We found a substantial difference in auscultatory performance between experts and residents under the same conditions at the bedside. All residents had great difficulty in recognizing important diagnoses such as aortic regurgitation. The level of bedside diagnostic skills was very low. The original feature of this study was the use of real patients. In fact, we consider that this methodology offers the ideal opportunity for creating a more realistic situation than cardiac tapes or mannequins. Nonetheless, we found the same low level of diagnostic skill observed in previous studies for trainees in internal medicine or family practice: residents in pediatrics found a diagnostic accuracy of 33% using an adult size mannequin [8
] and trainees in internal medicine and family practice recognized 20% of auscultatory events in a study using tape recordings [7
]. Furthermore, our study provides information about the considerable gap between experts and residents. Obviously, one of the major objectives of any training program should be the narrowing of this gap.
Auscultation skills are better evaluated in real conditions where the elimination of contaminating background noise is not always possible, in contrast with a perfect audiotape recording. Furthermore, the bedside testing includes the option of changing the position of the patient, thus allowing the doctor to assess the radiation pattern of murmurs and the change in character of the murmur. The gold standard was the echocardiography and therefore, as expected, even the experts were unable correctly to identify all the diagnoses. Residents managed to identify about half of what an expert can achieve. Interestingly, the performance levels observed for expert cardiologists with an audiotape range from 80 to 90 percent [7
], compared to 62% in our study. This study confirms that a low level of proficiency in cardiac auscultation is found not just in English-speaking countries [9
] but also in others, including French-speaking countries. So this finding is not related to language, but rather, as suggested by Mangione [9
] to the rapid and unlimited access to sophisticated technology in the western world, which gives the false illusion that a precise clinical diagnosis is unnecessary or useless but just time-consuming.
We found that an improvement in diagnostic skills could be achieved by means of a training program consisting of bedside auscultation 45 minutes once a week over a 5-month period. No significant improvement was noted in this study in the identification of sounds and murmurs by auscultation alone, which suggests that a bedside teaching course could lead mainly to a better interpretation of the sounds and murmurs being heard. Nevertheless, this training offers encouraging prospects because it shows that more frequent exposure to patients in a didactic setting can improve diagnostic skills of physicians during postgraduate training.
In an era of increasing awareness of cost effectiveness, physicians are having to decide how to avoid both the overuse and underuse of instrument-based examinations. Obviously, this decision will essentially depend on the quality of the clinical evaluation. In our case, residents were clearly less skillful than experts in making important diagnoses, e.g. diastolic murmurs, which were not heard by the trainees in 60 % of cases. One could argue that the interpretation of auscultatory findings could prove difficult without a detailed clinical history. But in the case of bicuspid aortic valve, for example, a "minor" congenital malformation with the potential for serious long-term consequences, there is usually no significant history, and the screening and clinical diagnosis – and thus the indication for further important investigation – depend solely on the auscultation skill of physicians. Such missed cases could prove detrimental to the patients concerned. By contrast, overdiagnosis could lead to greater and inappropriate utilization of resources and higher care costs. Referral should always be appropriate. Obviously, a further erosion of skills will lead to greater use of technology to compensate for the growing lack of clinical knowledge, but also to increasing numbers of missed patients who actually need to be referred. Only a structured course and a real emphasis on auscultatory skills during postgraduate training will help to improve this situation.
Finally, it is notable that self-confidence was not a predictor of success. This shows how residents have an inaccurate perception of their own abilities in this field, and also highlights the need for an improvement in teaching by giving feed-back to trainees to correct their self perception. Hopefully, this could avoid over-generous self-assessments and a consequent underestimation or overestimation of the risks inherent in a clinical situation.
An important limitation of this study was the absence of a clear-cut control group. We considered the participants to be their own controls before and after the training. Among the 20 trainees, 10 were not able to participate in the intervention and could not be used as a control group because of the high turn over of our training site. Though when the control group is not randomly selected, validity of the data is also questionable. We decided not to conduct a formal randomized clinical trial, believing it to be unethical to refuse the teaching course to residents during such a relatively long period of their postgraduate training. However, because no study was found using real patients, such a prospective observational study can be useful [12
]. A recent study [13
] with 15 residents using simulated heart sounds found an improvement with a teaching course in the same pre/post intervention design but the author considered as an important limitation the use of sounds from a stimulator and not from real patients. Our study gives data for that last point and is original in that perspective. A second limitation is the small sample size of physicians involved in this study and therefore it is difficult to draw broad generalisations from the study. It would be of interest to have similar studies repeated at other institutions with real patients as well.