Assessing the clinical significance of echocardiograms in determining treatment of patent ductus arteriosus in neonates.

BACKGROUND: To evaluate the utility of echocardiogram (ECHO) in detection and treatment of patent ductus arteriosus (PDA) and hemodynamically significant PDA (hsPDA) in preterm neonates. METHODS: This was a retrospective case-control study of all preterm infants born or admitted to the level III Neonatal Intensive Care Unit in McMaster Children's Hospital from January 2009 to January 2013. These cases were further classified into the following sub-groups: group A) hsPDA confirmed on ECHO; and the control, group B) PDA (but not hemodynamically significant) confirmed on ECHO. Patients without an ECHO were excluded from all analyses. The primary outcome was incidence of treatment for PDA. RESULTS: PDA treatment was administered in 83.3% and 11.2% of patients in groups A and B respectively (P < 0.05). Among patients with a hsPDA within group A, 17% did not receive treatment, while 11% of patients with non-hemodynamically significant PDA received treatment for the PDA. Within the cohort of patients who received treatment for a hsPDA, gestational age below 35 weeks as well as murmurs heard on auscultation were both found to be predictors of treatment. CONCLUSION: While the ECHO remains the gold standard for detecting pathological PDA, there is evidence that other traditional clinical measures continue to guide clinical practice and treatment decisions. Further research is required to gain an understanding of how clinical measures and ECHO may be used in conjunction to optimize resource utilization.

Cardiotocography versus intermittent auscultation of fetal heart on admission to labour ward for assessment of fetal wellbeing.

BACKGROUND: The admission cardiotocograph (CTG) is a commonly used screening test consisting of a short (usually 20 minutes) recording of the fetal heart rate (FHR) and uterine activity performed on the mother's admission to the labour ward. This is an update of a review published in 2012. OBJECTIVES: To compare the effects of admission cardiotocography with intermittent auscultation of the FHR on maternal and infant outcomes for pregnant women without risk factors on their admission to the labour ward. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register to 30 November 2016 and we planned to review the reference list of retrieved papers SELECTION CRITERIA: All randomised and quasi-randomised trials comparing admission CTG with intermittent auscultation of the FHR for pregnant women between 37 and 42 completed weeks of pregnancy and considered to be at low risk of intrapartum fetal hypoxia and of developing complications during labour. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility and quality, and extracted data. Data were checked for accuracy. MAIN RESULTS: We included no new trials in this update. We included four trials involving more than 13,000 women which were conducted in the UK and Ireland and included women in labour. Three trials were funded by the hospitals where the trials took place and one trial was funded by the Scottish government. No declarations of interest were made in two trials; the remaining two trials did not mention declarations of interest. Overall, the studies were assessed as low risk of bias. Results reported in the 2012 review remain unchanged.Although not statistically significant using a strict P < 0.05 criterion, data were consistent with women allocated to admission CTG having, on average, a higher probability of an increase in incidence of caesarean section than women allocated to intermittent auscultation (risk ratio (RR) 1.20, 95% confidence interval (CI) 1.00 to 1.44, 4 trials, 11,338 women, I² = 0%, moderate quality evidence). There was no clear difference in the average treatment effect across included trials between women allocated to admission CTG and women allocated to intermittent auscultation in instrumental vaginal birth (RR 1.10, 95% CI 0.95 to 1.27, 4 trials, 11,338 women, I² = 38%, low quality evidence) and perinatal mortality rate (RR 1.01, 95% CI 0.30 to 3.47, 4 trials, 11,339 infants, I² = 0%, moderate quality evidence).Women allocated to admission CTG had, on average, higher rates of continuous electronic fetal monitoring during labour (RR 1.30, 95% CI 1.14 to 1.48, 3 trials, 10,753 women, I² = 79%, low quality evidence) and fetal blood sampling (RR 1.28, 95% CI 1.13 to 1.45, 3 trials, 10,757 women, I² = 0%) than women allocated to intermittent auscultation. There were no differences between groups in other secondary outcome measures including incidence and severity of hypoxic ischaemic encephalopathy (incidence only reported) (RR 1.19, 95% CI 0.37 to 3.90; 2367 infants; 1 trial; very low quality evidence) and incidence of seizures in the neonatal period (RR 0.72, 95% CI 0.32 to 1.61; 8056 infants; 1 trial; low quality evidence). There were no data reported for severe neurodevelopmental disability assessed at greater than, or equal to, 12 months of age. AUTHORS' CONCLUSIONS: Contrary to continued use in some clinical areas, we found no evidence of benefit for the use of the admission CTG for low-risk women on admission in labour.Furthermore, the probability is that admission CTG increases the caesarean section rate by approximately 20%. The data lacked power to detect possible important differences in perinatal mortality. However, it is unlikely that any trial, or meta-analysis, will be adequately powered to detect such differences. The findings of this review support recommendations that the admission CTG not be used for women who are low risk on admission in labour. Women should be informed that admission CTG is likely associated with an increase in the incidence of caesarean section without evidence of benefit.Evidence quality ranged from moderate to very low, with downgrading decisions based on imprecision, inconsistency and a lack of blinding for participants and personnel. All four included trials were conducted in developed Western European countries. One additional study is ongoing.The usefulness of the findings of this review for developing countries will depend on FHR monitoring practices. However, an absence of benefit and likely harm associated with admission CTG will have relevance for countries where questions are being asked about the role of the admission CTG.Future studies evaluating the effects of the admission CTG should consider including women admitted with signs of labour and before a formal diagnosis of labour. This would include a cohort of women currently having admission CTGs and not included in current trials.

