Abstract
Background. Class IC antiarrhythmic drugs (IC-AADs) are recommended as first-line therapy in treatment of lone paroxysmal atrial fibrillation (AF) along with catheter ablation of pulmonary veins. Despite previous attempts to identify predictors of IC-AADs` efficacy, the choice between IC-AADs agents is still most often carried out using empirical approach.
Aim. To determine the predictors of IC-AADs ` efficacy in patients with paroxysmal AF in the absence of structural heart disease.
Materials and methods. Seventy four patients (22 men, 52 women, average age 65 [57; 70] years) were treated with IC-AADs: 26 patients were prescribed lappaconitine hydrobromide (Al) (allapinin at a dosage of 75 mg/day or allaforte 50–100 mg/day), 25 patients were prescribed propafenone (P) 450–600 mg/day, 23 patients – diethylaminopropionylethoxycarbonylaminophenothiazine hydrochloride (ethacizine, E) 150 mg/day. The average frequency of AF paroxysms was 2 [0.4; 6.25] per month. Patients were divided into 2 groups depending on the effect of AADs.
Results. Over a 12 months follow-up IC-AADs therapy was effective in 28 (37.8%) patients (Eff+ group), in the remaining 46 (62.2%) patients AF recurrences or side effects demanding AADs withdrawal were registered (Eff-group). A DC value greater or equal to 5 ms predicted the effectiveness of IC-AADs therapy with 79% sensitivity and 77% specificity (OR 12, 95% CI 3.07–49.5, p0.0001). In the Al group the deceleration capacity (DC) value greater or equal to 5.25 ms allowed predicting therapy effectiveness with 86% sensitivity and 100% specificity (OR 7, 95% CI 1.14; 43; p=0.002). In the E group, the DC index was characterized by high sensitivity (80%) and specificity (85%) for a threshold value of 5.9 ms. In case of DC above this value, the probability of E therapy efficacy increased by 22-times (OR 22, 95% CI 1.5; 314; p=0.009). In group P, the DC medians in the Eff+ and Eff- groups did not differ significantly (p=0.821). However, at low DC values (less than 4 ms) P turned out to be the most effective compared to other two IC-AADs: its effectiveness was 50%, which was significantly higher compared to E (0%) and Al (0%) (p=0.046).
Conclusion. Estimation of the DC level before starting IC-AADs can make it easier to choose a specific drug from this group and improve treatment results: at DC above 5.2 ms, it is advisable to use Al, at DC≥6 ms – Al or E, at DC less than 4 ms – P.
Reference23 articles.
1. Antiarrhythmic drugs for atrial fibrillation: lessons from the past and opportunities for the future
2. 2020 Clinical guidelines for Atrial fibrillation and atrial flutter
3. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)
4. Фомина И.Г., Тарзиманова А.И., Ветлужский А.В., и др. Пропафенон при восстановлении и сохранении синусового ритма у больных с персистирующей формой фибрилляции предсердиЙ: новые результаты исследования «ПРОМЕТЕЙ». Consilium Medicum. 2006;8(11):82-5 [Fomina IG, Tarzimanova AI, Vertluzhskyi AV. Propafenon in restoring and maintaining sinus rhythm in patients with persistant atrial fibrillation. Consilium Medicum. 2006;8(11):82-5 (in Russian)].
5. Соколов С.A., Бомонина Е.В. Сравнительная эффективность и безопасность аллапинина, этацизина и амиодарона и выбор оптимальной антиаритмической терапии по контролю ритма при пароксизмальной мерцательной аритмии. Кардиология: Новости. Мнения. Обучение. 2015;3(6) [Sokolov SF, Bomonina EV. Comparative efficacy and safety of allapinine, ethacyzin and amiodarone: choice of optimal antiarrhythmic therapy for rhythm control in case of paroxysmal atrial fibrillation. Kardiologiia: Novosti. Mneniia. Obucheniie. 2015;3(6) (in Russian)].