Left Atrial Systolic Force in Hypertensive Patients with Left Ventricular Hypertrophy: A Predictor of Incident Atrial Fibrillation. The LIFE Study

It remains unknown whether left atrial systolic force (LASF), a measure of left atrial function, can be used as a predictor of new-onset atrial fibrillation (NOAF). Furthermore, the effect of the treatment with atenolol and losartan on LASF is unclear. A total of 758 patients without atrial fibrillation at baseline were enrolled from the Losartan Intervention For Endpoint (LIFE) reduction in hypertension echocardiography sub-study. Participants of the LIFE study were randomized to either atenolol-or losartan-based treatment. The mean follow-up was 59 months. LASF was calculated using the average mitral orifice area and mitral peak. The velocity was obtained by Doppler echocardiography. At baseline, 25% of patients had a LASF ≤ 10.3 kdyn. Compared to other quartiles, this quartile had a higher proportion of men, lower heart rate, body mass index, and age. After controlling for these variables, patients in the first quartile had a lower stroke volume compared to other quartiles. New-onset AF occurred in 29 (8.1/1,000 patient-years of follow-up) patients. In multivariable Cox regression analyses with backward elimination, increasing LASF was associated with a lower risk of NOAF (hazard ratio [HR] = 0.90 [95% confidence interval 0.85-0.96], p = 0.001). Integrated discrimination improvement was 0.054 (p = 0.004) and there was a borderline significant net reclassification improvement of 19.2% (p = 0.075). Over time LASF decreased more in the atenolol-based than the losartan-based treatment group (< 0.001). Low LASF was associated with a higher risk of new-onset AF. Losartan-based treatment was associated with better preservation of LASF compared to atenolol-based treatment.