John Ritter's widow Amy Yasbeck details the fatal misdiagnosis she says led to his death

John Ritter's widow Amy Yasbeck is opening up about the actor's final hours more than two decades after his death.

In September 2003, Ritter died at the age of 54 after suffering an acute aortic dissection, a tear in the inner layer of the aorta, the body's largest artery that delivers blood away from the heart.

Ahead of Aortic Dissection Awareness Week and what would have been Ritter's 78th birthday on Sept. 17, Yasbeck, who founded the John Ritter Foundation for Aortic Health, and the actor's son...