Rate control in atrial fibrillation: choice of treatment and assessment of efficacy

Use of Diltiazem in Chronic Rate Control for Atrial Fibrillation: A Prospective Case-Control Study

Atrial fibrillation (AF) is a multifaceted disease requiring personalised treatment. The aim of our study was to explore the prognostic impact of a patient-specific therapy (PT) for rate control, including the use of non-dihydropyridine calcium channel blockers (NDDC) in patients with heart failure (HF) or in combination with beta-blockers (BB), compared to standard rate control therapy (ST), as defined by previous ESC guidelines. This is a single-centre prospective observational registry on AF patients who were followed by our University Hospital. We included 1112 patients on an exclusive rate control treatment. The PT group consisted of 125 (11.2%) patients, 93/125 (74.4%) of whom were prescribed BB + NDCC (±digoxin), while 85/125 (68.0%) were HF patients who were prescribed NDCC, which was diltiazem in all cases. The patients treated with a PT showed no difference in one-year overall survival compared to those with an ST. Notably, the patients with HF in ST had a worse prognosis (p < 0.001). To better define this finding, we performed three sensitivity analyses by matching each patient in the PT subgroups with three subjects from the ST cohort, showing an improved one-year survival of the HF patients treated with PT (p = 0.039). Our results suggest a potential outcome benefit of NDCC for rate control in AF patients, either alone or in combination with BB and in selected patients with HF.

Personalizing configuration for atrial fibrillation external electrical cardioversion to improve first shock efficacy

BACKGROUND

Despite the common use of biphasic electrical cardioversion (ECV) to convert atrial fibrillation (AF), we lack definite recommendations on electrode configuration.

METHODS

We adopted a quasi-experimental design enrolling all candidates to ECV for AF. In the first stage, two units were involved, one using antero-apical pads (AAP) and the second antero-posterior adhesive patches (APP). These data enabled the creation of a decision algorithm to personalize the ECV approach, which was subsequently validated during the second stage.

RESULTS

A total of 492 patients were enrolled overall. In the first stage, APP and AAP presented similar conversion rates (87.4 vs. 86.9% at first attempt of a step-up protocol, P = 0.661). While body surface area (BSA) ≤2.12 m2 was an independent predictor in the overall population, the two components (height and weight) acted differently in the two configurations: being height ≤1.73 m2 a significant cut-off value in the AAP subgroup, and weight <83 kg in the APP subgroup. Considering these cut-offs, we developed a decision algorithm for electrode configuration. In the second stage, algorithm validation confirmed an improvement in the first shock efficacy with respect to the results of the first stage (93.2 vs. 87.2%, P = 0.025), with a significant reduction in shock impedance (70.8 ± 15.3 vs. 81.8 ± 15.6, P < 0.001).

CONCLUSION

Patients with high BSA require high energy shocks for sinus rhythm restoration with ECV. Weight seems to affect more APP configuration, while height seems to impact more for the AAP. These findings have the potential to optimize ECV in clinical practice.

Gene and Cell Therapy for Cardiac Arrhythmias

PURPOSE

In the last decade, interest in gene therapy as a therapeutic technology has increased, largely driven by an exciting yet modest number of successful applications for monogenic diseases. Setbacks in the use of gene therapy for cardiac disease have motivated efforts to develop vectors with enhanced tropism for the heart and more efficient delivery methods. Although monogenic diseases are the logical target, cardiac arrhythmias represent a group of conditions amenable to gene therapy because of focal targets (biological pacemakers, nodal conduction, or stem cell-related arrhythmias) or bystander effects on cells not directly transduced because of electrical coupling.

METHODS

This review provides a contemporary narrative of the field of gene therapy for experimental cardiac arrhythmias, including those associated with stem cell transplant. Recent articles published in the English language and available through the PubMed database and other prominent literature are discussed.

FINDINGS

The promise of gene therapy has been realized for a handful of monogenic diseases and is actively being pursued for cardiac applications in preclinical models. With improved vectors, it is likely that cardiac disease will also benefit from this technology. Cardiac arrhythmias, whether inherited or acquired, are a group of conditions with a potentially lower threshold for phenotypic correction and as such hold unique potential as targets for cardiac gene therapy.

