Mitral Valve, Double Orifice

INTRODUCTION

Background: Double orifice mitral valve (DOMV) is an uncommon anomaly of surgical importance characterized by a mitral valve with a single fibrous annulus with 2 orifices opening into the left ventricle (LV). Subvalvular structures, especially the tensor apparatus, invariably show varying degrees of abnormality. While DOMV may allow normal hemodynamic flow between the left atrium and LV, it can significantly obstruct mitral valve inflow or mitral valve incompetence. When either stenosis or incompetence is severe, surgical correction is necessary. Preoperative recognition of DOMV and an awareness of the associated anatomic variations are important to achieve good surgical correction.

 

Pathophysiology: The normal mitral valve consists of a large central orifice located between a large sail-like anterior leaflet and a smaller C-shaped posterior leaflet, while in DOMV the orifice is divided into 2 parts by abnormal tissue. Three major types of DOMV are recognized, as follows:

 

  • Eccentric or hole type: This is the most common variety (about 85% of all patients) and is characterized by a small accessory orifice situated at either the anterolateral or posteromedial commissure. Other anomalies of the valve apparatus, such as cleft leaflets, accessory papillary muscles, fused papillary muscles, and crossing chordae tendineae, commonly are present. When the accessory orifice is located at the posteromedial commissure, a common atrioventricular canal usually is present. Conversely, the atrioventricular canal normally is divided if the accessory orifice is located at the anterolateral commissure.

     

  • Central or bridge type: In about 15% of patients with DOMV, a central bridge of fibrous or abnormal leaflet tissue connects the 2 leaflets of the mitral valve, dividing the orifice into medial and lateral parts. These 2 openings may be equal or unequal, and papillary muscles usually are normal with chordae surrounding each orifice inserting into 1 papillary muscle.

     

  • Duplicate mitral valve: This has 2 mitral valve annuli and valves, each with its own set of leaflets, commissures, chordae, and papillary muscles.

The combined area of DOMV in the presence of an atrioventricular canal defect ranges from 85-90% of normal expected area; however, in the absence of an associated atrioventricular defect, the combined area may be significantly less than normal. Reduction in the effective valve area is caused by the abnormal structure, including large bridging tissue, bulky abnormal leaflets, fused chordae, or abnormal papillary muscles.

Associated congenital heart defects are common, although DOMV can occur as an isolated anomaly. The most common associated lesion is common atrioventricular canal defect (endocardial cushion defect). Other lesions include ventricular septal defect, coarctation of aorta, interrupted aortic arch, subaortic stenosis, patent ductus arteriosus, and primum atrial septal defect. Occasionally, DOMV is observed with secundum atrial septal defect, tetralogy of Fallot, hypoplastic left heart syndrome, Ebstein anomaly of tricuspid valve, dysplastic tricuspid valve, parachute mitral valve, truncus arteriosus, pulmonary stenosis, or bicuspid aortic valve.

The mitral valve can function reasonably well in about 50% of all patients with DOMV. In the remaining patients, it can cause significant mitral stenosis (MS) or mitral regurgitation (MR).

Mitral stenosis

Obstruction to mitral valve inflow results from a reduction in the total mitral valve area. When MS is significant, a diastolic pressure difference builds up between the left atrium and LV. The rise in left atrial and pulmonary venous pressure leads to exudation of fluid into the interstitium of the lung and increased pulmonary stiffness (the main cause of breathlessness). In severe cases, frank pulmonary edema develops.

Persistent pulmonary venous hypertension leads to pulmonary arterial hypertension, a rise in pulmonary vascular resistance, and, eventually, failure of the right ventricle (RV) with tricuspid regurgitation.

Mitral regurgitation

About 25% of patients with DOMV present with MR as the dominant hemodynamic abnormality, especially when it is associated with an atrioventricular canal defect. Similar to MS, MR also causes left atrial and pulmonary venous hypertension. Clinical effects depend upon the severity and duration of MR. LV outflow obstruction from associated subaortic stenosis or coarctation can aggravate MR. With increasing MR, cardiac output is maintained by increasing LV diastolic volume and hypertrophy. In chronic MR, LV function deteriorates, leading to further worsening of pulmonary venous congestion, pulmonary hypertension, and right heart failure. Ventricular dysfunction secondary to chronic dilatation often is irreversible even after correction of the primary mitral lesion. The left atrium tends to enlarge markedly in MR and may cause pressure effects on the left bronchus.

