Decreased septal motion is the result of a weakened ability of the heart to contract. It is commonly seen in acute myocardial infarction. This is when large areas of myocardial ischemia or necrosis cause a decrease in myocardial contraction and a weakening of the interventricular septal movement. Coronary artery plaque leads to severe narrowing of the lumen, which can lead to a decrease in the heart’s ability to eject blood, and can also cause a weakening of septal motion. High blood pressure is very harmful to the heart, and long-term high blood pressure can lead to cardiac hypertrophy. When the ventricles hypertrophy, the septum also thickens. When the thickening reaches a certain level, it affects septal motion. Hypertrophic cardiomyopathy also has a weakened septum because the heart is hypertrophied.