Hi,
Atrial fibrillation with heart failure should be promptly treated to prevent complications like thromboembolism, end stage heart failure etc. Rhythm control and rate control measures are required for your husband. What was the underlying cause for atrial fibrillation? If any cause is present that should be treated first to control this situation. Drugs like beta blockers, calcium channel blockers, digoxin are useful in controlling rate.
Rhythm can be controlled with drugs or procedures like electrical cardioversion etc. I would recommend that your husband gets a cardiologist’s consultation as earlier as possible for thorough evaluation and assistance on treatment. Best.
Your husband should already be at the doctor's office, at the least, and a trip to the ER might be the better choice. If he is already being treated, then call his doctor, and tell them what is goig on. They will tell you what your next step should be.
hope this helps...