 

Frequency:

  • Internationally: No data are available on the incidence of DOMV. Approximately 50% of all cases of DOMV are detected during investigation of other congenital heart diseases (CHDs). More than 100 cases of DOMV are reported in the English literature.

CLINICAL

History:

  • DOMV is detected in 1 of the following 3 ways:
    • Most commonly, DOMV is diagnosed as an associated lesion with other congenital heart defects. Thus, pulmonary congestion and heart failure from a common atrioventricular canal or ventricular septal defect (VSD) are aggravated by an abnormal mitral valve. Conversely, conditions such as tetralogy of Fallot reduce the mitral valve flow and mask the presence of DOMV. In such patients, DOMV is not detected unless specifically looked for.
    • DOMV may be detected as the anatomic cause when investigating patients, especially at a young age, for symptomatic mitral valve disease.
    • Occasionally, DOMV is an incidental finding in asymptomatic patients who undergo echocardiography for any reason.
  • Symptoms of DOMV: The severity of symptoms depends upon the degree of left atrial hypertension. Common symptoms include 1 or more of the following:
    • Dyspnea, nocturnal cough, and tachypnea occur from pulmonary venous congestion and increased lung stiffness.
    • Frequent respiratory infections and wheezing occur from pulmonary congestion, increased fluid exudation, and airway narrowing.
    • Poor feeding, failure to thrive, fatigue, and sweating occur because of heart failure and reduced cardiac output.
    • Occasionally, the child with DOMV can present with acute pulmonary edema or generalized edema.
    • Hemoptysis and syncope can occur in older patients with DOMV.

Physical:

  • Physical signs in DOMV with MS
    • Children with severe MS often are quite ill with respiratory distress, tachypnea, and subcostal recession.
    • Reduced pulse volume and peripheral cyanosis indicate diminished cardiac output and poor tissue perfusion.
    • Central cyanosis can develop in the presence of pulmonary edema.
    • Jugular venous pressure rises with the onset of right heart failure.
    • Palpation reveals a parasternal heave from the hypertrophied RV and, occasionally, a diastolic thrill at the apex.
    • The first heart sound may be normal or accentuated, while the pulmonary second sound generally is loud because of pulmonary hypertension. Unlike acquired MS, an opening snap is not commonly heard.
    • A low-pitched mid diastolic murmur of varying intensity is audible at the mitral area. It often is heard best in the left lateral decubitus and is especially loud when MS is associated with a VSD or mitral regurgitation.
    • In chronic severe MS, signs of tricuspid incompetence, such as systolic expansile pulsation in the jugular vein and liver and a pansystolic murmur at the lower sternal border, appear. This murmur typically accentuates on inspiration.
  • Physical signs in DOMV with MR
    • The child with severe MR can present with respiratory distress and pulmonary edema.
    • The pulse often is brisk, while the apical impulse is displaced downwards and outwards and has a hyperdynamic quality because of LV hypertrophy.
    • The first and second heart sounds usually are normal in intensity, though the second heart sounds may be widely split. A third heart sound is common at the apex.
    • A blowing pansystolic murmur is heard at or just inside the apex and often is conducted towards the sternum rather than towards the axilla.
    • Severe MR can cause a low-pitched apical diastolic murmur from large diastolic flow across the mitral valve.
    • Pulmonary hypertension and tricuspid incompetence can occur in MR, though not as commonly or as severely as in MS.

DIFFERENTIALS

Cor Triatriatum
Mitral Stenosis, Supravalvular Ring
Mitral Valve Insufficiency


Other Problems to be Considered:

Mitral stenosis, valvar
Pulmonary hypertension, congenital heart disease


WORKUP

Lab Studies:

  • Investigate to quantify the hemodynamic abnormality and to define the valve anatomy before undertaking surgical treatment.
  • No specific laboratory blood tests are required for diagnosis.