IMPLICATIONS

There has been a proliferation of research on the potential of gene therapy for cardiac arrhythmias. This body of investigation forms a strong basis on which further developments, particularly with viral vectors, are likely to help this technology progress along its translational trajectory.

Home care for heart failure: can caregiver education prevent hospital admissions? A randomized trial in primary care

AIM

To assess the feasibility and effectiveness of a low-complexity, low-cost model of caregiver education in primary care, targeted to reduce hospitalizations of heart failure patients.

METHODS

A cluster-randomized, controlled, open trial was proposed to general practitioners, who were invited to identify patients with heart failure, exclusively managed at home and continuously attended by a caregiver. Participating general practitioners were then randomized to: usual treatment; caregiver education (educational session for recognizing early symptoms/signs of heart failure, with recording in a diary of a series of patient parameters, including body weight, blood pressure, heart rate). The patients were observed at baseline and during a 12-month follow-up.

RESULTS

Three hundred and thirteen patients were enrolled (163 in the intervention, 150 in the usual care group), 63% women, mean age 85.3 ± 7.7 years. At the end of the 12-month follow-up, a trend towards a lower incidence of hospitalizations was observed in the intervention group (hazard ratio 0.73; 95% CI 0.53-1.01 P = 0.061). Subgroup analysis showed that for patients with persistent/permanent atrial fibrillation, age less than 90 years or Barthel score equal to or greater than 50 a significant lower hospital admission rate occurred in the intervention group (hazard ratio 0.63; 95% CI 0.39-0.99; P = 0.048, hazard ratio 0.66; 95% CI 0.45-0.97; P = 0.036 and hazard ratio 0.61; 95% CI 0.41-0.89; P = 0.011, respectively).

CONCLUSION

Caregivers training for early recognition of symptoms/signs of worsening heart failure may be effective in reducing hospitalizations, although the benefit was evident only in specific patient subgroups (with persistent/permanent atrial fibrillation, age <90 years or Barthel score ≥ 50), with only a positive trend in the whole cohort.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03389841.

New-onset atrial fibrillation: an update

New-onset atrial fibrillation (NOAF) is the most common perioperative complication of heart surgery, typically occurring in the perioperative period. NOAF commonly occurs in patients who are elderly, or have left atrial enlargement, or left ventricular hypertrophy. Various factors have been identified as being involved in the development of NOAF, and numerous approaches have been proposed for its prevention and treatment. Risk factors include diabetes, obesity, and metabolic syndrome. For prevention of NOAF, β-blockers and amiodarone are particularly effective and are recommended by guidelines. NOAF can be treated by rhythm/rate control, and antithrombotic therapy. Treatment is required in patients with decreased cardiac function, a heart rate exceeding 130 beats/min, or persistent NOAF lasting for ≥ 48 h. It is anticipated that anticoagulant therapies, as well as hemodynamic management, will also play a major role in the management of NOAF. When using warfarin as an anticoagulant, its dose should be adjusted based on PT-INR. PT-INR should be controlled between 2.0 and 3.0 in patients aged < 70 years and between 1.6 and 2.6 in those aged ≥ 70 years. Rate control combined with antithrombotic therapies for NOAF is expected to contribute to further advances in treatment and improvement of survival.

Atrial fibrillation burden and atrial fibrillation type: Clinical significance and impact on the risk of stroke and decision making for long-term anticoagulation

