There’s been some buzz about polarized bicycle interval education in biking following the Velonews podcast, Quick Communicate, hosted two interviews with Dr. If each of the chambers contracted concurrently, then blood couldn't stream with the heart as the AV valves would avoid blood movement in between the atria and ventricles. https://friendlybookmark.com/story17906967/the-5-second-trick-for-polarized-heart