Mitral opening clock

Specialty: Cardiovascular.

• mitral opening click
• opening snap mitral

Why it occurs

• Rheumatic mitral stenosis with mobile but thickened valve leaflets
• Congenital mitral stenosis
• Myxoma of the left atrium (which simulates an opening cloc or mitral obstruction)
• Increased flow through the mitral valve (large ventricular septal defect, patent ductus arteriosus)

Initial workup

Transthoracic and transesophageal echocardiogram (TEE) to quantify the mitral valve area by planimetry and half-pressure time, evaluate the transmitral mean diastolic gradient, estimate the pulmonary artery pressure, assess the involvement of the subvalvular apparatus using the Wilkins scale (for suitability for balloon valvuloplasty) and rule out thrombi in the left appendage; 12-lead electrocardiogram; Chest x-ray to identify growth of the left atrium (double right contour) and lines of pulmonary congestion.

Standard management

• Furosemide — loop diuretic indicated to reduce pulmonary venocapillary pressure and relieve symptoms of dyspnea; 20 to 40 mg per day orally
• Atenolol — beta blocker to prolong diastolic filling time by reducing heart rate, optimizing flow through the stenotic valve; 25 to 50 mg once daily orally, adjusting to target heart rate of 60-70 bpm
• Warfarin — vitamin K antagonist oral anticoagulant, mandatory indicated in patients with mitral stenosis and concomitant atrial fibrillation or embolic history; dose adjusted to maintain a target INR between 2.0 and 3.0
• Digoxin (cardiac glycoside for control of ventricular response in patients with concomitant atrial fibrillation; 0.125 to 0.25 mg once daily orally, monitoring serum levels and ions).