evaluation of a neonate with a murmur

7/28/2019 Evaluation of a Neonate With a Murmur

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Evaluation of a Newborn With a MurmurYuliya Turiy, MD, MPH, Robert J. Yetman, MD, Polly F. Cromwell, MSN, RN, CPNP

J Pediatr Health Care. 2013;27(3):226-229.

IntroductionThe incidence of murmurs in children has been reported to be as high as 90% (Frommelt, 2004). However, theprevalence of structural heart disease is only 8 to 10 per 1000 live births, with approximately one quarter ofthese children having critical congenital heart disease (CHD), defined as requiring surgical or catheterintervention in the first year of life (Mahle et al., 2009). Therefore it is the job of the primary care provider toidentify the newborns who require investigation of their murmur. This article will focus on the assessment of anotherwise well newborn infant presenting with a murmur.

History

Perinatal history and family history are crucial to the evaluation of a newborn with a murmur. Detailedpregnancy history and medical records should be obtained from the mother, including the following information:

Results of prenatal ultrasounds

o A normal prenatal ultrasound does not completely rule out CHD because fewer than 50% ofcases of CHD are identified on a routine prenatal ultrasound (Mahle et al., 2009)

Medications

Alcohol and other drug exposure

Comorbid pregnancy conditions (e.g., hypertension and diabetes mellitus)

Family history should focus on the following information:

Congenital abnormalities

Inheritable diseases with known cardiac lesions (e.g., hypertrophic cardiomyopathy)

Childhood deaths and siblings or first-degree relatives with structural heart disease

o Epidemiologic studies have shown that the relative risks of CHD were 3.2, 1.8, and 1.1 with afamily history of CHD in first-, second-, and third-degree relatives, respectively (Oyen et al.,2009)

The following specific questions related to the infant should be asked:

Feeding history (How much? How often? How long?)

o Infants with structural heart disease tend to have more difficulty with feedings, have moreassociated symptoms while feeding, and have poorer weight gain

Any associated symptoms while feeding (e.g., tachypnea, diaphoresis, fussiness, retractions, orcyanosis)

Weight gain

Activity level and general disposition.

Physical Examination
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Vital signs should include heart rate, respiratory rate, blood pressure (BP), and pulse oximetry readings(preductal and postductal). The infant's general disposition and color also should be noted. Inconsolability,diaphoresis, pallor, or central cyanosis should raise the clinician's suspicion for a structural heart disease.Central cyanosis is always abnormal and must be differentiated from acrocyanosis (bluish discoloration ofhands and feet), which is a normal and common phenomenon in newborns.

Four Extremity Blood Pressure Measurements

Four extremity BP readings traditionally have been used in the assessment of an asymptomatic murmur in aneonate to eliminate coarctation of the aorta or interrupted aortic arch as diagnostic possibilities. A BP that is20 mm Hg higher in the arms than in the legs should prompt further investigation. However, Crossland, Funess,Abu-Harb, Sadagopan, and Wren (2004) found a significant variation in the measurement of four-extremity BPsin neonates. These differences can be attributed to equipment differences and difficulty in obtaining anaccurate BP in all four extremities in an uncooperative infant. These investigators determined that four-extremity BP measurement is not a reliable screening tool for these conditions. If one of these lesions issuspected based on physical examination, particularly if weak femoral pulses are appreciated, anechocardiogram is warranted regardless of the lower and upper extremity BPs.

Cardiac Examination

Cardiac examination should note the following information:

Location of the point of maximum intensity

The presence of precordial bulge, substernal heave, and precordial thrill

First and second heart sounds and any additional heart sounds such as S3, S4, and murmurs

o First heart sounds are best heard at the lower left sternal border and usually are single

o Second heart sounds are heard best along the left upper sternal border; they are audibly splitin 80% of newborn infants by 48 hours of age (Duff &McNamara, 1998) and vary withrespiration

o Any abnormality in the second heart sound should raise suspicion for a congenital heartdefect

o Any murmur that is diastolic, louder than a II/VI, or harsh in quality is considered abnormal

Although physical examination still remains the mainstay of clinical diagnosis, several studies have shown thatthe effectiveness of auscultation alone is limited and dependent on practitioner's level of experience. One studyfound that the clinical assessment alone by a pediatric cardiologist had a sensitivity of 80.5% and a specificityof 90.9% for differentiating an innocent murmur from a pathologic one (Griebsch et al., 2007). Ageliki andcolleagues (2011) also found that auscultation alone has a limited ability to distinguish a pathologic from aninnocent murmur. In addition, they found great variation between the levels of clinical experience (i.e., anattending physician versus a fellow versus a resident). Another study found that fully trained pediatricians couldassess the significance of a neonatal heart murmur with a specificity of 95.5% but a sensitivity of only 33%.Interestingly, the same study found no significant difference between the ability of a pediatric cardiologist and apediatrician to judge a pathologic murmur (Gokman et al., 2009).

