Resumption of sinus rhythm in patients with heart failure and permanent atrial fibrillation undergoing cardiac resynchronization therapy: a longitudinal observational study

Rhythm and rate control strategies in patients with long-standing persistent atrial fibrillation treated with cardiac resynchronization: the results of the randomized Pilot-CRAfT study

BACKGROUND

Atrial fibrillation (AF) is common in cardiac resynchronization therapy (CRT) recipients. It is a marker of impaired CRT response mainly mediated by the reduction of effectively captured biventricular paced beats (BiVp). There are no randomized trials comparing strategies to maintain high BiVp percentage.

OBJECTIVE

To compare the efficacy of rhythm vs rate control strategies in CRT recipients with long-standing persistent AF.

METHODS

We performed a randomized trial including CRT recipients with persistent AF resulting in low BiVp%. All patients received amiodarone, the rhythm control group received external electrical cardioversion (EC), and the rate control group received atrioventricular node ablation, if needed. The primary end-point was 12-month BiVp% (NCT).

RESULTS

43 patients were included in the analysis. The mean age was 68.4 (SD: ± 8.3) years and the mean BiVp% 82.4% ± 9.7%. AF lasted 25 ± 19 months. The mean baseline left ventricular ejection fraction (LVEF), left atrium area, and the maximal oxygen uptake (VO2max) were: 30 ± 8%, 33 ± 7 cm2, and 14 ± 5 mL/(kg*min), respectively. The EC success rate was 58%. 38% patients remained in sinus rhythm (SR) after 12 months. BiVp% increased similarly in both arms reaching 99% [95% CI 97.3-99.8] and 98% [94.0-99.0], P = 0.14 in rhythm and rate control groups, respectively. LVEF raised significantly only in the rhythm control group (ΔLVEF 4.1 (± 7.3), P = 0,018) which was driven by the patients who maintained SR. No differences in VO2max, QoL, clinical and safety end-points were observed.

CONCLUSION

Despite comparable BiVp% in both groups, only restoration of SR led to improved left ventricular ejection fraction in CRT patients with long-standing AF.

TRIAL REGISTRATION

NCT01850277 registered on 22/04/2013.

Spontaneous Sinus Rhythm Restoration in Patients With Refractory, Permanent Atrial Fibrillation Who Underwent Conduction System Pacing and Atrioventricular Junction Ablation

Ablate and pace (A&P) with conduction system pacing (CSP) improves outcomes in patients with symptomatic permanent atrial fibrillation (AF). Data on spontaneous sinus rhythm restoration (SSRR) in this setting are lacking. This study aimed to assess the incidence and the predictors of SSRR in a population of patients with permanent AF who underwent A&P with CSP. Prospective, observational study, enrolling consecutive patients with symptomatic permanent AF (of documented duration >6 months) and uncontrolled, drug-refractory high ventricular rate, who underwent A&P with CSP. The incidence and predictors of SSRR were prospectively assessed. A total of 107 patients (79.0 ± 9.1 years, 33.6% male, 74.8% with New York Heart Association class ≥III, 56.1% with ejection fraction <40%) were enrolled: 40 received His' bundle pacing, 67 left bundle branch area pacing. During a median follow-up of 12 months SSRR was observed in 14 patients (13.1%), occurring a median of 3 months after A&P (interquartile range 1 to 6; range 0 to 17). Multivariable analysis identified a duration of permanent AF <12 months (hazard ratio 7.7, p = 0.040) and a left atrial volume index <49 ml/m2 (hazard ratio 14.8, p = 0.008) as independent predictors of SSRR. In patients with coexistence of both predictors the incidence of SSRR was of 41.4%. In a population of patients with symptomatic, permanent AF, treated with A&P with CSP, SSRR was observed in 13% of patients during follow-up. A duration of permanent AF <12 months and a left atrial volume index <49 ml/m2 were independent predictors of this phenomenon.

Pacemaker and Atrioventricular Junction Ablation in Patients With Atrial Fibrillation—A Systematic Review of Systematic Review and Meta-Analysis

Background

Cardiac resynchronization therapy (CRT) could be considered for heart failure (HF) patients with atrial fibrillation (AF) unless a potent ventricular capture strategy is conducted. However, the benefit of a pacemaker (PM; as part of CRT) in patients with AF and whether atrioventricular junction (or nodal) ablation (AVAB) can improve the prognosis of these patients compared with those treated medically to support ventricular capture are unclear.

