State of play and future direction with NOACs: An expert consensus.

Atrial fibrillation (AF) and venous thromboembolism (VTE) are cardiovascular conditions significant in contemporary practice. In both, the use of anticoagulation with vitamin K antagonists (VKAs) has been traditionally used to prevent adverse events. However, VKA therapy is associated with challenges relating to dose maintenance, the need to monitor anticoagulation, and bleeding risks. The non-vitamin K oral anticoagulants (NOACs) are becoming accepted as a clear alternative to VKA therapy for both AF and VTE management. The aim of this paper was to review contemporary evidence on the safety of NOACs in both conditions. A comprehensive literature review was conducted to explore key safety issues and expert consensus was achieved from eight professionals specialised in AF and VTE care. Consensus-based statements were formulated where available evidence was weak or contradictory. The expert statements in this paper form a key overview of the safety of NOACs compared with VKA therapy, and the comparative safety of different NOACs. It is apparent that a detailed patient work-up is required in order to identify and manage individual risk factors for bleeding and thrombosis prior to NOAC therapy. Additional measures, such as dose reductions, may also be used to maintain the safety of NOACs in practice.

The changing circumstance of atrial fibrillation - progress towards precision medicine.

The prevalence of atrial fibrillation (AF) in the general population is between 1% and 2% in the developed world and is higher in men than in women. The arrhythmia occurs much more commonly in the elderly, and the estimated lifetime risk of developing AF is one in four for men and women aged 40 years and above. Projected data from multiple population-based studies in the USA and Europe predict a two- to threefold increase in the number of AF patients by 2060. The high lifetime risk of AF and increased longevity underscore the important public health burden posed by this arrhythmia worldwide. AF has multiple aetiologies and a broad variety of presentations. The primary pathologies underlying or promoting the occurrence of AF vary more than for any other cardiac arrhythmia, ranging from autonomic imbalance to organic heart disease and metabolic disorders, such as diabetes mellitus, metabolic syndrome, hyperthyroidism and kidney disease, and lifestyle factors such as smoking, alcohol consumption and participation in endurance sports. Biomarkers are increasingly being investigated and, together with clinical and genetic factors, will eventually lead to a clinically valuable detailed classification of AF which will also incorporate pathophysiological determinants and mechanisms of the arrhythmia. In turn, this will allow the development and application of precision medicine to this troublesome arrhythmia.

Atrial fibrillation in the military patient: a review.

Atrial fibrillation (AF) is the most common sustained atrial arrhythmia, and increases an individual's risk of morbidity and mortality from cardiovascular and thromboembolic events. In this article, we review the pathophysiology and clinical presentations of AF and describe appropriate investigations and management likely to be appropriate for a military population, in line with current National Institute for Health and Care Excellence and European Society of Cardiology guidelines. The implications for the individual's Medical Employment Standard in the UK Armed Forces, with specific reference to specific military occupational activities such as aviation, diving and driving occupationally, are also reviewed.

Edoxaban vs. warfarin in patients with atrial fibrillation on amiodarone: a subgroup analysis of the ENGAGE AF-TIMI 48 trial.

BACKGROUND: In the ENGAGE AF-TIMI 48 trial, the higher-dose edoxaban (HDE) regimen had a similar incidence of ischaemic stroke compared with warfarin, whereas a higher incidence was observed with the lower-dose regimen (LDE). Amiodarone increases edoxaban plasma levels via P-glycoprotein inhibition. The current pre-specified exploratory analysis was performed to determine the effect of amiodarone on the relative efficacy and safety profile of edoxaban. METHODS AND RESULTS: At randomization, 2492 patients (11.8%) were receiving amiodarone. The primary efficacy endpoint of stroke or systemic embolic event was significantly lower with LDE compared with warfarin in amiodarone treated patients vs. patients not on amiodarone (hazard ratio [HR] 0.60, 95% confidence intervals [CIs] 0.36-0.99 and HR 1.20, 95% CI 1.03-1.40, respectively; P interaction <0.01). In patients randomized to HDE, no such interaction for efficacy was observed (HR 0.73, 95% CI 0.46-1.17 vs. HR 0.89, 95% CI 0.75-1.05, P interaction = 0.446). Major bleeding was similar in patients on LDE (HR 0.35, 95% CI 0.21-0.59 vs. HR 0.53, 95% CI 0.46-0.61, P interaction = 0.131) and HDE (HR 0.94, 95% CI 0.65-1.38 vs. HR 0.79, 95% CI 0.69-0.90, P interaction = 0.392) when compared with warfarin, independent of amiodarone use. CONCLUSIONS: Patients randomized to the LDE treated with amiodarone at the time of randomization demonstrated a significant reduction in ischaemic events vs. warfarin when compared with those not on amiodarone, while preserving a favourable bleeding profile. In contrast, amiodarone had no effect on the relative efficacy and safety of HDE.

Ischaemic stroke prevention in patients with atrial fibrillation and high bleeding risk: opportunities and challenges for percutaneous left atrial appendage occlusion.