Electronic Fetal Monitoring and Cesarean Birth: A Scoping Review.

BACKGROUND: In many United States hospitals, electronic fetal monitoring (EFM) is used continuously during labor for all patients regardless of risk status. Application of EFM, particularly at labor admission, may trigger a chain of interventions resulting in increased risk for cesarean birth among low-risk women. The goal of this review was to summarize evidence on use of EFM during low-risk labors and identify gaps in research. METHODS: We conducted a scoping review of studies published in English since 1996 that addressed the relationship between EFM use and cesarean among low-risk women. We screened 57 full-text articles for appropriateness. Seven articles were included in the final review. RESULTS: The largest study demonstrated an 81 percent increased risk of primary cesarean birth when EFM was used in labor, but did not differentiate between high- and low-risk pregnancies. Four randomized controlled trials examined the association of admission EFM with obstetric outcomes; only one considered cesarean birth as a primary outcome and found a 23 percent increase in operative birth when EFM lasted more than 1 hour. A study examining application of continuous EFM before and after 4 centimeters dilatation found no differences between groups. CONCLUSIONS: In general, the research on this topic suggests an association between the use of EFM and cesarean birth; however, more well-designed studies are needed to examine benefits of EFM versus auscultation, determine if EFM is associated with use of other technologies that could cumulatively increase risk of cesarean birth, and understand provider motivation to use EFM over auscultation.

High Order Statistics and Time-Frequency Domain to Classify Heart Sounds for Subjects under Cardiac Stress Test.

This paper considers the problem of classification of the first and the second heart sounds (S1 and S2) under cardiac stress test. The main objective is to classify these sounds without electrocardiogram (ECG) reference and without taking into consideration the systolic and the diastolic time intervals criterion which can become problematic and useless in several real life settings as severe tachycardia and tachyarrhythmia or in the case of subjects being under cardiac stress activity. First, the heart sounds are segmented by using a modified time-frequency based envelope. Then, to distinguish between the first and the second heart sounds, new features, named α(opt), ß, and γ, based on high order statistics and energy concentration measures of the Stockwell transform (S-transform) are proposed in this study. A study of the variation of the high frequency content of S1 and S2 over the HR (heart rate) is also discussed. The proposed features are validated on a database that contains 2636 S1 and S2 sounds corresponding to 62 heart signals and 8 subjects under cardiac stress test collected from healthy subjects. Results and comparisons with existing methods in the literature show a large superiority for our proposed features.

Intelligent Structured Intermittent Auscultation (ISIA): evaluation of a decision-making framework for fetal heart monitoring of low-risk women.