Methods and Results

Systematic reviews and meta-analyses investigating the roles of PMs and AVAB in patients with AF were obtained in a search of the PubMed, Embase, and Medline databases and then analyzed with respect to the following outcomes: mortality, left ventricular ejection fraction, and clinical findings including the New York Heart Association class, 6-min walk distance (6MWD), quality of life as assessed in a specific questionnaire, and response to CRT. The quality of the included reviews was assessed using the Assessing the Methodological Quality of Systematic Reviews 2 tool, which includes 16 items. This study was finally based on 13 systematic reviews or meta-analyses. The results showed that patients with AF have higher all-cause mortality rates compared with patients with sinus rhythm and that AVAB can reduce all-cause mortality in patients with AF. Although the functional improvement was better in sinus rhythm than in patients with AF, in the latter, AVAB increased the 6MWD and reduced the CRT nonresponse rate in patients with AF.

Conclusion

Atrial fibrillation is associated with a higher all-cause mortality rate in patients with CRT implantation. AVAB, by increasing the 6MWD and survival, can improve the prognosis of these patients.

Atrial fibrillation associated with heart failure treated by a 2-lead CRT-DX system (BIO-AffectDX): Study design and clinical protocol

Background

Evidence to support use of cardiac resynchronization therapy (CRT) among patients with both heart failure (HF) and atrial fibrillation (AF) is largely limited to retrospective or post hoc subanalyses. Data from a prospectively enrolled and contemporary cohort are needed.

Objective

We aim to better characterize the changes from baseline in HF patients with concomitant AF subsequently implanted with a 2-lead CRT-DX system capable of sensing in the atrium, aggregating diagnostics, and delivering CRT therapy. The primary objective of this study is to evaluate the percentage of all HF subjects with an improvement in a clinical composite score from pre-CRT implant to 12 months.

Methods

The study is a US-based, prospective, observational multicenter clinical trial conducted at up to 50 sites and enrolling approximately 400 subjects with a follow-up period of 1 year. Multiple subject assessments, atrial rhythm status, and device interrogation will be collected at follow-up visits occurring at 3, 6, and 12 months postimplant.

Results

A Clinical Events Committee will adjudicate subject HF events, arrhythmia events, death events, and all device-classified ventricular tachycardia and ventricular fibrillation episodes with treatment that are collected throughout the follow-up period. Their decisions are based on independent physician review of the data from sites and device interrogation.

Conclusion

The BIO-AffectDX study aims to provide further insight into the expected outcomes from CRT treatment in patients with HF and AF.

Cardiac resynchronization therapy defibrillators in patients with permanent atrial fibrillation

Aims

There are conflicting data on the benefit of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with permanent atrial fibrillation (AF). We aimed to compare patient outcomes according to the presence or absence of permanent AF at device implantation.

Methods and results

We retrospectively analysed remote monitoring data from 1141 CRT defibrillators. Propensity score with inverse‐probability weighting method was used to balance AF and sinus rhythm (SR) groups. Analysis endpoints included total mortality, appropriate defibrillation shocks, and CRT percentage. There were 229 patients (20.1%) in the AF group and 912 patients (79.9%) in the SR group. Compared with SR patients, AF patients were older (median age, 77 vs. 72 years, P < 0.001), more frequently male (82.5% vs. 75.5%, P = 0.02), and had higher heart rate (75.7 vs. 71.0 b.p.m., P < 0.001). Of the 229 AF patients, 162 (70.7%) received suboptimal CRT (<98%) and 67 (29.3%) had adequate CRT (≥98%). During a median follow‐up of 24 months, total mortality did not differ between AF and SR groups (propensity‐score‐weighted hazard ratio, HR 1.32 [95% confidence interval, 0.82–2.15], P = 0.25). The risk of appropriate shocks was significantly higher in the AF group with <98% CRT than in the SR group (weighted‐HR, 1.99 [1.21–3.26], P = 0.006) and was similar in the AF group with ≥98% CRT versus the SR group (1.29 [0.66–2.53], P = 0.45). During follow‐up, sinus rhythm was recovered in 23 patients in the AF group (10%) after a median time of 106 (42–256) days. The rate of sinus rhythm recovery in the AF group was 4.5 (95% CI, 2.8–6.7) per 100 patient‐years; the rate of permanent AF occurrence in the SR group was 2.5 (95% CI, 1.9–3.3) per 100 patient‐years.

Conclusions

Although mortality was similar across patient groups, patients with permanent AF and suboptimal CRT had twofold higher risk of appropriate shocks than SR patients or AF patients with CRT ≥ 98%.

Rationale and feasibility of the atrioventricular single-lead ICD systems with a floating atrial dipole (DX) in clinical practice

Cardiac implantable electronic devices establish proper therapy for the prevention of sudden cardiac death, significantly reducing the morbidity and mortality of patients with arrhythmias and heart failure. It is well-known that the number of electrodes increases the risk of complications. To preserve the benefit of atrial sensing without the need to implant an additional lead, a single-lead ICD system with a floating atrial dipole (DX ICD lead) has been developed. Besides all of the potential benefits, the necessity of a reliable and stable atrial sensing via the floating dipole could be the main concern against the use of this lead type. In the current generation of DX devices, the specially filtered atrial signal seems to be high enough and stable over time, which is crucial in the early detection of atrial arrhythmias, discrimination between different forms of tachycardias in order to prevent inappropriate ICD therapy, and achieving an optimal atrioventricular and interventricular synchrony in patients with a two-lead CRT-DX system. The present review summarizes the benefits and potential drawbacks of the DX ICD systems based on the available literature, furthermore, proposes an evidence-based algorithm of ICD type selection.

