OBJECTIVE Congenital interatrial shunt can unload the left atrium (LA) and may lower the risk of new-onset heart failure (HF) or atrial fibrillation (AF). We evaluated the risk of new-onset HF or AF in patients with and without interatrial shunt.

METHODS We enrolled 2660 consecutive patients with acute stroke or transient ischemic attack (TIA) who underwent transesophageal echocardiography at Seoul National University Bundang Hospital from January 1, 2006 to December 31, 2018. The primary outcomes were 10-year new-onset HF, new-onset AF, and new-onset HF or AF composite.

RESULTS Overall, 466 (17.5%) patients with an interatrial shunt had smaller E velocity (0.66 ± 0.21 vs. 0.69 ± 0.22 m/s, P = 0.037) and smaller E/e' (9.1 ± 4.0 vs. 10.0 ± 5.0, P = 0.001) than 2194 (82.5%) patients without an interatrial shunt. The 10-year incidence of AF, HF, and AF or HF composite was lower in patients with an interatrial shunt (10-year AF, 11.2 vs. 17.8%, P < 0.001; 10-year HF, 6.2 vs. 10.4%, P = 0.005; 10-year AF or HF composite, 16.5 vs. 23.4%, P = 0.001). In multivariable analysis, the presence of an interatrial shunt was associated with a 38% (HR 0.62, 95% CI 0.40-0.96), 40% (HR 0.60; 95% CI 0.39-0.93), and 26% (HR 0.74; 95% CI 0.57-0.96) reduced risk for new-onset HF, AF, and new-onset HF or AF composite, respectively.

CONCLUSION In patients with interatrial shunt, the risk of AF and HF was lower. Interatrial shunt may be beneficial, and the closure of an interatrial shunt should be performed only in carefully selected patients. An interatrial shunt can unload the left atrium. In patients with stroke or TIA, the presence of an interatrial shunt was associated with a reduced risk for new-onset HF and AF. AF atrial fibrillation, HF heart failure, HR hazard ratio, LA left atrium.