Imaging Studies:

  • Chest radiography
    • Diagnose left atrial enlargement (the most common abnormality in DOMV) if straightening of the left upper cardiac border (mitralization), widening of the tracheal carina, and elevation of the left bronchus are present. In older children, the enlarged left atrium can be observed as a double density near the right atrial border, tending to enlarge in a posterior direction. A barium-swallow study of the esophagus in lateral projection shows a rounded indentation of the anterior wall. Mitral incompetence, if severe, causes LV enlargement.
    • Prominent upper lobe veins, increased interstitial markings, and Kerley lines indicate pulmonary venous hypertension. In severe cases, alveolar edema produces a hazy appearance in the hilar regions of both lung fields. The pulmonary trunk and its branches become dilated with the rise in pulmonary arterial pressure.
  • Echocardiography
    • Two-dimensional echocardiography with Doppler is the most important tool for diagnosis and detailed assessment of patients with DOMV.
    • Systematically examine the mitral valve using multiple views for imaging and Doppler interrogation. Pay particular attention to evaluate all components of the mitral valve apparatus.
    • The 2 orifices in DOMV are observed best in a cross-sectional view of the LV in short axis, scanning the ventricle from the apex to the base. Apical and subcostal 4-chamber views also are useful to visualize the subvalvular apparatus.
    • Identify the relative positions of the 2 openings and measure the area. Carefully study the nature and size of the bridging tissue and leaflets. Any associated congenital heart defect also may be identified and quantified.
    • Look for and measure the enlargement of the left atrium, LV, RV, and pulmonary artery on 2-dimensional echocardiography.
    • M-mode echocardiography of the pulmonary valve often shows signs of pulmonary hypertension such as an abbreviated "a wave, midsystolic closure, and systolic flutter of the pulmonary leaflets.
  • Doppler echocardiography
    • Doppler study and color flow mapping are useful to show the pattern of flow through the mitral valve.
    • Assess severity of mitral regurgitation in a semiquantitative manner from the area of the regurgitant jet in the left atrium.
    • The severity of mitral obstruction can be quantified by measuring the mean velocity of diastolic flow through the mitral valve; the mean diastolic velocity and the pressure half-time (time taken for the peak diastolic velocity to fall to half its initial value) correlate well with severity of MS.
    • Obtain a good estimate of the systolic pulmonary artery pressure by measuring the peak velocity of the tricuspid regurgitant jet in the right atrium.
  • Transesophageal echocardiography
    • Transesophageal echocardiography generally is not necessary in children to assess DOMV because adequate information may be obtained from transthoracic windows.
    • In older patients, especially in heavy individuals or patients with emphysematous chests, transesophageal study can provide clear visualization of all valve components.
    • Thrombi in the left atrium can be detected.
    • At all ages, transesophageal echocardiography performed intraoperatively is extremely useful to assess adequacy of mitral valve repair in the operating room.

Other Tests:

  • Electrocardiography
    • Sinus rhythm commonly is present. Occasionally, atrial flutter or atrial fibrillation can develop in patients with DOMV with chronic left atrial dilatation.
    • Left atrial enlargement occurs in most patients with DOMV and is diagnosed by wide bifid P waves (P mitral pattern) in limb leads and/or increased P terminal force in lead V1.
    • Tall peaked P waves in inferior leads indicate right atrial hypertrophy because of pulmonary hypertension and tricuspid incompetence.
    • The mean frontal plane QRS axis may be normal or shifted to the right.
    • RV hypertrophy is common in stenotic DOMV, while mitral incompetence is associated with LV hypertrophy.
    • Electrocardiographic findings may be modified by the presence of associated congenital heart defects.

Procedures:

  • Cardiac catheterization
    • Cardiac catheterization often is necessary to quantify the hemodynamic effects of abnormal mitral valve function.
    • DOMV with obstruction is characterized by elevation of left atrial pressure. Pressure tracings obtained from the pulmonary artery wedge position reflect left atrial pressure and avoid the need to enter the left atrium by puncturing the interatrial septum. Simultaneous pressure recording shows pulmonary artery wedge pressure is significantly higher than LV pressure throughout diastole.
    • In patients with mitral regurgitation, the left atrial and pulmonary artery wedge pressures are elevated, but no gradient can be demonstrated across the mitral valve at end of diastole; LV diastolic pressure often is increased.
    • Cardiac output and vascular resistance may be measured; associated shunts and obstructive lesions, if any, also may be identified and measured at cardiac catheterization.
  • Cardiac angiography
    • With the availability of high-quality echocardiography, cardiac angiography has a limited role in the assessment of DOMV. Echocardiography is superior to angiography in defining anatomic and functional valve abnormalities.
    • LV angiography may be performed to confirm the severity of MR and to assess LV function.
    • Cardiac angiography also is important to assess other associated defects.

