|Year : 2016 | Volume
| Issue : 3 | Page : 174-178
Innocent versus pathologic murmurs: A challenge of neonatal examination
Mohammad Reza Khalilian1, Arash Malekian2, Mohammad Reza Aramesh2, Masoud Dehdashtian2, Taleie Maryam2
1 Department of Pediatrics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2 Department of Pediatrics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
|Date of Web Publication||28-Sep-2016|
Dr. Mohammad Reza Khalilian
Department of Pediatrics, Shahid Beheshti University of Medical Sciences, Tehran
Source of Support: None, Conflict of Interest: None
Objective: Auscultation is one of the most important procedures in routine examination of neonates for congenital heart disease (CHD). Differentiating between innocent and pathologic murmurs during auscultation is very hard and usually unfeasible. The aim of this study was to assess the ability of clinical examination in comparison to echocardiographic examination to differentiate innocent from pathological murmurs and also to define the prevalence of heart murmurs in neonates. Materials and Methods: In the current cross-sectional study, 7113 neonates were examined in a period of 1 year by two neonatologists. If heart murmurs or unnatural sounds were auscultated during the examination, the observations were categorized as "probably pathologic" or "probably innocent" and the neonates were then referred to a pediatric cardiologist for echocardiography. Results: Prevalence of heart murmurs was found to be 19.26 for every thousand live births. According to the clinical examinations, 55% of murmurs were categorized as innocent and 45% as pathologic. Echocardiographic results revealed that in fact 50.8% of cases were either normal or had physiological defects and 49.2% were pathologic. Sensitivity, specificity, positive predictive value, and negative predictive value of clinical examination in differentiating between innocent and pathologic murmurs were found to be 79.7%, 88.5%, 87%, and 81.8%, respectively, and the false-positive and false-negative rates were found to be 11.5% and 20.3%, respectively. Conclusion: Although these numbers show that clinical examination is adequate for differentiating between innocent murmurs and CHD, however the false-positive and false-negative rates in clinical examination, stress that echocardiography must be performed for a better CHD diagnosis.
Keywords: Heart murmur, innocent, neonatal, pathologic
|How to cite this article:|
Khalilian MR, Malekian A, Aramesh MR, Dehdashtian M, Maryam T. Innocent versus pathologic murmurs: A challenge of neonatal examination. J Clin Neonatol 2016;5:174-8
|How to cite this URL:|
Khalilian MR, Malekian A, Aramesh MR, Dehdashtian M, Maryam T. Innocent versus pathologic murmurs: A challenge of neonatal examination. J Clin Neonatol [serial online] 2016 [cited 2020 Jul 12];5:174-8. Available from: http://www.jcnonweb.com/text.asp?2016/5/3/174/191254
| Introduction|| |
Congenital heart disease (CHD) is a serious problem in prenatal and neonatal infants and the most common heart disease in children. It is considered as one of the main causes of mortality among term infants., CHD is the structural abnormality of the heart or intrathoracic great vessels which can have notable importance in cardiovascular functionality. The incidence of CHD has been reported between 6 and 10 per 1000 live births,,, and it is of great significance to detect these abnormalities during infancy. Most infants with CHD are usually first diagnosed in routine neonatal examinations.
One of the most important means of diagnosing CHD is auscultation of the heart in routine neonatal examination which results in the diagnosis of the CHD in infants in 50% of the cases. Thus, it is used as a screening test for detecting CHD. Heart murmurs occur due to turbulence in blood flow which is caused by passing of high velocity blood from a narrow cross-section. Heart murmurs are heard in about 0.6% of infants at routine examination of the newborn. About half of these murmurs are pathologic and the remaining innocent. Differentiating between pathologic and innocent murmurs is possible but very hard and depends on intensity, time, type, and existence of other cardiovascular complications.
Although most of heart murmurs are innocent, that is the most common reason for referrals to a pediatric cardiologist. In the evaluation of murmurs, the electrocardiogram and echocardiogram are often included. Innocent murmurs can usually be heard in the left sternal border, are usually soft (Grade I/VI to II/VI), and have no audible click, and the infant has normal pulse. On the other hand, pathologic murmurs are pansystolic, loud (≥ Grade III/VI), harsh, best heard in the upper left sternal border and have abnormal second heart sounds. Even when the aforementioned distinctions are present, discerning between pathological and innocent murmurs is a complicated task and the gold standard for differentiating between them is the use of echocardiography. Early diagnosis of CHD can significantly reduce morbidity and mortality rate among infants and neonates. Pinpointing the cause of heart murmurs can eliminate the parents' stress and anxiety about the health of their children. The current study was performed to assess the prevalence of heart murmur and ability of clinical examination to differentiate between innocent and pathologic heart murmurs in neonates.
