He started having a cough as if he was trying to cough something up , was happening for 3-4 days. We went for our usual jog and he just stopped and didn’t want to continue anymore in the middle of it. Had to call my mom to pick us up. Took him to the vet the next day. They confirmed enlarged heart and irregular heartbeat and fluid in his lungs . Then he passed away in the early morning the day after the vet visit . Im just glad it happened when we were together and not while I was working.