Two hearts, a normal on the left and one with heart failure with preserved ejection fraction (HFpEF) on the right. The heart with HFpEF has a thicker, stiffer left ventricular wall and therefore, less room in the ventricle chamber to fill with an adequate amount of blood to be pumped around the body. A Johns Hopkins Medicine study shows obesity weakens heart muscle in this common form of heart failure. Credit: Graphic created by M.E. Newman, Johns Hopkins Medicine, using public domain image of the heart.