Predictors of rhythm outcomes after cardiac resynchronization therapy in atrial fibrillation patients: When should we use an atrial lead?

BACKGROUND

Cardiac resynchronization therapy (CRT) is widely used in atrial fibrillation (AF) patients and could impact rhythm stability.

HYPOTHESIS

We aimed to identify predictors of sinus rhythm (SR) stability or AF progression in a real-word cohort of CRT-AF patients.

METHODS

From 330 consecutive implantable cardioverter-defibrillator implantations due to ischemic or dilated cardiomyopathy, 65 (20%) patients with AF history (paroxysmal, n = 32) underwent a CRT implantation with an atrial electrode and were regularly followed every 4-6 months. Rhythm restoration was attempted for most AF patients based on symptoms, biventricular pacing (BP), and lack of thrombi.

RESULTS

After 33 months, 18 (28%) patients progressed to permanent mode switch (MS≥99%) and 20 (31%) patients had stable SR (MS < 1%). Logistic regression showed that history of persistent AF (OR: 8.01, 95%CI: 2.0-31.7, p = .003) is associated with higher risk of permanent MS. In persistent AF patients, a bigger left atrium (OR: 1.2 per mm, 95%CI: 1.03-1.4, p = .025) and older age (OR: 1.15 per life-year, 95%CI: 1.01-1.3, p = .032) were predictors of future permanent MS. Paroxysmal AF at implantation (OR: 5.96, 95%CI: 1.6-21.9, p = .007) and increased BP (OR: 1.4 per 1%, 95%CI: 1.05-1.89, p = .02) were associated with stable SR. In persistent AF patients, stable SR correlated with higher BP (98 ± 2 vs. 92 ± 8%, p < .001).

CONCLUSION

In patients with AF undergoing CRT implantation, persistent AF, LA dilatation and advanced age relate to future permanent MS (AF), whereas high BP promotes SR stability. These findings could facilitate the management of CRT-AF patients and guide therapy in order to maximize its effect on rhythm.

Clinical significance of left ventricular reverse remodeling after catheter ablation of atrial fibrillation in patients with left ventricular systolic dysfunction

BACKGROUND

Left ventricular (LV) reverse remodeling (LVRR) after catheter ablation of atrial fibrillation (AFCA) has not been fully described. This study investigated the predictors and clinical outcomes of LVRR after AFCA in patients with LV systolic dysfunction.

METHODS

Of 3319 consecutive patients who underwent first-time AFCA between January 2012 and October 2019, 376 with a baseline LV ejection fraction of <50% were retrospectively evaluated. They were subjected to 256-slice multidetector computed tomography (MDCT) scanning at baseline and 3 months after AFCA. The LVRR was defined as a decrease in the LV end-systolic volume of ≥15%.

RESULTS

The prevalence of LVRR was 83% (n = 306). Multivariate logistic regression analysis including age, body mass index, diabetic status, beta-blocker use, and LV diastolic diameter revealed that the predictors of LVRR were non-paroxysmal atrial fibrillation (AF) (odds ratio, 2.68; 95% confidence interval, 1.42-5.05; p = 0.002) and absence of apparent underlying structural heart disease (4.81; 2.31-10.0; p <0.001). The prevalence of LVRR differed depending on AF recurrence pattern prior to the post-MDCT [no episode vs. paroxysmal episode (lasting <7 days) vs. persistent episode (lasting ≥7 days), 84% vs. 81% vs. 63%, respectively, p = 0.023]. During a median follow-up of 32 months, the incidence of paroxysmal form of AF recurrence was similar, whereas persistent form of AF recurrence was less frequent in patients with LVRR (10.5% vs. 18.6%, p = 0.018). Heart failure hospitalizations (2.3% vs. 15.7%, p <0.001), cardiovascular deaths (0.7% vs. 4.3%, p = 0.015), and all-cause deaths (1.3% vs. 5.7%, p = 0.018) were similarly less frequent in those with LVRR.

CONCLUSIONS

LVRR after AFCA, which was predicted by non-paroxysmal AF without any apparent structural heart disease at baseline, was associated with persistent form of AF recurrence prior to the evaluation. LVRR was associated with favorable clinical outcomes.

Nonpharmacological Treatment of Atrial Fibrillation: What Is the Role of Device Therapy?

