This ischemia may be secondary to coronary artery disease, or a result of the previously described changes in microvasculature.[11] Ischemia can result in impaired relaxation of the heart; when myocytes fail to relax appropriately, myosin cross bridges remain intact and generate tension throughout diastole and thus increase stress on the heart. This is termed partial persistent systole. Ischemia may manifest in distinct ways, either as a result of increasing tissue oxygen demand, or diminished ability of the heart to supply oxygen to the tissue.