HISTORY 18-year-old man. CHIEF COMPLAINT: Heart murmur present since early infancy. PRESENT ILLNESS: Although normal at birth, a heart murmur was heard at the six week check-up and has persisted since that time. asymptomatic with normal growth and development. He has been Question: What category of heart disease is suggested by this history? 25-1
Answer: A significant murmur beginning in infancy is almost certainly due to a congenital heart defect. The absence of symptoms suggests that the murmur represents either mild ventricular outflow obstruction or a shunt lesion. The absence of a murmur at birth suggests the latter, as a shunt murmur does not occur until pulmonary vascular resistance falls following birth. The fact that the murmur was heard as early as six weeks after birth is against the diagnosis of atrial septal defect. This relates to the fact that the systolic murmur in atrial septal defect is soft and difficult to hear in a young infant. Proceed 25-2
PHYSICAL SIGNS a. GENERAL APPEARANCE - Normal 18-year-old man. b. VENOUS PULSE - The CVP is estimated to be 3 cm of H 2 O. UPPER RIGHT STERNAL EDGE JUGULAR VENOUS PULSE Question: How do you interpret the venous pulse? 25-3
Answer: The venous pulse is normal in mean pressure and wave form. c. ARTERIAL PULSE - (BP = 100/60 mm Hg) UPPER RIGHT STERNAL EDGE S1 S2 CAROTID ECG Question: How do you interpret the arterial pulse? 25-4
Answer: The arterial pulse is normal. If a moderate or large shunt at the great vessel level were present, one would expect a wide pulse pressure and a bounding arterial pulse. PHONO UPPER RIGHT STERNAL EDGE APEXCARDIOGRAM Question: How do you interpret the apexcardiogram? 25-5
Answer: The apexcardiogram is normal. e. CARDIAC AUSCULTATION PHONO LOWER LEFT STERNAL EDGE S1 S2 S1 S2 ECG 0.2 sec Question: How do you interpret these acoustic events? 25-6
Answer: There is a holosystolic murmur at the lower left sternal edge. It is less intense at the apex. These findings are consistent with a ventricular septal defect. There is neither a third heart sound nor a flow rumble at the apex indicating that the shunt is small. A large flow ventricular septal defect would result in significantly increased mitral valve flow producing an apical diastolic flow rumble. e. CARDIAC AUSCULTATION (continued) ECG 1 2L 2 EXPIRATION 1 A2 P2 1 A2 P2 0.1 sec INSPIRATION Question: sternal edge? How do you interpret the acoustic events at the upper left 25-7
Answer: There is normal inspiratory splitting of the second heart sound. The short, early crescendo-decrescendo murmur is due primarily to the turbulence of flow across the pulmonary outflow tract during maximum ejection ( innocent murmur). Radiation of the murmur from the lower left sternal edge may also contribute. f. PULMONARY AUSCULTATION Question: How do you interpret the acoustic events in the pulmonary lung fields? Proceed 25-8
Answer: In all lung fields, there are normal vesicular breath sounds. ELECTROCARDIOGRAM I II III avr avl avf V1 V2 V3 V4 V5 V6 NORMAL STANDARD Question: How do you interpret this ECG? 25-9
Answer: The ECG is within normal limits. CHEST X RAYS PA LATERAL Questions: 1. How do you interpret the chest X rays? 2. Based on the history, physical examination, ECG and chest X rays, what is your diagnosis and plan to further evaluate this patient? 25-10
Answers: 1. The chest X rays are normal. The absence of increased pulmonary arterial vascularity and the normal heart size are consistent with a small shunt. 2. Based on the history, physical examination, ECG, and chest X rays, the patient has a small ventricular septal defect not requiring surgical closure. An echocardiogram provides additional diagnostic information. The patient s study follows. 25-11
LABORATORY- ECHOCARDIOGRAM RV LA = Left Atrium LV = Left Ventricle RV = Right Ventricle Ao = Aorta LV VSD Ao VSD = Ventricular Septal Defect LA TWO-DIMENSIONAL PARASTERNAL LONG AXIS Question: How do you interpret this echocardiogram? Proceed 25-12
Answer: The echocardiogram demonstrates a structure which moves anteriorly in systole (arrows) and appears to be attached to the ventricular septum. This structure represents a so-called aneurysm of the ventricular septum. Its formation is one mechanism by which a membranous ventricular septal defect may close. In some patients, an early systolic sound, best heard at the lower left sternal edge with the patient sitting, may indicate the presence of such a septal aneurysm. While cardiac catheterization is not indicated in this patient a study which demonstrates the septal defect and associated aneurysm follows. Proceed 25-13
LABORATORY(continued) LEFT VENTRICULAR ANGIOGRAM Left Anterior Oblique The arrows clearly outline a pedunculated aneurysm of the membranous ventricular septum. Proceed for associated hemodynamic data. 25-14
