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HISTORY 18-year-old black man. CHIEF COMPLAINT: Evaluation of murmur. PRESENT ILLNESS: The murmur was noted on routine pre-college physical examination. The patient is an asymptomatic All-State halfback. He vaguely recalls a murmur having been noted in the past. His history is otherwise entirely negative. Question: Is a specific diagnosis suggested by this history? 22-1 Answer: No. While the patient’s murmur may be significant, the negative history suggests the murmur could be innocent. PHYSICAL SIGNS a. GENERAL APPEARANCE - Normal muscular 18-year-old black man. b. VENOUS PULSE - The CVP is estimated to be 3 cm H2O. UPPER RIGHT STERNAL EDGE JUGULAR VENOUS PULSE Question: How do you interpret the venous pulse? 22-2 Answer: The venous pulse is normal in mean pressure and wave form, showing a dominant “a” wave preceding the first heart sound followed by the “x” descent, “v” wave, and “y” descent. c. ARTERIAL PULSE - (BP = 110/70 mm Hg) S1 S2 UPPER RIGHT STERNAL EDGE CAROTID ECG Question: How do you interpret the carotid arterial pulse? 22-3 Answer: The arterial pulse is normal in upstroke, peak, and downstroke. d. PRECORDIAL MOVEMENT PHONO UPPER RIGHT STERNAL EDGE S1 S2 APEXCARDIOGRAM Question: How do you interpret the patient’s precordial movement? 22-4 Answer: There is a normal brief apical impulse at the 5th intercostal space in the midclavicular line. e. CARDIAC AUSCULTATION ECG 1 2 1 1 2L A2 P2 EXPIRATION 0.1 sec A2 P2 INSPIRATION Question: What is your interpretation of the acoustic events at the upper left sternal edge? 22-5 Answer: There is normal inspiratory splitting of the second heart sound. In addition, a short, early, systolic, crescendo-decrescendo murmur is present. Since the murmur is in early systole when the majority of blood leaves the ventricles, it is likely related to turbulence of flow alone, and less likely related to a significant degree of obstruction of the outflow tract. It is likely generated over the pulmonary valve and artery, as it is best heard at the upper left sternal edge. Note also the absence of an ejection sound. e. CARDIAC AUSCULTATION (continued) LOWER LEFT STERNAL EDGE Question: How do you interpret the acoustic events at the lower left sternal edge? 22-6 Answer: There is normal splitting of the first sound due to mitral and tricuspid closure respectively. e. CARDIAC AUSCULTATION (continued) S1 S2 S1 S2 APEX .16 SECONDS ECG Question: How do you interpret the heart sound marked by the arrow? 22-7 Answer: The arrow marks the third heart sound (S3). In a young adult patient such as this one it may be heard normally, i.e., whether an S3 is abnormal or not is judged by the context in which it occurs (by “the company it keeps”). f. PULMONARY AUSCULTATION Question: How do you interpret the acoustic events in the pulmonary lung fields? Proceed 22-8 Answer: In all lung fields, there are normal vesicular breath sounds. ELECTROCARDIOGRAM I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 Question: How do you interpret this ECG? 22-9 Answer: The ECG is normal. Note there is slight “J” point elevation (early repolarization) in several leads, which is a common variant. CHEST X RAYS RA = Right Atrium AA SVC = Superior Vena Cava AA = Aortic Arch PA = Pulmonary Artery S V C PA LAA = Left Atrial Appendage LV = Left Ventricle C = Greatest Cardiac Dimension T = Greatest Thoracic Dimension (C/T = Cardiothoracic Ratio) LAA RA C LV T Question: What is your interpretation of this PA chest X ray? POSTEROANTERIOR (PA) 22-10 Answer: The PA chest X ray is normal. The structures forming the heart’s borders in this and the following views are labeled. When hemodynamically significant lesions are present, these structures may be selectively enlarged. Note also the cardiothoracic ratio is normal (<50%). CHEST X RAYS (continued) RV = Right Ventricle LA = Left Atrium RV LA LV = Left Ventricle LV Question: What is your interpretation of this left lateral chest X ray? LEFT LATERAL 22-11 Answer: The lateral chest X ray is normal. When the left atrium is enlarged, it displaces the barium-filled esophagus posteriorly. When the right ventricle is enlarged, it may obscure the substernal space. Proceed 22-12 The history, physical examination, ECG and chest X rays are all normal. The only question raised is the significance of the murmur, and it is typical of an “innocent” murmur. In addition, the second heart sound is normal and there is no ejection sound. Because the bedside examination alone has defined the murmur as “innocent,” no further evaluation is indicated. Question: What is the hemodynamic explanation for this patient’s murmur? 22-13 Answer: The murmur occurs in early systole due to turbulence in the pulmonary artery associated with rapid flow during the early ejection period of the right ventricle (2/3 of the stroke volume leaves the ventricle during the first 1/3 of systole). It is commonly heard in the young patient whose circulation is dynamic. It may be less prominent when the patient is erect due to a decrease in venous return. It is best heard over the pulmonary outflow tract which lies just below the chest wall at the upper left sternal edge. Question: What organic cardiac lesions should have been considered in this patient? 