TREATMENT

Medical Care: General principles of management

Patients with DOMV can be evaluated as outpatients. Admit to the hospital for cardiac catheterization, treatment of severe heart failure or pulmonary edema, and for surgical treatment.

Management depends upon the type and severity of mitral valve dysfunction. Isolated DOMV causing neither obstruction nor regurgitation needs no active intervention; however, provide long-term follow-up care in these patients to detect the onset of hemodynamic problems or complications.

All patients with significant degrees of MS or regurgitation require medical and, possibly, surgical treatment.

  • Role of medical therapy
    • Use medical therapy for initial stabilization and to relieve pulmonary edema.
    • Control congestive heart failure (CHF) while awaiting detailed assessment and surgical repair.
    • Use medical therapy as an adjunct to surgical repair in the postoperative period.
    • Medical therapy may be the only option in small infants. Control of CHF may defer surgery until the child grows to an appropriate age and size.
  • Adjunctive therapy

     

    • Administer potassium supplements to all patients receiving frusemide or thiazide diuretics.

       

    • Restrict physical activity in symptomatic patients.

       

    • Treat patients with severe pulmonary venous congestion in a sitting or propped-up position.

       

    • Administer parenteral morphine in patients with pulmonary edema to help relieve anxiety and reduce pulmonary congestion.

       

    • Administer oxygen by a nasal catheter or mask to improve oxygenation in acute pulmonary edema.

       

    • Vigorously treat concurrent infections or other aggravating factors.

       

    • Correcting anemia, if present, is important. Increasing the oxygen-carrying capacity by a packed-cell transfusion in patients with severe symptoms or heart failure may provide considerable relief.

       

    • All patients with DOMV need antibiotic prophylaxis against infective endocarditis when they undergo any dental or surgical procedure.

Surgical Care:

  • The principles of surgical treatment of DOMV are to correct abnormal mitral valve function in DOMV.
  • Perform surgical repair in all symptomatic patients with DOMV and significant degrees of MS or mitral regurgitation.
  • Perform early operation for DOMV in the presence of intractable heart failure or pulmonary edema, pulmonary arterial hypertension, worsening LV function, or a progressive increase in heart size from ventricular dilatation.
  • Adjust the type of operation, depending upon anatomic abnormality in the mitral valve apparatus. Make every effort to define the anatomy in detail before undertaking surgery. In many patients, the valve may be amenable to repair and reconstruction; however, if the valve mechanism is markedly abnormal, mitral valve replacement is necessary.
  • Selected cases of DOMV with MS may be amenable to balloon dilatation.

Consultations:

  • Cardiologist
  • Cardiothoracic surgeon

Diet:

  • Asymptomatic patients with DOMV require no special diet.
  • Counsel patients to avoid excess intake of salt or reduce salt intake in presence of heart failure. Use salt restriction cautiously in infants.
  • Restrict fluid intake to approximately 60-80 mL/kg/d in infants with CHF.

Activity: Patients with pulmonary venous congestion or CHF should avoid strenuous exertion.

MEDICATION

Medical therapy for DOMV consists of drugs for control of CHF. The 3 groups of drugs used are diuretics (to promote excretion of excess water), positive inotropic drugs (to improve myocardial contraction), and vasodilators (to reduce arterial resistance).

