Long QT in Newborn....

[MommyOfParker]

I'm not sure if I am doing this correctly. I am trying to post this in the expert forum. I hope this works! Here is my question. I'm sorry it is sooo long!

My son was in the NICU the first few days of his life because he had a low heart rate (the lowest was 90). Although his heart rate stabilized in a few hours his EKG showed he had a prolonged qt interval. The cardiologist said it was caused by a medication I had been taking throughout my pregnancy.  At the hospital they did three EKGs. I just obtained his medical records today and im very confused. The first EKG showed a QTc of 485 (0 days old),  the second (1 day old) showed a QTc of 449, and the third (2 days old) showed a QTc of 459. The notes say the first EKG shows a prolonged QT interval and the notes from the second day say, "EKG shows QTC still prolonged" and the third note says his EKG is normal???? Why is 459 normal when it is longer than 449 which was considered prolonged? Is the range for a 1 day old baby different from that of a two day old? Maybe i am reading it wrong? Thank u for your help!

[MommyOfParker]

Thank you so much for your help. My little guy is almost four month now, and i have been worrying since the day he was born. There is not a whole lot of information on the internet regarding prolonged qt interval in newborns, and i struggled to understand what i  did find! I'm hoping i can convince my baby's doctor to do a follow up EKG just to be safe (i'm a worrier) but because of your post, i feel much more comfortable and i now understand why the cardiologist didnt think he needed follow up. Thank you again!

[Marie M Gleason, M.D.]

The corrected QT interval on an electrocardiogram (ECG/EKG) in a newborn is not the same as it is in older infants and children.  It is common for the QTc to be between 440 and 500 msec in the first week of life.  After this time, it should revert to the "normal" and in fact the normal QTc can be up to 450 msec in males.  So the variable QTc interval in the first 3 days of life does not mean much, UNLESS there is a family history of prolonged QT syndrome.  If there is no family history of sudden cardiac death in young people or people who needed defibrillators inserted, or a known family history of prolonged QTc, it sounds like your child's 3 ECGs are normal variants.  If the heart rate has completely normalized, and all the rest is negative, then there is no strong indication to do anything.  If there is any lingering concern, one could always repeat the ECG in a few weeks to months.