The American Heart Association does not support federally mandated screening, suggesting the decision should be done on a local level. The AHA also recommends that high school athletes get a physical exam and fill out a questionnaire about personal and family medical history before further testing is pursued.

Money is the biggest hurdle to mandatory testing, with opponents arguing there aren’t enough deaths to justify the expense.

“That’s crazy,’’ said Mendez, shaking her head. “Really, how much is a life worth?”

Screenings typically cost about $150, but many area doctors say they can be done for a lot less.

In South Florida, Miami Children’s Hospital began offering free EKGs for middle and high school athletes about a year ago at its main campus and seven other clinic locations in Miami, Broward and Palm Beach counties. Dr. Anthony Rossi, director of the cardiac intensive care unit, said hospital administrators thought it was an important enough screening tool to assume the costs.

“How can there even be a debate about this?” Rossi said. “This is absolutely doable. Every child in every school should have an EKG as part of a routine physical before participating in sports.”

Rossi and other cardiologists said recent studies show that SCD, though rare, is far more common among young athletes than previously thought. A 2011 University of Washington study found that the death rate among young athletes was about 1 in 43,000 — not the 1 in 300,000 cited by some groups.

SCD is usually caused by a structural defect or by troubles with the heart’s electrical circuitry. Experts say that subtle warning signs — shortness of breath, fatigue, lightheadedness and dizziness —are often overlooked by the athlete and family or misdiagnosed by a doctor.

Toti Mendez, who experienced some of those symptoms, was initially told he had a respiratory problem. Cardiologists say an EKG can detect not only hypertrophic cardiomyopathy, a thickening of the heart muscle, but other problems in the heart as well.

“About 70 percent of deaths that occur in young athletes can be prevented,” said Dr. Robert Myerburg, professor of medicine and physiology at the University of Miami’s Miller School of Medicine. “This is really something we should be doing.”

As an advocate for EKG screening of student athletes, Myerburg has spoken to legislators and the Florida High School Athletic Association about the topic, but “they just don’t get the picture. They don’t realize how important this is.”

Myerburg said an EKG can be done for much less than the typical $150 estimate. Medicare, he pointed out, pays $27 for the test and mass screenings could reduce that price further. “I don’t understand why we’re taking such a regressive position on this,” he said.

Neither can Maruchi Mendez.

“After Toti died, I visited all his doctors to ask, ‘Where did we go wrong? What could I have done differently?’” she said. “The more I found out, the more I realized that we have to make parents and schools aware that this exists but also push to get screening for the athletes.”

She hopes Toti’s story will serve as a cautionary tale for other young athletes.

“They have to understand that they’re not Superman. They need to listen to their bodies.”

Her crusade, as well as twin granddaughters born after Toti’s death, have helped her fill time. Writing the book, she said, also has made her feel closer to her youngest son. But nothing has dulled the pain of loss.

“When your child dies,” Mendez said, “you are never fully happy no matter what else is going on in your life. You are never whole again.”