Drug Category: Diuretics -- Promotes excretion of water and electrolytes by the kidneys. Used to treat heart failure or hepatic, renal, or pulmonary disease when sodium and water retention has resulted in edema or ascites. Useful to remove excess water that accumulates in CHF. Relieve symptoms that are associated with pulmonary congestion and reduce peripheral edema.
Drug Name
Furosemide (Lasix) -- DOC for rapid relief of pulmonary congestion and edema from heart failure. Useful for maintenance therapy of CHF in patients with DOMV. Promotes renal excretion of water by inhibition of electrolyte transport system in the ascending limb of the loop of Henle. Increases solute and water excretion, even in the presence of a declining glomerular filtration rate.
Adult Dose 20-80 mg/d PO/IV/IM; titrate up to 600 mg/d for severe edematous states
Pediatric Dose 2-5 mg/kg/d PO divided bid/tid
1-2 mg/kg/dose IV bid/tid
Contraindications Documented hypersensitivity; hepatic coma, anuria, and state of severe electrolyte depletion
Interactions Antagonizes muscle relaxing effect of tubocurarine; auditory toxicity appears to be increased with coadministration of aminoglycosides and furosemide; hearing loss of varying degrees may occur; anticoagulant activity of warfarin may be enhanced when administered concurrently with this medication
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Titrate dose to achieve optimal diuresis without undue electrolyte imbalance or other adverse effects; monitor serum electrolyte levels at periodic intervals; observe for dehydration, hypokalemia, hyponatremia, hypochloremic alkalosis, hyperuricemia, hypomagnesemia, and sensorineural hearing loss
Drug Name
Chlorothiazide (Diuril) -- Causes increased excretion of water by inhibiting reabsorption of sodium chloride in the distal renal tubule. Less potent than furosemide, thiazide diuretics are useful in maintenance therapy of CHF. In severe heart failure or refractory edema, thiazides act synergistically with furosemide to promote diuresis.
Adult Dose 125-500 mg/d PO qd or divided bid
Pediatric Dose 20 mg/kg/d PO divided bid
Contraindications Documented hypersensitivity; anuria or renal decompensation
Interactions May decrease effects of anticoagulants, antigout agents, and sulfonylureas; may increase toxicity of allopurinol, anesthetics, antineoplastics, calcium salts, loop diuretics, lithium, diazoxide, digitalis, amphotericin B, and nondepolarizing muscle relaxants
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Monitor serum electrolyte levels at periodic intervals; observe for hypokalemia, hyponatremia, hypochloremic alkalosis, hyperuricemia, hypomagnesemia, hypercalcemia, hyperglycemia, rise in serum LDL cholesterol and triglyceride levels, and pancreatitis
Drug Name
Hydrochlorothiazide (Esidrix, HydroDIURIL) -- Causes increased excretion of water by inhibiting reabsorption of sodium chloride in the distal renal tubule. Less potent than furosemide. Useful in maintenance therapy of CHF. In severe heart failure or refractory edema, thiazides act synergistically with furosemide to promote diuresis.
Adult Dose 12.5-50 mg/d PO divided bid; not to exceed 200 mg/kg/d
Pediatric Dose 2 mg/kg/d PO divided bid
Contraindications Documented hypersensitivity; anuria or renal decompensation
Interactions May decrease effects of anticoagulants, antigout agents, and sulfonylureas; may increase toxicity of allopurinol, anesthetics, antineoplastics, calcium salts, loop diuretics, lithium, diazoxide, digitalis, amphotericin B, and nondepolarizing muscle relaxants
Pregnancy B - Usually safe but benefits must outweigh the risks.
Precautions Monitor serum electrolyte levels at periodic intervals; observe for hypokalemia, hyponatremia, hypochloremic alkalosis, hyperuricemia, hypomagnesemia, hypercalcemia, hyperglycemia, rise in serum LDL cholesterol and triglyceride levels, and pancreatitis
Drug Name
Spironolactone (Aldactone) -- Counteracts secondary hyperaldosteronism that occurs in cardiac failure. Inhibits sodium absorption in the collecting duct. Has a potassium-sparing diuretic effect. Used alone, it produces relatively mild diuresis. Can be used in conjunction with furosemide for synergistic action in severe CHF.
Adult Dose 25-100 mg/d PO divided bid
Pediatric Dose 2-4 mg/kg/d PO divided bid
Contraindications Documented hypersensitivity; anuria, renal failure, or hyperkalemia
Interactions May decrease effect of anticoagulants; potassium and potassium sparing diuretics may increase toxicity of spironolactone
Pregnancy D - Unsafe in pregnancy
Precautions Renal and hepatic impairment; monitor serum potassium level; special care combination with captopril; observe for hyperkalemia, metabolic acidosis, rash, and gynecomastia
Drug Category: Inotropic agents -- Positive inotropic agents increase the force of contraction of the myocardium and are used to treat acute and chronic CHF. Some may also increase or decrease the heart rate (ie, positive or negative chronotropic agents), provide vasodilatation, or improve myocardial relaxation. These additional properties influence the choice of drug for specific circumstances.
Drug Name
Digoxin (Lanoxin) -- DOC to improve cardiac failure by a positive inotropic effect on the myocardium. Helps to control fast ventricular rate, especially in the presence of atrial arrhythmia.
Preparations commonly used for pediatric patients include tablets (0.125 mg, 0.25 mg) or elixir (0.05 mg/mL). Capsules and a parenteral injection are also available.
Adult Dose Total digitalizing dose (TDD): 1-1.5 mg PO in divided doses over 1 d
Maintenance dose: 0.125-0.375 mg/d PO qd or divided bid
Pediatric Dose TDD:
