Risk of Stroke and Incident Atrial Fibrillation in Patients in Sinus Rhythm With Nonischemic Dilated Cardiomyopathy

Nonischemic dilated cardiomyopathy (NIDCM) is associated with an increased risk of atrial fibrillation (AF) and stroke, especially in patients with high CHA₂DS₂-VASc. We aimed to identify variables associated with incident AF or stroke using left atrial deformation analysis and its prognostic value added to CHA₂DS₂-VASc score. Patients with NIDCM and left ventricular ejection fraction <50% in sinus rhythm were included between January 2015 and December 2019. Left atrial volume index (LAVI) and atrial strain were used in combination with the CHA₂DS₂-VAS score to predict ischemic stroke or incident AF. Proportional hazards Cox regression was used to provide hazard ratios (HRs). There were 338 patients included. After a median follow-up of 3.6 years, the end point occurred in 41 patients (12.1%). LAVI outperformed other echocardiographic parameters, with a significant improvement in risk reclassification compared with CHA₂DS₂-VASc alone (net reclassification index 0.6, increase in Harrell's C from 0.63 to 0.73, p = 0.003), and remained significant after multivariate adjustment. LAVI was associated with both components of the end point separately. The best cutoff for LAVI was 44 ml/m². LAVI ≥44 ml/m² increased the risk of the end point among those with CHA₂DS₂-VASc ≥3 (HR 6.0, 95% confidence interval 2.6 to 13.5) but not in those with CHA₂DS₂-VASc <3 (HR 1.2, 95% confidence interval 0.3 to 4.5). Competing risk analysis did not alter the results. In conclusion, LAVI might be used to assess the risk of incident AF or stroke in NIDCM. Patients with LAVI ≥44 ml/m² and CHA₂DS₂-VASc ≥3 could be at high risk of AF and stroke and may benefit from more intensive surveillance.