I AM SO GLAD!!!
OH I'm so glad you did not take them. I have the same heart thing as you, a slight MVP, and was fine until I tried Endurox to help my marathon running. WELLLLL I ended up in the ER with my heartrate going 220 nonstop, and scared as **** (they called it a panic attack, but it was set off by the ephedra and caffeine - it happened while I was petting the dog, not exercising).
They also found I had high blood pressure: a deadly combo!!!
Since my stupid days, I have lost 60 pounds and lowered my BP to normal, but I still have the heart palps if I take any sort of stimulant. So I have lost all this weight (my BMI is now 23, it was 30) and gained muscle as well I am confident people can lose weight without thermogenics. The only metabolism enhancer you need is interval training cardio and body building. Works better than drugs and is healthier too.