184 - Effects of Physiological and Pharmacologic interventions on Heart Murmurs and sounds

Respiration Systolic murmurs due to TR or pulmonic blood flow through a normal or stenotic valve and diastolic murmurs of TS or PR generally increase with inspiration, as do right-sided S3 and S4. Left-sided murmurs and sounds usually are louder during expiration, as is the PES.

Valsalva maneuver Most murmurs decrease in length and intensity. Two exceptions are the systolic murmur of HCM, which usually becomes much louder, and that of MVP, which becomes longer and often louder. Following release of the Valsalva maneuver, right-sided murmurs tend to return to control intensity earlier than left-sided murmurs.

After VPB or AF Murmurs originating at normal or stenotic semilunar valves increase in the cardiac cycle following a VPB or in the cycle after a long cycle length in AF. By contrast, systolic murmurs due to AV valve regurgitation either do not change, diminish (papillary muscle dysfunction), or become shorter (MVP).

Positional changes With standing, most murmurs diminish, two exceptions being the murmur of HCM, which becomes louder, and that of MVP, which lengthens and often is intensified. With squatting, most murmurs become louder, but those of HCM and MVP usually soften and may disappear. Passive leg raising usually produces the same results.

Exercise Murmurs due to blood flow across normal or obstructed valves (e.g., PS, MS) become louder with both isotonic and submaximal isometric (handgrip) exercise. Murmurs of MR, VSD, and AR also increase with handgrip exercise. However, the murmur of HCM often decreases with near maximum handgrip exercise. Left-sided S4 and S3 are often accentuated by exercise, particularly when due to ischemic heart disease.

Note: TR, tricuspid regurgitation; TS, tricuspid stenosis; PR, pulmonic regurgitation; HCM, hypertrophic cardiomyopathy; MVP, mitral valve prolapse; PS, pulmonic stenosis; MS, mitral stenosis; MR, mitral regurgitation; PES, pulmonic ejection sound; VSD, ventricular septal defect; AR, aortic regurgitation; VPB, ventricular premature beat; AF, atrial fibrillation.