Rare heart condition led to CFD diver Juan Bucio’s death: autopsy

A rare heart condition led to Chicago Fire Department diver Juan Bucio’s accidental death while trying to save a man from the Chicago River on Memorial Day, according to autopsy results released Tuesday afternoon.

Eight weeks after the May 28 rescue attempt near the 2600 block of South Ashland, Bucio’s official cause of death was determined to be “asphyxia with depletion of air from diving tank due to cardiac arrhythmia due to lymphocytic myocarditis,” the Cook County medical examiner’s office announced. His death was ruled an accident.

Lymphocytic myocarditis is “a rare cause of cardiovascular disease that can cause heart failure,” and in Bucio’s case it led to cardiac arrhythmia, or “the improper beating of the heart,” according to the medical examiner.

Bucio’s main oxygen supply “likely became exhausted while underwater” and he didn’t switch to a backup supply, according to a consultant’s review of the diver’s equipment that was ordered by the federal Occupational Safety and Health Administration. Bucio was “distressed due to the heart condition,” medical examiner’s spokeswoman Becky Schlikerman said.

Bucio, a 46-year-old firefighter who specialized in diving, lost contact with his partner as they attempted to rescue 28-year-old Alberto Lopez, who fell overboard while boating with friends in the river’s South Branch.

The moment Bucio went under the water was caught on video by WBBM-TV (Channel 2), showing confusion in the moments before fellow divers located him. Radio transmissions indicate he was underwater for several minutes.

Paramedics performed CPR but Bucio was “pulseless” on the way to Stroger Hospital, where he was pronounced dead, according to a CFD incident report released Tuesday.

The review of Bucio’s diving equipment showed it appeared “used but well maintained.”

Consultant Craig Jenni wrote in a report submitted last week to OSHA that Bucio’s gear “functioned as designed, however the diver likely exhausted the primary gas supply, which created a task-loaded situation that became too overwhelming for the diver to resolve such that the diver sank to depth unable to self-rescue.”

Jenni suggested Bucio’s death “may have been averted if the diver had been using a gas-integrated dive computer with visual and audio alarms warning the diver and his dive partner when approaching minimum safe cylinder pressure.”

Lymphocytic myocarditis typically occurs in about 22 out of 100,000 cases, with a major metro-area hospital usually seeing just one or two cases per year, according to Dr. Allen Anderson, medical director of the Center for Heart Failure at Northwestern Medicine’s Bluhm Cardiovascular Institute.

The condition is typified by inflammation and white blood cells within the weakened heart muscle, and while it is linked to certain viruses, patients might not show symptoms ahead of a major event like an arrhythmia, Anderson said.

“Lots of times, people don’t know they have it,” Anderson said. “This is like a lightning strike, out of the blue.”

A routine physical would not detect the condition, Anderson said.

The fire department is reviewing Bucio’s autopsy as part of its own ongoing investigation, CFD spokesman Larry Langford said.

Bucio joined the CFD in 2003 and had been a member of the dive team since 2007. He is survived by his two sons, ages 7 and 9, and nine siblings.

The body of Lopez — the man whom Bucio had been summoned to rescue — was found in the river four days later by friends who said they had been unsatisfied with Chicago police search efforts. Lopez was a father of three young children who worked in carpentry to support his family in Mexico.