Efficacy of antiarrhythmic drug therapy in preventing recurrence of atrial fibrillation and long-term cardiovascular prognosis in patients with asymptomatic paroxysmal atrial fibrillation.

We evaluated the efficacy of antiarrhythmic drug therapy (AAD) and long-term cardiovascular prognosis in patients with asymptomatic paroxysmal atrial fibrillation (AF). This retrospective study included 334 patients (229 men and 105 women, mean age, 69 +/- 11 years, mean follow-up, 60 +/- 11 months) who were divided into two groups; patients with symptomatic AF (group I) and those with asymptomatic AF (group II) on the basis of subjective symptoms. (1) Actuarial rates of patients without AF recurrence, those with AF recurrence and with electrical/pharmacological cardioversion to restore sinus rhythm, and those with conversion to permanent AF despite AAD were 40%, 41%, and 19%, respectively, in group I, and 22%, 24%, and 54%, respectively, in group II at the end of the follow-up period. At 60 months, the percentage of patients with conversion to the permanent form of AF was significantly greater in group II than in group I (P < 0.05, group I versus group II). (2) Survival rates free from symptomatic thromboembolism at 36, 60, and 120 months were 96%, 93%, and 88%, in group I, and 82%, 76%, and 71%, respectively, in group II (P < 0.05, group I versus group II). In patients not undergoing anticoagulant therapy, the annual rate of symptomatic thromboembolism was significantly greater in group II (5.3%) than in group I (2.3%) (P < 0.05), while in patients undergoing anticoagulant therapy there was no significant difference in the annual rate of symptomatic thromboembolism between group I (0.9%) and group II (1.8%). The clinical course of asymptomatic paroxysmal AF is refractory to AAD when compared to symptomatic AF, meaning that anticoagulant therapy is required to prevent symptomatic thromboembolism in this group.