What is an apical impulse?

It is a brief early systolic outward thrust , followed by late systolic retraction felt by the palpating finger when the LV contracts and rotates , the LV apex and the adjacent interventricular septum hits against the chest wall. It is usually felt at the 5th left intercostal space just inside the mid clavicular line , lasting less than 30% of systole and occupying less than 3 square cms area. Source : Horwitz ,signs and symptoms in clinical cardiology .1985. Lippincot