Atrial fibrillation is the most common arrhythmia in the adult population, and its incidence and prevalence are still rising. Cardiac devices are widely used in clinical practice in the management of various rhythm disturbances and heart failure treatment. Many patients who receive a pacemaker, implantable cardioverter-defibrillator, or cardiac resynchronization therapy also experience atrial fibrillation in the course of their life. Therefore, this review aims to describe the role of these devices in the treatment and prevention of atrial fibrillation in the device recipients. In addition, all these implantable devices also serve as permanent ECG (electrocardiogram) monitors, thus providing important information about the presence and characteristics of atrial fibrillation that may or may not be detected by the patient but can modify our therapeutical approach with regard to the stroke prevention.

Outcomes of cardiac resynchronisation therapy in patients with heart failure with atrial fibrillation: a systematic review and meta-analysis of observational studies

Background

Cardiac resynchronisation therapy (CRT) is beneficial in selected patients with heart failure (HF) in normal sinus rhythm (NSR). We sought to evaluate the impact of CRT with or without atrioventricular junction (AVJ) ablation in patients with HF with concomitant atrial fibrillation (AF).

Methods and results

Literature was searched (inception through 30 August 2017) for observational studies that reported outcomes in patients with HF with CRT and AF that reported all-cause and cardiovascular mortality. Thirty-one studies with 83, 571 patients were included. CRT did not decrease mortality compared with internal cardioverter defibrillator or medical therapy alone in patients with HF and AF with indications for CRT (OR: 0.851, 95% CI 0.616 to 1.176, p=0.328, I2=86.954). CRT-AF patients had significantly higher all-cause and cardiovascular mortality than CRT-NSR patients ([OR: 1.472, 95% CI 1.301 to 1.664, p=0.000] and [OR: 1.857, 95% CI 1.350 to 2.554, p=0.000] respectively). Change in left ventricular ejection fraction was not different between CRT patients with and without AF (p=0.705). AVJ ablation, however, improved all-cause mortality in CRT-AF patients when compared with CRT-AF patients without AVJ ablation (OR: 0.485, 95% CI 0.247 to 0.952, p=0.035). With AVJ ablation, there was no difference in all-cause mortality in CRT-AF patients compared with CRT-NSR patients (OR: 1.245, 95% CI 0.914 to 1.696, p=0.165).

Conclusion

The results of our meta-analysis suggest that AF was associated with decreased CRT benefits in patients with HF. CRT, however, benefits patients with AF with AVJ ablation.

Role of Atrioventricular Junctional Ablation and Cardiac Resynchronization Therapy in Patients with Chronic Atrial Fibrillation

There remains a great deal of uncertainty whether general application of cardiac resynchronization therapy (CRT) to patients with atrial fibrillation (AF) provides any benefit assuming all other eligibility criteria are met. Preliminary observations suggest that performing atrioventricular junction ablation can improve the results of CRT in patients with AF by rendering the patient pacemaker dependent. Ongoing randomized clinical trials may provide more definitive answers in the future.

Atrial Fibrillation in Patients with Heart Failure: Current State and Future Directions

Heart failure affects nearly 26 million people worldwide. Patients with heart failure are frequently affected with atrial fibrillation, and the interrelation between these pathologies is complex. Atrial fibrillation shares the same risk factors as heart failure. Moreover, it is associated with a higher-risk baseline clinical status and higher mortality rates in patients with heart failure. The mechanisms by which atrial fibrillation occurs in a failing heart are incompletely understood, but animal studies suggest they differ from those that occur in a healthy heart. Data suggest that heart failure-induced atrial fibrosis and atrial ionic remodeling are the underlying abnormalities that facilitate atrial fibrillation. Therapeutic considerations for atrial fibrillation in patients with heart failure include risk factor modification and guideline-directed medical therapy, anticoagulation, rate control, and rhythm control. As recommended for atrial fibrillation in the non-failing heart, anticoagulation in patients with heart failure should be guided by a careful estimation of the risk of embolic events versus the risk of hemorrhagic episodes. The decision whether to target a rate-control or rhythm-control strategy is an evolving aspect of management. Currently, both approaches are good medical practice, but recent data suggest that rhythm control, particularly when achieved through catheter ablation, is associated with improved outcomes. A promising field of research is the application of neurohormonal modulation to prevent the creation of the "structural substrate" for atrial fibrillation in the failing heart.

Development of Heart Failure From Transient Atrial Fibrillation Attacks in Responders to Cardiac Resynchronization Therapy

OBJECTIVES

This study aimed to clarify the clinical impact of transient atrial fibrillation (AF) attacks themselves and the efficacy of cardiac resynchronization therapy (CRT) in patients with intermittent AF.

BACKGROUND

The benefit of CRT in patients with intermittent AF, especially the effect of the AF attacks themselves, remains unclear.

