This is perfectly absurd.  Why on earth would breastfeeding increase
the risk of heart attack?  There would be no real way to prove it
anyways because of the extreme rarity of atherosclerosis in women of
childbearing age.  Heart attack can mean anything in "press and lay
parlance".  For example, a woman who dies of an arrythmia would often
be said to die of a heart attack.  Sudden death at this age would be
more likely due to an arrythmia than myocardial ischemia, and that for
sure would have nothing to do with breastfeeding.

Jack Newman, MD, FRCPC