Auscultatory and Phonocardiographic Findings in Healthy Children with Systolic Murmurs.

Systolic murmurs in healthy children are common and occasionally cause difficulty in differential diagnosis. Our main object has been to make a graphic study of these murmurs in relation to rightand left-sided cardiac events and discuss their differentiation from organic murmurs. The opportunity has been taken to give some normal measurements used routinely in phonocardiography in our department. Basal ejection vibrations can be recorded with electronic amplification in most normal subjects (McKee, 1938), and any slight increase in their intensity makes them audible with the stethoscope. The murmur is soft (at rest) and short, finishing well before the second sound, usually similar in intensity at the pulmonary area, left sternal edge, and mitral area, and often possessing a grunty or musical quality (Still, 1909; Harris and Friedman, 1952; Harris, 1955; Lessof and Brigden, 1957; Wells, 1957): it is frequent in children, becoming louder with increased stroke flow from exertion, excitement, and bradycardia, or associated with hyperkinetic states, and tends to disappear after puberty. Differentiation of this physiological ejection murmur (Mannheimer, 1940) from a pansystolic regurgitant murmur is easy because the ejection murmur finishes before its valve closure sound. The difficulty is to decide whether an ejection murmur is truly physiological, or due to increased stroke flow from a regurgitant aortic or pulmonary valve or left-to-right shunt, or due to stenosis, or simply to minimal valve distortion or roughening (e.g. acute rheumatic valvulitis, mild chronic valvulitis, bicuspid valve). Pulmonary stenosis and left-to-right shunting atrial septal defect can be excluded at once by analysing the effect of continued respiration on the second heart sound, and minimal damage to this valve without stenosis or regurgitation is extremely rare. An aortic systolic murmur may be more difficult to assess, and it had been hoped to obtain information by timing the onset and peak of the murmur in relation to aortic and pulmonary ejection. Phonocardiograms taken simultaneously with the electrocardiogram and carotid pulse have been used to give an indication of the normal electromechanical interval of the left ventricle, isometric time, and duration of ejection.