Hi, Welcome to health care magic, Stomach belching is caused mainly because of air swallowing known as erophagia. If it is associated with stomach tightness and heaviness in chest then the other causes could be acute gastritis or irritable bowel syndrome. There may be chances of drugs induced which he is taking post-angioplasty but need not to worry as it can be cured y medications and certain dietary factors modifications. So,he should undergo routine blood count,ESR,liver function tests,urinalysis and ultrasound abdomen to detect the underlying cause. He would require medications like antibiotics (quinolones and antiprotozoal combination),antacids like proton pump inhibitors(pantoprazole or rabeprazole) for symptomatic relief. Avoid excess carbohydrates and fatty foods, avoid oily and spicy foods. If your problems persists then u should consult physician or gastroenterologist to treat underlying cause. Hope this will help you. Thanks and regards.