Listen for: Two sounds per beat: S1 ("lub") then S2 ("dub"). At a normal rate the pause after S2 (diastole) is longer than the pause after S1 (systole). Nothing in either pause.
Usually means: The baseline. Compare every abnormal sound against it.
References1
- Bickley LS, Szilagyi PG, Hoffman RM, Soriano RP. Bates' Guide to Physical Examination and History Taking. 13th ed. Philadelphia: Wolters Kluwer; 2021. Cardiovascular system chapter.