METHODS

Among our cohort of 269 consecutive CRT patients, we compared the percent of biventricular pacing (BIVP%) and other clinical characteristics between patients with intermittent AF and those with sinus rhythm (SR).

RESULTS

During a median follow-up of 942 days (interquartile range: 379 to 1,464 days) a total of 22 patients, including 59% of CRT responders, developed heart failure (HF) due to a transient AF attack itself, and that accounted for 21% of all HF events. The BIVP% during the AF attacks was significantly lower than that during SR (p < 0.05). When compared to the SR groups, patients with intermittent AF had a significantly higher risk of developing HF or death (hazard ratio: 2.2; 95% confidence interval: 1.3 to 3.8). However, the patients who received a BIVP% of ≥90% during AF attacks were comparable to those with SR (hazard ratio: 1.2; 95% confidence interval: 0.4 to 3.0).

CONCLUSIONS

A substantial number of patients developed HF due to transient AF attacks themselves even in the CRT responders, and the reason was mainly due to the loss of the BIVP%.

Atrioventricular junction ablation in patients with atrial fibrillation treated with cardiac resynchronization therapy: positive impact on ventricular arrhythmias, implantable cardioverter-defibrillator therapies and hospitalizations

AIMS

We sought to determine whether atrioventricular junction ablation (AVJA) in patients with cardiac resynchronization therapy (CRT) implantable cardioverter-defibrillator (ICD) and with permanent atrial fibrillation (AF) has a positive impact on ICD shocks and hospitalizations compared with rate-slowing drugs.

METHODS AND RESULTS

This is a pooled analysis of data from 179 international centres participating in two randomized trials and one prospective observational research. The co-primary endpoints were all-cause ICD shocks and all-cause hospitalizations. Out of 3358 CRT-ICD patients (2720 male, 66.6 years), 2694 (80%) were in sinus rhythm (SR) and 664 (20%) had permanent AF-262 (8%) treated with AVJA (AF + AVJA) and 402 (12%) treated with rate-slowing drugs (AF + Drugs). Median follow-up was 18 months. The mean (95% confidence intervals) annual rate of all-cause ICD shocks per 100 patient years was 8.0 (5.3-11.9) in AF + AVJA, 43.6 (37.7-50.4) in AF + Drugs, and 34.4 (32.5-36.5) in SR patients, resulting in incidence rate ratio (IRR) reductions of 0.18 (0.10-0.32) for AF + AVJA vs. AF + Drugs (P < 0.001) and 0.48 (0.35-0.66) for AF + AVJA vs. SR (P < 0.001). These reductions were driven by significant reductions in both appropriate ICD shocks [IRR 0.23 (0.13-0.40), P < 0.001, vs. AF + Drugs] and inappropriate ICD shocks [IRR 0.09 (0.04-0.21), P < 0.001, vs. AF + Drugs]. Annual rate of all-cause hospitalizations was significantly lower in AF + AVJA vs. AF + Drugs [IRR 0.57 (0.41-0.79), P < 0.001] and SR [IRR 0.85 (073-0.98), P = 0.027].

CONCLUSION

In AF patients treated with CRT, AVJA results in a lower incidence and burden of all-cause, appropriate and inappropriate ICD shocks, as well as to fewer all-cause and heart failure hospitalizations.

CLINICAL TRIAL REGISTRATION

NCT00147290, NCT00617175, NCT01007474.

Atrial fibrillation and cardiac resynchronization therapy

PURPOSE OF REVIEW

Atrial fibrillation and heart failure are commonly encountered in current clinical practice. This review aims to revisit the complex interaction of these two common situations and the best treatment whenever both occurs, especially focusing on heart failure patients undergoing cardiac resynchronization therapy (CRT).

RECENT FINDINGS

It has been recently confirmed that in patients undergoing cardiac resynchronization therapy, 100% biventricular pacing percentage should be pursued. Large observational studies confirmed that atrioventricular junction ablation is very often the only way to gain 100% biventricular pacing in atrial fibrillation.

SUMMARY

On the basis of the recent observational extensive data, in patients presenting intermediate or elevated atrial tachycardia-atrial fibrillation burden, atrioventricular junction ablation may represent a fundamental tool to achieve full CRT delivery, thus, conferring marked improvements in global cardiac function, and by extension, in survival. Atrial fibrillation patients should not be excluded from CRT, provided that maximal biventricular pacing is warranted.

Comparative Effectiveness of Cardiac Resynchronization Therapy Among Patients With Heart Failure and Atrial Fibrillation: Findings From the National Cardiovascular Data Registry's Implantable Cardioverter-Defibrillator Registry

BACKGROUND

Atrial fibrillation is common in patients with heart failure, but outcomes of patients with both conditions who receive cardiac resynchronization therapy with defibrillator (CRT-D) compared with an implantable cardioverter-defibrillator (ICD) alone are unclear.

