Atrial fibrillation (AF) may interfere with several therapeutic options for heart failure (HF): beta-blockers (BB), cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillator (ICD).

AF and BB in HF. Two meta-analyses of randomized trials, that compared BB with placebo in HF patients, found that BB significantly reduced mortality in HF patients with sinus rhythm (SR), but not in HF patients with AF. On the other hand, data from the Swedish HF registry and Danish AF registry showed that BB can reduce mortality both in HF patients with AF and SR. Further randomized trials are needed to clarify BB effect in HF patients with AF and to resolve these contradictory findings. In the meantime, BB remain a standard medical therapy for all HF patients with reduced ejection fraction, irrespective of rhythm disorder. (1)

AF and CRT. AF is often present in CRT patients and interferes with effective biventricular pacing (BVP). When conducted to the ventricles with R-R interval similar or shorter than the lower pacing rate, AF partially or completely precludes BVP and reduces CRT delivery. The BVP >98% is a cut-point value for the benefit in survival in SR and AF patients. In a study of 54.0190 patients with CRT-defibrillator, the presence of AF and BVP<98% was associated with an increased risk of death. Treatment of AF in CRT patients depends on the type of AF. Catheter ablation of AF is superior to amiodarone in patients with paroxysmal or persistent AF, and AV node ablation is superior to rate control drugs in patients with permanent AF. (2)

AF and ICD. AF may interfere with ICD therapy in two ways; a) by inducing inappropriate ICD shock when its rapid ventricular rate reaches a device’s programmed detection zone of VT/VF, and b) by triggering episodes of VT/VF and consequent appropriate device therapy. AF is the most common mechanism for inappropriate shocks in ICD patients. Patients who receive appropriate or inappropriate shocks have a substantially higher risk of death than similar patients who did not receive such shocks. The risk associated with inappropriate shocks is limited to those receiving shocks for AF. (3) To minimize this risk, it is necessary to use detection zone appropriately, to consider monitoring zone for slow VT, to ensure adequate rate or rhythm control, and to activate specific discrimination algorhythms.