Atrial fibrillation (AF) is a common arrhythmia increasing the risk of morbidity and adverse outcomes (stroke, heart failure, death). AF is found in 1-2% of the general population, with increasing prevalence with aging. Its exact epidemiological profile is incomplete and underestimated, because 10-40% of AF patients (particularly the elderly) can be asymptomatic ("clinically silent or subclinical AF"), with occasional electrocardiographic diagnosis. The research interest on silent AF has increased by the evidence that its outcome is no less severe, in terms of risks of stroke and death, than that for symptomatic patients. Data collected from more than 18,000 patients indicate that cardiac implantable electrical devices (CIEDs) are validated tools for detecting silent AF and measuring the time spent in AF, defined as "AF burden." A maximum daily AF burden of ≥5-6min, but particularly ≥1h, is associated with a significant increase in the risk of stroke, and may be clinically relevant to improve current risk stratification based on risk scores and for "personalizing" prescription of oral anticoagulants. An in-depth study of the temporal relationship between AF and ischemic stroke showed that data from CIEDs reveal a complex scenario, by which AF is certainly a risk factor for cardioembolic stroke, with a cause-effect relationship related to atrial thrombi, but can also be a simple "marker of risk," with a noncausal association with stroke. In such cases, stroke is possibly related to atheroemboli from the aorta, the carotid arteries, or other sources.

Beta-blockers or Digoxin for Atrial Fibrillation and Heart Failure?

In patients with atrial fibrillation (AF) and heart failure (HF) with or without systolic dysfunction, either rhythm control or rate control is an acceptable primary therapeutic option. If a rate control strategy is chosen, treatment with a beta-blocker is almost always required to achieve rate control. Adequate ventricular rate control is usually a resting rate of less than 100 beats per minute, but lower resting rates may be appropriate. Non-dihydropyridine calcium channel blockers are often contraindicated when AF is associated with HF with systolic dysfunction. There have been recent debates on a possible reduced efficacy of beta-blockers as well as safety issues with digoxin when treating HF patients with AF. The benefit of beta-blockers on survival may be lower in patients with HF with reduced ejection fraction when AF is present. Digoxin does not improve survival but may help to obtain satisfactory rate control in combination with a beta-blocker. Digoxin may be useful in the presence of hypotension or an absolute contraindication to beta-blocker treatment.

The Use of Gene Therapy for Ablation of Atrial Fibrillation

Atrial fibrillation is the most common clinically significant cardiac arrhythmia, increasing the risk of stroke, heart failure and morbidity and mortality. Current therapies, including rate control and rhythm control by antiarrhythmic drugs or ablation therapy, are moderately effective but far from optimal. Gene therapy has the potential to become an attractive alternative to currently available therapies for atrial fibrillation. Various gene transfer vectors have been developed for cardiovascular disease with viral vectors being most widely used due to their high efficiency. Several gene delivery methods have been employed on different therapeutic targets. With increasing understanding of arrhythmia mechanisms, novel therapeutic targets have been discovered. This review will evaluate state-of-art gene therapy strategies and approaches including sinus rhythm restoration and ventricular rate control that could eventually prevent or eliminate atrial fibrillation in patients.

AF burden is important - fact or fiction?

Asymptomatic atrial fibrillation (AF) is common and in view of its prognostic impact (the same as of clinically overt AF) knowledge of the overall AF burden (defined as the amount of time spent in AF) appears to be important, both for scientific and clinical reasons. Data collected on more than 12,000 patients indicate that cardiac implantable electrical devices (CIEDs) are validated tools for measuring AF burden and that AF burden is associated with an increased risk of stroke. A maximum daily AF burden of ≥ 1 h carries important negative prognostic implications and may be a clinically relevant parameter for improving risk stratification for stroke. Decision-making should primarily consider the context in which asymptomatic, subclinical arrhythmias are detected (i.e. primary or secondary prevention of stroke and systemic embolism) and the risk profile of every individual patient with regard to thromboembolic and haemorrhagic risk, as well as patient preferences and values. Continuous monitoring using CIEDs with extensive data storage capabilities allow in-depth study of the temporal relationship between AF and ischaemic stroke. The relationships between AF and stroke are complex. AF is certainly a risk factor for cardioembolic stroke, with a cause-effect relationship between the arrhythmia and a thromboembolic event, the latter being related to atrial thrombi. However, AF can also be a simple 'marker of risk', with a non-causal association between the arrhythmia and stroke, the latter being possibly related to atheroemboli from the aorta, the carotid arteries or from other sources.

