Lutembacher syndrome is an extremely rare clinical entity characterized by a concomitant presence of an atrial septal defect and mitral stenosis. Both congenital and acquired disorders may be involved in the pathogenesis. Patients may be asymptomatic or present with severe clinical manifestations, depending on the severity of the defects. Cardiac ultrasonography, supported by electrocardiography and a thorough physical examination, is the mainstay of diagnosis.
The clinical presentation of patients with Lutembacher syndrome depends on several factors - the size of the defect, severity of mitral valve stenosis and the ability of the right ventricle to overcome increased pressure . Patients may be asymptomatic for decades or they can suffer from severe hemodynamic instability and heart failure early on  . An atrial septal defect (ASD) invariably causes left-to-right shunting, while the occurrence of mitral stenosis further increases pressure in the left atria, directly contributing to the transfer of blood into the right heart  . Consequently, symptoms arise due to reduced left ventricular output - exercise intolerance, palpitations, and fatigue  . Prolonged shunting and severe mitral stenosis (or even insufficiency) can lead to atrial dilation and rhythm abnormalities, such as atrial fibrillation . On the other hand, right ventricular overload and reduced compliance may progress to pulmonary hypertension and congestive heart failure, in which case a poor prognosis is observed  . The majority of reports suggest that a predilection toward female gender exists  , whereas rheumatic fever, particularly in developing countries, seems to be the most important precipitating factor for mitral valve disease . Although approximately 4% of ASDs are accompanied by a mitral valve defect, Lutembacher syndrome is very rarely reported in general practice  . Nevertheless, its early recognition may be pivotal, especially in the setting of severe left-to-right shunting and pulmonary hypertension.
Despite its rare nature, Lutembacher syndrome can be diagnosed only if a thorough workup is conducted. Firstly, a detailed patient history should reveal the onset and course of symptoms. Secondly, a meticulous physical examination, particularly cardiac auscultation and inspection of the thorax, must be conducted and serves as one of the key steps in making an initial diagnosis  . A loud first heart sound (S1) accompanied by an early-to-mid diastolic murmur is a typical sign of mitral stenosis, whereas splitting of the second heart sound (S2) and presence of third and fourth heart sounds (S3 and S4, respectively), most prominently on the left sternal border during inspiration, are features that may point to ASD . In addition, systolic murmurs at the left parasternal area can be heard on the grounds of increased pulmonary valve flow, holosystolic murmurs increasing during respiration may arise because of tricuspid regurgitation, while continuous murmurs might be encountered as well, the reason being persistent shunting through the ASD . Physical examination can also reveal weak arterial pulses (due to reduced systemic blood flow) and elevated jugular venous pressure . When valid clinical suspicion toward valvular or structural heart disease exists, electrocardiography (ECG), plain chest radiography and echocardiography are necessary to confirm the diagnosis . P wave (bifid P wave in lead II) and QRS complex abnormalities (right bundle branch block, right ventricular hypertrophy, and right axis deviation) can be seen on ECG . In addition, left atrial enlargement and pulmonary congestion may be noted on chest X-rays . Doppler echocardiography, however, is the gold standard in the diagnosis of Lutembacher syndrome, as it may detect altered hemodynamic pathways and visualize ASD and impaired flow through the mitral valve .