22-14 Answer: An atrial septal defect causes a similar systolic murmur, but one would expect wide fixed splitting of the second heart sound and a mid-diastolic murmur at the lower left sternal edge. Mild valvular pulmonary stenosis also may have a similar murmur but a pulmonary ejection sound usually is present following the first sound. Other diagnostic considerations include idiopathic dilatation of the pulmonary artery and subvalvular aortic stenosis. The lack of any support for an organic lesion on complete non-invasive bedside examination is the main reason to conclude that this patient’s murmur is innocent, i.e., the murmur is judged by “the company it keeps,” and in this case, it is all normal. Question: What other types of innocent systolic murmurs may be heard in youth? 22-15 Answer: a. The vibratory systolic (Still’s) murmur. This is most often heard in young children between the lower left sternal edge and apex. It is early systolic and has a buzzing quality. It is thought to be due to vibrations emanating from normal structures in one or both ventricles. A tracing from a healthy 5-year-old is shown below. LOWER LEFT STERNAL EDGE VIBRATORY MURMUR S1 S2 ECG Proceed 22-16 Answer (continued): b. The supraclavicular murmur. This murmur is also heard in children in early systole, and is often bilateral. It likely originates in the brachiocephalic arteries. Posterior movement of the shoulders may result in a decrease in the murmur. Question: Are there other “innocent” murmurs that can be heard in the adult? Proceed 22-17 Answer: In the past, the “aortic sclerotic” murmur was considered an “innocent” murmur of the elderly. It is associated, however, with an increased risk of atherosclerotic heart disease. It is best heard at the upper right sternal edge and is early to midsystolic. It is likely caused by slight fibrosis of the cusps and dilatation of the aortic root that occur with age. The murmur results from turbulence of blood in the aortic root during maximum ejection from the left ventricle. A typical phonocardiogram from a 65-year-old man is shown below. “AORTIC SCLEROTIC” MURMUR UPPER RIGHT STERNAL EDGE S1 A2 CAROTID ECG Question: Are there innocent murmurs that are not systolic? 22-18 Answer: Yes. Two continuous innocent murmurs may be heard. a. The venous hum - This murmur may be heard in most children in the supraclavicular fossa, especially on the right. It is enhanced by head maneuvers and obliterated by pressure on the internal jugular vein as shown in the tracing below taken on a normal 10-year-old. It is due to the dynamic venous circulation in youth. For the same reason, it may be heard in anemic and thyrotoxic adults. PRESSURE b. The mammary souffle may be heard in the parasternal areas in lactating females and is likely due to turbulence in arterial vessels supplying the breasts. Proceed 22-19 While no further evaluation is indicated, a diagrammatic illustration relating intracardiac pressure and flow to the acoustic events found in this patient follows, and explains the reason for the common systolic murmur occurring in early systole with a crescendo-decrescendo configuration. Proceed 22-20 LABORATORY PRESSURE (mm Hg) ECG PAp Pulmonary Artery Pressure (PAp) a v Right Atrial Pressure (RAp) Right Ventricular Pressure (RVp) RAp RVp SYSTOLE PHONOCARDIOGRAM (UPPER LEFT STERNAL EDGE) S1 A-V VALVE CLOSURE S2 SEMILUNAR VALVE CLOSURE S1 S2 Proceed 22-21 LABORATORY (continued) PHONOCARDIOGRAM (UPPER LEFT STERNAL EDGE) SYSTOLE VOLUME (cc.) S1 S1 A-V VALVE CLOSURE S2 SEMILUNAR VALVE CLOSURE S2 RVv RIGHT VENTRICULAR VOLUME (RVv) A - First 1/3 systole - 2/3 of blood ejected A B B - Last 2/3 of systole - 1/3 of blood ejected Proceed for Summary 22-22 SUMMARY The judgement that this patient’s murmur is innocent is based on an orderly approach to bedside diagnosis. The murmur is innocent because of its specific characteristics, but also because of the “company it keeps” on bedside examination. Proceed 22-23 To Review This Patient with a Classic Innocent Murmur: The HISTORY is negative. PHYSICAL SIGNS: a. The GENERAL APPEARANCE is that of a healthy, normal young man. b. The JUGULAR VENOUS PULSE mean venous pressure is normal at 3 cm H2O. The wave form is normal with a dominant “a” wave due to atrial contraction. c. The CAROTID VESSEL is normal in upstroke, peak, and downstroke. d. PRECORDIAL MOVEMENT reveals a normal brief apical impulse in the fifth intercostal space at the midclavicular line, occurring at the time of the first heart sound. Proceed 22-24 e. CARDIAC AUSCULTATION reveals normal splitting of the first sound at the lower left sternal edge of .03 seconds. There is normal inspiratory splitting of the second heart sound at the upper left sternal edge of .06 seconds. An innocent (functional) murmur is heard at the upper left sternal edge in early systole during maximal flow from the right ventricle, and is due to turbulence in the pulmonary artery. A physiologic third sound is heard at the apex. The murmur and third sound are judged as normal by the fact that the remainder of the examination is negative. f. PULMONARY AUSCULTATION reveals normal vesicular breath sounds in all lung fields. The ELECTROCARDIOGRAM shows early repolarization, a normal variant. The CHEST X RAYS are normal. No LABORATORY work is necessary. TREATMENT is reassurance. 22-25