Premature infants: 0.02 mg/kg PO divided q8h
Full-term infants: 0.03 mg/kg PO divided q8h
1-24 months: 0.04-0.05 mg/kg PO divided q8h
>2 years: 0.03-0.04 mg/kg PO divided q8h
Maintenance dose:
Infants: 6-8 mcg/kg/d PO
2-5 years: 10-15 mcg/kg/d PO
5-10 years: 7-10 mcg/kg/d PO
>10 years: 3-5 mcg/kg/d PO
<10 years: Recommend daily maintenance dose be divided bid
Contraindications Documented hypersensitivity; beriberi heart disease, idiopathic hypertrophic subaortic stenosis, constrictive pericarditis, and carotid sinus syndrome
Interactions Medications that may increase digoxin levels include alprazolam, benzodiazepines, bepridil, captopril, cyclosporine, propafenone, propantheline, quinidine, diltiazem, aminoglycosides, PO amiodarone, anticholinergics, diphenoxylate, erythromycin, felodipine, flecainide, hydroxychloroquine, itraconazole, nifedipine, omeprazole, quinine, ibuprofen, indomethacin, esmolol, tetracycline, tolbutamide, and verapamil
Medications that may decrease serum digoxin levels include aminoglutethimide, antihistamines, cholestyramine, neomycin, penicillamine, aminoglycosides, PO colestipol, hydantoins, hypoglycemic agents, antineoplastic treatment combinations (including carmustine, bleomycin, methotrexate, cytarabine, doxorubicin, cyclophosphamide, vincristine, procarbazine), aluminum or magnesium antacids, rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin, and aminosalicylic acid
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Hypokalemia may reduce positive inotropic effect of digitalis; IV calcium may produce arrhythmias in digitalized patients; hypercalcemia predisposes patient to digitalis toxicity, and hypocalcemia can make digoxin ineffective until serum calcium levels are normal; institute magnesium replacement therapy in patients with hypomagnesemia to prevent digitalis toxicity; patients diagnosed with incomplete AV block may progress to complete block when treated with digoxin; hypothyroidism, hypoxia, and acute myocarditis
Drug Category: Vasodilators -- Drugs that produce vasodilation include angiotensin converting enzyme (ACE) inhibitors, nitrates, and direct vasodilators (eg, hydralazine), of these drug classes, ACE inhibitors are frequently used, as their adverse effects are the most tolerated. They reduce afterload on the LV by decreasing systemic arterial resistance. Particularly helpful in patients with MR, in whom a fall in afterload leads to a decrease in the severity of regurgitation and improves ventricular function. DOC is captopril. Newer drugs from this category such as enalapril and lisinopril also are used for treatment of CHF, but experience with their use in children is limited.
Drug Name
Captopril (Capoten) -- Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion.
Adult Dose 25-150 mg/d PO divided tid; not to exceed 150 mg tid
Pediatric Dose 0.10.5 mg/kg/dose PO tid; may gradually increase to a maximum of 6 mg/kg/d PO divided tid
Contraindications Documented hypersensitivity; renal impairment
Interactions NSAIDs may reduce hypotensive effects of captopril; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases captopril levels; probenecid may increase captopril levels; the hypotensive effects of ACE inhibitors may be enhanced when administered concurrently with diuretics
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Pregnancy category D in second or third trimester; caution in renal impairment, valvular stenosis, or severe CHF; initiate at low doses and gradually increase according to blood pressure, patient tolerance, and clinical effects; observe for hypotension, rash, cough, dizziness, fatigue, hyperkalemia, hypoglycemia, uremia, proteinuria, and neutropenia
Drug Name
Enalapril (Vasotec) -- Competitive inhibitor of ACE. Reduces angiotensin II levels, decreasing aldosterone secretion.
Adult Dose 5-30 mg/d PO divided bid
Pediatric Dose 0.20.5 mg/kg/d PO divided bid
Contraindications Documented hypersensitivity; renal impairment
Interactions NSAIDs may reduce hypotensive effects of captopril; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases captopril levels; probenecid may increase captopril levels; the hypotensive effects of ACE inhibitors may be enhanced when administered concurrently with diuretics
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Pregnancy category D in second or third trimester; caution in renal impairment, valvular stenosis, or severe CHF; initiate at low doses and gradually increase according to blood pressure, patient tolerance, and clinical effects; observe for hypotension, rash, cough, dizziness, fatigue, hyperkalemia, hypoglycemia, uremia, proteinuria, and neutropenia
Drug Name
Lisinopril (Zestril, Prinivil) -- Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion.
Adult Dose 10-30 mg/d PO divided bid
Pediatric Dose Not established, limited data suggests: 0.21 mg/kg/d PO divided bid
Contraindications Documented hypersensitivity; renal impairment
Interactions NSAIDs may reduce hypotensive effects of captopril; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases captopril levels; probenecid may increase captopril levels; the hypotensive effects of ACE inhibitors may be enhanced when administered concurrently with diuretics
Pregnancy C - Safety for use during pregnancy has not been established.
Precautions Pregnancy category D in second or third trimester; caution in renal impairment, valvular stenosis, or severe CHF; initiate at low doses and gradually increase according to blood pressure, patient tolerance, and clinical effects; observe for hypotension, rash, cough, dizziness, fatigue, hyperkalemia, hypoglycemia, uremia, proteinuria, and neutropenia

