Chapter 13: Cardiovascular Disease

MURMURS

Normal Heart Sounds

• S1, produced by tricuspid and mitral valve closure, may split with respirations.

• S2, produced by aortic (A2) and pulmonic (P2) valve closure, normally splits.

  • P2 should be soft after infancy.

• S3 can represent normal, rapid ventricular refilling; early diastolic gallop rhythm

• S4 can represent high output state or poor compliance of ventricular walls; late diastolic gallop

EPIDEMIOLOGY

• Up to 90% of children have a murmur at some point in their lives.

• 2–7% of murmurs in children represent pathology.

DESCRIPTION AND GRADING

Murmurs are graded for intensity on a six-point system:

• Grade I: Very soft, detected after careful auscultation in a quiet environment.

• Grade II: Soft, readily heard but faint, roughly equal to S1/S2.

• Grade III: Moderately intense, louder than S1/S2, without a palpable precordial thrill.

• Grade IV: Loud with a palpable precordial thrill present.

• Grade V: Loud, heard with only the stethoscope edge touching the chest.

• Grade VI: Loud, heard without the stethoscope touching the chest.

SITES OF AUSCULTATION

See Figure 13-1 to correlate the following points:

1. Carotid arteries. Common murmurs heard here: carotid bruit, aortic stenosis (AS).

2. Aortic valve. Right upper-sternal border. Common murmur: AS. Valvular stenosis will often have an ejection click.

3. Pulmonic valve. Left upper-sternal border. Common murmurs: pulmonary valve stenosis, atrial septal defect (ASD), pulmonary flow murmur, pulmonary artery stenosis, patent ductus arteriosus (PDA).

4. Tricuspid valve. Left lower-sternal border. Common murmurs: ventricular septal defect (VSD), Still's murmur, hypertrophic obstructive cardiomyopathy (HOCM), tricuspid regurgitation, endocardial cushion defect.

5. Mitral valve. Apex. Common murmurs: mitral regurgitation, mitral valve prolapse, Still's murmur.

6. This site correlates with areas of venous confluence. Common murmurs: venous hum or subclavian bruit.

Innocent Murmurs

• Typically from turbulent blood flow rather than structural disease, and lacking hemodynamic significance.

• Common to all innocent murmurs are:

  • Absence of structural heart defects.

  • Normal heart sounds (S1, S2) with normal peripheral pulses.

  • Normal chest radiographs and electrocardiogram (ECG).

  • Asymptomatic.

  • Usually systolic and graded less than III.

  • No association with cardiovascular disease.

  • Accentuated in high-output states (fever and anemia).

• Pulmonary flow murmurs and Still's murmurs are heard best in supine patients.

• A Still's murmur may disappear with the Valsalva maneuver.

• Pulmonary flow murmurs are augmented by exhalation and diminished by inhalation.

• A venous hum is continuous, disappears in the supine position, and can be eliminated with ...