New approaches to atrial fibrillation management: treat the patient, not the ECG

Atrial fibrillation causes a significant burden on patients and the health care system. The main goals of atrial fibrillation therapy are to improve symptoms and reduce morbidity. There have been significant recent developments in both stoke prophylaxis and rhythm/rate control. The results of the ACTIVE W study emphasize the importance of effective oral anticoagulant therapy in patients with moderate-to-high risk for stroke. The RE-LY study showed superiority of dabigatran, an oral direct thrombin inhibitor, over warfarin in the prevention of stroke, or systemic embolism. Dronedarone, a new antiarrhythmic drug with multiple class effects, has been recently approved by the US Food and Drug Administration for the treatment of atrial fibrillation. Dronedarone has moderate rhythm and rate control efficacy; however, dronedarone significantly reduced cardiovascular hospitalization, cardiovascular death, and stroke in the large ATHENA trial. There is also an important shift in the paradigm of the goals of atrial fibrillation therapy. Instead of focusing solely on the electrocardiographic outcomes of treatment and considering "rhythm versus rate control," one needs to consider "symptom control" as well as patient well-being. This review will suggest that patient based outcomes rather than ECG-based outcomes should be the primary goals of treatment. Original reports and reviews on specific topics were identified through Medline. Randomized controlled trials were selected as the primary source of information. Analysis included critical review of the evidence available to date.

Pharmacotherapy of atrial fibrillation: an old option with new possibilities

BACKGROUND

Atrial fibrillation is the most common sustained arrhythmia observed worldwide. Despite modern ablative treatment options, pharmacotherapy remains the first-line therapy in patients with atrial fibrillation.

OBJECTIVE

Based on recently published guidelines for the management of atrial fibrillation, the present paper reviews the current and emerging concepts of pharmacotherapy in atrial fibrillation.

METHODS

A MEDLINE search was conducted using the keyword 'atrial fibrillation' and 'drug therapy'. The reviewed literature included clinical trials and published reviews as well as clinical guidelines.

RESULTS

The mainstay of atrial fibrillation therapy is the prevention of thromboembolic events. With growing knowledge of the pathophysiology of atrial fibrillation new drug targets have been identified that promise improved outcomes in atrial fibrillation management and this will allow individual drug treatment in the near future.

Thoracoscopic microwave ablation of atrial fibrillation

The aim of the study was to assess the safety and efficacy of thoracoscopic microwave ablation in treating atrial fibrillation (AF). AF predisposes to embolic complications and may cause heart failure. The treatment of AF is still challenging in spite of the promising results of endocardial radiofrequency approach. The present study is a follow-up study of 22 patients (mean age 45 years, range 21-59) with disabling paroxysmal (n=10) or persistent (n=12) AF who underwent a thoracoscopic microwave isolation of pulmonary veins. The patients had a lone AF. All the patients had suffered from severely disabling AF for >1 year (range 1-16 years) without any response to antiarrhythmic medication. The patients have been followed-up on an average of 11 months (range 3-22 months). During the follow-up, 13 (60%) patients have become asymptomatic without any documentation of AF since at least two months, six (27%) patients with anti-arrhythmic medication have clinically improved. Because of major intrathoracic bleeding and because of liver damage the thoracoscopy wound had to be expanded to open thoracotomy in two patients. Thoracoscopic AF microwave ablation seems to be a promising alternative to endocardial ablation in the treatment of highly symptomatic paroxysmal and persistent AF.

Rate control in patients with pacemaker affected by brady-tachy form of sick sinus syndrome

BACKGROUND

In sinus node disease (SND) atrial tachyarrhythmias (ATs) may frequently occur, after implant of a pacemaker for bradycardia, and are to be managed by rate or rhythm control.

METHODS

We evaluated ventricular heart rate (HR) during AT, AT-related symptoms and hospitalizations in 333 patients who received DDDRP pacemakers for SND.

