Getting back to weight loss

I am finally getting back to focusing on diet and heavy duty exercise after nine months. Last August I was in an accident and severely broke my wrist. An EKG led to a cardiologist consult with led to the discovery of a genetic heart condition in which exercise could lead to death. Yeah me! I had an ICD implanted in March and just recently got cleared for activity. The low impact exercise plus the beta-blockers haven't been kind to my weight loss plans, but it time to recommit and see what I can do. My doctor would prefer that I never exercise again as exercise is a trigger for my condition and could lead to sudden cardiac arrest. It really is hard to listen to the doctor while eating pretty good and walking and still gaining weight.