Long QT Syndrome

[david2951]

  Hi, I have infrequent palpitations and occasional lightheadedness. I am very fit and a young athlete, but I recently took some tests to finally figure out why I've had these palpitations all my life. On my Holter study it showed a slightly high QTc interval of around 453ms. (another sheet said 448ms). I understand that anything above 430-440ms is borderline and possibly indicative of long qt syndrome. So, I was just wondering regarding long qt syndrome, if it is what I have and it is a gene inheritance deal is sleeping a trigger of symptoms and problems for people with LQT1 and LQT2, or is that just with the rarer LQT3.? I tend to think I might have LQT1 because I am deaf in one ear. I'm just a little worried about sleeping, at least before I get the medicines I would need to control it if they end up diagnosing it as such. I have temporarily ceased my running training (I was due for my post-spring season week break anyways) as of two days ago until we figure this out, so I'm not worried about provoking an arrhythmia from exercise right now. Also, given that I am an athlete, if this does turn out to be a case of LQT1 would it be most advisable to talk with my cardiologist about maybe looking into an ICD? I would really rather not give up my athletic career if I don't have to and I heard that ICD's allow people to continue with things like running since they are 99% effective at stopping fatal arrhythmias. Thanks.

[is_something_wrong]

Hello,

In this post, replied by a Cleveland Clinic MD / Cardiologist above, you forgot to mention that you had a prolonged QRS caused by RBBB, as you wrote in the other post, and that your baseline QTc was 420 msec...

As your QRS prolongs (due to insynchronous depolarization), so will the QT, which represent the sum of depolarization and repolarization of the heart.

The problem with long QT is a prolonged repolarization. The reason for a long QT with delayed depolarization and normal repolarization is purely mathematical.

[CCFHeartMD 15]

Hello is hard to give specific recommendation through internet without seen the results of your tests but from what you described, your pretest probability of having a congenital long QT syndrome (LQTS) is low with a QTc of 460 ms. Diagnosing LQTS in a patient with a borderline QTc (440 ms to 460 ms) is difficult and further testing is usually needed to determine whether the patient has QT prolongation and congenital LQTS. Factors that can increase the probability of having LQTS include resting ECG findings (specially QTc ≥480 ms), treadmill exercise test findings, history of recovered sudden death, syncope (passing out) with or without exercise, family history of LQTS or sudden death. As you already know, triggers of arrhythmia vary with the LQTS type: ~60% with exercise in LQT1 vs 13 percent in types 2 and 3; and ~35% at rest or during sleep in LQT3 vs ~15% in LQTS1 and 30% in LQT2. It is reasonable to stop doing intense physical activity in the meantime, but try no to draw a conclusion before completing your cardiac workup and discussing the results with your doctor. Good luck.