Complex sentence: In current variants, the ability to revert ventricular fibrillation has been extended to include both atrial and ventricular arrhythmias as well as the ability to perform biventricular pacing in patients with congestive heart failure or bradycardia.
Split into simpler sentences: In current variants, the ability to revert ventricular fibrillation has been extended to include both atrial and ventricular arrhythmias. There also exists the ability to perform biventricular pacing in patients with congestive heart failure or bradycardia.