Patients with atrial fibrillation (AF) are at an increased risk of ischaemic stroke. The efficacy of stroke prevention with vitamin K antagonists in these patients has been well established. However, associated bleeding risks may offset the therapeutic benefits in patients with risk factors for bleeding. Despite improvements achieved by novel oral anticoagulants, bleeding remains a clinically relevant problem, especially gastrointestinal bleeding. Percutaneous occlusion of the left atrial appendage (LAA) may be considered as an alternative stroke prevention therapy in AF patients with a high bleeding risk. This paper explores patient groups in whom oral anticoagulation may be challenging and percutaneous LAA occlusion (LAAO) has a potentially better risk-benefit balance. The current status of LAAO and future directions are reviewed, and particular challenges for LAA occlusion requiring further clinical data are discussed. This article is a summary of the Third Global Summit on LAA occlusion, 15 March 2013, Barcelona, Spain.

Novel oral anticoagulants and stroke prevention in atrial fibrillation and chronic heart failure.

Heart failure (HF) and atrial fibrillation (AF) frequently coexist and share a reciprocal relationship. The presence of AF increases the propensity to HF and can worsen its severity as well as escalating the risk of stroke. Despite the proven efficacy of vitamin K antagonists and warfarin for stroke prevention in AF, their use is beset by numerous problems. These include their slow onset and offset of action, unpredictability of response, the need for frequent coagulant monitoring and serious concerns around the increased risks of intracranial and major bleeding. Three recently approved novel anticoagulants (dabigatran, rivaroxaban and apixaban) are already challenging warfarin use in AF. They have a predictable therapeutic response and a wide therapeutic range and do not necessitate coagulation monitoring. In this article, the relationship between HF and AF and the mechanisms for their compounded stroke risk are reviewed. The evidence to support the use of these three NOACs amongst patients with AF and HF is further explored.

Atrial fibrillation: the rate versus rhythm management controversy.

The fundamental management strategy for atrial fibrillation (AF) is still debated. There is no doubt that those patients at risk of thromboembolic events should be offered anticoagulant therapy. However, it is uncertain whether rhythm control (restoration and maintenance of sinus rhythm) or rate control (adjustment to a physiological ventricular rate while allowing AF to continue) is the preferred primary treatment option for the reduction of symptoms and major cardiovascular (CV) outcomes associated with AF. Several well conducted trials comparing the two strategies led to the conclusion that there was little to choose between them. However, guidelines leaned towards recommending rate control as the initial strategy, and reserved rhythm control for those who remained symptomatic. Recently this status quo is being increasingly challenged by the clear demonstration that left atrial catheter ablation is effective at suppressing AF resistant to traditional antiarrhythmic drugs, such as those that failed to demonstrate any superiority when compared with rate control. Also, recently introduced antiarrhythmic therapy may have superior efficacy with regard to reducing unexpected CV hospitalization, CV mortality and stroke. In addition, there is a growing perception that atrial remodelling should be best prevented by early rhythm control rather than delaying until rate control has proven unsatisfactory. For these reasons the results of large randomised clinical trials, which recruit patients soon after the presentation of AF and compare 'aggressive' modern rhythm control against the guideline approach of primary rate control, are eagerly awaited. In the meantime the pendulum of clinical opinion has begun to swing towards a rhythm control strategy.

The unravelling of primary myocardial impairment in Marfan syndrome by modern echocardiography.

Use of echocardiography has dramatically changed the way in which patients with Marfan syndrome are diagnosed, monitored and treated. Owing to the lethal nature of aortic complications, priority has been given to the assessment of the aortic root. Echocardiographic studies on patients with Marfan syndrome have also provided data supporting primary myocardial involvement, although this evidence has remained controversial for several years. Use of more sensitive ultrasound techniques has demonstrated mild myocardial impairment in these patients. Biventricular function assessment should be added to the aortic root evaluation, so that appropriate treatment may be offered to support myocardial function.

Conventional and dedicated atrial overdrive pacing for the prevention of paroxysmal atrial fibrillation: the AFTherapy study.

AIMS: This investigation was conducted to determine the effectiveness of several conventional overdrive pacing modalities (single rate and rate responsive pacing at various lower rates) and of four dedicated preventive pacing algorithms in the suppression of paroxysmal atrial fibrillation (AF). METHOD AND RESULTS: In this multi-centre, randomized trial, 372 patients with drug-refractory paroxysmal AF were enrolled. Patients received a dual-chamber pacing device capable of delivering conventional pacing therapy as well as dedicated AF prevention pacing therapies and to record detailed AF-related diagnostics. The primary endpoint was AF burden, whereas secondary endpoints were time to first AF episode and averaged sinus rhythm duration. During a conventional pacing phase, patients were randomized to single rate or rate-responsive pacing with lower rates of either 70 or 85 min(-1) or to a control group with single rate pacing at 40 min(-1). In the subsequent preventive pacing phase, patients underwent pacing at a lower rate of 70 min(-1) with or without concomitant application of four preventive pacing algorithms. A substantial amount of data was excluded from the analysis because of atrial-sensing artefacts, identified in the device-captured diagnostics. In the conventional pacing phase, no significant differences were found between various lower rates and the control group receiving single rate pacing at 40 min(-1) or between single rate and rate-responsive pacing. Patients receiving preventive pacing with all four therapies enabled had a similar AF burden compared with patients treated with conventional pacing at 70 min(-1) (P = 0.47). CONCLUSIONS: The results do not demonstrate a significant effect of conventional atrial overdrive pacing or preventive pacing therapies. However, the observations provided important information for further consideration with respect to the design and conduct of future studies on the effect of atrial pacing therapies for the reduction of AF.