RESULTS

In days with 24 hours of AT, mean daily HR during AT was > 80, 90, 100, 110, and 120 beats per minute (bpm) in 191 (57%), 114 (34%), 55 (16%), 23 (7%), and 11 (3%) patients, respectively. The proportion of patients with a mean daily HR > 80 bpm during AT despite the use of rate control agents was 28% among patients treated with calcium-channel blockers, 43% with digoxin, 49% with a combination of agents, 54% with amiodarone, 64% with sotalol, and 69% with beta blockers. Patients with HR > 100 bpm experienced a higher prevalence of both AT-related hospitalizations and cardiovascular hospitalizations than those with HR < or = 100 bpm (36% vs 21%, P = .013; 42% vs 28%, P = .003) and a significantly higher number of AT-related symptoms (1.8 +/- 0.9 vs 1.4 +/- 1.0, P = .008).

CONCLUSIONS

Limited attention has been dedicated to rate control in patients with pacemaker. This is the first study to evaluate the prevalence and implications of inappropriate rate control in patients with pacemaker. We found that in a substantial proportion of patients with SND who have recurrent ATs despite pacing, mean daily HR during AT is high and that these patients present increased hospitalizations and more symptoms, thus suggesting the need to improve rate control.

Electrical cardioversion for persistent atrial fibrillation or atrial flutter in clinical practice: predictors of long-term outcome

Despite the results of Atrial Fibrillation Follow-up Investigation of Rhythm Management and Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation trials, which favour a general shift in atrial fibrillation (AF) therapeutic approach towards control of ventricular rate, a strategy based on restoration of sinus rhythm could still play a role in selected patients at lower risk of AF recurrence. We explored possible predictors of relapses after external electrical cardioversion among patients with persistent AF or atrial flutter (AFL). We analysed the clinical characteristics and conventional echocardiographic parameters of patients with persistent AF/AFL enrolled in an institutional electrical cardioversion programme. Among 242 patients (AF/AFL, 195/47; mean age 62+/-13 years), sinus rhythm was restored in 215 (89%) and maintained in 73 (34%) at a follow-up of 930 days (median). No baseline clinical/echocardiographic variables predicted acute efficacy of cardioversion at logistic regression analysis. However, two variables predicted long-term AF/AFL recurrence among patients with successful cardioversion at multivariate Cox's proportional hazards analysis: (i) duration of arrhythmia>or=1 year (HR, 2.07; 95% CI, 1.29-3.33) and (ii) presence of previous cardioversion (HR, 1.67; 95% CI, 1.17-2.38). These variables also presented high-positive predictive values (72% and 80% respectively). Whereas the high acute efficacy of electrical cardioversion (approximately 90%) does not appear to be predictable, two simple clinical variables could help identify patients at higher risk of long-term AF/AFL recurrence after successful electrical cardioversion. We think there could be a case for initially attempting external electrical cardioversion to patients who have had AF/AFL for <1 year. In such patients, the chance of long-term success appears to be relatively high.

Vernakalant (RSD1235): a novel, atrial-selective antifibrillatory agent

This review summarizes the mechanistic properties and the recent experience in the development of a new antiarrhythmic agent, RSD1235 (recently named vernakalant), for the acute conversion of atrial fibrillation to sinus rhythm. Atrial fibrillation is the most common sustained cardiac arrhythmia that is observed in clinical practice and is associated with increased morbidity and mortality, resulting from stroke and exacerbation of heart failure. At present, there is a lack of pharmacologic agents that are able to safely and effectively convert the arrhythmia back to sinus rhythm. Vernakalant has the electrophysiologic properties of a multiple ion channel blocker, developed using a novel approach to target potassium channels that are selectively present in human atria rather than ventricles, and using a rate-dependent blocking strategy for its additional sodium channel block. This paper reviews the mechanism of action of this drug, its performance in preclinical models of efficacy and human disease, and its actions on patients in the completed and published preregistration clinical trials for vernakalant. Overall, vernakalant converted 51.5% of patients who had < 7 days duration of atrial fibrillation and it did this without significantly more cardiovascular adverse events than placebo. Therefore, it must be considered as an important new agent for the treatment of this growing health problem.

