Echocardiography or auscultation?


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Echocardiography or auscultation?

  1. 1. CMEEchocardiography or auscultation?How to evaluate systolic murmursClarence Shub, MD ABSTRACTOBJECTIVE To compare cardiac physical examination with echocardiography for evaluatingsystolic murmurs.QUALITY OF EVIDENCE Three databases were searched for studies comparing echocardiographyand auscultation as to sensitivity and diagnostic accuracy: MEDLINE (Ovid Online), EMBASE,and Current Contents. The quality of reported data is lowered by subjective interpretation ofresults of both cardiac physical examination and echocardiography, especially Doppler colour flowimaging.MAIN MESSAGE In adults, functional systolic murmurs can usually be distinguished from organicmurmurs. Pathologic murmurs frequently have one or more associated clinical abnormalities. If aclinician determines a murmur is benign, results of echocardiography are very likely to be normal,especially in young and middle-aged adults. According to current guidelines, echocardiographyshould not be ordered for “innocent” systolic murmurs in patients who are asymptomatic andhave otherwise normal findings on examination. If patients with functional systolic murmurs couldbe identified and not routinely referred for echocardiography, great cost savings could be realized.CONCLUSION Echocardiography is not required for all patients with systolic murmurs and shouldnot replace cardiac physical examination. RÉSUMÉOBJECTIF Comparer l’examen physique et l’échocardiographie comme moyen d’évaluer lessouffles systoliques cardiaques.QUALITÉ DES PREUVES Les études comparant l’échocardiographie et l’auscultation en termesde sensibilité et de précision diagnostique ont été répertoriées dans trois bases de données:MEDLINE (Ovid Online), Embase et Current Contents. Une interprétation subjective desrésultats amoindrit la qualité des données rapportées, tant pour l’examen physique que pourl’échocardiographie, et particulièrement dans le cas du Doppler couleur.PRINCIPAL MESSAGE Il est généralement possible de distinguer un souffle systolique fonctionneld’un souffle organique chez l’adulte. Les souffles pathologiques s’accompagnent souvent d’uneou de plusieurs anomalies cliniques. Lorsqu’un médecin considère qu’un souffle est bénin, lesrésultats de l’échocardiographie risquent fort d’être normaux, notamment chez les sujets jeuneset d’âge moyen. Les directives actuelles recommandent de ne pas prescrire d’échocardiographiepour un souffle systolique « bénin » chez un patient asymptomatique dont l’examen clinique est parailleurs normal. Le fait d’identifier les patients qui ont des souffles systoliques fonctionnels et dene pas les diriger systématiquement en échocardiographie permettrait une réduction sensible descoûts.CONCLUSION Il n’est pas nécessaire de prescrire une échocardiographie à tout patient qui présenteun souffle systolique, et cet examen ne devrait pas remplacer l’examen physique du cœur.This article has been peer reviewed.Cet article a fait l’objet d’une évaluation externe.Can Fam Physician 2003;49:163-167. VOL 49: FEBRUARY • FÉVRIER 2003  Canadian Family Physician • Le Médecin de famille canadien 163
  2. 2. cme Echocardiography or auscultation? lthough auscultation played a large role English articles were retrieved. MeSH terms used for A in cardiac diagnosis, widespread and increasing use of Doppler echocardiog- raphy in the past 15 to 20 years has MEDLINE included “echocardiography” (expanded to retrieve all varieties of echocardiography, includ- ing Doppler and transesophageal), “physical exami- diminished its importance. As a result, there have nation,” “heart auscultation,” and “heart sounds,” been parallel decreases in auscultation skills and in including “heart murmurs.” The search included confidence in using them. This review will compare sensitivity and specificity data along with diagnostic cardiac physical examination with echocardiogra- errors, clinical competence, and cost-benefit analyses. phy for evaluating systolic murmurs and show that The quality of reported data is limited by the echocardiography is not required for all patients with subjective nature of the results of both cardiac systolic murmurs. physical examination and echocardiography, espe- One of the most common auscultator y findings cially Doppler colour flow imaging. Most studies are is a systolic murmur. It occurs in more than 80% of retrospective and observational cohort studies with children and up to 52% of adults.1 Its prevalence and relatively small numbers. Also, most studies compare importance var y widely, depending on the group cardiac physical examination performed by cardiolo- studied.1 Benign or “innocent” systolic murmurs are gists or cardiac fellows with echocardiography; few relatively common. Among elderly outpatients, the studies compare physical examination performed by prevalence of systolic murmurs ranges from 29% to family physicians with echocardiography. A weakness 60%, and results of echocardiography are normal of echocardiography data, in terms of the comparison, in 44% to 100% of cases.1 Some of this variability is is their qualitative, subjective nature and the fact related to varying definitions of “normal” (eg, consid- that physicians could misinterpret the physiologic ering