Handgrip Maneuver and Mitral Regurgitation Murmurs
The statement is FALSE: handgrip exercise increases the intensity of most MR murmurs, including those from typical mitral regurgitation, but mitral valve prolapse (MVP) is a notable exception where the murmur may behave differently due to unique hemodynamic effects. 1
Handgrip Effect on Standard MR Murmurs
Handgrip exercise increases afterload and makes most MR murmurs louder, not quieter. 1
- Isometric handgrip exercise augments murmurs of mitral regurgitation, ventricular septal defect (VSD), and aortic regurgitation (AR) by increasing systemic vascular resistance and afterload 1
- This increased afterload raises the pressure gradient between the left ventricle and left atrium, worsening the regurgitant fraction and making the murmur more prominent 2
- Studies demonstrate a 42% increase in regurgitant area during handgrip, with ischemic MR showing even greater increases (59%) 2
- Approximately 54% of patients with MR show increased regurgitation severity during dynamic handgrip exercise 3
The Mitral Valve Prolapse Exception
MVP behaves paradoxically compared to other causes of MR because handgrip increases left ventricular volume and reduces the degree of prolapse. 1
- In MVP, maneuvers that decrease LV preload (standing, Valsalva) cause the click-murmur complex to occur earlier and often become louder or longer 1, 4, 5
- Conversely, maneuvers that increase LV volume (squatting, handgrip, passive leg raising) cause the prolapse to occur later in systole and the murmur typically softens or may disappear 1, 4, 5
- The 2020 ACC guidelines specifically note that MR severity increases with maneuvers that decrease LV preload in patients with MVP, but handgrip (which increases afterload AND preload through increased venous return) has a net effect of reducing prolapse 1
Clinical Mechanism Explained
The key distinction lies in the pathophysiology:
- Standard MR (functional, ischemic, rheumatic): Handgrip increases afterload → increases pressure gradient across incompetent valve → worsens regurgitation 1, 2
- MVP: Handgrip increases LV volume → reduces the degree of leaflet displacement into the left atrium → decreases prolapse and may reduce regurgitation 1
Important Clinical Caveats
- The timing of MR in MVP matters significantly: mid-late systolic MR has different hemodynamic consequences than holosystolic MR, with lower regurgitant volumes despite similar effective regurgitant orifice areas 6
- Post-ventricular premature beat, systolic murmurs from atrioventricular valve regurgitation do not change or may become shorter in MVP, unlike semilunar valve murmurs which increase 1
- During Valsalva maneuver, the MVP murmur becomes longer and often louder, which is the opposite response of most other murmurs 1
Practical Application for Bedside Diagnosis
Use dynamic maneuvers systematically to differentiate MVP from other causes of MR: 1, 4, 5
- Standing or Valsalva: MVP murmur moves earlier and intensifies; other MR murmurs decrease
- Squatting or handgrip: MVP murmur moves later and softens; other MR murmurs increase
- The midsystolic click in MVP moves closer to S1 with standing and later toward S2 with squatting 4, 5
This algorithmic approach allows bedside differentiation without immediate echocardiography, though imaging remains essential for definitive diagnosis and severity assessment 4, 5.