A dozen years later, Maruchi Mendez still chokes on her words when she talks about her son, a star baseball pitcher. A strapping athlete scouted by the pros, he keeled over in his South Miami backyard while playing catch.

Ramiro “Toti” Mendez was dead at 20 from sudden cardiac death — a tragedy that Mendez and many cardiologists believe could have been prevented with a routine test.

“An athlete gets tested for how fast he can run, how far he can throw, how high he can jump,” said Mendez. “Scouts know his grades and his test scores. But we don’t really know if everything is working inside.”

Since Toti’s shocking death, Mendez has championed one cause, a crusade that has led her to lobby legislators, pushed her to pore over medical research and, now, has inspired her to write a book, Finding Home: A Memoir of a Mother’s Undying Love and an Untold Secret ( Reedy Press, $16.95) A Spanish translation published by Penguin will be out in April.

Sudden cardiac death, commonly referred to as SCD, is the No. 1 killer of young athletes. The American Academy of Pediatrics estimates that 2,000 people under 25, most of them high-school age, die from it every year in the United States. That’s why Mendez has devoted the last decade to campaigning for high school and college athletes to be screened for heart trouble with an electrocardiogram, or EKG, before they take to the practice field.

This routine exam would have likely detected Toti’s cardiomyopathy, the underlying abnormality that led to his death.

That knowledge haunts Mendez, who, at 65, still lives in the house she shared with Toti and three older children from a first marriage.

“I feel like we failed him’’ said Mendez , who writes poignantly of Toti’s life, from his adoption in Spain and childhood in Miami to his all-too untimely death.

As a ball player, Toti racked up honors. He was named Miami-Dade County’s 1998 player of the year during his tenure at baseball powerhouse Westminster Christian School, where he had stellar statistics on the mound and at the plate, an earned run average of 1.34 as a pitcher and a batting average of .444. He went on to play at Florida International University.

But routine athletic physicals during his career failed to screen for a “silent killer’’ she’d never even heard of before a visit to a cardiologist weeks before his death in April 2000.

“Outside Toti looked the picture of health,” Mendez said, pointing to the many pictures she keeps around the house. “But his heart … his heart…”

Using EKGs as part of an athletic physical is a subject of considerable debate and policies mandating them for student athletes vary widely. Most European countries, as well as Japan, require the tests for competitive athletes, including those playing school sports. So does the International Olympic Committee. The U.S. Olympic Committee, on the other hand, does not.

Florida has no such requirement either, though Mendez pushed for just such a bill two years after her son’s death. One state, Pennsylvania, passed the Sudden Cardiac Prevention Act last year. Though it does not mandate EKG screenings, it requires every participant in youth sports, both at the club and school level, as well as every parent and every coach to go online annually and review the signs and symptoms of SCD. Children are removed from the field if they show any of the symptoms, and they can’t play again without the permission of a medical professional.