hearts
  (and Mom to the above mentioned patient!)
  Case Manager,
  World ACM Association
  darlene-***@****
  s_hearts***@****
  
       Resting ECG for Long QT in 11 yr old male

[CCF Cardio MD-SGM]

Dear Ms. Long,
I regret the delay in responding to your original question.  Long QT Syndrome (LQTS)  is typically seen in several well-defined settings.  It can occur in association with antiarrhythmic drug therapy (or therapy with a small number of other medications) and in the context of congenital disorders.  In your son