Effect of Digoxin vs Beta-Blockers on Left Atrial Strain for Heart Rate-Controlled Atrial Fibrillation: The DIGOBET-AF Randomized Clinical Trial

Background and Objective Left atrial strain (LAS) has prognostic value in patients with atrial fibrillation (AF). Consequently, therapies that improve LAS may help reduce AF-related adverse cardiac events. We aimed to compare how digoxin and bisoprolol modulate LAS in patients with AF being treated with rate control. Methods This was a bicentric randomized controlled trial. Patients with AF, na & iuml;ve to beta-blockers and digoxin, and scheduled for treatment with a rate control strategy were randomized to receive oral bisoprolol 5-10 mg daily or digoxin 0.25 mg daily. The primary aim was to compare the change in peak LAS before and after 30 days of treatment between the two groups. Results A total of 60 patients, equally distributed between the two groups, completed the trial. By day 30, there was no significant difference in global peak LAS between the groups. However, when analyzed separately, the two-chamber view showed a significantly higher peak LAS in the digoxin group than in the BB group (mean 7.5 +/- standard deviation 3.2% vs. 5.9 +/- 3.4%; p = 0.004). Similarly, the four-chamber view also showed a higher peak LAS in the digoxin group (7.2 +/- 3.6% vs. 6.4 +/- 3.8%; p = 0.047). Considering the entire LAS curve rather than solely the peak value, digoxin significantly increased all LAS curves. In the global and four-chamber view, the digoxin maximum effect occurred significantly earlier than the peak of the LAS curve (p < 0.001). This effect remained constant over the cardiac cycle in the two-chamber curve (p < 0.001). Conclusion Our findings suggest that, in patients with rate-controlled AF, digoxin positively modulates LAS when compared with bisoprolol. Clinical Trials Registration NumberNCT05540600, https://clinicaltrials.gov.