BACKGROUND: Research-informed fetal monitoring guidelines recommend intermittent auscultation (IA) for fetal heart monitoring for low-risk women. However, the use of cardiotocography (CTG) continues to dominate many institutional maternity settings. METHODS: A mixed methods intervention study with before and after measurement was undertaken in one secondary level health service to facilitate the implementation of an initiative to encourage the use of IA. The intervention initiative was a decision-making framework called Intelligent Structured Intermittent Auscultation (ISIA) introduced through an education session. RESULTS: Following the intervention, medical records review revealed an increase in the use of IA during labour represented by a relative change of 12%, with improved documentation of clinical findings from assessments, and a significant reduction in the risk of receiving an admission CTG (RR 0.75, 95% CI, 0.60-0.95, p = 0.016). CONCLUSION: The ISIA informed decision-making framework transformed the practice of IA and provided a mechanism for knowledge translation that enabled midwives to implement evidence-based fetal heart monitoring for low risk women.

Echocardiographic screening in a resource poor setting: borderline rheumatic heart disease could be a normal variant.

OBJECTIVE: To estimate the echocardiography confirmed prevalence of rheumatic heart disease (RHD) in school children in Fiji. DESIGN: Cross-sectional observational study. SETTING: Ten primary schools in Fiji. PATIENTS: School children aged 5-14 years. INTERVENTIONS: Each child had an echocardiogram performed by an echocardiographic technician subsequently read by a paediatric cardiologist not involved with field screening, and auscultation performed by a paediatrician. MAIN OUTCOME MEASURES: Echocardiographic criteria for RHD diagnosis were based on those previously published by the National Institutes of Health (NIH) and World Health Organization (WHO), and data were also analyzed using the new World Heart Federation (WHF) criteria. Prevalence figures were calculated with binomial 95% confidence intervals. RESULTS: Using the modified NIH/WHO criteria the prevalence of definite RHD prevalence was 7.2 cases per 1000 (95% CI 3.7-12.5), and the prevalence of probable RHD 28.2 cases per 1000 (95% CI 20.8-37.3). By applying the WHF criteria the prevalence of definite and borderline RHD was 8.4 cases per 1000 (95% CI 4.6-14.1) and 10.8 cases per 1000 (95% CI 6.4-17.0) respectively. Definite RHD was more common in females (OR 5.1, 95% CI 1.1-48.3) and in children who attended school in a rural location (OR 2.3, 95% CI 0.6-13.50). Auscultation was poorly sensitive compared to echocardiography (30%). CONCLUSION: There is a high burden of undiagnosed RHD in Fiji. Auscultation is poorly sensitive when compared to echocardiography in the detection of asymptomatic RHD. The results of this study highlight the importance of the use of highly sensitive and specific diagnostic criteria for echocardiography diagnosis of RHD.

Utility of auscultatory screening for detecting rheumatic heart disease in high-risk children in Australia's Northern Territory.

OBJECTIVES: To evaluate the utility of auscultatory screening for detecting echocardiographically confirmed rheumatic heart disease (RHD) in high-risk children in the Northern Territory, Australia. DESIGN: Cross-sectional screening survey. SETTING: Twelve rural and remote communities in the NT between September 2008 and June 2010. PARTICIPANTS: 1015 predominantly Indigenous schoolchildren aged 5-15 2013s. INTERVENTION: All children underwent transthoracic echocardiography, using a portable cardiovascular ultrasound machine, and cardiac auscultation by a doctor and a nurse. Sonographers and auscultators were blinded to each others' findings and the clinical history of the children. Echocardiograms were reported offsite, using a standardised protocol, by cardiologists who were also blinded to the clinical findings. MAIN OUTCOME MEASURES: Presence of a cardiac murmur as identified by nurses (any murmur) and doctors (any murmur, and "suspicious" or "pathological" murmurs), compared with echocardiogram findings. RHD was defined according to the 2012 World Heart Federation criteria for echocardiographic diagnosis of RHD. RESULTS: Of the 1015 children screened, 34 (3.3%) had abnormalities identified on their echocardiogram; 24 met echocardiographic criteria for definite or borderline RHD, and 10 had isolated congenital anomalies. Detection of any murmur by a nurse had a sensitivity of 47.1%, specificity of 74.8% and positive predictive value (PPV) of 6.1%. Doctor identification of any murmur had 38.2% sensitivity, 75.1% specificity and 5.1% PPV, and the corresponding values for doctor detection of suspicious or pathological murmurs were 20.6%, 92.2% and 8.3%. For all auscultation approaches, negative predictive value was more than 97%, but the majority of participants with cardiac abnormalities were not identified. The results were no different when only definite RHD and congenital abnormalities were considered as true cases. CONCLUSIONS: Sensitivity and positive predictive value of cardiac auscultation compared with echocardiography is poor, regardless of the expertise of the auscultator. Although negative predictive value is high, most cases of heart disease were missed by auscultation, suggesting that cardiac auscultation should no longer be used to screen for RHD in high-risk schoolchildren in Australia.

