Nicholas Brendon Cause of Death Revealed as Cardiovascular Disease

nicholas brendon died of atherosclerotic and hypertensive cardiovascular disease, according to a May 5 report from the Putnam County Coroner’s office. He was 54. The disclosure adds medical detail to the March 20 announcement of his death and replaces the family’s earlier statement that he had passed in his sleep of natural causes.

Todd Zeiner's May 5 report

Todd Zeiner said the mechanism of death was a 90% blockage of the right coronary artery. The report also listed acute pneumonia and previous myocardial infarction as contributing factors, along with a markedly enlarged heart and severe stenosis of the right coronary artery. Moderate stenosis of the left anterior descending and left circumflex arteries appeared in the autopsy as well.

Zeiner wrote that Brendon was a longtime smoker and had been apprehensive about going to a hospital after recent back surgery. That detail fits the medical record’s narrower explanation: the death was ruled natural, but it came after a cardiac history that had already reached the point of hospitalization in August 2022.

Theresa Fortier's 911 call

Theresa Fortier was at Brendon’s residence and called 911. In Zeiner’s report, she said Brendon had been having a persistent cough, had been self medicating with over the counter medications, and had been complaining about chest pain; she also said she recommended a hospital and he declined. Law enforcement at the scene found no obvious signs of foul play and assisted with cataloging the scene, with nothing out of place or disturbed.

For readers tracking Brendon’s final days, the practical detail is the medical chain the coroner laid out: chest pain, cough, prior heart damage, acute pneumonia, and a blocked coronary artery. The family had said he was on medications and treatment to manage his diagnosis and was optimistic about the future at the time of his passing, while also noting that he had recently found a passion in painting and art.

Family statement on March 20

The family’s March 20 statement, posted on his official Instagram page, said, “We are heartbroken to share the passing of our brother and son, Nicholas Brendon. He passed in his sleep of natural causes,” and added, “Those who truly knew him understood that his art was one of the purest reflections of who he was.” The new report does not change that Brendon was found dead of natural causes; it fills in the underlying cardiac and respiratory conditions behind that conclusion.