Mitral valve disease

Considerations

Auscultation remains the main screening test for valvular heart disease. Systolic murmurs in the young and slim are very common and are generally benign and of no consequence. The cause of a murmur should however be ascertained, particularly when dealing with an applicant planning to do a career in aviation or in older pilots first presenting with a heart murmur. An innocent murmur is systolic, soft and musical, and heard at the upper left sternal border. There is no historical or clinical suggestion of any heart disease.

Rheumatic heart disease is fortunately uncommon in a population of applicants for a medical certificate. One needs to remember however that NZ has a relatively high incidence of rheumatic fever.

Lesions that produce volume overload are better tolerated then those producing pressure overloads.

Rheumatic mitral stenosis and / or regurgitation can lead to atrial fibrillation (AF) and cerebral embolism, particularly if associated with atrial dilatation. Fast AF poses a risk of syncope, particularly if associated with mitral stenosis. There is an elevated risk of endocarditis.

The mitral annulus may be calcified, usually in the elderly, or dilated. Leaflets may be affected by rheumatic fever, endocarditis, myxomatous degeneration or redundant tissue, causing prolapse. There may be rupture of the chordae tendinae or papillary muscle rupture or dysfunction from endocarditis of ischaemia.

Mitral valve prolapse is relatively common, being found in 5-8% of the general population. Mild mitral prolapse and regurgitation not associated with ventricular or atrial dilatation is acceptable. More than mild mitral regurgitation, ventricular dilation [>6cm diastolic or >4.1cm systolic dimension] and atrial dilatation of 4.5 cm or more are of concern to flight safety.

The ECG may show signs of left atrial (LA) enlargement, left ventricular hypertrophy (LVH) or AF. Cardiac echocardiography is the most useful and often the only test needed. It allows evaluation of chambers size and function, identification of any anatomical abnormalities, estimate the severity of any regurgitation and establish a base line for follow-up.

Information to be provided

• An echocardiogram report on the first occasion that an applicant presents with a history of rheumatic fever or that a murmur is heard, other than a faint typical flow murmur in a young applicant;
• Other tests such as stress ECG, as recommended by the investigating cardiologist or advised by CAA.
• Subsequent recurrent reports and investigations as advised by the investigating cardiologist or CAA.

Disposition

Mitral regurgitation (MR)

An applicant with no more than mild mitral prolapse and / or regurgitation may be assessed as having a condition that is not of aeromedical significance provided:

• The applicant is asymptomatic; and
• There is no history of any tachyarrhythmia or AF;
• There is no history of cardiac ischaemia; and
• The ventricular dimensions and ejection fraction are normal; and
• The left atrium is less than 4.5 cm in diameter; and
• The mitral valve is not myxomatous;
• Any regurgitation is classified as mild by the investigating cardiologist;
• Any regurgitation is not due to ruptured chordae or LV wall dysfunction;
• The applicant undergoes a cardiologist review and echocardiogram every two years or more frequently if so advised by the treating cardiologist or CAA;
• Trivial to mild MR in the absence of any valve or LV abnormality does not need any further follow up.

An applicant, who does not meet the conditions outlined here, should be considered as having a condition that is of aeromedical significance.

Mitral stenosis (MS)

An applicant with mitral stenosis should be considered as having a condition that is of aeromedical significance, unless:

• The applicant is in sinus rhythm; and
• The ECG is normal; and
• The valve area is over 2 cm2 ; and
• The pressure gradient across the valve is < 5 mmHg; and
• The mitral stenosis is considered to be mild by the investigating cardiologist.