REPORT: Kalas Died of Heart Disease

From ESPN:

Autopsy results show that longtime Phillies' TV and radio broadcaster Harry Kalas died from heart disease.

A spokeswoman at the Washington D.C. chief medical examiner's office said Kalas, who died Monday, had high blood pressure and suffered from atherosclerotic cardiovascular disease. The disease, in which plaque buildup restricts blood flow in arteries, is a major cause of heart attacks and strokes.

So there it is, the final answer.

So long Harry, you will be missed.