Choice of the optimal antiarrhythmic therapy still remains a challenge. Most frequently, antiarrhythmic agents used to reestablish and maintain sinus rhythm do not provide satisfactory clinical effect. Understanding electrophysiological mechanisms of initiation and maintenance of atrial fibrillation is the best way to develop optimal therapeutic approaches. This aim of this study was to assess the prospects of correcting paroxysmal (persistent) form of atrial fibrillation with termination treatment, ACE inhibitors, and omega-3-polyunsaturated fatty acids. The subjects of the study were 90 patients with documented episodes of atrial fibrillation of less than 48-hour duration. The observation lasted 12 months. The results show that "tablets in the pocket" strategy is the most effective and safe method of treatment of rare episodes of atrial fibrillation in patients with mild structural heart diseases; the terminating effectiveness of propanorm was 79% during hospital treatment and 88% in outpatients in the selected group of patients without a significant number of side effects. Treatment with lisinopril (dapril) was followed by a decrease in the number of paroxysms, duration of arrhythmia episodes, and a tendency to transformation into asymptomatic form. A possible mechanism of this positive effect of dapril on the paroxysmal form of atrial fibrillation is leveling of local electrophysiological effects of angiotensin II in a form of changing time of intra- and interventricular atrial conduction. Adding omega-3-polyunsaturated fatty acids to termination therapy decrease the number atrial fibrillation episodes and the time to their termination.