Which physical signs become more pronounced during a Valsalva maneuver?

Physical Signs Enhanced During Valsalva Maneuver

During the Valsalva maneuver, two cardiac murmurs characteristically become louder and more pronounced: the systolic murmur of hypertrophic cardiomyopathy (HCM) and the murmur of mitral valve prolapse (MVP), which becomes both longer and often louder. 1, 2, 3, 2

Key Physical Findings That Increase with Valsalva

Murmurs That Become Louder

• Hypertrophic Cardiomyopathy (HCM): The systolic murmur becomes much louder during Valsalva 1, 2, 3, 2, 4

  • This is a harsh crescendo-decrescendo systolic murmur heard along the left sternal border
  • The increased intensity occurs because Valsalva decreases venous return and left ventricular volume, which worsens the dynamic left ventricular outflow tract obstruction
  • Case reports document gradients increasing from 55 mmHg at rest to 114 mmHg during Valsalva 5

• Mitral Valve Prolapse (MVP): The murmur becomes longer and often louder 1, 2, 3, 2

  • This is typically a late systolic murmur that may be preceded by a mid-systolic click
  • The decreased left ventricular volume during Valsalva causes earlier and more pronounced prolapse of the mitral valve leaflets

Murmurs That Decrease with Valsalva

Most other cardiac murmurs decrease in both length and intensity during the Valsalva maneuver 1, 2, 3, 2. This includes:

• Aortic stenosis
• Mitral regurgitation (except MVP)
• Ventricular septal defect
• Aortic regurgitation
• Mitral stenosis
• Tricuspid regurgitation

Clinical Application

When examining a patient with a systolic murmur, perform the Valsalva maneuver to differentiate HCM or MVP from other causes. The technique involves:

• Having the patient bear down against a closed glottis for 10-30 seconds, generating at least 30-40 mmHg of intrathoracic pressure 6
• Auscultating during the strain phase when venous return is reduced

Diagnostic Algorithm

1. If the murmur increases with Valsalva → Consider HCM or MVP

   • Order echocardiography immediately 2, 7
   • HCM murmur: harsh, crescendo-decrescendo, left sternal border
   • MVP murmur: late systolic, often with click, apex

2. If the murmur decreases with Valsalva → Consider valvular stenosis or regurgitation (other than MVP)

   • Further evaluation based on murmur characteristics and clinical context

Important Caveats

After release of the Valsalva maneuver, right-sided murmurs return to baseline intensity earlier than left-sided murmurs 1, 2, 3, 2. This temporal difference can help lateralize the lesion.

The Valsalva response is particularly valuable because it provides immediate bedside diagnostic information without requiring imaging, though echocardiography should always be performed when a systolic murmur increases during Valsalva to confirm the diagnosis and assess severity 2, 7, 4.