My 24-year-old patient said she had mitral valve prolapse (MVP) and a heart murmur, but I couldn't hear the murmur. Could you explain why?-R.Y., MICH.
Joan E. King, RN, C, ACNP, ANP, PhD, replies: As you know, in MVP, the two leaflets of the mitral valve may fail to close properly during systole. The most common physical finding in MVP is a midsystolic click, although in some patients you may also hear a late systolic murmur. However, changes in the left ventricular volume may change the presence or quality of both the click and the murmur. If the patient lies down, performs an isometric "hand grip," or squats, left ventricular volume increases, reducing the likelihood that the leaflets will prolapse. In these cases, the click and the murmur may no longer be audible. Conversely, diminished left ventricular volume lets the leaflets prolapse more into the left atrium, making the click and murmur more pronounced.
To enhance the click or the murmur, have the patient quickly stand upright from a supine position or perform the Valsalva maneuver. Listen with the diaphragm of the stethoscope at or medial to the apex and lower left sternal border. Because these maneuvers reduce venous return and left ventricular volume, a greater degree of prolapse occurs and you're more likely to hear the click and murmur.
Mitral valve prolapse affects up to 4% of the population and usually is idiopathic. The condition also may be associated with scoliosis, pectus excavatum, Marfan syndrome, or Ehlers-Danlos syndrome. Although MVP usually is benign, be sure to ask the patient if she experiences nonspecific or atypical chest discomfort, fatigue, dyspnea, palpitations, or episodes of tachycardia, orthostasis, or light-headedness. Note the pattern of these signs and symptoms and correlate them with the patient's fluid status. Signs and symptoms may intensify if she's volume depleted or dehydrated; for example, during illnesses such as gastritis, or with intense exercise when fluid replacement is inadequate.
An MVP diagnosis is confirmed by two-dimensional and Doppler echocardiography, which can determine if the leaflets prolapse, if they're thickened, and if mitral regurgitation is present. Teach the patient to stay well hydrated to reduce the degree of prolapse.
By helping your patient understand her role in self-care, you can help her maintain an active lifestyle and avoid possible complications associated with MVP.
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