From the Guidelines
Proper cardiac auscultation requires a systematic approach using both the diaphragm and bell of the stethoscope in a quiet environment, beginning with the patient in a supine position at 30-45 degrees, and examining the four traditional cardiac listening areas. The approach should include using the diaphragm to detect high-pitched sounds like S1 and S2, and the bell for low-pitched sounds like S3, S4, and murmurs, listening for rate, rhythm, intensity, and quality of heart sounds, noting any murmurs, rubs, or gallops 1. For suspected murmurs, characterization should include timing (systolic/diastolic), location, radiation, intensity (grade I-VI), pitch, and quality, with follow-up including additional positions such as left lateral decubitus to accentuate mitral sounds, leaning forward for aortic regurgitation murmurs, and standing/squatting to differentiate hypertrophic cardiomyopathy from other conditions 1. The evaluation of patients with heart murmurs may vary greatly depending on considerations such as the timing of the murmur in the cardiac cycle, its location and radiation, and its response to various physiological maneuvers, with echocardiography recommended for patients with diastolic or continuous heart murmurs, apical or left sternal edge holosystolic or late systolic murmurs, and midsystolic murmurs of grade 3 or greater intensity 1. Combining auscultation with patient history, physical examination, and appropriate diagnostic tests like ECG, echocardiography, or cardiac stress testing based on findings ensures a thorough evaluation of cardiac function and helps identify structural or functional abnormalities requiring further investigation. Key points to consider in the approach to cardiac auscultation include:
- Using both the diaphragm and bell of the stethoscope
- Examining the patient in a quiet environment
- Characterizing murmurs by timing, location, radiation, intensity, pitch, and quality
- Utilizing additional positions to accentuate specific heart sounds
- Combining auscultation with other diagnostic tests for comprehensive assessment
- Considering the patient's symptoms, medical history, and physical examination findings in the evaluation process 1.
From the Research
Proper Technique for Cardiac Auscultation
- The proper technique for cardiac auscultation involves the use of a stethoscope to listen to the heart sounds and murmurs, with emphasis on the diagnostic and prognostic significance of these sounds 2.
- The stethoscope remains a valuable and cost-effective clinical tool that can enable well-trained and experienced cardiac auscultators to make a rapid and accurate cardiac diagnosis with fewer additional studies 2.
Follow-up for Cardiac Auscultation
- Follow-up for cardiac auscultation may involve the use of computer-assisted auscultation (CAA) to provide a visual display of heart sounds and murmurs, and to distinguish between innocent and pathological murmurs [(3,4)].
- CAA may serve as an objective tool for the screening of structural heart disease and facilitate the teaching of cardiac auscultation 3.
Limitations of Cardiac Auscultation
- Cardiac auscultation has limited accuracy for the detection of valvular heart disease in asymptomatic patients and is a poor diagnostic screening tool in primary care, particularly for overweight subjects 5.
- Auscultation alone does not suffice to correctly diagnose and treat patients with heart failure or a murmur, and an echocardiographic exam is mandatory in all patients with more than a soft systolic murmur, any diastolic murmur, cardiac symptoms and/or ECG changes 6.
Clinical Applications of Cardiac Auscultation
- Cardiac auscultation is a key clinical skill, particularly for the diagnosis of valvular heart disease 5.
- The technique can be used to detect heart murmurs, which are extremely common, and to differentiate between innocent and pathological murmurs 6.
- However, the utility of cardiac auscultation has declined due to the widespread availability of echocardiography and diminishing emphasis on the importance of clinical examination 5.