| Materials and Methods|| |
The present investigation is a cross-sectional study from a leading cardiac center in Imam Khomeini Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Southwest Iran, during March 2013 to March 2014. A total of 5178 newborns admitted to the nursery and 1935 patients who admitted to neonatal ward and Neonatal Intensive Care Unit (NICU) were examined by two neonatologists. The examinations were performed in a special quiet room with appropriate temperature using Littman neonatal stethoscope. The newborns in nursery were examined within 48 h of birth and the admitted newborns immediately after being admitted to the neonatal ward and NICU. Neonates who underwent fetal echocardiography and diagnosed with cardiac defect were excluded from the study because of bias that we already know the diagnosis, and also neonates with major malformations such as musculoskeletal disorders, syndromic faces, and gastrointestinal disorders because of high cardiac defect probability were not enrolled in this study. Neonates with clinical findings to assess that a neonate is cyanotic or acyanotic obtained from physical examination (assess tongue, lips, and nail beds), and pulse oximeter was not used.
Aortic, tricuspid, pulmonary, and mitral areas were auscultated. S1, S2, and in the presence of abnormal sounds, S3, S4, click, and heart murmurs were recorded. When heart murmurs were present, murmur intensity and timing (early systolic, holosystolic, diastolic, and continuous) were also recorded. A questionnaire was filled in using the information in the patients' file (gender, gestational age, maternal age, central cyanosis, and abnormal heartbeats). The cases in which murmurs were auscultated were then categorized as either "probably pathologic" or "probably innocent" and the neonate was referred to a pediatric cardiologist who examined the patients using a Vivid 3 echocardiography device with a 7 s probe and the results were added to the patient questionnaire. Transient defects such as patent foramen ovale and patent ductus arteriosus (PDA) without significant hemodynamic disturbance and peripheral pulmonary stenosis are categorized as physiologic heart defects.
All the parents were informed about the study. This project was approved by the Ethical Research Committee of Ahvaz Jundishapur University of Medical Science.
| Results|| |
From the 7113 examined neonates, 137 (1.92%) were found to have heart murmurs. This shows a prevalence of 19.26 in every 1000 live births. From these, nine neonates were excluded from the study because fetal echocardiography had been performed and another eight patients were excluded because they were diagnosed with major malformation.
According to the results of the clinical examination, the murmurs in 66 cases (55%) were innocent and 54 cases (45%) were pathologic. Echocardiography (the gold standard for diagnosis of CHD) showed that 61 neonates (50.8%) were either normal or had physiological defects and 59 neonates (49.2%) had CHD.
Area under the receiver operating characteristic curve (that shows the probability of a positive identification) was found to be 84.1%. Furthermore, a sensitivity of 79.7%, specificity of 88.5%, positive predictive value of 87%, negative predictive value of 81.8%, false-positive counts of 11.5%, and false-negative counts of 20.3% were obtained for detection of CHD in clinical examinations.
From the seven false-positive cases, six patients were found to have PDA without significant hemodynamic disturbance and one had normal echocardiography results. Furthermore, from the 12 false-negative cases, ten patients were diagnosed with isolated atrial septal defect (ASD), one with ASD + left ventricular hypertrophy, and the last with ASD + ventricular septal defect (VSD) + PDA.
From all cases, 56 (53.3%) were from the nursery and 64 (46.7%) from the neonatal ward and NICU. From the 59 neonates who were found to have CHD according to echocardiography, 42 were from the wards, and from the 61 neonates who were found to be normal or had physiological defects, 39 were from the nursery. P value of these cases was <0.001 which shows a significant difference between the prevalence of CHD between neonates in nursery and neonates in neonatal ward and NICU.
From the 120 cases with heart murmur, 51.7% were males and 48.3% females and there was no significant relationship between sex and prevalence of CHD (P = 0.588). The range of gestational age was 35-42 weeks. 33 (27.5%) neonates were born preterm (before 37 weeks) and the rest were term, and there was no significant relationship between gestational age and prevalence of CHD (P = 0.98). Maternal age ranges between 16 and 42 years that two of the mothers were <18 years old, 111 were between 18 and 35, and 7 were higher than 35, and there was no significant relationship between mother's age and prevalence of CHD (P = 0.731). The intensity of the heart murmur in 15 cases (12.5%) was I/VI, in 81 (67.5%) was II/VI, in 24 (20%) was III/VI. No murmur with intensity higher than III/VI was identified. Since in all 61 cases whose echocardiography results showed normal hearts or structural physiologic defects, the murmur was ≤II/VI, P was ≤0.001, and there is a significant relationship between intensity of the auscultated murmur and lack of prevalence of true CHD.
