apex beat n.
A pulsation, either visible or palpable or both, made by the apex of the left ventricle of the heart as it strikes the chest wall in systole.
The position of the apex beat alone can not determine this, neither can the limit to the right of the sternum.
This point will be between the fifth and sixth ribs, and can generally be determined by feeling the apex beat.
During an attack of unconsciousness in which there was no apex beat for about four minutes, the electrocardiogram was taken.
The stethoscope is attached as nearly as possible over the apex beat of the heart by means of a light harness of canvas.