Sorry, but according to Wizards CustServ, the IHS does indeed end the effect. From the Wizards boards:
Q Can Iron Heart Surge remove:
3. The spell "Bestow Curse".
4. Ability score damage.
5. Level drain.
6. The influence of an antimagic field. (*)
If you use Iron Heart Surge against an effect which does not solely
target you, but also affects an area, do you end the entire effect or
do you just dismiss it from yourself?
Ability score damage is not an ongoing effect. It is the result of an
attack, spell, or ability. So no - damage, even ability score damage,
will not be removed by Iron Heart Surge.
5. In most cases, level
drain is similar to damage when determining if Iron Heart Surge removes
it from the martial adept. If something level drained you, this is a
permanent result, not an effect with an ongoing duration. You would not
be able to use Iron Heart Surge to remove level drain.
6. Yes, you would be able to end the antimagic field if you chose to do so with Iron Heart Surge.
7. If the effect does not solely target you, such as the antimagic field in number 6, it will still end the entire effect.