Many heart conditions can cause an audible sound known as a cardiac click. A cardiac click is simply an abnormal clicking sound that occurs before, during, or immediately after each heartbeat. These sounds are usually the result of heart value problems, such as mitral valve prolapse, mitral stenosis, or pulmonic stenosis. In short, due to various heart valves not opening or closing properly, they make a popping or clicking sound that can be heard with a stethoscope. Known as adventitious sounds, cardiac clicks are an audible medical sign of possible structural problems within the heart.
One of the most common reasons a doctor or other medical professional may hear a cardiac click is mitral valve prolapse. The mitral valve allows blood from the left atrium to flow into the left ventricle and to the rest of the body. As blood flows through, the mitral valve closes to prevent blood from flowing back into the left atrium. Patients with mitral valve prolapse have misshapen, oversized, or defective mitral valves that do not close properly. When the valve closes, a telltale audible click is heard, known as the mid-systolic click.
Alternatively, the mitral valve in patients with mitral stenosis does not open properly. While in mitral valve prolapse, the valve does not close properly during contractions of the heart, mitral stenosis occurs when the muscle relaxes, a period known as diastole. Between contractions, at the beginning of diastole, the mitral valve opens. Hearts with mitral stenosis produce a clicking sound when the valve opens, which can also sound like a cardiac click.
Pulmonary stenosis, also known as pulmonary valve stenosis, is the result of an obstruction between the right ventricle and the pulmonary artery. Such obstructions are typically congenital, much like mitral valve prolapse and mitral stenosis. Also like mitral stenosis, pulmonic stenosis causes a cardiac click when the pulmonary valve does not open fully. Blood flow to the lungs, intended to absorb oxygen for transport to the left side of the heart, is restricted. As a result of a cardiac click known as an ejection click, pulmonic stenosis produces a slightly different clicking sound than clicks caused by mitral valve problems.
Although it is the result of defects in various heart valves, most cardiac clicking sounds cause few symptoms or problems beyond the audible sound. Severe deformities, additional heart problems, and age can wear down faulty valves, eventually leading to heart or lung problems. However, most patients experience few, if any, problems from a cardiac click.