Hello! After a careful assessment of your discussion about the problem, It appears to be a complication of old myocardial infarction suffered by your father. He is lucky to be survived the most dangerous type amongst all the Ischemic heart diseases. He is presently having Dilated Cardiomyopathy due to a permanent functional loss of some of the myocardial tissue. Although the prognosis is not so good having had 10 years for the CABG, he can definitely survive more symptom free years by a proper management under an eminent cardiologist. The commonly prescribed medications being diuretics, Angiotensin converting enzyme inhibitors, Angiotensin receptor blockers, beta blockers, Co-enzyme Q10. Also he needs a gradual, personalized cardiac rehabilitation program alongwith a dietary control program & a psychotherapy. Thanks & wishing a long life for your father!