Any abnormality in the second heart sound should raise suspicion for a congenital heart defect.

Diagnostic StudiesPulse Oximetry

The use of pulse oximetry to screen for structural heart disease, in particular for lesions classified as criticalcongenital cyanotic heart disease, has been studied and is increasingly common for routine assessments ofneonates. Current recommendations come from a careful analysis of the published and unpublished datareviewed by a work group comprising the Secretary's Advisory Committee on Heritable Disorders in Newbornsand Children, the American Academy of Pediatrics, the American Heart Association, and the American Collegeof Cardiology Foundation (Kemper et al., 2011). These recommendations state that:


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Screening should begin after the first 24 hours of life and be completed on the second day of life

Readings should be obtained from right upper extremity and either a right or a left lower extremity(preductal and postductal)

A screen is considered positive if the oxygen saturation is < 90% in any one extremity, oxygensaturation is < 95% in both extremities on three measures each separated by 1 hour, or a > 3%

absolute difference in oxygen saturation between upper and lower extremity readings is noted on threeseparate measures taken 1 hour apart

Chest Radiographs and Electrocardiograms

In addition to a thorough history and physical examination, chest radiographs and electrocardiograms (ECGs)often are used by practitioners to evaluate an asymptomatic murmur.

Several congenital cardiac lesions will have ECG abnormalities:

Right ventricular hypertrophy beyond what is expected in the neonatal period can be indicative of right-sided obstructive lesions such as pulmonary valve stenosis

Left ventricular hypertrophy raises concerns for left-sided obstructive lesions such as aortic orsubaortic stenosis and coarctation of the aorta

Right or left axis deviation can be indicative of an atrial septal defect or atrioventricular canal defect

Atrial septal defect also can present as incomplete right bundle branch block (O'Connor, McDaniel, &Brady, 2008)

A study by Danford, Gumbiner, Martin, and Fletcher (2000) showed that an ECG and a chest radiograph canbe helpful in diagnosing certain cardiac lesions and do not significantly mislead the examiner. For example, anECG can aid in diagnosis of an atrial septal defect or pulmonary valve stenosis and a chest radiograph can behelpful in the diagnosis of a moderate to large ventricular septal defect. Danford and colleagues postulate thatan ECG and a chest radiograph remain a reasonable option to be included in the full workup of a child with anasymptomatic murmur.

However, other studies have found that although some cardiac defects will have ECG and chest radiographic

findings, the ability of those findings to change the management of these infants remains controversial. A studyby Oeppen, Fairhurst, and Argent (2002) found that a chest radiograph was not only unlikely to help in definingthe exact cardiac defect present, but it also did not change the overall management of the patient. In addition, astudy looking at the cost-effectiveness of the various modalities of evaluation of a heart murmur found that themost cost-effective evaluation is either immediate referral to a pediatric cardiologist or an echocardiogramperformed by an experienced pediatric echocardiographer (Yi, Kimball, Tsevat, Mrus, & Kotagal, 2002). Theseinvestigators also found that the addition of a chest radiograph and ECG added little to the initial evaluation andresulted in a selective referral for echocardiography and/or pediatric cardiology that was not cost-effective (Yi etal., 2002).

Echocardiogram

An echocardiogram remains the study of choice to diagnose CHD. It is noninvasive, has a high detection ratefor CHD, and can be performed easily at the bedside. Tworetzky and colleagues (1999) found that anechocardiogram has a 95% diagnostic accuracy in both isolated cardiac lesions such as ventricular septal

defects and more complex pathology such as tetralogy of Fallot. The use of Doppler techniques and higherresolution probes also has increased the accuracy of the traditional two-dimensional echocardiogram to detectCHD.

However, an echocardiogram is not without its own limitations. It is highly operator dependant and is mostaccurate when performed by a trained pediatric echocardiographer and read by a pediatric cardiologist. Inaddition, the acoustic windows can vary greatly depending on the size of the patient, and they can be limited inpostoperative patients. The quality of the echocardiogram also depends greatly on the cooperation of thepatient, which is a difficult task to achieve in a pediatric population.


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New imaging techniques such as three-dimensional echocardiography, cardiac magnetic resonance imaging,and computed tomography are emerging to compliment two-dimensional echocardiography. These studies areparticularly useful in delineating more complex CHD lesions by creating a full three-dimensional reconstructionof the heart. Cardiac magnetic resonance imaging also is able to determine cardiac function, ventricularvolume, and velocity and volume of blood flow without relying on geometrical assumptions (Roest & De Roos,2012). However, given the higher complexity of these studies, the two-dimensional echocardiogram remainsthe initial study of choice.