METHODS AND RESULTS

Using the National Cardiovascular Data Registry's ICD Registry linked with Medicare claims, we identified 8951 patients with atrial fibrillation who were eligible for CRT-D and underwent first-time device implantation for primary prevention between April 2006 and December 2009. We used Cox proportional hazards models and inverse probability-weighted estimates to compare outcomes with CRT-D versus ICD alone. Cumulative incidence of mortality (744 [33%] for ICD; 1893 [32%] for CRT-D) and readmission (1788 [76%] for ICD; 4611 [76%] for CRT-D) within 3 years and complications within 90 days were similar between groups. After inverse weighting for the probability of receiving CRT-D, risks of mortality (hazard ratio, 0.83; 95% confidence interval, 0.75-0.92), all-cause readmission (hazard ratio, 0.86; 95% confidence interval, 0.80-0.92), and heart failure readmission (hazard ratio, 0.68; 95% confidence interval, 0.62-0.76) were lower with CRT-D compared with ICD alone. There was no significant difference in the 90-day complication rate (hazard ratio, 0.88; 95% confidence interval, 0.60-1.29). We observed hospital-level variation in the use of CRT-D among patients with atrial fibrillation.

CONCLUSIONS

Among eligible patients with heart failure and atrial fibrillation, CRT-D was associated with lower risks of mortality, all-cause readmission, and heart failure readmission, as well as with a similar risk of complications compared with ICD alone.

Management of Patients with Atrial Fibrillation: Focus on Treatment Options

Atrial fibrillation (AF) is leading cardiac arrhythmia with important clinical implications. Its diagnosis is usually made on the basis on 12-lead ECG or 24-hour Holter monitoring. More and more clinical evidence supports diagnostic use of cardiac event recorders and cardiovascular implantable electronic devices (CIED). Treatment options in patients with atrial fibrillation are extensive and are based on chosen rhythm and/or rate control strategy. The use and selected contraindications to AF related pharmacotherapy, including anticoagulants are shown. Nonpharmacological treatments, comorbidities and risk factors control remain mainstay in the treatment of patients with AF. Electrical cardioversion consists important choice in rhythm control strategy. Much progress has been made in the field of catheter ablation and cardiac surgery methods. Left atrial appendage occlusion/closure may be beneficial in patients with AF. CIED are used with clinical benefits in both, rhythm and rate control. Pacemakers, implantable cardioverter-defibrillators and cardiac resynchronization therapy devices with different pacing modes have guaranteed place in the treatment of patients with AF. On the other hand, the concepts of permanent leadless cardiac pacing, atrial dyssynchrony syndrome treatment and His-bundle or para-Hisian pacing have been proposed. This review summarizes and discusses current and novel treatment options in patients with atrial fibrillation.

Atrioventricular Node Ablation

Cardiac resynchronization therapy (CRT) is a device-based, nonpharmacologic approach that has shown to improve the outcome in patients with heart failure in terms of mortality and morbidity reduction. Large randomized trials have virtually enrolled patients in New York Heart Association class III-IV, with reduced left ventricular ejection fraction, with evidence of electrical dyssynchrony, and receiving optimal medical therapy and who were in sinus rhythm. Guidelines remain imprecise as to defining differentiated approaches according to the forms of atrial fibrillation other than permanent. These recommendations remain unsupported by evidence derived from randomized controlled trials, which are much needed.

Cardiac Resynchronization in Patients with Atrial Fibrillation

Atrial fibrillation (AF) occurs in one of four patients undergoing cardiac resynchronization therapy (CRT).-Without special therapy, the prognosis of AF patients with CRT has been generally worse than those in sinus rhythm. The importance of a high percentage of biventricular pacing (BIV%) was confirmed in a large study where the mortality was inversely associated with BIV% both in the presence of normal sinus and atrial paced rhythm and with AF. The greatest reduction in mortality was observed with BIV% >98%. Patients with BIV% >99.6% experienced a 24% reduction in mortality (p < 0.001) while those with BIV% <94.8% had a 19% increase in mortality. The optimal BIV% cut-point was 98.7%. This cutoff would appear mandatory but it would be best to approach 100%. Careful evaluation of device interrogation data upon which the BiV% is based is essential because the memorized data can vastly overestimate the percentage of truly resynchronized beats since it does not account for fusion and pseudofusion between intrinsic (not paced) and paced beats. The recently published randomized CERTIFY trial provides unequivocal proof of the value of AV junctional (AVJ) ablation in CRT patients with AF. This trial confirmed the favorable results of AVJ ablation by many other studies and two important meta-analyses and therefore established the firm recommendation that the procedure should be performed in most, if not all, patients with permanent AF as well as those with frequent and prolonged episodes of paroxysmal AF. Patients after AVJ have improved mortality with a mortality similar to those in sinus rhythm. The AVJ ablation procedure carries the theoretical risk of device failure and death in pacemaker dependent patients. An inappropriate first ICD shock for AF seems to increase mortality. Increased long-term mortality after an inappropriate shock may be due to the underlying atrial arrhythmia substrate as opposed to the effect of the shock itself.

