The side lengths of a right triangle form a so-called Pythagorean triple. A triangle that is not a right triangle is sometimes called an oblique triangle. Special cases of the right triangle include the isosceles right triangle (middle figure) and 30-60-90 triangle (right figure).
The first pacemaker was implanted on 8th October 1958 in a 43 year old man called Arne Larsson with complete heart block and Stokes-Adams attacks. Technological innovations between 1973 and 1980 rendered obsolete the reliable pacemaker of 1970.
They send impulses from the pulse generator to the heart muscle, as well as sense the heart's electrical activity. Each impulse causes the heart to contract. The pacemaker may have one to three leads, depending on the type of pacemaker needed to treat your heart problem. There are different types of pacemakers 1  : Single chamber pacemakers use one lead in the upper chambers (atria) or lower chambers (ventricles) of the heart.