Does patient gender impact resident physicians' approach to the cardiac exam?

BACKGROUND: Physical examination remains an important part of the initial evaluation of patients presenting with chest pain but little is known about the effect of patient gender on physician performance of the cardiovascular exam. OBJECTIVE: To determine if resident physicians are less likely to perform five key components of the cardiovascular exam on female versus male standardized patients (SPs) presenting with acute chest pain. DESIGN: Videotape review of SP encounters during Objective Structured Clinical Examinations (OSCEs) administered by the Emory University Internal Medicine Residency Program in 2006 and 2007. Encounters were reviewed to assess residents' performance of five cardiac exam skills: auscultation of the aortic, pulmonic, tricuspid, and mitral valve areas and palpation for the apical impulse. PARTICIPANTS: One hundred forty-nine incoming residents. MAIN MEASURES: Residents' performance for each skill was classified as correct, incorrect, or unknown. KEY RESULTS: One hundred ten of 149 (74 %) of encounters were available for review. Residents were less likely to correctly perform each of the five skills on female versus male SPs. This difference was statistically significant for auscultation of the tricuspid (p = 0.004, RR = 0.62, 95 % CI 0.46-0.83) and mitral (p = 0.007, RR = 0.58, 95 % CI = 0.41-0.83) valve regions and palpation for the apical impulse (p < 0.001, RR = 0.27, 95 % CI = 0.16-0.47). Male residents were less likely than female residents to correctly perform each maneuver on female versus male SPs. The interaction of SP gender and resident gender was statistically significant for auscultation of the mitral valve region (p = 0.006) and palpation for the apical impulse (p = 0.01). CONCLUSIONS: We observed significant differences in the performance of key elements of the cardiac exam for female versus male SPs presenting with chest pain. This observation represents a previously unidentified but potentially important source of gender bias in the evaluation of patients presenting with cardiovascular complaints.

Evaluation of the clinical utility of a carotid bruit.

BACKGROUND: Uncertainty exists over whether listening for carotid bruits as part of the clinical examination is informative in terms of predicting the presence or severity of carotid stenosis. AIM: We sought to undertake a comprehensive meta-analysis and meta-regression of all studies to date that have assessed the relationship between a carotid bruit and severity of degree of stenosis. METHODS: Electronic databases were used to identify all published studies in humans evaluating the association between bruit and stenosis published until and including October 2011. Pooled sensitivity, specificity and diagnostic odds ratio (DOR) were calculated for each stenosis group. Summary receiver operating characteristic (SROC) curve analysis was performed in studies assessing clinically relevant (i.e. >70%) stenosis. Meta-regression was performed in all studies, using random effects. RESULTS: We identified 26 studies evaluating the association between carotid bruit and stenosis, in 15 117 arteries. For clinically relevant stenosis (i.e. >70%), we found pooled sensitivity 0.53 [95% confidence interval (CI): 0.5-0.55], specificity 0.83 (95% CI: 0.82-0.84) and DOR 4.32 (95% CI: 2.78-6.66). SROC curve analysis gave an area under the curve of 0.73. Meta-regression analysis showed a (non-significant) (P = 0.067) inverse relationship between carotid bruit and stenosis. CONCLUSION: The carotid bruit is of moderate value for detecting clinically relevant carotid stenosis. It gives high specificity but low sensitivity. The likelihood of a carotid bruit does not increase at increasing degrees of stenosis.

Cardiotocography versus intermittent auscultation of fetal heart on admission to labour ward for assessment of fetal wellbeing.