Atrioventricular Node Ablation

Cardiac resynchronization therapy (CRT) is a device-based, nonpharmacologic approach that has shown to improve the outcome in patients with heart failure in terms of mortality and morbidity reduction. Large randomized trials have virtually enrolled patients in New York Heart Association class III-IV, with reduced left ventricular ejection fraction, with evidence of electrical dyssynchrony, and receiving optimal medical therapy and who were in sinus rhythm. Guidelines remain imprecise as to defining differentiated approaches according to the forms of atrial fibrillation other than permanent. These recommendations remain unsupported by evidence derived from randomized controlled trials, which are much needed.

The changing landscape of cardiac pacing

A number of trials have shown that irrespective of baseline QRS duration, left ventricular (LV) dysfunction and heart failure are more common in patients with right ventricular (RV) than in those with biventricular (BiV) pacing. By contrast, preliminary results of the BIOPACE trial (follow-up 5.6 years) yielded a disappointing comparison of RV vs. BiV pacing. Pacemaker-induced cardiomyopathy (PIC) may occur in patients with normal and abnormal LV ejection fractions (LVEF) and tends to occur if there is RV pacing more than 40 % of the time. Yet, some pacemaker-dependent patients do not develop LV dysfunction. PIC can be improved in about two thirds of patients by upgrading to a BiV system and the results are comparable to de novo BiV pacing in patients with a wide QRS complex. The findings of the BLOCK HF trial (2013) suggested that patients requiring pacing virtually 100 % of the time might benefit from BiV pacing irrespective of the LVEF (< 50 %), manifestations of heart failure, QRS duration, or functional class. These characteristics would generate many patients for BiV pacing. However, these recommendations should now be weighed against a more conservative approach based on the recently announced results of the BIOPACE trial. Organizational guidelines recommend BiV pacing for bradycardia irrespective of QRS duration for patients with LVEF < 35 %. At this time, BiV pacing for antibradycardia therapy (irrespective of QRS duration) has to be individualized in the setting of a normal or decreased LVEF (> 35 %) and according to the expected percentage of RV pacing. The benefit of BiV pacing should be considered against procedural complications, which are more frequent than with traditional RV pacing.

Comparison of the rhythm control treatment strategy versus the rate control strategy in patients with permanent or long-standing persistent atrial fibrillation and heart failure treated with cardiac resynchronization therapy - a pilot study of Cardiac Resynchronization in Atrial Fibrillation Trial (Pilot-CRAfT): study protocol for a randomized controlled trial

BACKGROUND

The only subgroups of patients with heart failure and atrial fibrillation in which the efficacy of cardiac resynchronization therapy has been scientifically proven are patients with indications for right ventricular pacing and patients after atrioventricular junction ablation. However it is unlikely that atrioventricular junction ablation would be a standard procedure in the majority of the heart failure patients with cardiac resynchronization therapy and concomitant atrial fibrillation due to the irreversible character of the procedure and a spontaneous sinus rhythm resumption that occurs in about 10% of these patients.

METHODS/DESIGN

Pilot-CRAfT is the first randomized controlled trial evaluating the efficacy of a rhythm control strategy in atrial fibrillation patients with cardiac resynchronization therapy devices. The aim of this prospective, single center randomized controlled pilot study is to answer the question whether the patients with cardiac resynchronization therapy and permanent atrial fibrillation would benefit from a strategy to restore and maintain sinus rhythm (that is 'rhythm control' strategy) in comparison to rate control strategy. The study population consists of 60 patients with heart failure and concomitant long-standing persistent or permanent atrial fibrillation who underwent a cardiac resynchronization therapy device implantation at least 3 months before qualification. Study participants are randomly assigned to the rhythm control strategy (including electrical cardioversion and pharmacotherapy) or to the rate control group whose goal is to control ventricular rate. The follow-up time is 12 months. The primary endpoint is the ratio of effectively captured biventricular beats. The secondary endpoints include peak oxygen consumption, six-minute walk test distance, heart failure symptom escalation, reverse remodelling of the heart on echo and quality of life.

TRIAL REGISTRATION

NCT01850277 registered on 22 April 2013 (ClinicalTrials.gov).

