Enlarged heart --what are symptoms?

Depends: An enlarged heart detected on cxr could be entirely asymptomatic. The most common cause is a thickened heart muscle due to hypertension. Rarer is a cardiomyopathy or a weakened heart. Those could be associated with signs and symptoms of congestive heart failure, namely shortness of breath, fatigue, dizziness, swelling in legs.

None, alone: If the cause of the enlarged heart is disease, it's the symptoms of the disease. If hypertension, it's not called the silent killer for nothing. All fat people, and all people who enjoy high-level physical fitness from aerobic training have enlarged hearts. This is not the reason being fat is bad, and if you're fit, then the symptom is being happy and healthy.