Was in the hospital.labs, ekg, heart monitor, and chest ct.ct report showed borderline prominent heart. what does this mean? can it cause sudden death?

Big heart: Your heart may be either normal or slightly large. The diagnosis can be somewhat subjective, but the heart is supposed to be greater than 50% of the thoracic diameter to be considered enlarged. To be meaningful this one piece of data has to be correlated with your symptoms and lab data. An enlarged heart can be due to heart failure and cardiomyopathy among others.

Not likely: Radiologists usually qualitatively describe the size of the heart as normal, borderline enlarged, or enlarged (mildly, moderately, markedly). This gives the referring physician an idea of the seriousness of any underlying disorder. A borderline heart may mean nothing more than you have hypertension, and certainly would not mean you are at risk of sudden death. Discuss with your md.