Combined management of atrial fibrillation and heart failure: case studies

Atrial fibrillation (AF) and heart failure (HF) are omnipresent cardiovascular disorders with a substantial impact on morbidity and mortality. As both share common risk factors, their pathophysiology is highly interrelated and a lot of patients present with both conditions. Surprisingly, despite their high prevalence, there is a paucity of evidence regarding the optimal combined management of AF and HF. The initial treatment for new-onset AF in the context of HF should focus on anticoagulation, rate control and prompt electrical cardioversion in case of hemodynamic instability. Subsequently, attention should focus upon the underlying pathophysiological substrate. This often requires multidisciplinary collaboration, not only between different subspecialties of cardiology, but also among medical and paramedical caregivers, especially when underlying HF is present. AF often contributes to worsening HF symptoms, but options to maintain sinus rhythm are less successful in patients with structural heart disease. Therefore, rhythm control strategies, whether medical or through catheter/surgical ablation, should target specific groups of patients with a high likelihood of perceived benefit. Indeed, morbidity and mortality are similar with rate versus rhythm control in the general population. Carefully performed cardiac imaging is vital to select these cases that might benefit most from rhythm control. A special group of HF patients are the one with cardiac devices, as they can be continuously monitored, even through remote care systems. The latter likely involves dedicated nurse practitioners and general physicians. Again, a collaborative environment with a disease management strategy is needed to ensure an optimally working device and maximized benefits for the patient.

Is cardiac resynchronization therapy an antiarrhythmic therapy for atrial fibrillation? A systematic review and meta-analysis

The impact of cardiac resynchronization therapy (CRT) on atrial fibrillation (AF) burden is poorly characterized. To assess the influence of CRT on AF, we performed a systematic literature search in MEDLINE using the MeSH headings "cardiac resynchronization therapy" or "cardiac pacing, artificial" and "atrial fibrillation." Selected studies were peer-reviewed and written in English. Most studies enrolled patients meeting traditional CRT criteria. Ten observational studies and two secondary analyses of clinical trials were identified. Although ten studies suggest that CRT favorably impacts AF, one secondary analysis of a clinical trial showed no effect of CRT on new-onset AF. In a meta-analysis of three studies examining the effect of CRT on persistent or permanent AF, the combined rate of conversion from persistent or permanent AF to sinus rhythm was 0.107 (95 % confidence interval 0.069-0.163). Prospective studies, particularly among patients not meeting traditional CRT criteria, are needed.

Optimizing cardiac resynchronization therapy for congestive heart failure

In patients with advanced systolic heart failure and mechanical dyssynchrony, cardiac resynchronization therapy (CRT) is an effective means of improving symptoms and reducing mortality. There are now several recognized approaches to optimize CRT. Imaging modalities can assist with identifying the myocardium with the latest mechanical activation for targeted left ventricular lead implantation. Device programming can be tailored to maximize biventricular pacing, and thereby is its benefit. Cardiac imaging has shown that atrioventricular and interventricular intervals can be adjusted to further reduce dyssynchrony. We review these various approaches that maximize the benefit derived from CRT.

Management strategies in atrial fibrillation in patients with heart failure

Atrial fibrillation (AF) and heart failure (HF) frequently occur together, and their coexistence is associated with a poor prognosis. AF and HF share risk factors, but their relationship involves complex hemodynamic, neurohormonal, inflammatory, ultrastructural, and electrophysiologic processes that extend beyond epidemiological associations. The shared mechanisms underlying AF and HF have important implications for the treatment of AF in patients with HF. This article focuses on reviewing contemporary data as it pertains to AF management in patients with HF and provides insight into investigational therapies currently under development.

Feasibility and efficacy of electrical cardioversion after cardiac resynchronization implantation in patients with permanent atrial fibrillation

PURPOSE

Patients with permanent atrial fibrillation (AF) who undergo cardiac resynchronization therapy (CRT) may spontaneously recover sinus rhythm during follow-up. We tested the feasibility and efficacy of electrical cardioversion attempted after 3 months of CRT in patients with permanent AF and measured the long-term maintenance of sinus rhythm.

METHODS

Twenty-eight consecutive patients with permanent AF in whom CRT defibrillators had been implanted were scheduled for internal electrical cardioversion after 3 months (group A) and were compared with a control group of 27 patients (group B).

RESULTS

In group A, 22 patients (79 %) were eligible for cardioversion; sinus rhythm was restored in 18 (82 %) of these, with no procedural complications. After 12 months, 16 patients (58 %) in group A were in sinus rhythm, compared with one group B patient who spontaneously recovered sinus rhythm (4 %, p < 0.001). On 12-month evaluation, ejection fraction had improved in both groups, but a reduction in left ventricular end-systolic volume was recorded only in group A patients (p = 0.018 versus baseline).

CONCLUSIONS

In patients with permanent AF, the rhythm control strategy consisting of internal cardioversion, performed by means of the implanted cardioverter-defibrillator after 3 months of CRT, was associated with a high rate of sinus rhythm resumption on long-term follow-up and with a better echocardiographic response to CRT than that seen in patients treated according to a rate control strategy.