Father died of cardiomyopathy, brothers postmortem shown lv hypertrophy. i had a echocardiography as i was having palpitations and tightening which has shown that i have a moderately dilated lv at 5.6cm, normal mass and volume. should i be worried?

I generally say "worrying, usually doesn't help anything", though, a healthy level of concern and diligence to staying on top of this, and adhering to any, medication, diet, exercise recommendations, or any other suggested therapies should be very useful. Since you have a family history, with your father, as well as some symptoms yourself, I feel it is good you have a doctor/cardiologist involved

Cardiomyopathy is too broad of a term to be able to help. Was it due to alcohol or high blood pressure or narrowed arteries in heart. Most common cause is high blood pressure not treated well. Discuss with your Dr and show them your family tree.