as soon as my Dr. put me on Metoprolol -my fibrillation has stopped- but this throbbing/ thumping sound in my head --may be the inner ear but if I plug my ears, its not in the outer ear ---this causes a distortion in hearing sounds and voices are muffled --the traffic on a freeway is unbearable. I also take losartan potassium. Had just had my ears tested shortly before and had perfect hearing. Any help??