age-related valve sclerosis as pathologic). degrees of valve regurgitation as “pathologic” in oth- Referrals for echocardiography in the United erwise healthy people.5 States’ Medicare population have increased progres- sively. As echocardiography became widely available Evidence favouring echocardiography and more technologically advanced,2 great increases Even under ideal conditions, cardiac physical in use and cost followed. In the United States, the examination does not identify pathologic conditions number of echocardiographic studies performed accurately or correctly judge the severity of cardiac from 1986 to 1989 increased 143% and accounted for lesions. Information obtained from auscultation is more than $126 million in Medicare expenditures. subjective, depends on the examiner’s expertise, and Trends were similar in Ontario: expenditures for does not result in a permanent objective recording.6 echocardiography increased 53% from 1989 to 1992 It is not readily duplicated by other examiners. Its and accounted for 36% of all health care expenditures precision for examining systolic murmurs is only for noninvasive cardiac diagnostic tests.3 Growing use fair (κ statistic 0.03) in a clinical setting.1 Improper of this technology is not confined to North America.4 interpretation of auscultatory information does not When primar y care physicians hear systolic necessarily arise from the inexperience or ineptitude murmurs, their diagnostic options include ordering of examiners. Even experienced clinicians disagree echocardiography for further assessment or doing about heart sounds and murmurs. Certain auditory a comprehensive clinical examination to attempt to limitations (eg, insensitivity to low-frequency sounds, differentiate benign (or innocent) systolic murmurs masking of low-intensity sounds by adjacent loud from abnormal ones. sounds) contribute to the inaccuracy. In a structured search strategy,1 relevant studies Quality of evidence analyzing systolic murmurs showed that cardiologists Three databases were searched for studies comparing and senior cardiac fellows were efficient at identifying echocardiography with physical examination in terms abnormal and normal murmurs, but noncardiologist of sensitivity and diagnostic accuracy: MEDLINE examiners were not. There were very few data on the (Ovid Online) from 1980 to the present, and EMBASE latter group. and Current Contents from 1998 to the present. Only Because cardiac physical examination is rela- tively cr ude compared with newer noninvasive Dr Shub is a Consultant in the Division of diagnostic techniques and not always reliable, Cardiovascular Diseases and Internal Medicine at the American Heart Association and American College Mayo Clinic in Rochester, Minn. of Cardiology (AHA/ACC) 7 current guidelines164 Canadian Family Physician • Le Médecin de famille canadien  VOL 49: FEBRUARY • FÉVRIER 2003
  3. 3. cme Echocardiography or auscultation?recommend echocardiography for patients with or to history and electrocardiographic [ECG] and chestwithout symptoms “if clinical features indicate at radiograph results) were asked to determine whetherleast a moderate probability that a murmur reflects murmurs were functional or organic and significantstructural heart disease.” Determining that level of or insignificant. Echocardiography was used as theprobability remains a challenge. These guidelines reference standard. Approximately 20% of patientswere generated by a committee who assessed the had functional murmurs. The sensitivity of physicalsensitivity, specificity, and diagnostic accuracy of examination for detecting significant heart disease wasmore than 3000 studies (1990 to 1995) graded by 79%. Significant heart disease was missed in only twoconsensus and classified according to the weight patients (2%), both of whom had aortic stenosis. Minor,of evidence.7 insignificant lesions that were missed by physical exam- The gradual degradation of auscultation skills is ination were noted more frequently. The authors con-becoming increasingly apparent in training programs, cluded that, in adults, functional murmurs can usuallydespite efforts to preserve them by using simulation be distinguished from organic murmurs. Whether inclu-technology in medical education.8,9 A study of 314 sion of history and ECG and chest radiography resultssenior internal medicine and family practice residents would have altered the outcome of clinical assessmentin several US training programs showed that only 20% and the results of this study is unknown.of abnormal heart sounds were correctly identified Roldan et al13 compared auscultation with trans-from auscultator y tapes. 