QTc interval

Hello Dr.

My recent ECG shows QTc=442 and i have done 5 ECG's in the last year where the QTc value ranging from 380-440 as follows (442, 435, 426, 406, 435, and 380). My doc seems to be not concerned and he says QTc  500. I am not sure about this as i read a lot about how serious is having long QTc. I need some feedback form a doctors about my above QTc readings, are they OK or shall i go for more tests. I had my last Stress ECG and Echo done 8 months back and all come normal. Please advice!!!

[is_something_wrong]

No doctors here, this is a community :)

How high was your heart rate at your recent EKG? At high heart rates, the QTc calculating formula often fails, so the QTc seems higher than it really is. Females also have longer QT interval than men. QT varies a lot, depending on what you eat, stress levels, etc.

There is a difference between "normal" values and "dangerous" values as far as I know. When the normal interval is 360 to 440 (in men) and 380 to 460 (in women) that means that 95% of all tested individuals will have a QT value (at heart rate 60) in this range. It does NOT mean that the other 2,5% on the long side (2,5% on the short side also) have "prolonged QT disease" or LQTS. This affects about 1 out of 5000, or 0,02%.

Your risk of complications to prolonged QT (ventricular arrhythmias) increases when the QT time is above 500 msec as your doctor told you.

If your doctor said you're OK, I would trust that.