Amount of ephedrine in ECA stack is really pretty low. It won't have significant stimulant effects past the first couple of days, caffeine in the stack is probably more stimulating than ephedrine.

The stack is good exactly because it provides good appetite suppression to stimulation ratio. You can reduce your hunger by taking a lot of amphetamines, but stimulation will be huge before appetite suppression becomes significant.

And you seem to have some heart problems. In such case, maybe it's a better idea not to take even mildly stimulating drugs, and go for a willpower-based diet, preferably one with a pseudo-cultish background like paleo or Atkins to help you stay on track.

(I recommended ECA for appetite suppression and fat loss, I don't have any opinion on their use for attention deficit or any other problem).