What Causes Difficulty Breathing In A Heart Patient?

My 65 year old husband (CAD patient) has violent stomach movement during sleep. It almost looks like his heart is beating out of his chest and causing his chest wall to convulse. It appears that he is struggling to breathe sometimes, though he says he has no angina. He takes many meds, including psych drugs and heart drugs. He also had treatment for apnea, though this looks like something more heart related. He saw the cardiologist yesterday and said he has the heart of a 20-year-old! Could this be heart failure? Thank you kindly.