Complex sentence: Today, the most common indications for digoxin are atrial fibrillation and atrial flutter with rapid ventricular response, but beta-blockers or calcium channel-blockers should be the first choice.
Split into simpler sentences: Today, the most common indications for digoxin are atrial fibrillation and atrial flutter with rapid ventricular response. Beta-blockers and/or calcium channel-blockers should be the first choice.