Hi my heart s left ventricle diameter is 10.5 cm. My resting heart rate is 48 to 50 per min. I m 47 years old, 6 2 , 240 lbs workout at the gym weight lifting, I m muscular and always been active. Is my left ventricle s size too enlarged. I always known I had an enlarged heart, but always was told not to worry. So, I never paid attention to the size.