Despite their high prevalence among recipients of left ventricular assist devices (LVADs), atrial arrhythmias do not confer increased risks of death, thromboembolism or bleeding in this high-risk population, according to a retrospective analysis of 418 consecutive LVAD recipients at Cleveland Clinic. Moreover, among LVAD patients with paroxysmal or persistent atrial arrhythmias, rhythm control measures had no effect on clinical outcomes.
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“Evidence to date has been mixed on whether atrial arrhythmias affect mortality and other outcomes in patients with LVADs, who represent a population with the most advanced form of heart failure,” says Cleveland Clinic electrophysiologist Daniel Cantillon, MD, corresponding author of the study, published in the April issue of JACC: Clinical Electrophysiology (2019;5:459-466). “We reviewed our cumulative experience to add to the evidence on this question, and we also undertook the first systematic investigation of the effect of rhythm control on clinical outcomes in LVAD recipients with atrial arrhythmias.”
The shape of the study
He and colleagues conducted a retrospective multivariable survival analysis of all patients implanted with an LVAD at Cleveland Clinic from January 2004 through June 2016. Their aim was to assess the association of death, thromboembolism and major bleeding with atrial fibrillation (AF) and atrial flutter (AFL) and with exposure to rhythm control measures among those who had AF or AFL.
Four hundred eighteen patients received an LVAD during the study period and made up the study cohort, which was 80% male and had a median age of 58 years (interquartile range, 50 to 67) and median follow-up of 445 days after LVAD implantation (interquartile range, 165 to 936).
Prevalence and effects of atrial arrhythmias
Analysis of these patients’ records revealed that 302 of them had AF and/or AFL after LVAD placement (72%), with 242 having AF alone, 45 having both AF and AFL, and 15 having AFL alone. The 72% prevalence of AF/AFL after LVAD implantation was up from 57% before implantation.
Notably, patients with (n = 302) and without (n = 116) AF/AFL had statistically comparable rates of mortality (39% vs. 38%) and major bleeding (46% vs. 49%) during follow-up, and those with AF/AFL had significantly fewer thromboembolic events than those without AF/AFL (13% vs. 23%; P < 0.01).
“The high prevalence of AF/AFL in this study is consistent with previous studies of LVAD recipients,” Dr. Cantillon observes. “However, its finding that atrial arrhythmias had no negative effect on mortality or adverse events aligns with two prior studies but conflicts with two other studies that showed increased mortality among patients with persistent AF. The jury appears to still be out on the effect of these arrhythmias on outcomes in this population.”
He adds that the unexpected finding of significantly lower rates of thromboembolism in patients with AF/AFL may be explained in part by the use of different anticoagulation regimens between patients with and without AF/AFL. “Patients with an atrial arrhythmia were more likely to be discharged on an antiplatelet drug plus an anticoagulant and less likely to be discharged on one of these agents alone,” he explains.
Effects of rhythm control
Among the 238 patients with paroxysmal or persistent AF/AFL, 166 (70%) were exposed to rhythm control, which consisted of antiarrhythmic drugs (almost exclusively amiodarone) in 163 patients, electrical cardioversion in 34 patients, implantable cardioverter-defibrillator shocks in four patients and surgical AF ablation (at the time of LVAD placement) in two patients. No patients had catheter ablation.
When these 166 patients were compared with the 72 patients with persistent AF/AFL who did not receive rhythm control measures, exposure to rhythm control was associated with a lower burden of AF, but it was not associated with significant reductions in mortality, thromboembolism or bleeding.
“These findings argue that a rhythm control strategy may not lead to improved outcomes in LVAD patients with atrial arrhythmias,” says Dr. Cantillon, “although there may be situations where rhythm control is desirable to ease symptoms or treat tachycardia-mediated heart failure. Identifying these circumstances will require further study.”
In an accompanying editorial in JACC: Clinical Electrophysiology, two cardiologists from the University of Chicago’s Pritzker School of Medicine write that Dr. Cantillon and colleagues “should be commended for examining and promoting this important clinical question of rhythm control in the largest published dataset [of LVAD patients] with rigorous retrospective chart analysis.” They conclude that “the stage is set for formal prospective testing” to “affirm or refute the value of sinus rhythm in LVAD patients.”
A moving target
Study co-author Edward Soltesz, MD, MPH, adds that further insight on arrhythmia management in LVAD recipients is likely as LVAD technology continues to evolve.
“Because of our study’s time frame, less than 1% of the LVADs placed in this study were the latest-generation device [HeartMate III™],” says Dr. Soltesz, Surgical Director of Cleveland Clinic’s Kaufman Center for Heart Failure and Recovery. “The risk profiles of LVADs can be expected to improve with time, and the necessary anticoagulation regimens will likely evolve. Ongoing study will help ensure that our understanding of the effects of atrial arrhythmias on LVAD patients keeps pace with LVAD technologies.”