The Auscultatory Gap in Sphygmomanometry

Abstract

An auscultatory gap in sphygmomanometry is a period of abnormal silence or diminished intensity during one of the Korotkov sound phases. During the silent gap the pulse wave is palpable. The common auscultatory gap occurs in the second or murmur phase. Although recognized clinically a year after Korotkov introduced the auditory method (1906), the clinical importance of the auscultatory gap was not recognized until 1917, when Cook and Taussig emphasized the need for preliminary palpation of the pulse. Failure to determine palpatory pressure could lead to failure to recognize 5% of patients with hypertension. Sporadic reports (1927, 1928) reemphasized the importance of the unrecognized gap in masking hypertension. Another decade passed, however, before official recommendations were made to avoid this pitfall. The gap is recognized only when the point of obliteration of the pulse is determined by palpation prior to deflation of the armcuff.