The Functional Heart Murmur: a Wastebasket Diagnosis

The pulmonary systolic murmur1 The Functional Heart Murmur: has its genesis in the pulmonary trunk. It is commonly observed in late child A Wastebasket Diagnosis hood, adolescence, and in the young adult during pregnancy. It is best heard in the left second intercostal Rudolph J. Napodano, MD, FACC space, in the supine position, and its Rochester, New Y o rk intensity increases on held expiration. It is usually of Grade 3 or less inten sity, varies in frequency, and is con It is extremely helpful for the examiner to separate murmurs of fined to early and mid-systole, most nonorganic origin into one of two categories. The innocent heart often reaching its peak within the first murmur group defines five specific entities: the pulmonary systolic half of systole. It may migrate toward murmur, the vibratory systolic murmur, the supraclavicular systolic the left clavicle. There is no associated ejection sound and splitting of the murmur, the mammary souffle, and the venous hum. All other second sound is physiologic. nonorganic murmurs are classified as functional, and are produced The vibratory systolic murmur2 by a clinically recognizable alteration in anatomy and/or physiology occurs almost exclusively, in child affecting the circulatory system. This paper discusses each category hood; its highest incidence is noted and provides information regarding bedside diagnosis of selected between the ages of three and ten murmurs. years. It is typically a Grade 3 or less, medium frequency, vibratory sound, confined to the first half of systole. It is best appreciated parasternally at the A physician often identifies a heart trocardiogram), the physician is almost left third and fourth intercostal space, murmur during a routine physical ex always able to diagnose the murmur but may also be audible at the apex. It amination. When the sound is due to accurately. does not radiate widely or predictably an acquired or congenital pathological It is extremely helpful, even essen and has a tendency to increase in abnormality, the examiner is usually tial, to acknowledge that a genuine intensity following exercise. Splitting able to recognize its genesis. However, difference does exist between a func of the second sound is physiologic and the physician is most frequently pre tional and an innocent heart murmur. there is no associated ejection click. sented with a cardiovascular murmur A functional murmur is invariably Patients with this murmur who have which is an isolated finding, or which associated with certain clinically recog been followed for many years demon simply may not fit in with the other nizable alterations affecting the anat strate a benign cardiovascular data observed at the bedside. It is in omy and/or physiology of the circula course. 2 ’ 3 This murmur disappears just such a setting that the examiner is tory system. The innocent murmur is when adulthood is reached. most inclined to explain this finding not. The latter is genuinely harmless, The supraclavicular systolic mur- on a functional or innocent heart and should always imply a favorable mur is typically confined to the right murmur basis. Once the murmur is prognosis. Using this line of reasoning, or left supraclavicular areas. However, assigned this label, physicians at all there are very few clinical situations in on occasion it may migrate inferiorly, levels of training and practice tend to which the physician is presented with and is audible at the right or left show little interest in the further an innocent heart murmur. The func second intercostal space. In this latter definition and analysis of the sound. tional murmur, on the other hand, is instance, it must be differentiated Perloff describes a cardiovascular associated with a multiplicity of be from aortic and pulmonic stenosis or murmur as a “relatively prolonged nign, and sometimes not so benign, an atrial septal defect. Characteristi series of auditory vibrations that can pathophysiologic states. cally, the murmur occurs in early to be characterized according to intensity mid-systole, is harsh and may reach (loudness), frequency (pitch), con Grade 4 intensity. In the latter in figuration (shape), quality, duration, stance, it is associated with a thrill direction of radiation, and timing in which is typically confined to the right the cardiac cycle.” 