What is the proper technique for assessing heart sounds using a stethoscope in patients with varying medical histories and demographics?

Proper Technique for Cardiac Auscultation

Use a systematic, position-based approach examining all four valve areas with both the diaphragm and bell of the stethoscope, incorporating dynamic maneuvers to distinguish pathologic from innocent findings. 1

Systematic Examination Sequence

Patient Positioning

• Begin with the patient supine, then reassess in left lateral decubitus position and sitting upright leaning forward, as heart sounds and blood pressure vary significantly with position. 1
• Document the patient position when recording findings, as this affects the interpretation of auscultatory findings. 1

Stethoscope Technique

• Examine all four primary valve areas (aortic, pulmonic, tricuspid, mitral) using both the diaphragm and bell of the stethoscope. 1
• The diaphragm is best for high-frequency sounds, while the bell detects low-frequency sounds like S3 and S4. 1

Structured Assessment of Heart Sounds

Basic Heart Sound Evaluation

• Document heart rate and rhythm (regular versus irregular) from physical examination or ECG tracing. 1
• Assess S1 intensity and any splitting, noting variations across valve areas. 1
• Evaluate S2 for intensity, physiologic splitting, and abnormal splitting patterns, as this provides critical diagnostic information. 1
• Listen for S3 (mid-diastolic sound indicating volume overload or heart failure) using the bell at the apex in left lateral decubitus position. 1
• Assess for S4 (late-diastolic sound indicating decreased ventricular compliance) using the bell at the apex. 1

Murmur Characterization

• Document murmur timing (systolic versus diastolic), location (specific valve area), intensity (grade 1-6), quality (harsh, blowing, musical), and radiation pattern. 1

Dynamic Maneuvers for Differentiation

Valsalva Maneuver

• Use the Valsalva maneuver to distinguish pathologic from innocent murmurs—most murmurs decrease, but hypertrophic cardiomyopathy increases (65% sensitivity, 96% specificity). 1, 2

Position Changes

• Assess the effect of standing from squatting on murmur intensity—hypertrophic cardiomyopathy and mitral valve prolapse increase (95% sensitivity, 84% specificity for HCM). 1, 2

Handgrip Exercise

• Use sustained handgrip exercise to evaluate murmur changes—mitral regurgitation and ventricular septal defect increase (68% sensitivity, 92% specificity), while aortic stenosis decreases. 1, 2

Population-Specific Considerations

Pregnancy

• Normal findings in pregnancy include: louder S1 with prominent splitting, physiologically split S2 (may appear fixed in later pregnancy), S3 present in most patients, and soft grade 1-2 midsystolic murmur at mid to upper left sternal edge. 1, 3
• These findings result from a 50% increase in circulating blood volume, increased cardiac output, and heart rate elevation of 10-20 bpm. 3
• Concerning findings requiring evaluation: any diastolic murmur, grade 3 or greater systolic murmur, new symptoms (dyspnea beyond normal pregnancy, chest pain, syncope), or signs of heart failure. 1, 3

Asymptomatic Young Adults

• Grade 1-2 midsystolic murmurs in asymptomatic young adults with otherwise normal cardiac examination typically do not require extensive workup. 3, 2
• Innocent murmurs are especially common in high-output states including pregnancy, thyrotoxicosis, anemia, and arteriovenous fistula. 2

Indications for Echocardiography

Mandatory Echocardiography

• All diastolic murmurs (virtually always represent pathology). 1, 2
• Grade 3 or greater midsystolic murmurs (cannot reliably distinguish benign from pathologic aortic stenosis by examination alone). 1, 2
• All holosystolic or late systolic murmurs (indicate regurgitant lesions). 1, 2
• Systolic murmurs with abnormal dynamic auscultation suggesting hypertrophic cardiomyopathy or mitral valve prolapse. 1

Clinical Context Requiring Imaging

• Any systolic murmur with symptoms including heart failure, syncope, myocardial ischemia, or signs of endocarditis. 2

Critical Pitfalls to Avoid

• Do not rely solely on stethoscope examination to exclude significant valvular disease—echocardiography is required for definitive assessment of suspected pathology. 1
• Recognize that trivial valvular regurgitation detected by echocardiography is common in normal patients and does not always correlate with auscultatory findings. 1
• Always assess S2 splitting pattern systematically, as abnormal splitting provides important diagnostic clues (e.g., fixed splitting in atrial septal defect, reversed splitting in aortic stenosis). 1, 2
• Document specific murmur characteristics systematically rather than using vague descriptors. 1