Complex bradycardia and cardiorenal syndrome in an elderly patient:Case reportSI Rui,YIN Tao,LI Yan,ZHOU Jing-yu,XING Yu-jie,LUAN Rong-hua,WANG Hai-chang,TAO Ling(Department of Cardiology,Xijing Hospital,Fourth Military Medical University,Xi’an 710032,Sh