Lutembacher syndrome is defined as a combination of mitral stenosis and a left-to-right shunt at the atrial level. Typically, the left-to-right shunt is an atrial septal defect (ASD) of the ostium secundum variety. Both these defects, ASD and mitral stenosis, can be either congenital or acquired.
The definition of Lutembacher syndrome has undergone many changes. Currently, any combination of ASD, congenital or iatrogenic, and mitral stenosis, congenital or acquired, is referred as Lutembacher syndrome.
Symptoms are mainly due to the ASD, and signs and symptoms vary according to the size of the ASD. With a large ASD, symptoms of pulmonary congestion, typical of isolated mitral stenosis, do not appear until late in the course of the disease. Conversely, these symptoms may appear early if the patient has an associated small ASD or develops pulmonary hypertension for other reasons. Patients with large ASD and moderate-to-severe mitral stenosis have signs and symptoms due mainly to right ventricular overload and right-sided heart failure, while patients with a small ASD and moderate-to-severe mitral stenosis have signs and symptoms of pulmonary congestion typical of mitral stenosis.
- The patient may or may not have a history of rheumatic fever.
- Fatigue and reduced exercise tolerance result from decreased systemic blood flow. The presence of mitral stenosis and left-to-right blood flow in diastole through the ASD reduces the forward flow of blood into the left ventricle, thereby reducing systemic blood flow and leading to fatigue and poor exercise tolerance.
- Palpitations are a common presenting symptom. Because of the augmented left-to-right shunt caused by higher left atrial pressure and mitral stenosis, both atria are dilated. This predisposes patients to atrial arrhythmias; atrial fibrillation is very common.
- Weight gain, ankle edema, right upper quadrant pain, and ascites are seen more commonly in patients with large ASD. Such symptoms are manifestations of the development of right-sided heart failure. A chronically increased left-to-right blood flow at the atrial level can eventually lead to right-sided heart failure.
- Paroxysmal nocturnal dyspnea, orthopnea, and hemoptysis are signs of pulmonary venous congestion. Such symptoms are caused by mitral stenosis and are seen less frequently in Lutembacher syndrome than in isolated mitral stenosis. They are more common in patients with small ASD and are probably more common in patients who develop reverse Lutembacher syndrome. In some patients with large pulmonary blood flow due to a large left-to-right shunt, orthopnea can develop because of decreased compliance of the lungs.
Isolated mitral stenosis is now known to be a rare congenital disorder, and most cases of mitral stenosis initially thought to be congenital were, in fact, caused by rheumatic mitral valve disease.
Initially, high left atrial pressure due to mitral stenosis was thought to stretch open the patent foramen ovale (PFO), causing left-to-right shunt and providing another outlet for the left atrium. Acquired ASD is almost always iatrogenic, either intentional or as a complication of a percutaneous interventional procedure. The incidence of left-to-right atrial shunt following mitral valvuloplasty is estimated at 11-12%.
The hemodynamic effects of this syndrome are a result of the interplay between the relative effects of ASD and mitral stenosis. As a result, in the presence of mitral stenosis, blood flows to the right atrium through the ASD instead of going backward into the pulmonary veins, thus avoiding pulmonary congestion. This happens at the cost of progressive dilatation and, ultimately, failure of the right ventricle and reduced blood flow to the left ventricle.
Physical examination reveals signs due to the ASD and mitral stenosis, which are modified because of the presence of both lesions in the same patient.
- Small volume
- Rhythm regular or irregular -Atrial fibrillation most common arrhythmia
Jugular venous pulse
- Distended jugular veins, even in the absence of right heart failure
- Large a waves when sinus rhythm is present
- Increased right ventricular pressure a more important determinant than equalization of atrial pressures in increasing jugular venous pressure
- Left parasternal lift, caused by transmitted right ventricular and pulmonary artery impulse, is common.
- Left ventricular impulse is unimpressive, owing to reduced filling of the left ventricle secondary to mitral stenosis.
- A tapping apex impulse due to the palpable, loud first heart sound of mitral stenosis may be present.
- A diastolic thrill at the apex is unusual.
- Loud first heart sound, opening snap, and a mitral early-to-mid diastolic murmur are the classic auscultatory findings of mitral stenosis and are variably present.
- Reduced transmitral pressure gradient resulting from decompression of the left atrium through the ASD and displacement of the left ventricular apex due to a large right ventricle attenuate these classic findings of mitral stenosis.
- Development of pulmonary hypertension and, consequently, an increase in right atrial and left atrial pressures may increase transmitral pressure gradient and bring out these auscultatory findings, but this phenomenon is canceled by further dilatation of the right ventricle, thus obscuring the left ventricular apex.
- The second heart sound (S2) may be widely split for 2 reasons. Increased right heart flow of ASD can result in late closure of the pulmonary component of the S2, and decreased left ventricular and aortic flow, secondary to mitral stenosis and ASD, can cause early closure of the aortic component of S2.
Additional heart sounds and murmurs
- Third and fourth heart sounds of right ventricular origin may be audible at the left sternal border and are louder with inspiration.
- Systolic murmurs are due to the following: ASD along the upper left parasternal area - Typically a flow murmur due to increased flow across the pulmonic valve; Tricuspid regurgitation along the lower left parasternal area - Due to the displaced tricuspid valve secondary to right ventricular dilatation; common; Holosystolic murmur at the left parasternal area due to tricuspid regurgitation - Usually increases with inspiration (Carvallo sign), which differentiates it from ASD and mitral regurgitation.
- Mid diastolic murmurs are due to the following: Increased flow across the tricuspid valve due to ASD or accompanying tricuspid stenosis, best heard at left lower sternal border or at apex for reasons already mentioned; Mitral stenosis, best heard with stethoscope bell at apex after exercise and with patient in left lateral position
- Continuous murmur in the lower right sternal area is due to continuous shunting of blood across a small ASD in the presence of severe mitral stenosis. This is an unusual finding on physical examination.
Abdomen: Ascites and hepatomegaly may be noted in the presence of right heart failure.
Extremities: Ankle edema may be present in the presence of right-sided heart failure.
- Mortality and morbidity rates are related to the relative severity of the individual lesions.
- Prognosis is generally good and patients have lived into their ninth decade without developing any cardiac symptoms.
- Some women have had multiple pregnancies without complications.
- Low-sodium diet
- Activity as tolerated
- Right-sided heart failure: diuretics.
- Management of arrhythmias.
- Subacute bacterial endocarditis prophylaxis: high risk for infective endocarditis.
- Surgery is now performed early rather than late because the rates of heart failure and cardiac arrhythmia increase with age. Patients with pulmonary hypertension and irreversibly increased pulmonary vascular resistance (Eisenmenger's syndrome) invariably develop progressive right-sided heart failure after trial septal defect (ASD) closure and die.
- Percutaneous closure of the ASD with a clamshell device and mitral valvuloplasty provides a nonsurgical approach to correct these defects.
- Mitral valvuloplasty alone can be complicated by development of ASD secondary to trans-septal puncture performed as a part of the procedure.