BACKGROUND: The admission cardiotocograph (CTG) is a commonly used screening test consisting of a short (usually 20 minutes) recording of the fetal heart rate (FHR) and uterine activity performed on the mother's admission to the labour ward. OBJECTIVES: To compare the effects of admission CTG with intermittent auscultation of the FHR on maternal and infant outcomes for pregnant women without risk factors on their admission to the labour ward. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 May 2011) (CENTRAL) (The Cochrane Library 2011 Issue 2 of 4), MEDLINE (1966 to 17 May 2011), CINAHL (1982 to 17 May 2011), Dissertation Abstracts (1980 to 17 May 2011) and the reference list of retrieved papers. SELECTION CRITERIA: All randomised and quasi-randomised trials comparing admission CTG with intermittent auscultation of the FHR for pregnant women between 37 and 42 completed weeks of pregnancy and considered to be at low risk of intrapartum fetal hypoxia and of developing complications during labour. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility and quality, and extracted data. Data were checked for accuracy. MAIN RESULTS: We included four trials involving more than 13,000 women. All four studies included women in labour. Overall, the studies were at low risk of bias. Although not statistically significant using a strict P < 0.05 criterion, data are consistent with women allocated to admission CTG having, on average, a higher probability of an increase in incidence of caesarean section than women allocated to intermittent auscultation (risk ratio (RR) 1.20, 95% confidence interval (CI) 1.00 to 1.44, four trials, 11,338 women, T² = 0.00, I² = 0%). There was no significant difference in the average treatment effect across included trials between women allocated to admission CTG and women allocated to intermittent auscultation in instrumental vaginal birth (RR 1.10, 95% CI 0.95 to 1.27, four trials, 11,338 women, T² = 0.01, I² = 38%) and fetal and neonatal deaths (RR 1.01, 95% CI 0.30 to 3.47, four trials, 11339 infants, T² = 0.00, I² = 0%).Women allocated to admission CTG had, on average, significantly higher rates of continuous electronic fetal monitoring during labour (RR 1.30, 95% CI 1.14 to 1.48, three trials, 10,753 women, T² = 0.01, I² = 79%) and fetal blood sampling (RR 1.28, 95% CI 1.13 to 1.45, three trials, 10,757 women, T² = 0.00, I² = 0%) than women allocated to intermittent auscultation. There were no differences between groups in other secondary outcome measures. AUTHORS' CONCLUSIONS: Contrary to continued use in some clinical areas, we found no evidence of benefit for the use of the admission cardiotocograph (CTG) for low-risk women on admission in labour.We found no evidence of benefit for the use of the admission CTG for low-risk women on admission in labour. Furthermore, the probability is that admission CTG increases the caesarean section rate by approximately 20%. The data lacked power to detect possible important differences in perinatal mortality. However, it is unlikely that any trial, or meta-analysis, will be adequately powered to detect such differences. The findings of this review support recommendations that the admission CTG not be used for women who are low risk on admission in labour. Women should be informed that admission CTG is likely associated with an increase in the incidence of caesarean section without evidence of benefit.

An ultra-sensitive wearable accelerometer for continuous heart and lung sound monitoring.

This paper presents a chest-worn accelerometer with high sensitivity for continuous cardio-respiratory sound monitoring. The accelerometer is based on an asymmetrical gapped cantilever which is composed of a bottom mechanical layer and a top piezoelectric layer separated by a gap. This novel structure helps to increase the sensitivity by orders of magnitude compared with conventional cantilever based accelerometers. The prototype with a resonant frequency of 1100Hz and a total weight of 5 gram is designed, constructed and characterized. The size of the prototype sensor is 35mm×18mm×7.8mm (l×w×t). A built-in charge amplifier is used to amplify the output voltage of the sensor. A sensitivity of 86V/g and a noise floor of 40ng/√Hz are obtained. Preliminary tests for recording both cardiac and respiratory signals are carried out on human body and the new sensor exhibits better performance compared with a high-end electronic stethoscope.

Autonomous auscultation of the human heart employing a precordial electro-phonocardiogram and ensemble empirical mode decomposition.

