(CBS) – Monster Beverage says it was heart trouble — not caffeine toxicity — that killed a 14-year-old who has become the poster child for Chicago efforts to regulate energy drinks.

Defense Attorney Daniel Callahan said pathologists found Anais Fournier had heart trouble from age four — scar tissue on the heart and a heart inflammation — when she died after drinking two big cans of Monster on two successive days.

Callahan said the medical examiner in Maryland did no caffeine screens at all before attributing the girl’s death to caffeine toxicity.

The controversy comes as public health officials report a jump in emergency-room caffeine treatments, from 1,000 to 16,000 between 2005 and 2008 nationwide.

Fournier’s parents are suing Monster and criticizing energy drinks on national TV.

Ald. Ed Burke, who’s proposing an ordinance banning the sale of all energy drinks in Chicago, argues energy drinks have additives that enhance the effects of caffeine.

A hearing is set for Tuesday.