Contractility

One of the many miracles of human construction and physiology is the fact that cardiac muscles have intrinsic contractility. This means a single muscle cell contracts spontaneously (until it runs out of oxygen and glucose). The degree, duration, and coordination of these contractions are exquisitely monitored and controlled via the rest of the body's systems, all of which depend on the heart to deliver glucose and oxygen. The primary management of the heart's activities falls, of course, to the brain, which is the heart's primary customer, consuming fully 20% of its output. One of the many wonders of technology is the echocardiogram (a form of ultrasound or sonar) which can record the heart's contractions in response to stress (increased oxygen demand), without exposing the patient to radiation. In the hands of a skilled radiologist, the echo is a wonderful tool that helps us understand the workings of the heart, and hopefully assist us in helping out if the body's autoregulatory mechanisms are overwhelmed by disease. Be thankful for contractility today!