Cardiac pacemaker in adult humans is about 70 beats per minute. Because the sinoatrial node is responsible for the rest of the heart's electrical activity, it is sometimes called the "primary pacemaker". If the SA node does not function properly and is unable to control the heart rate, a group of cells further down the heart will become the ectopic pacemaker of the heart. These cells form the Atrioventricular node (or AV node), which is an area between the left atrium and the right ventricle within the atrial septum, will take over the pacemaker responsibility. The cells of the AV node normally
Cardiac contractility modulation heart structure can be partially reversed by Cardiac contractility modulation through a process known as reverse remodeling of the heart. Development of cardiac contractility modulation began in the late 1990s. Studies on individual cardiac muscle cells using a patch-clamp technique had already shown, in 1969, that a voltage applied during the absolute refractory period through leads between the interior of the cell and its outside environment increased the calcium influx through the cell membrane and improved the contraction of cardiac muscle cells. In 2001, scientists observed that a similar effect occurs even if the voltage is applied exclusively outside the