Longtime UA broadcaster and rugby coach Dave Sitton died of a pulmonary embolism, Pima County's chief medical examiner told the Star today. 

A pulmonary embolism is a blood clot in the lungs that can cause sudden death, Gregory Hess said. The cause of death isn't always immediately apparent, he said. Former Arizona basketball player Shawntinice Polk died in 2005 of what was later diagnosed as a pulmonary embolism; she was 22. 

Sitton, 58, died Aug. 12 in Tucson. The suddenness of his death led many friends to believe he had suffered a heart attack. In fact, symptoms of pulmonary embolisms include chest pain and shortness of breath, similar to a heart attack. 

The UA on Sunday held a public memorial service for Sitton, a UA grad who spent the last 40 years in Tucson.

Read more in Wednesday's Arizona Daily Star.