Hi, i do care for your concern. The drug you are taking is a calcium channel inhibitor. This cause vaso dilation to produce decrease in blood pressure, and also have action on cardiac muscles. The swelling may be produced due to the drug, hence decrease of dose may be recommended, however since he is suffering from AFib the cardiac cause may also cause pedal edema. i would advise to consult your physician, to rule of other cardiac feature such as ventricular hypertrophy, before altering the dose. Hope I have answered your question. If you have any further questions I will be happy to help.