Heart & Cardiology/Lonq qtc


Ecg 2
Ecg 2  
I have had several panic attacks and did several ecgs. Some ecgs coming from one hospital
Had high qtc readings, i believe that machine used bazett:
Bpm 128 .. Qt 310 Qtc 456. The cardiologist said its high brcoz of tachycardia.
The second one bpm 104 Qt 346 Qtc 461
I freaked out showed him the ecg he manually calculated it
And said qtc is 416. The other ecgs were at another hosp showing qtc of 399 at
Bpm 102, 117 and 90. I believe this hospital uses another
Formula. Problem is i dont know which ecgs and bumbers to trust
As i have high anxiety and need to start zoloft
But am afraid to start .. What is more accurate the ecg or the cardio s
Manual calculatiob? What if the machine is right and i
Start zoloft? I did echo nd halter came back normal. Thanks

ANSWER: Hi,  http://myheart.net/articles/

Machines tend to overestimate the QTc and therefore its common for cardiologists to have to correct this manually. Secondly you don't have a vey long qtc or an overly concerning ekg pattern.

QTc values that are greater than  470 ms are practically never seen among healthy individuals when their heart rate is 60 to 70 bpm however around 2% of healthy adults (and more children) have QTc that is greater than 480 ms when their heart rate is greater than 90 bpm. This basically means that whenever a long QTc is found during a fast heart rate that the first step should be to repeat the EKG once the heart rate slows down. You should do that. Also if you are concerned you can of course repeat the tracing after starting zoloft to see if it has prolonged.

Hope that was helpful,

---------- FOLLOW-UP ----------

QUESTION: Thank you Doctor,
The problem is that it is difficult for my heart to go below 90, I am very anxious and very worried about this case. At 90 bpm I believe according to Bazett formula, the QTC was 423 and according to the other ECG from the other hospital 399. Shall I just get it over with behind me that I don't have a prolonged QT and start Zoloft? Thank you again

Hi, based on what we discussed earlier and also the fact that a local specialist told you it was ok, you can be relatively reassured. To reassure you further you can always repeat the qt after starting zoloft. You certainly don't fall in to a high risk category.

Hope that was helpful,  

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Mustafa Ahmed MD


Cardiology, Interventional Cardiology, Cardiac Surgery, Hypertension, Pulmonary Embolism, Structural and Valve Disease


Board Certification Internal Medicine and Cardiology Interventional and Structural Cardiology


Multiple Publications In High Quality Peer Reviewed Journals. Internationally Recognized.

MD from The Royal Victoria University of Manchester, England Medicine, Cardiology, Interventional Cardiology, Research Training - University of Alabama

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