An Aventura woman was not strangled but instead collapsed from an undiagnosed heart ailment, falling neck-first onto a magazine rack, a defense expert told jurors Tuesday.

Dr. John Marraccini, the former Palm Beach County medical examiner, also said that Eleonora “Lina” Kaufman’s other injuries to her neck tissue and body likely stemmed from failed rescue efforts from her husband and paramedics.

“This poor woman had a heart problem. She didn’t know about it,” Marraccini said.

Miami-Dade prosecutors disagree. On trial for second-degree murder: her husband, Adam Kaufman, a real estate executive who is charged with strangling her inside the bathroom of their Aventura home in November 2007.

The health of Eleonora Kaufman had been a major point of contention, with prosecutors saying the woman was healthy with no major diagnosed health issues. Her mother testified for Adam Kaufman last week, saying she complained frequently of dizzy spells and had fainted numerous times in recent years.

Defense lawyers called Marraccini to the stand Tuesday to rebut last week’s testimony by Miami-Dade’s medical examiner, Dr. Bruce Hyma, who ruled that the healthy 33-year-old woman was the victim of “mechanical asphyxia.”

Prosecutor Matthew Baldwin, in a heated cross examination, tried to poke holes in Marraccini’s credibility, noting that he hadn’t practiced as a full-time medical examiner in years and was being paid more than $30,000 as a defense witness.

Using the magazine rack itself, Marraccini kneeled to show Baldwin how the woman’s neck markings corresponded to the container’s strap and the spine of the magazines shown in a crime-scene photo.

Baldwin pointed out that Marraccini’s analysis of the strange marks on Kaufman’s neck did not seem to show the transfer mark of a metal bar on the rack.

“At the end of the day, no transfer is complete,” Marraccini said.

With no eyewitnesses or evidence of marital strife, prosecutors built their circumstantial case on Hyma’s testimony that injuries deep in her neck muscles, abrasions on her neck and shoulders and burst blood vessels showed that she was the victim of strangulation. Adam Kaufman also gave shifting versions of how he discovered his wife’s body, paramedics testified.

Hyma also said that a 3-millimeter scar found in the heart — found in heart samples by Marraccini after Kaufman’s arrest — were insignificant and that the scar was healing. “She died with it, not because of it,” Hyma said.

Marraccini, however, testified that he believed the scar he discovered was much larger and more significant than portrayed by Hyma and two other associate medical examiners.

The forensic pathologist said that a virus caused an “electrical disturbance” in the heart that caused her to faint. He acknowledged that the virus was not common in adults with healthy immune systems, but said otherwise healthy patients have been known to die suddenly of heart problems.

Inflammation in her Kaufman’s heart showed that the organ was still troubled, even if the initial disease started months before, Marraccini said. Hyma testified last week that the “inflammatory cells” were normal and not life-threatening.

Marraccini theorized that when her heart ailment made Kaufman ill, she went to the bathroom, stood up away from the toilet and collapsed onto the magazine rack. He called it “positional asphyxia,” an accidental death.

Last week, a University of Florida physics expert testified that Kaufman’s neck would not have hit the magazine rack had she slumped over from sitting on the toilet.