1 When a murmur is supraclavicular fossa. Hyperextension so defined and characterized, and of the arms, thus compressing the when it is considered in the context of subclavian artery against the first rib, “the company it keeps” (ie, clinical will attenuate or abolish the murmur. history, positive and pertinent negative This is a useful differential bedside physical findings, chest x-ray, and elec- Innocent Heart Murmurs maneuver. There are five murmurs which com The genesis of the mammary souf prise the innocent heart murmur fle2 is thought to be arterial. It is From the Department of Medicine, Uni versity of R o c h e ste r S ch o o ! o f M edicin e and group1’3 (Table 1). Each murmur has associated with pregnancy, lactation, Dentistry, and St. Mary's Hospital, Roches unique and clearly identifiable clinical and the early postpartum period. It ter, New York. Requests for reprints should be addressed to Dr. Rudolph J. Napodano, features. In addition, they are either may be audible to the right or left of Department of Medicine, St. Mary's Hospi the sternum and anywhere from the tal, 89 Genesee Street, Rochester, NY systolic or continuous in timing, and 14611. are never confined to diastole alone. second to sixth intercostal spaces. The THE JOURNAL OF FAM ILY PRACTICE, VOL. 4, NO. 4, 1977 6 3 7 murmur is either continuous or sys The most common innocent mur- tolic, and when continuous the sys Table 1. Innocent Heart Murmur Group mur is the venous hum.1'3 It is con tolic component is more readily appre mon in childhood and a hyperdynamic ciated. It is typically described as a Pulmonary systolic murmur state is suggested when this hum is harsh murmur, variable in intensity, Vibratory systolic murmur observed in an adult. The murmur is Supraclavicular systolic murmur and confined to the higher fre Mammary souffle typically continuous, the diastolic quencies. If the murmur is continuous Venous hum component being the louder. It varies it must be distinguished from a patent in intensity, rarely may even reach ductus arteriosus. If it occurs in sys Grade 6, and may be audible either tole alone other congenital and ac above or below the clavicles. When quired pathological lesions must be appreciated below the clavicles it js considered. Specific bedside man sometimes confused with the murmur euvers may help the examiner in this attenuates or obliterates the murmur. of patent ductus arteriosus. Lateral differential. The mammary souffle is Also, there is frequently cycle-to-cycle rotation and extension of the head more intense in the supine position and day-to-day variation in the inten away from the side being examined and usually diminishes or disappears sity and duration of the murmur.2,3 tends to accentuate the murmur.2 The completely when the patient assumes Termination of the pregnancy or lacta sound diminishes or completely dis the upright position. Local compres tion results in eventual disappearance appears during a Valsalva maneuver, sion over the area of the sound usually of the murmur. return of the head to the normal Table 2. Comparative Physical Findings: Innocent Heart Murmur Group Characteristics Pulmonary Vibratory Supraclavicular Mammary Venous Systolic Systolic Systolic Souffle Hum Origin Pulmonary trunk Pulmonary valve Brachiocephalic Arteries of Brachiocephalic large arteries breast large veins Intensity 3 or less 3 or less 3 or less, 3 or less V ariable, (grade) rarely 4 in rarely may be 5 or 6 R supraclavicular fossa Pitch Medium — high Medium Variable High V ariable Timing in Early to mid-systolic Early to mid-systolic Early to mid-systolic Systolic or continuous Systolic or continuous cardiac with systolic with diastolic cycle component t component t Radiation L clavicle No specific pattern R and L 2nd ICS No specific pattern R and L 2nd ICS Maximum L 2nd ICS L 3rd, 4th ICS, R supraclavicular Variable V ariable, Intensity parasternally fossa may be loudest below clavicles Specific physiological split S-2 physiological split S-2 no ejection sound no ejection sound no ejection sound identifiable no ejection sound no ejection sound tR supraclavicular fossa t supine or with light t head rotated laterally characteristics best heard best heard with bell 1 or abolishes murmur pressure over site of away from site of with diaphragm t — supine and after on hyperextension of sound ausculation t —supine and on exercise arms J. or abolishes in l or abolishes with held inspiration upright position or Valsalva or pressure with firm pressure over vein of origin over site of sound Differential Pulmonic stenosis Atrial septal defect Aortic stenosis Patent ductus Patent ductus arteriosus diagnosis Atrial septal defect Pulmonic stenosis arteriosus Mitral and pulmonary valvular lesions 6 3 8 THE JOURNAL OF FAMILY PRACTICE, VOL. 4, NO. 4, 1977 position, or direct pressure over the heart sound favor a functional basis The ease and accuracy of identifying vein of origin.2,3 Table 2 compares for the murmur. the origin of a heart murmur depend the characteristics of the innocent There are numerous clinical situa upon a physician’s factual data base, heart murmur group. tions in which the cardiac rate and/or experience in auscultation, and de output are varied. ' These may so veloped clinical judgment. We must affect the dynamics of blood flow carefully define a so-called nonorganic through the cardiac chambers and murmur. If the diagnosis is innocent great vessels that a systolic ejection heart murmur, a specific clinical pro murmur is produced.

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