Association between pulmonary hypertension and an atrial septal defect

In this Journal, Lange et al. describe the use of exerciseechocardiography to identify pulmonary hypertension in thepresence of an atrial septal defect (ASD) [1].Atrial septal defectAn ASD is a relatively common congenital heart diseasewith a birth prevalence of 1.6 per 1000 live births, and aprobabilityofsurvivalintoadulthoodof97%[2,3].Differenttypes of ASDs exist, and the secundum type, located at thefossa ovalis, is the most common (75 %) [4]. An ASD ischaracterised by a left-to-right shunt with volume overloadof the right heart and pulmonary overcirculation. This mightresult in arrhythmias, right heart failure, pulmonary arterialhypertension, and paradoxical embolism, the last mentioneddue to a right-to-left shunt. Echocardiography is the primarydiagnostic technique, and cardiac catheterisation is requiredin cases of a suspected increase in pulmonary artery pres-sure (PAP). Indication for ASD closure is the presence of asignificant shunt with signs of right ventricular volumeoverload without the presence of a severely increased pulmo-nary vascular resistance (PVR) ( 50 mmHg withorwithout additionalfindings[7].Exercise echocardiographyis not recommended by the current PH guideline [7]. Inaddition, exercise causes an increase in mean PAP of up to3 mmHg per 1 l/min increase in cardiac output in healthyindividuals, and this is related to age and gender [9, 10]. Thedefinite diagnosis of PAH should always be confirmed byright heart catheterisation.Pulmonary hypertension and ASDPulmonary arterial hypertension is noted in 9 to 35 % ofpatient with a secundum type ASD, both open and closed[11, 12]. The definition of PH differs among the differentepidemiological studies. Predictors for the occurrence ofPAH are age, size of the defect, non-closed status, andfemale sex [12, 13]. Pulmonary vascular disease related tothe systemic-to-pulmonary shunt might be prevented byearly correction of the defect in most patients. The windowof opportunity for correction and prevention of PAH islesionspecific(pre-orpost-tricuspid)andpulmonaryvascular