Yeah I went up to 1500 mg and started to get irregular heartbeats. For a month I got irregular heartbeats even without taking niacin, it was very scary. It didn't stop until I left for Europe for a month and a half and let my diet and healing go down the drain.
Also, I agree with you elan about the emotional and mental aspect of healing on this forum. I used to get very bad thoughts in my head, suicidal thoughts at times. However traveling to Europe for a month and a half helped me recover mentally and emotionally. No more thoughts dark thoughts!