<unk>  is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by the inflow of blood from the atria. The reason the<unk>  does not occur until the middle<unk>  of diastole is probably that, during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle.
Third heart sound
Heart click
Graham Steell murmur
Apex beat
Pulsus alternans
Austin Flint murmur
Grand Rounds
Right axis deviation