10 Residents who received esophageal echocardiography in 143 asymptomaticformal auscultatory training had greater confidence outpatients and healthy volunteers (mean age, 38in their skills, but no greater accuracy. years). Prevalence of functional murmurs was 31%. A comparison of auscultation skills in US, Canadian, Functional murmurs were correlated with low soundand British internal medicine trainees showed that intensity (predominantly grade 1) and early systolicperformance was slightly better in Canada than in the timing. Pathologic murmurs frequently had one orUnited States, but was poor in all three countries.11 more associated clinical abnormalities. Of the 10For practising US physicians, economic forces (ie, subjects with abnormal valves who had apparentlydeclining reimbursement for ser vices) have con- normal results on clinical examination, only two (20%)strained the time necessar y to perform adequate had more than mild regurgitation identified by echo-physical examinations, prompting busy clinicians to cardiography. The valve abnormalities in eight otherstruncate cardiac examinations, which leads to even (80%) were of no clinical significance. Other studies4further erosion of clinical skills. have also shown that when clinicians determine Determining the cost-effectiveness of routine echo- murmurs to be benign, echocardiographic results arecardiography for patients with systolic murmurs must normal in the vast majority of instances, especially ininclude the implications of missed diagnoses when young and middle-aged adults.1,4,14relying on physical examination alone and changes in In a retrospective review of 169 general medicinemanagement that result from the echocardiographic patients with systolic murmurs who were examinedinformation obtained. This approach is especially by noncardiologists, age, male sex, and murmurimportant in hospitals (eg, intensive care units),3 intensity of grade 3 or more were predictors (withwhere echocardiography could significantly reduce use of a logistic regression model) of positive echo-the rate of missed cardiac diagnoses, compared with cardiography results.15 In that study, if women ≤35physical examination, and significantly expedite years with murmurs grade 2 or lower had not beentherapy, which in turn could limit other testing and referred for echocardiography, 47% of the studiesshorten hospital stays. Finally, today’s clinicians could have been avoided without loss of sensitivity.might be uncomfortable with even a modicum of The prediction model used was developed from thediagnostic uncertainty, knowing that a safe, painless, data but was not tested prospectively. Further studiesnoninvasive diagnostic test (ie, echocardiography) is assessing the reliability of clinical examinations, espe-readily available. cially in primary care settings, are warranted. Clinical evaluation of systolic murmurs includesEvidence favouring comprehensive more than just auscultation. 1,13 Comprehensiveclinical cardiac assessment clinical assessment includes clinical history to deter-Attenhofer Jost et al12 studied 100 consecutive adults mine whether patients have symptoms. Symptomatic(mean age, 58 years) with systolic murmurs of unknown patients generally require additional testing; asymp-cause. The examining cardiologists (who were blinded tomatic patients might not. The nonauscultator y VOL 49: FEBRUARY • FÉVRIER 2003  Canadian Family Physician • Le Médecin de famille canadien 165
  4. 4. cme Echocardiography or auscultation? components of clinical assessment are well known increased intraventricular systolic velocities; venous (Table 1 16). So-called, dynamic auscultation, an hum; and other vibratory phenomena. Clinical char- attempt to alter loading conditions (eg, Valsalva acteristics of functional or benign systolic murmurs maneuver) can be easily performed in the office or are outlined in Table 213. After comprehensive clini- at bedside.1 Finally, as part of overall comprehen- cal assessment, patients deemed to have functional sive clinical assessment, results of ECG and chest systolic murmurs do not need to be referred for echo- radiography should be considered. Abnormalities cardiography. on ECG (eg, left ventricular hypertrophy) or chest In the guidelines for management of patients with radiography (eg, cardiomegaly) generally prompt valvular heart disease, an AHA/ACC task force20 rec- further assessment. The advantage of integrating ommended that: physical examination, ECG, and chest radiography as a diagnostic strategy has been demonstrated in 2-D echocardiography and color flow Doppler imaging patients with dyspnea.17 The incremental diagnostic are not necessary for all patients with cardiac murmurs usefulness of incorporating chest radiography and and usually add little but expense in the evaluation of ECG in asymptomatic children with systolic mur- asymptomatic patients with short, grade 1-2 systolic murs has been questioned in some studies 18 but murmurs and otherwise normal physical findings. shown to be useful in others.19 Functional murmurs in adults have been related Also in the guidelines for appropriate use of to aortic flow or, less commonly, pulmonar y flow; echocardiography, a class 3 indication (ie, echocar- diography should not be ordered) includes “inno- Table 1. Evaluation of systolic murmurs cent” murmurs in asymptomatic patients who have using comprehensive cardiac assessment16 otherwise normal examinations. If an examiner was History (asymptomatic vs symptomatic) “uncertain,” this was considered a class 2A indication Auscultation (weight of e dence or opinion in favour of usefulness Nonauscultatory components or efficacy) for ordering the test. A problem with this latter provision is the increasing trend to diagnostic • Blood pressure,* pulse, respiration “uncertainty” as clinical skills weaken. • Carotid pulse, jugular veins • Precordial palpation Caution advised • Heart sounds† Despite the advantages of echocardiography, primary care physicians