Does a low heart rate always mean an enlarged heart size?

I was having this discussion with someone who says that a person with a low resting heart rate automatically has an enlarged heart. I once had my heart checked. While my resting heart rate was around 35 bpm, my heart size was rather average. I recently read something that said that an athlete does NOT automatically have an enlarged heart. I can't find that article anymore. Does anyone know in what way a low heart rate has to do with the size of your heart and if all swimmers have larger hearts than average people?