If you've gotten the same response from two different cardiologists, it sounds as though it's a communication problem. Cardiologists (and doctors in general) go to school for a long time, and they actually learn stuff that is pretty darned difficult. However, the art of talking with patients isn't much taught. So, it becomes your job as a patient to try to find a way to state your concerns in a way that does two things: 1. Make your worries clear without being offensive and doctrinaire (because after all, you don't know as much as the doc), and 2. Engage the doctor's sympathy to get a good, clear explanation for the best approach to your health.
Perhaps the responsibility should not have to rely on the patient, but often it does. We may have to find a way to make a personal connection to get the best result.