The research presented in this paper serves to provide a tool to autonomously screen for cardiovascular disease in the rural areas of Africa. With this tool, cardiovascular disease can potentially be detected in its initial stages, which is essential for effective treatment. The autonomous auscultation system proposed here utilizes recorded heart sounds and electrocardiogram signals to automatically distinguish between normal and abnormal heart conditions. Patients that are identified as abnormal by the system can then be referred to a specialist consultant, which will save a lot of unnecessary referrals. In this study, heart sound and electrocardiogram signals were recorded with the prototype precordial electro-phonocardiogram device, as part of a clinical study to screen patients for cardiovascular disease. These volunteers consisted of 28 patients with a diagnosed cardiovascular disease and, for control purposes, 34 persons diagnosed with healthy hearts. The proposed system employs wavelets to first denoise the recorded signals, which is then followed by segmentation of heart sounds. Frequency spectrum information was extracted as diagnostic features from the heart sounds by means of ensemble empirical mode decomposition and auto regressive modelling. The respective features were then classified with an ensemble artificial neural network. The performance of the autonomous auscultation system used in concert with the precordial electro-phonocardiogram prototype showed a sensitivity of 82% and a specificity of 88%. These results demonstrate the potential benefit of the precordial electro-phonocardiogram device and the developed autonomous auscultation software as a screening tool in a rural healthcare environment where large numbers of patients are often cared for by a small number of inexperienced medical personnel.

Modulation filtering for heart and lung sound separation from breath sound recordings.

Separation of heart and lung sounds from breath sound recordings is a challenging task due to the temporal and spectral overlap of the two signals. In this paper, the use of a spectro-temporal representation to improve signal separation is investigated. The representation is obtained by means of a frequency decomposition (termed modulation frequency) of temporal trajectories of short-term spectral components. Experiments described herein suggest that improved separability of heart (HS) and lung sounds (LS) is attained in the modulation frequency domain. Bandpass and bandstop modulation filters are designed to separate HS and LS signals from breath sound recordings, respectively. Visual and auditory inspection, quantitative analysis, as well as algorithm execution time are used to assess algorithm performance. Log-spectral distances below 1 dB corroborate our listening test which found no audible artifacts in separated heart and lung sound signals.

Collecting, storing and transmitting heart sounds.

We have developed a system whereby heart sounds and accompanying electrocardiogram may be recorded in digital format, stored as files and transmitted as any other digital file. The present system is implemented on a Macintosh System 7.1 platform, but will run under System 7.0 to System 7.5. The code is written in object oriented C++. The data are presently taken using a standard heart sound microphone and ECG amplifier. The data collection program stores the sampled channels as 16 bit words. Each channel is sampled at 2 kb/s for periods of time ranging from 10 to 30 seconds. Our program then reads the file, displays it under a viewer and allows for high fidelity reproduction of the sounds.

The teaching and practice of cardiac auscultation during internal medicine and cardiology training. A nationwide survey.

OBJECTIVES: To assess the time and importance given to cardiac auscultation during internal medicine and cardiology training and to evaluate the auscultatory proficiency of medical students and physicians-in-training. STUDY DESIGN: A nationwide survey of internal medicine and cardiology program directors and a multicenter cross-sectional assessment of students' and housestaff's auscultatory proficiency. SETTING: All accredited U.S. internal medicine and cardiology programs and nine university-affiliated internal medicine and cardiology programs. PARTICIPANTS: Four hundred ninety-eight (75.6%) of all 659 directors surveyed; 203 physicians-in-training and 49 third-year medical students. INTERVENTIONS: Directors completed a 23-item questionnaire, and students and trainees were tested on 12 prerecorded cardiac events. MAIN OUTCOME MEASURES: The teaching and proficiency of cardiac auscultation at all levels of training. RESULTS: Directors attributed great importance to cardiac auscultation and thought that more time should be spent teaching it. However, only 27.1% of internal medicine and 37.1% of cardiology programs offered any structured teaching of auscultation (P = 0.02). Programs without teaching were more likely to be large, university affiliated, and located in the northeast. The trainees' accuracy ranged from 0 to 56.2% for cardiology fellows (median, 21.9%) and from 2% to 36.8% for medical residents (median, 19.3%). Residents improved little with year of training and were never better than third-year medical students. CONCLUSIONS: A low emphasis on cardiac auscultation appears to have affected the proficiency of medical trainees. Our study raises concern about the future of this time-honored art and, possibly, other bedside diagnostic skills.