Cardiac resynchronization therapy in clinical practice: need for electrical, mechanical, clinical and logistic synchronization

Considering the relatively short history of cardiac resynchronization therapy (CRT), the amount of available evidence of efficacy is impressive, and effectiveness studies are now required. Transfer of our experimentally gained knowledge into the real world raises issues that call for synchronization among the many specialists involved in chronic heart failure (CHF) management and CRT decision making. From an economic perspective, the demonstrated ability of CRT to reduce hospitalizations could help ease the burden on health systems derived from the growing incidence of CHF. Recent American College of Cardiology/American Heart Association guideline revisions should encourage a synchronized approach to rational deployment of CRT in selected patients. Nevertheless, current QRS criteria for CRT candidacy do not directly address the key issue of identification of patients with a pacing-correctable mechanical dyssynchrony (and in clinical trials, 25-30% of implanted patients did not respond to CRT). Echocardiography could become an important adjunct (or even an alternative) to QRS duration for patient selection; routine implementation would require use of straightforward, reproducible measurements, possibly obtainable on standard equipment. Echocardiography could also help optimize site location, although this would not eliminate lead placement problems. A series of issues remain open for investigation, including the potential of CRT in patients with atrial fibrillation, impact of devices with defibrillation ability, effects of electrical/pharmacological tailoring, need for confirmation that efficacy of CRT extends into the long term and possible use of CRT in mild CHF. Interdisciplinary synchronization in the various phases of CRT (screening, proposing, implementing, optimizing and monitoring) should eventually help develop a coordinated system for patient referral.

Controversies in atrial fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia, and contributes greatly to cardiovascular morbidity and mortality. Many aspects of the management of atrial fibrillation remain controversial. We address nine specific controversies in atrial fibrillation management, briefly focusing on the relations between mechanisms and therapy, the roles of rhythm and rate control, the definition of optimum rate control, the need for early cardioversion to prevent remodelling, the comparison of electrical with pharmacological cardioversion, the selection of patients for long-term oral anticoagulation, the roles of novel long-term anticoagulation approaches and ablation therapy, and the potential usefulness of upstream therapy targeting substrate development. The background of every controversy is reviewed and our opinions expressed. Here, we hope to inform physicians about the most important controversies in this specialty and stimulate investigators to address unresolved issues.

Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device

Predictors of ATP efficacy in brady/tachy patients.

BACKGROUND

Recent options to treat atrial tachyarrhythmias (ATA) include implantable devices delivering antitachycardia pacing therapies (ATP). No prospective study selected patients with higher chances of episode termination by ATP or indicated the most effective ATP use. Our aim was to study ATP efficacy in patients with brady-tachy form of sinus node disease (SND), identifying clinical factors, ATA characteristics, and device features predicting ATP efficacy.

METHODS AND RESULTS

Three hundred and sixteen patients (105 M, aged 71.1+/-8.8 years) received a DDDRP pacemaker and were prospectively followed. Median follow-up was 18 months: 37,125 ATA episodes occurred in 217 patients; ATP treated 5,536 of them. Overall, ATP efficacy was 50.0%. A multivariate analysis identified longer arrhythmia cycle lengths (OR=1.25; CI=1.07-1.47) and shorter delays to ATP delivery (OR=0.15; CI=0.10-0.22) as independent predictors of ATP efficacy for episodes preceded by >or=5 minutes of sinus rhythm. Additionally, ATP efficacy for all treated episodes was predicted by lower New York Heart Association (NYHA) class (OR=0.64; CI=0.42-0.98), episode classification as nonimmediate recurrence of ATA (non-IRAT) (OR=0.07; CI=0.02-0.33), absence of overlap in the device detection windows (OR=0.54; CI=0.32-0.91), and flecainide treatment (OR=2.22; CI=1.04-4.71).

CONCLUSIONS

In patients paced for SND, multivariate analysis shows that ATP efficacy is associated to longer arrhythmia cycle lengths, shorter ATP delivery delays, NYHA class I, episode classification as non-IRAT, absence of overlap in the atrial arrhythmia device detection windows, and flecainide treatment.