Summary

Currently we have no universal guidelines on further workup of an asymptomatic neonate with a murmur, andthe approach to these infants varies greatly from practitioner to practitioner. The initial evaluation of suchinfants should always include the following elements:

Vital signs

Pulse oximetry readings as previously outlined

A thorough physical examination

If, on the basis of these data, the examiner feels comfortable with the diagnosis of a benign neonatal murmur,

standard follow-up with a general practitioner and close monitoring is within reason. However, if the examinerhas any concerns (based either on the data or on his or her comfort level), further evaluation is warranted. Inareas where a pediatric cardiology consultation is available, the cardiologist then can make the appropriaterecommendations for further studies and follow-up. In areas where a pediatric cardiologist is not readilyavailable, the addition of a chest radiograph or an ECG may aid in the diagnosis of several specific cardiaclesions, and an echocardiogram, if available, may aid in the accurate diagnosis and dictate appropriate follow-up. For the remotely located clinician, telemedicine is an option. Multiple studies have found that telemedicinein pediatric cardiology is safe, cost-effective, yields accurate diagnoses, and serves as a valuable resource forthe primary care clinician (Gomes et al., 2010; Sable et al., 2002). The advent of telemedicine technology hasprovided these patients and clinicians with access to pediatric cardiologists without the need to travel to atertiary care center.

References

Ageliki KA, Sotirios F, Sotirios T, Alexandra M, Gabriel D, Stefanos M. Accuracy of cardiac

auscultation in asymptomatic neonates with heart murmurs: Comparison between pediatric traineesand neonatologists. Pediatric Cardiology. 2011;32:473477

Crossland DS, Furness JC, Abu-Harb M, Sadagopan SN, Wren C. Variability of four limb bloodpressure in normal neonates.Archives of Disease in Childhood Fetal and Neonatal Edition.2004;89:F325F327

Danford DA, Gumbiner CH, Martin AB, Fletcher SE. Effects of electrocardiography and chestradiography on the accuracy of preliminary diagnosis of common congenital cardiac defects. PediatricCardiology. 2000;21:334340

Duff FD, McNamara GG. History and physical examination of the cardiovascular system. In: Garson A,Bricker JT, Fisher DJ, Neish SR editor. The science and practice of pediatric cardiology. Baltimore,MD: Williams & Wilkins; 1998;p. 693

Frommelt MA. Differential diagnosis and approach to a heart murmur in term infants. Pediatric Clinicsof North America. 2004;51:10231032

Gokman Z, Tunaoglu FS, Kula S, Ergenekon E, Ozkiraz S, Olgunturk R. Comparison of initialevaluation of neonatal murmurs by pediatrician and pediatric cardiologist. Journal of Fetal NeonatalMedicine. 2009;22:10861091


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Gomes R, Ross R, Lima S, Carmo P, Ferreira R, Menezes I, et al Pediatric cardiology andtelemedicine: Several years' experience of cooperation with remote hospitals. Revista Portuguesa deCardiologia. 2010;29(2):181192

Griebsch I, Knowls RL, Brown J, Bull C, Wren C, Dezateux CA. Comparing the clinical and economiceffects of clinical examination, pulse oximetry and echocardiography in newborn screening forcongenital heart defects: A probabilistic cost-effectiveness model and value of information analysis.

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Kemper AR, Mahle WT, Martin GR, Coolie WC, Kumar P, Morrow WR, et al Strategies forimplementing screening for critical congenital heart disease. Pediatrics. 2011;128(5):e1259e1267

Mahle WT, Newburger JW, Matherne GP, Smith FC, Hoke TR, Koppel R, et al Role of pulse oximetryin examining newborns for congenital heart disease: A scientific statement from the American HeartAssociation and American Academy of Pediatrics. Circulation. 2009;120:447458

O'Connor M, McDaniel N, Brady WJ. The pediatric electrocardiogram part III: Congenital heart diseaseand other cardiac syndromes. The American Journal of Emergency Medicine. 2008;26:497503

Oeppen RS, Fairhurst JJ, Argent JD. Diagnostic value of the chest radiograph in asymptomaticneonates with a cardiac murmur. Clinical Radiology. 2002;57:736740

Oeyn N, Pousen G, Boyd HA, Wohlfahrt J, Jensen P. Recurrence of congenital heart disease infamilies. Circulation. 2009;120:295301

Roest A, De Roos A. Imaging of patients with congenital heart disease. Nature Reviews: Cardiology.2012;9(2):101115

Sable C, Cummings S, Pearson G, Schratz L, Cross R, Quivers E, et al Impact of telemedicine on thepractice of pediatric cardiology in community hospital. Pediatrics. 2002;109(1):e3

Tworetzky W, McElhinney D, Brook M, Reddy M, Hanley F, Silverman N. Echocardiographic diagnosisalone for the complete repair of major congenital heart defects. Journal of American College ofCardiology. 1999;33(1):228233

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J Pediatr Health Care. 2013;27(3):226-229. 2013 Mosby, Inc.

evaluation of a neonate with a murmur

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