cardiac resynchronization in atrial fibrillation trial - a pilot study

Conditions: Atrial Fibrillation; Heart Failure

Summary: the purpose of this prospective randomized study is to determine whether patients on cardiac resynchronization therapy with concomitant long-standing persistent or permanent atrial fibrillation would benefit from a strategy to restore and maintain sinus rhythm (rhythm control strategy) in comparison to a rate control strategy in terms of higher biventricular paced beats percentage.

due to a lack of sufficient data the present guidelines on treatment of patients with atrial fibrillation (af) and cardiac resynchronization therapy (crt) devices are of low scientific evidence. the efficacy of crt in af patients is limited by the percentage of the effective biventricular paced beats (bivp%), which should exceed 95%-98% - a goal which is seldom obtained by means of pharmacological rate control strategy. the only treatment strategy which effect is scientifically established is an atrioventricular junction ablation (avja) but the use of this method is limited. on the other hand, about 10% of patients with persistent forms of af experience a spontaneous sinus rhythm (sr) resumption after crt implantation. moreover, sr resumption and it's maintenance by means of single external electrical cardioversion in af patients has been proven feasible. a strategy of rhythm control in af patients on crt could provide high bivp% and improve the efficacy of crt in this group of patients. to show superiority of the rhythm control strategy over the rate control strategy a sample size of 60 patients was calculated based on following assumptions: two-tailed test, a type i error of 0.05, a power of 80%, efficacy (mean bivp%) of rate control strategy 90%, efficacy (mean bivp%)of rhythm control strategy 98% and 8% drop-out rate to fulfill the criteria of intention-to-treat analysis. due to presumed lack of statistical power the secondary end points and safety endpoints will be considered exploratory.

Eligibility criteria:
inclusion criteria: * permanent or long-standing persistent atrial fibrillation (definitions according to the latest european society of cardiology guidelines on af) * at least 3 months after a procedure of a crt device implantation * a crt device with a presence of a right atrial electrode * age: ≥18 years old * effectively biventricular paced captured beats \<95% * effective therapy with oral anticoagulants for at least 3 months * written informed consent exclusion criteria: * reversible causes of af * significant valve disease * advanced a-v block (including: avja) * contraindications to amiodarone (hyperthyroidism, not compensated hypothyroidism, drug intolerance, qt\>460ms for men, qt\>450 for women) * long-qt syndrome * decompensation of the heart failure within 48 hours before the qualification * cardiac transplantation in 6 months * life expectancy less than 1 year * chronic dialysis * la diameter \>6cm * alcohol abuse * pregnancy/lack of effective contraceptive therapy (in case of females in the reproductive age) * participation in other clinical trial

Keywords: atrial fibrillation cardiac resynchronization therapy heart failure rhythm control strategy