Pediatric Mitral Valve Prolapse Clinical Presentation

Updated: Mar 21, 2017
  • Author: Poothirikovil Venugopalan, MBBS, MD, FRCPCH; Chief Editor: Syamasundar Rao Patnana, MD  more...
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Presentation

Physical Examination

Most patients are asymptomatic, and mitral valve prolapse (MVP) is an incidental auscultatory finding. Beta-blockers may markedly attenuate or abolish the symptoms, a fact that is important to remember while evaluating a patient who is receiving these agents. Findings are more marked when patients are examined in the outpatient department rather than in the inpatient setting, reflecting the contributory role of adrenergic state.

Chest pain

Chest pain occurs in 10% of patients diagnosed with mitral valve prolapse and may be caused by any of the following factors:

  • Excessive stretching of the chordae tendineae, leading to traction on papillary muscles

  • Coronary microembolism from platelet aggregates and fibrin deposits in the angle between the left atrium and the posterior mitral leaflet

  • Inappropriate tachycardia and excessive postural changes and physical and emotional stresses

  • Hyperadrenergic state, which increases myocardial oxygen demand

  • Coronary artery spasm

Palpitations

Palpitations are present in 7.4% of patients. The occurrence may be related to cardiac arrhythmia, although this has not been conclusively proven.

Fatigability and dyspnea

These often develop upon exertion. The cause may be alterations in centrally modulated breathing cycle control.

Neuropsychiatric

Panic attacks may occur. Nervousness, presyncope, and syncope occur in 0.9% of patients.

Thromboembolism, arrhythmia, or vasodepressor-vasovagal problems may be involved.

Pulse

Findings are usually normal. Pulse is occasionally irregular in the presence of premature contractions.

Exaggerated tachycardia (high-volume in severe mitral regurgitation [MR]) following exertion is not unusual.

Skeletal abnormalities

These are observed in two thirds of patients and do not fit into any of the recognized connective tissue disorders, although an occasional patient may have Marfan syndrome or other related syndromes. Common findings are as follows:

  • Hypomastia

  • Thin children

  • Height-to-weight ratio greater than normal

  • Arm span greater than height (dolichostenomelia)

  • Arachnodactyly

  • Scoliosis

  • Narrow anteroposterior chest diameter (straight back)

  • Pectus excavatum or pectus carinatum

  • Cathedral palate

  • Crowding of teeth

  • Joint hypermobility

Auscultation

Apical midsystolic nonejection click and late systolic murmur are the hallmarks, but either may occur alone.

The heart sounds are usually normal, but the first heart sound (S1) may be accentuated when prolapse occurs early in systole because of the summation of S1 and mitral click.

Multiple clicks occur when prolapse of different leaflets occurs at different times during the systole and may resemble pericardial friction rub.

In patients with redundant floppy mitral valves and significant MR, the murmur may be holosystolic and the click may be absent.

In cases in which the posterior mitral valve leaflet is prolapsing, the murmur may radiate along the left sternal border to the aortic area, thus mimicking left ventricular outflow tract murmur. If the anterior leaflet prolapses, the murmur radiates to the axilla and the spine.

Dynamic auscultation

In the sitting or standing position in late systole, the click may appear earlier and the murmur may be more prominent. The systolic click moves toward S1 upon standing, often merging with S1 if marked postural tachycardia occurs, and new clicks may appear. If an exaggerated heart rate response occurs, the murmur becomes longer and often louder to holosystolic. Occasionally the murmur is present only in the upright posture.

When squatting from standing position, the click and murmur may move back to late systole. Continuous auscultation, while the patient is standing from squatting position, reveals the click and murmur moving back to early systole on a beat-to-beat basis as the heart rate accelerates.

A systolic precordial honk or whooping sound may occasionally be heard with the murmur. Often these are heard only in the sitting or standing position and may be limited to a few beats immediately after standing.

Dynamic auscultatory changes reflect alterations in the timing of the mitral valve prolapse, the timing and extent of the MR, the expected changes in left ventricular volume, myocardial contractility, and heart rate. In the upright posture, venous return decreases, as does the left ventricular volume. The reflex tachycardia that occurs in the upright position further reduces left ventricular volume. Timing and degree of the prolapse are determined by the position of the mitral leaflets at end diastole, which, in turn, is dependent on the distance from the mitral valve annulus to the attachment of the chordae to papillary muscles. Low left ventricular end-diastolic volume shortens the mitral annular papillary muscle distance, allowing the leaflets to prolapse earlier in systole.

Prompt squatting from standing position increases venous return and left ventricular volume; thus, the systolic click and murmur may become late systolic. Squatting, however, may also be associated with an increase in peripheral vascular resistance, which, in turn, increases the tension on the mitral valve apparatus, preferentially directing blood flow into the left atrium, rather than to the peripheral circulation. The late systolic click and murmur then become accentuated in the squatting position.

Other maneuvers

Other maneuvers are possible but none is as practical as a systematically performed postural dynamic auscultation. These maneuvers include the following:

  • Leg elevation

  • Isometric hand grip exercise

  • Valsalva maneuver

  • Application of tourniquets to the extremities

  • Lower body negative pressure or amyl nitrate inhalation