A controlled study on the effect of verapamil on atrial tachycaarrhythmias in patients with brady-tachy syndrome implanted with a DDDR pacemaker

While verapamil has been proposed as a treatment for reducing electrophysiological remodeling due to atrial fibrillation and atrial tachyarrhythmias, no previous study has tested its effects in brady-tachy patients implanted with a dual-chamber pacemaker. Fourteen patients with frequent episodes of atrial fibrillation (> or =2 episodes/month) in the setting of brady-tachy syndrome, implanted with a DDDR pacing system with extensive monitor function (Selection 900, Vitatron) were enrolled. Four months after implantation, they were randomly allocated to a 2-month period of treatment with verapamil (240 mg/day) or to no treatment, followed by a crossover. The burden of atrial tachyarrhythmias, the total number of hours spent in atrial tachyarrhythmia and the mean number of hours per day spent in atrial tachyarrhythmia were retrieved from diagnostic devices. The accuracy of atrial tachyarrhythmias detection was confirmed independently by two observers. The main results showed that treatment with verapamil was associated with a trend towards an higher percentage of atrial pacing in comparison with control (mean value+/-S.D.=63.2+/-29.9% vs. 57.3+/-30.6%, median value 53% vs. 49%, P value at Wilcoxon signed rank test=0.069), but without any significant reduction in atrial tachyarrhythmia burden (4.5+/-11.8 vs. 3.3+/-9.1%) or total hours spent in atrial tachyarrhythmia (65+/-161 vs. 48+/-131 h). Palpitation episodes were not significantly reduced by verapamil treatment in comparison with control (10.3+/-7.8 vs. 6.1+/-6.5). In conclusion, verapamil does not exert any beneficial effect on documented episodes of atrial tachyarrhythmia in patients with brady-tachy syndrome implanted with a DDDR device. Moreover, this drug was ineffective in reducing the number of palpitation episodes reported by the patient.

Pharmacological cardioversion of atrial fibrillation: current management and treatment options

Atrial fibrillation (AF) is the most common form of arrhythmia, carrying high social costs. It is usually first seen by general practitioners or in emergency departments. Despite the availability of consensus guidelines, considerable variations exist in treatment practice, especially outside specialised cardiological settings. Cardioversion to sinus rhythm aims to: (i) restore the atrial contribution to ventricular filling/output; (ii) regularise ventricular rate; and (iii) interrupt atrial remodelling. Cardioversion always requires careful assessment of potential proarrhythmic and thromboembolic risks, and this translates into the need to personalise treatment decisions. Among the many clinical variables that affect strategy selection, time from onset is crucial. In selected patients, pharmacological cardioversion of recent-onset AF can be a safely used, feasible and effective approach, even in internal medicine and emergency departments. In most cases of recent-onset AF, pharmacological cardioversion provides an important--and probably more cost effective--alternative to electrical cardioversion, which can then be employed as a second-line therapy for nonresponders. Class IC agents (flecainide or propafenone), which can be safely used in hospitalised patients with recent-onset AF without left ventricular dysfunction, can provide rapid conversion to sinus rhythm after either intravenous administration or oral loading. Although intravenous amiodarone requires longer conversion times, it is still the standard treatment for patients with heart failure. Ibutilide also provides good conversion rates and could be used for AF patients with left ventricular dysfunction (were it not for high costs). For long-lasting AF most pharmacological treatments have only limited efficacy and electrical cardioversion remains the gold standard in this setting. However, a widely used strategy involves pretreatment with amiodarone in the weeks before planned electrical cardioversion: this provides optimal prophylaxis and can sometimes even restore sinus rhythm. Dofetilide may also be capable of restoring sinus rhythm in up to 25-30% of patients and can be used in patients with heart failure. The potential risk of proarrhythmia increases the need for careful therapeutic decision making and management of pharmacological cardioversion. The results of recent trials (AFFIRM [Atrial Fibrillation Follow-up Investigation of Rhythm Management] and RACE [Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation]) on rate versus rhythm control strategies in the long term have led to a generalised shift in interest towards rate control. Although carefully designed studies are required to better define the role of pharmacological rhythm control in specific AF settings, this alternative option remains a recommendable strategy for many patients, especially those in acute care.