I suffer from ADHD and CFS, but both are cured completely when I take tricyclic antidepressants (especially Nortriptyline).

However, the problem is that when I take them continuously, even at 5mg to 10mg, my QTc extends to 0.450 to 0.500 (my Qtc without Nortriptyline is about 0.410).

I also have tachycardia and my resting heart rate is 90 to 120 (strangely, my heart rate is lower after exercise than when I'm resting).

When I used Nortriptyline for 10 days in a row, I experienced symptoms similar to a heart attack (a strong feeling of pressure on the lower left side of my heart, a dull pain, a feeling I'd never felt before), and was taken to the hospital by ambulance, but they said there was nothing wrong with my heart. (It seems they treated it as a panic attack.)

You might say, "Then just don't take tricyclic antidepressants," but I can't function socially at all without Nortriptyline. Because of that, I was bedridden and shut-in for almost seven years.

You might be thinking, "Ask your doctor about that," but my doctor thinks there's no problem as long as it's not over 0.500. I think this is a little too optimistic.

I'm thinking of taking potassium and magnesium to prevent Qt prolongation, although it may only be a small help.

To sum up,

①At what level should Qt prolongation be taken seriously? Is 0.450-0.500 a clinically acceptable value?

②Are there any measures I can take to prevent Qt prolongation and sudden death that comes with it? (Like taking potassium)

I have a question about this score. Thank you for reading this far.