The thickest chamber of the heart is the left ventricle. The heart has four chambers, including the left atrium, left ventricle, right atrium, and right ventricle. The left ventricle is the part of the heart that pumps blood out to the blood vessels throughout the body, and its pumping needs to overcome the greatest resistance, requiring more contractions of the heart muscle cells to generate pumping force, therefore, the left ventricle is the thickest of the heart chambers. However, the left ventricle is not the thicker the better. Abnormal thickening of the left ventricle can be caused by high blood pressure, mitral regurgitation, aortic stenosis, hypertrophic heart disease, etc., which may lead to heart failure, sudden death, angina pectoris triggered by insufficient blood supply to the coronary arteries, and fainting caused by insufficient blood supply to the brain, among other risks. Therefore, patients with abnormal thickening of the left ventricle should go to the hospital in a timely manner to improve the examination and give targeted treatment after the cause of the disease is clarified.