Cardiac Resynchronization and Atrial Fibrillation: What's New?

Abstract

atrial fibrillation, congestive heart failure, crtContemporary cardiac resynchronization therapy (CRT) devices are equipped with reliable and extensive diagnostic and memory features yielding full disclosure of the frequency, duration, and overall burden of atrial tachyarrhythmias.These advanced diagnostic features have demonstrated the high frequency of symptomatic and asymptomatic atrial arrhythmias, mostly atrial fibrillation (AF) in CRT patients. The loss of atrial transport function and associated tachycardia frequently result in deterioration of cardiac function and clinical deterioration. AF compromises CRT delivery due to RR interval variability and competing tachycardia, and may even result in excessive rapid ventricular pacing during atrial tracking. Atrial arrhythmias represent an important cause of poor long-term CRT benefit and prognosis unless aggressive efforts are made to slow the ventricular rate (VR). Over the last 3-5 years many important reports have addressed the diagnosis and treatment of atrial tachyarrhythmias in CRT patients. These new developments and their clinical implications form the basis of this review. Because the overwhelming majority of arrhythmias consist of AF, we shall refer, as do many workers, to atrial tachyarrhythmias simply as AF. [1][2][3][4] Although approximately 25% of patients undergoing CRT have permanent AF, 5,6 virtually all the randomized CRT trials have excluded patients with preexisting permanent AF. Evidence from relatively small studies have suggested that the CRT benefit in AF is comparable (or somewhat attenuated) to that seen in sinus rhythm provided the VR is controlled with digoxin and β-blockers. 7-11 A recent meta-analysis of 23 observational studies in a total of 7,495 patients (25.5% in AF) followed for 33 months showed that AF was associated with a higher risk of nonresponders (P = 0.001) and all-cause mortality (P = 0.015). 12 Ablation of the atrioventricular Address for reprints: S.

Efficacy and safety of new-generation atrial antitachycardia pacing for atrial tachyarrhythmias in patients implanted with cardiac resynchronization therapy devices

“…The incidence of AF in patients implanted with CRT devices is 30-35% for paroxysmal AF and 20-25% for permanent AF [16,17]. AF exhibits loss of atrioventricular synchronicity and a higher risk for insufficient CRT delivery because of an uncontrolled heart rate, which causes hemodynamic deterioration [7,18].…”

Relationship between device‐detected subclinical atrial fibrillation and heart failure in patients with cardiac resynchronization therapy defibrillator

“…Another study 14 reported that AF in CRT patients was associated with an increase in HF hospitalization and death, mainly because uncontrolled ventricular rates reduce the delivery of an optimal of biventricular pacing. A biventricular pacing <90% was associated with a higher incidence of HF and death, and a biventricular pacing >98% significantly reduced HF and death.…”

Updates on His bundle pacing: The road more traveled lately

“…However, one third of these patients do not respond to conventional CRT (21,22). Permanent atrial fibrillation is one of the reasons for not responding to CRT (23) . Lack of response to CRT was also seen in patients with normal QRS and those with right bundle branch block (RBBB).…”