Opening Snap	brief, high-pitched, early diastolic sound (usually due to stenosis of an AV valve). Mitral: more audible in expiration, lower LSB and apex, follows S2. Tricuspid: more audible in its area, later in diastole than mitral.
Ejection Sound	sharp, high-pitched, early systolic sound (in aortic/pulmonary stenosis), it's an opening snap. Aortic: 2nd right ICS and apex. Pulmonary: Upper left sternal border.
Clicks (mid-systolic or non-ejection)	In mitral regurgitation often denote prolapse. Lower left sternal border and apex.
Pericardial Knock	An earlier, high-pitched S3 (early diastolic). In constrictive pericarditis.
Pericardial Friction Rub	Presystolic, systolic and early diastolic components. The Patient upright, leaning forward and in expiration.
Tumor Plop	Low-pitched, early or mid-diastolic, occurs in atrial mixoma.

Heart Sounds (cardiac cycle)