Triple-site pacing for cardiac resynchronization in permanent atrial fibrillation : acute phase results from a prospective observational study - Marques, Pedro; Menezes, Miguel Nobre; Lima da Silva, Gustavo; Bernardes, Ana; Magalhaes, Andreia; Cortez-Dias, Nuno; Carpinteiro, Luis A.; Sousa, João Carvalho de; Pinto, Fausto J. (2016)