should be aware of its limitations. • Abdominal examination (eg, ascites) Depending on the patient population studied and the • Extremities (edema) experience of the echocardiography laboratory, 5% to Dynamic auscultation (bedside maneuvers) 10% of studies remain inadequate for interpretation. Electrocardiography or chest radiography The technique is operator-dependent, in terms of both * Including pulse pressure. data acquisition and interpretation. Results might † Including clicks, ejection sounds, and splitting of S2, S3, and S4. be hard to reproduce. Criteria for age-related valve changes are not standard, and grading of severity of Table 2. Characteristics of benign (functional) valve regurgitation by colour flow imaging remains systolic murmurs13 qualitative, subjective, and unreliable. (Quantitative Grade 1-2 echocardiographic techniques are being introduced but have not yet become standardized, except in ter- Early systolic tiary care centres or research laboratories.) Finally, No associated diastolic murmur the incidence of diagnostic error is high in echo- No associated cardiac abnormalities (normal jugular venous cardiography performed on children in community- pressure, carotid arteries, results of palpation; no gallop sounds, based adult echocardiography laboratories.21 clicks, or ejection sounds; normal S2 splitting) No cardiac symptoms Glimpse into the future Normal electrocardiography and chest radiography With requisite background training in echocardiog- Carotid arteries, carotid pulse volume, and contour as assessed raphy, cardiologists using miniature, point-of-care by palpation; jugular venous pressure and contour (inspection); ultrasound devices can improve diagnostic accuracy.22 palpation, precordial palpation Ultrasound-assisted physical examination by primary166 Canadian Family Physician • Le Médecin de famille canadien  VOL 49: FEBRUARY • FÉVRIER 2003
  5. 5. cme Echocardiography or auscultation?care physicians is also being evaluated.23 Small, Editor’s key pointsportable, hand-held cardiac ultrasound devices are • Despite a decrease in auscultation skills that par-undergoing clinical testing,24 ostensibly as an exten- allels an increased reliance on echocardiographysion of physical examination, but they could become to assess heart murmurs, functional murmursthe stethoscope of the future. If they do, ultrasound can usually be distinguished from pathologictechniques will need to be taught in medical school. murmurs by clinical examination.Initial experience with, and reaction to, echocardiog- • Functional murmurs are usually early in the sys-raphy as a teaching tool for medical students has tole and low in intensity (grade 1).been positive.25 • If a murmur is judged functional in young or middle-aged adults with no other symptoms orConclusion signs, echocardiography is unnecessary.Time constraints on busy clinicians and the lure ofnoninvasive technology have contributed to the ero- Points de repère du rédacteursion of clinical skills and the declining importance • Malgré le fait que les médecins sont de moinsof clinical cardiac examination. For systolic mur- en moins habiles à l’auscultation alors qu’ils semurs, careful clinical assessment can reduce costs fi ent davantage à l’électrocardiographie pourby reducing unnecessar y testing. If patients with évaluer les souf fles cardiaques, il est néan-functional systolic murmurs can be identified and not moins possible de distinguer les souffles fonc- tionnels des souffles pathologiques à l’examenroutinely referred for echocardiography, substantial physique.cost savings can be realized. Cardiac examination • Les souffles fonctionnels s’entendent générale-should remain the first-line diagnostic tool of every ment tôt dans la systole et leur intensité est faibleclinician; echocardiography should not replace it. (grade 1).Echocardiography should be considered, however, • Quand un souffle est jugé fonctionnel chez unwhen examiners are uncertain about results of clini- sujet jeune ou d’âge moyen sans autres signescal examination or if they suspect a significant cardiac ou symptômes, l’électrocardiographie n’est pasabnormality. nécessaire. The future will decide whether the binaural stetho-scope becomes a museum relic like its predecessor, 10. Mangione S, Nieman LZ. Cardiac auscultatory skills of internal medicine and family prac-the monaural stethoscope of more than a century ago, tice trainees. A comparison of diagnostic proficiency. JAMA 1997;278:717-22. 11. Mangione S. Cardiac auscultatory skills of physicians-in-training: comparison of threeor remains a valid, useful clinical diagnostic tool. English-speaking countries. Am J Med 2001;111:505-6. 12. Attenhofer Jost CH, Turina J, Mayer K, Seifert B, Amann FW, Buechi M, et al. Echocardiography in the evaluation of systolic murmurs of unknown cause. Am J Med 2000;108:614-20.Competing interests 13. Roldan CA, Shively BK, Crawford MH. Value of the cardiovascular physical examina- tion for detecting valvular heart disease in asymptomatic subjects. Am J Cardiol 1996;77:None declared 1327-31. 14. Shry EA, Smithers MA, Mascette AM. Auscultation versus echocardiography in a healthy population with precordial murmur. Am J Cardiol 2001;87:1428-30.Correspondence to: Dr Clarence Shub, Division of 15. 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