LABORATORY(continued) - CATHETERIZATION DATA PRESSURE OXYGEN SITE (mm Hg) SATURATION(%) Superior Vena Cava Mean = 3 68 Right Atrium Mean = 3 68 Right Ventricle 25/3 73 Main Pulmonary Artery 23/9 Mean = 13 75 Left Atrium Mean = 5 98 Left Ventricle 100/5 98 Aorta 98/70 Mean = 80 98 Question: How do you interpret these data? 25-15
Answer: There is a significant increase in oxygen saturation at the right ventricular level (normal =<3%) indicating a left-to-right shunt. The slight further increase in saturation in the pulmonary artery reflects better mixing of shunt flow with systemic venous return rather than an additional shunt at the great vessel level. The left-to-right shunt calculates at 23% of pulmonary blood flow, that is, the ratio of pulmonary to systemic flow (Qp/Qs) is 1.3 to 1. Right heart pressures are normal as expected. Question: How would you treat this patient? 25-16
Answer: Surgery is not indicated for this small ventricular septal defect. The only significant risk is infective endocarditis. The patient was instructed in proper antibiotic prophylaxis at the time of dental manipulation (including cleaning and filling) and surgery of the gastrointestinal or genitourinary tract. Proceed for Summary 25-17
SUMMARY Ventricular septal defects may be isolated or occur in association with other cardiac abnormalities. In infants, they are the most commonly diagnosed congenital cardiac defect. Bicuspid, non-stenotic aortic valves are more common, but frequently go unrecognized because of the subtle nature of the physical signs. Ventricular septal defects are classified according to their location. The membranous defect lies beneath the crista supraventricularis in proximity to the tricuspid valve. Viewed from the left ventricle, these defects lie beneath the right aortic cusp. Proceed 25-18
SUMMARY (continued) Muscular defects are commonly small and located in the mid portion of the septum. Small defects usually close spontaneously. In infancy, muscular defects can be quite large, producing severe symptoms. The least common type is the supracristal ventricular septal defect which lies above the crista supraventricularis, immediately below the pulmonary valve, so that the valve seems to override the septum. Viewed from the left ventricle, the defect lies close to the aortic valve cusps. These defects may be large and rarely undergo spontaneous closure. Because of proximity to the aortic valve, aortic regurgitation is more likely to occur than in other types. This defect is more common in infants of Asian descent. Proceed 25-19
SUMMARY (continued) The majority of small ventricular septal defects close spontaneously during the first two years of life, most during the first six months. They may be obliterated by growth along the edge of the defect, redundant tricuspid leaflet tissue, or septal aneurysm formation. Of those that persist, few require surgical treatment. Obstructive pulmonary arteriolar disease does not occur due to small ventricular defects. Infective endocarditis is the only risk in those patients in whom the defect remains patent. If endocarditis occurs, the site is usually on the right ventricular wall or on the tricuspid valve. Aortic regurgitation occasionally is associated with a small membranous VSD. The typical pathology of a membranous infracristal defect follows. Proceed 25-20
PATHOLOGY VSD S R P M VSD RIGHT VENTRICULAR VIEW S = septal leaflet of tricuspid valve Arrow = papillary muscle of the conus LEFT VENTRICULAR VIEW R = right aortic cusp P = posterior aortic cusp M = mitral valve anterior leaflet In this specimen the defect is not as small as in the patient presented and is unassociated with a septal aneurysm. Proceed for Case Review 25-21
To Review This Case of a Small Ventricular Septal Defect: The HISTORY is typical, including the appearance of a murmur at six weeks of age without symptoms. PHYSICAL SIGNS: a. The GENERAL APPEARANCE is normal. b. The JUGULAR VENOUS PULSE is normal in mean pressure and wave form. c. The CAROTID ARTERIAL PULSE is normal. d. PRECORDIAL MOVEMENT is normal. Proceed 25-22
e. CARDIAC AUSCULTATION reveals normal first and second heart sounds. There is a loud holosystolic murmur at the lower left sternal edge which radiates well to the apex. The soft early crescendo-decrescendo murmur at the upper left sternal edge is due primarily to flow across the pulmonary outflow tract. f. PULMONARY AUSCULTATION reveals normal vesicular breath sounds in all lung fields. The ELECTROCARDIOGRAM and CHEST X RAYS are normal. LABORATORY STUDIES include the echocardiogram which demonstrates a ventricular septal aneurysm. Although invasive study is unnecessary, catheterization data from a typical case showed the ventricular septal defect, aneurysm and oxygen step-up at the ventricular level. TREATMENT consists of infective endocarditis prophylaxis. 25-23