atrial septal defect secundum ( asd ) is a common cardiac malformation , with an incidence of about 2 per 100.000 live births . it is most often closed in childhood , by catheter implanted device or surgical intervention , to prevent potential problems occurring later in adolescence or adulthood . only rarely its closure needs to be undertaken already in early infancy . reasons for the need of treatment in infancy are reported to be severe symptoms associated with pulmonary hyperperfusion and hypertension , often associated with pneumonia and lung hypoplasia , prematurity with chronic lung disease or with other malformations such as omphalocele , congenital diaphragmatic hernia or pulmonary vein stenosis . the shunting through secundum asd may become more obligatory if the left atrial emptying through the mitral ostium becomes obstructed as in case of enlarged coronary sinus , obstructive mitral valve itself , or by impaired compliance of a borderline left ventricle . a 4-week - old male infant presented to our department with tachypnea and pale cold skin . his weight was 3.2 kilograms . except for an absent big toe and a clubfoot , no other dysmorphic features were present . clinical features of heart failure consisted of tachycardia and tachypnea with intercostal and subcostal retractions . the second heart sound was loud ; a systolic murmur grade 2/6 was audible along the left sternal border . the chest x - ray showed cardiomegaly with enlarged right atrium and right ventricle in combination with increased pulmonary vascular markings . echocardiography demonstrated normal intracardiac anatomy ; a moderate - sized central secundum asd with a diameter of 6 mm ( figure 1 ) . a left to right shunt through a 4 mm wide patent ductus arteriosus ( pda ) was seen , with a low - pressure gradient between the aorta and pulmonary artery , suggesting pulmonary hypertension . the pulmonary venous flow was increased and preferentially pointing across the secundum asd into the right atrium . the left ventricle was borderline , its apex being at the same level as the right ventricle ( rv ) . left ventricular ( lv ) end - diastolic dimension measured in long - axis projection appeared normal ( 18.7 mm , z - score=0.16 ) , mitral valve annulus assessed in four - chamber view measured 10.1 mm ( z=1.33 ) and was not restrictive . the length of the lv was 33.8 mm , the rv length was 36.9 mm , and the lv / rv length ratio was 0.92 . the right ventricle was largely dilated ( figure 2 ) , the tricuspid valve annulus measured 13.3 mm ( z=+1.24 ) and pulmonary artery annulus 11.7 mm ( z=+1.75 ) . the pulmonary artery branches were also dilated , right pulmonary artery measuring 9.8 mm ( z=+2.74 ) . figure 1apical precordial four chamber view . small secundum atrial septal defect ( arrows ) , la , left atrium ; lv , left ventricle ; ra , right atrium ; rv right ventricle . 
  apical precordial four chamber view . small secundum atrial septal defect ( arrows ) , marginal left ventricle does not reach the apex . la , left atrium ; lv , left ventricle ; ra , right atrium ; rv right ventricle . 
 figure 2parasternal long - axis ( a ) and short - axis ( b ) view demonstrates marked right ventricular volume overload . ao , aorta ; la , left atrium ; lv , left ventricle ; rv , right ventricle . 
  parasternal long - axis ( a ) and short - axis ( b ) view demonstrates marked right ventricular volume overload . ao , aorta ; la , left atrium ; lv , left ventricle ; rv , right ventricle . diuretic treatment was started and surgery was postponed . however , heart failure with pulmonary hypertension persisted for six weeks , and the baby had to undergo operation . our echocardiographic findings were confirmed during surgery ; and both pda and secundum asd were closed . one year after operation , the lv had normal dimensions and both systolic and diastolic functions were normal . large asd is characterized by atrial left - to - right shunt leading to rv diastolic overload . in contrast , large pda leads to volume overload of the left atrium and lv . in our patient with heart failure due to large pda and a moderate - sized secundum asd , one would expect predominant pda hemodynamics , with an enlarged left heart , but the opposite was true . we explain this by decreased compliance of a borderline lv enabling the preferential shunting of a high volume of pulmonary venous blood across the atrial septum rather than into lv via the mitral valve . because many small - to - moderate asds may close spontaneously , repair of pda alone without cardiopulmonary bypass may be preferred . while planning the surgery in our patient it was difficult to differentiate to which extent the secundum asd represented the primary cause of the symptoms or only being a desired decompression route from a high - pressure left atrium . this is a common situation in infants with aortic coarctation and secundum asd , where factors influencing atrial shunt predisposing to heart failure are often present , including left ventricular , aortic or mitral valve hypoplasia . schroeder et al . have shown that mitral valve , but not aortic or left ventricular , size correlated with the development of heart failure and the need for asd closure shortly after coarctation repair . the presence of aortic coarctation in the setting of an asd , however , has not exactly the same hemodynamics . jean - st - michel et al . demonstrated that eliminating the left - to - right shunt by closing the secundum asd with a test balloon occlusion , in an infant with a marginal lv , forced blood through the mitral valve thus promoting lv filling . they observed that when blood was forced through the mitral valve , the left ventricle had the capacity to tolerate the extra volume . this report illustrates that in the patient with the major diagnosis of pda , the presence of a moderate - sized asd secundum in combination with a marginal lv may result in inadequate filling of this ventricle .
atrial septal defect ( asd ) is usually asymptomatic in infancy , unless pulmonary hypertension or severe co - morbidity is present . 
 we report a case of a 4-week - old infant with moderate - sized asd , small patent ductus arteriosus ( pda ) , and a borderline sized left ventricle that developed heart failure . despite the relatively small diameter of the asd , this defect influenced the mechanism of heart failure significantly . 
 after surgical closure of both pda and asd , the signs of pulmonary hypertension resolved and the patient developed a normal sized left ventricle . 
 this report illustrates that the presence of a small asd in combination with a marginal left ventricle may result in inadequate left ventricular filling , pulmonary hypertension and heart failure .