FOLLOW-UP

Further Inpatient Care:

  • Hemodynamic study by cardiac catheterization and angiography
  • Surgical treatment

Further Outpatient Care:

  • Monitor medications for compliance, dose requirement, and adverse effects.
  • Periodically check for electrolyte disturbances.
  • Provide follow-up care for prompt detection and treatment of intercurrent infections, arrhythmia, and other complications.

In/Out Patient Meds:

  • Medications for DOMV include diuretics, digoxin, potassium chloride, and vasodilators.
  • Antibiotics are indicated for intercurrent bacterial infections.
  • Counsel patient concerning antibiotic prophylaxis against infective endocarditis during dental and surgical procedures.

Transfer:

  • Transfer to a tertiary cardiac facility may be required for further diagnostic evaluation and surgical treatment.

Deterrence/Prevention:

  • Symptomatic patients with DOMV should avoid sports and other strenuous activity that could aggravate pulmonary congestion and CHF.

Complications:

  • Possible complications are MR, MS, pulmonary edema, recurrent respiratory infection, atrial fibrillation and other atrial arrhythmias, infective endocarditis, left atrial thrombus, and pulmonary arterial hypertension.

Prognosis:

  • Isolated DOMV is a rare but correctable defect, if the abnormality is recognized and appropriately treated.
  • When DOMV is associated with other congenital heart defects the long-term outcome depends upon the major cardiac abnormality.

Patient Education:

    • Impose activity restrictions on symptomatic patients.
    • Advise the patient concerning the need for periodic medical review.
    • Inform the patient regarding prophylaxis for infective endocarditis and prompt attention to all infections.
    • Counsel the patient about the need for regular anticoagulant therapy with coumadin in those who undergo valve replacement.

MISCELLANEOUS

Medical/Legal Pitfalls:

  • Failure to identify DOMV as the cause of mitral valve obstruction or regurgitation
  • Failure to identify DOMV as an associated defect in patients with atrioventricular canal defect and other CHDs
  • Failure to recognize associated abnormalities of the mitral valve apparatus in patients with DOMV

Special Concerns:

  • DOMV may not be detected easily in children with CHD; therefore, awareness of the problem and careful echocardiographic screening are important in all children with mitral valve disease.

PICTURES

 

Caption: Picture 1. Mitral valve, double orifice. Two-dimensional echocardiogram in parasternal short-axis view showing 2 mitral valve orifices.
Click to see larger picture
Picture Type: Photo
Caption: Picture 2. Mitral valve, double orifice. Two-dimensional echocardiogram of the mitral valve in apical view with color flow mapping, showing diastolic flow through 2 separate orifices.
Click to see larger picture
Picture Type: Photo