Cardiomyopathy

From Memory Alpha, the free Star Trek reference

Cardiomyopathy, which literally means "heart muscle disease," is the deterioration of the function of the myocardium (the actual heart muscle) for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death, or both.

Ralph Offenhouse, a Human rescued by the USS Enterprise-D in 2364 originally died of the condition, but was revived after his body was recovered in a cryogenically frozen state. (TNG: "The Neutral Zone")