What are the characteristics of a benign systolic murmur?

Bottom line:  Murmurs that are midsystolic and soft (grades 1-3) are usually benign when they occur in an asymptomatic child or young adult without other clinical evidence of heart disease.

Summary:  Walsh RA, et al.  Chapter 14, the History, Physical Examination, and Cardiac Auscultation.  In:  Hurst’s the Heart, 13th ed., 2011.  AccessMedicine.

Fig. 14-88 is an algorithm distinguishing between benign murmurs and those requiring further follow-up.