BACKGROUND: Adult patients with small, unrepaired atrial septal defects (ASD) have higher late mortality than the background population. In this nationwide study, we characterize the late natural history of adults with small, unrepaired ASD.

METHODS: Using the Danish National Patient Registry, we included all Danish patients, diagnosed between 1953 and 2011 with an unrepaired ASD. Additionally, all patients, aged 18-65, were invited for clinical testing. Patients also completed a general health survey for comparison with the general population.

RESULTS: We identified 723 patients with a small unrepaired ASD. Since the time of diagnosis, 182 patients had died, with an average lifespan of 63 years. The most common cause of death was heart failure. Furthermore, ASD patients had a higher burden of chronic disease than the general population (38.2% vs. 26.9%; p = 0.005), particularly lung disease (3.6% vs. 0.9%; p = 0.008). A total of 153 patients (mean age 32 y) underwent additional testing. On echocardiography an open defect was verified in 19.6% (n = 30) of the patients, of which half subsequently underwent intervention. Interestingly, 6-minute walking distance was markedly reduced (p < 0.0001 compared to normative values) no matter whether the defect was open or closed by echocardiography. Finally, 25.5% of the patients often felt stressed or nervous as compared with 16.3% of the general population (p = 0.004).

CONCLUSIONS: Patients with small, unrepaired ASD in adult life have reduced lifespan, more chronic diseases, impaired submaximal exercise capacity, and higher levels of stress than the general population. The current guidelines for intervention and follow-up may need to be reconsidered.