RYR2 and Paroxysmal atrial fibrillation: Regarding the synergy of RyR2 blockers with other antiarrhythmics, a study performed in United States, California (completed in 2020) evaluated the effect of ranolazine and dronedarone when given alone and in combination in patients with paroxysmal AF, and showed 0% of mortality and serious adverse effects (NCT01522651).