From the auscultated murmurs, 42 (35%) were holosystolic, 50 (41.7%) early systolic, and 28 (23.3%) continuous. None of the murmurs were diastolic. Of the 42 neonates, 41 neonates whose examination showed holosystolic murmurs were found to have CHD after echocardiography which clearly shows a significant relationship between murmur timing and prevalence of CHD (P < 0.001).
Central cyanosis (bluish of tongue, lips, and nail beds) was found in 8 (6.7%) of examined neonates. Echocardiography showed that they all had CHD and there is a significant relationship between central cyanosis and prevalence of CHD (P = 0.003).
Abnormal pulse was observed in 15 (12.5%) cases. We considered weak, bounding, pulsus bisferiens, pulsus alternans, pulsus bigeminus, and pulsus paradoxus as abnormal pulse. This result shows no significant relationship between abnormal pulse and prevalence of CHD (P = 0.370). The results of echocardiography showed that the most prevalent CHD in this study was VSD (25.42%). The types and prevalence of confirmed structural defects are shown in [Table 1]. Demographic and examination data are shown in [Table 2].
|Table 1: Types and prevalence of structural defects for infants with congenital heart disease |
Click here to view
| Discussion|| |
The prevalence of heart murmur in neonates in our study was 19.26/1000 live births. Cardiac examination and echocardiography showed that 50.8% of heart murmurs were pathologic. These numbers confirm the results obtained by Bansal and Jain in the Delhi Hospital of India that was 23.81 for every 1000 live births and 45% of them had CHD. Lardhi showed the prevalence of heart murmur was 13.7/1000 neonate. If a murmur is heard, there is a 42.5% chance of their being underlying structural defects. Ainsworth et al. showed in a 2-year prospective study that 7204 newborn babies underwent routine examination and murmurs were detected in 46 babies (0.6%), of whom 25 had a cardiac malformation. If a murmur is heard, there is a 54% chance of there being an underlying cardiac malformation. According to the results of this study, VSD was the most common CHD that was similar to other studies.,,, Sensitivity of 79.7%, specificity of 88.5%, positive predictive value of 87%, negative predictive value of 81.8%, false-positive counts of 11.5%, and false-negative counts of 20.3% were obtained for detection of CHD in clinical examinations in our study. These values are similar to the results obtained by Mackie et al. at McGill University (Canada), who obtained 80.5%, 90.9%, 91.9%, and 78.4% for the same parameters. Our study showed significant relationship between the auscultated murmur and prevalence of CHD. Furthermore, Arlettaz et al. found a significant relation between murmur intensities ≥III/VI and the occurrence of CHD. There is a significant relationship between central cyanosis and prevalence of CHD (P = 0.003). This is in contrast to a study of Mackie et al., who found no meaningful relation between these two parameters. Abnormal pulse was observed in 15 (12.5%) cases. This result shows no significant relationship between abnormal pulse and prevalence of CHD (P = 0.370). Like the current study, Mackie et al. observed no meaningful relation between pulse quality and CHD. Echocardiography provides a definitive diagnosis and is recommended for evaluation of any potentially pathologic murmur and evaluation of neonatal heart murmurs because these are more likely to be manifestations of structural heart disease. Although most of the PDAs in neonates close within 72 h after birth, we enrolled the ones with significant hemodynamic disturbance. This was one of our study limitations.
| Conclusion|| |
Although the routine neonate examination by neonatologists can to a reasonable extent differentiate between innocent and pathological murmurs, the false-positive rate of 11.5% and the false-negative rate of 20.3% stress that all neonates with heart murmurs were examined by the use of echocardiography to pinpoint the cause of murmur and adequately diagnose CHD. Failing to do so will cause a great deal of anxiety for parents whose children have been falsely diagnosed with CHD and the false-negative cases can lead to severe complications and even result in the death of the infant.
We acknowledge all the parents and patients for their commitment in this study. We would like to thank the Deputy of Research and Technology of Ahvaz Jundishapur University of Medical Sciences for supporting the research.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]