Just because you don't have any physical symptoms of cardiac problems doesn't mean you don't have any problems -- for example, 30% of the time, the first symptom of coronary artery disease is sudden death. Even if you're still young, have yearly checkups, complete with cardiology workups.
Cardiology experts point out that risk factors for cardiac disease include a history of stroke or heart disease, diabetes, obesity, high blood pressure, a sedentary lifestyle, high cholesterol, and a history of smoking. If you're prone to any combination of these items, consider yourself high risk.