Sudden cardiac death: opportunities for prevention.

The evidence base for implantable cardioverter-defibrillator (ICD) therapy requires expansion of guidance/indications to allow UK physicians to treat a broader range of patients. The ICD clinical consultees to the National Institute for Health and Clinical Excellence (NICE) review current guidance/guidelines, explain the evidence base, and suggest a UK ICD implantation strategy.

The negative effect of red tape on research.

PURPOSES: To describe the kind of the difficulties encountered when seeking research governance approval for a nationwide public health and genetic study-the Drug-Induced Arrhythmia Risk Evaluation study-in England. METHODS: Description of the processes followed when seeking research governance approval for the Drug-Induced Arrhythmia Risk Evaluation study-a case control study with annual follow-up of cases and controls over 5 years, set in the English National Health Service (NHS). RESULTS: The authors describe wide variations in NHS research governance approval procedures in England. CONCLUSION: NHS research governance procedures in England are impeding the process of epidemiological studies; there is the need for a centralised NHS R&D approval of studies, which is analogous to MREC for ethical approval.

Effects of ventricular rate and regularity on the velocity and magnitude of left atrial appendage flow in atrial fibrillation.

OBJECTIVE: To prospectively determine whether ventricular rate and regularity are significant determinants of the velocity and magnitude of left atrial appendage (LAA) flow. DESIGN AND PATIENTS: 12 patients with atrial fibrillation (AF), high degree atrioventricular block, and indwelling permanent pacemakers were studied. SETTING: Cardiology department of a tertiary referral centre. INTERVENTIONS: Pacing was triggered by an external programmable transcutaneous device. Patients were paced at 60, 120, and 150 beats/min in both regular and irregular rhythm. LAA flow velocity and magnitude were assessed with transoesophageal Doppler echocardiography. MAIN OUTCOME MEASURES: Peak and mean LAA inflow and outflow velocity, and time-velocity interval (TVI) of LAA flow. RESULTS: Increasing ventricular rate was associated with significantly lower peak inflow (p < 0.01), peak outflow (p < 0.05), mean inflow (p < 0.01), and mean outflow (p < 0.05) velocities and with a lower TVI of LAA filling and emptying velocities (p < 0.01). This effect was noted at rates of 60 beats/min compared with both 120 and 150 beats/min. At a pacing rate of 120 beats/min there was a significantly higher total TVI when pacing at a regular than at an irregular rhythm (40.16 (14.6) cm v 30.74 (10.9) cm, p < 0.05). CONCLUSIONS: In this study, LAA filling velocities in patients in AF were significantly influenced by paced ventricular rate and to a much lesser extent ventricular rhythm. These results suggest that rapid ventricular rates may predispose to stasis in the LAA in AF.

Rationale and design of a randomised controlled clinical trial on supplemental intake of n-3 fatty acids and incidence of cardiac arrhythmia: SOFA.

BACKGROUND: Evidence from earlier studies indicates that intake of very long-chain n-3 polyunsaturated fatty acids (n-3 PUFA, also named omega-3 fatty acids) as present in fish oil reduces the risk of sudden death. Sudden death forms a major part of mortality from cardiovascular disease and is in most cases a direct consequence of cardiac arrhythmia. n-3 PUFA may exert their protective effect through reducing the susceptibility for cardiac arrhythmia. OBJECTIVE: To investigate the effect of n-3 PUFA on the incidence of recurrent ventricular arrhythmia. This paper presents the rationale, design and methods of the Study on Omega-3 Fatty acids and ventricular Arrhythmia (SOFA) and discusses problems encountered in conducting a multicentre clinical trial on food. DESIGN: A randomised, parallel, placebo-controlled, double blind intervention study, which obeys the guidelines for Good Clinical Practice. SETTING: Multiple cardiology centres in Europe. SUBJECTS: A total of 500 patients with an implantable cardioverter defibrillator (ICD). An ICD detects, treats and stores cardiac arrhythmic events in its memory chip. INTERVENTIONS: Patients receive either 2 g/day of fish oil, containing approximately 450 mg eicosapentaenoic acid and 350 mg docosahexaenoic acid, or placebo for 12 months. PRIMARY OUTCOME: Spontaneous ventricular tachyarrhythmias as recorded by the ICD or all-cause mortality. CONCLUSION: SOFA is designed to answer the question whether intake of n-3 PUFA from fish-a regular food ingredient-can reduce the incidence of life-threatening cardiac arrhythmia. If this proves to be true, increasing the intake of n-3 PUFA could be an easy, effective and safe measure to prevent fatal arrhythmia in the general population.

Relationships between preclinical cardiac electrophysiology, clinical QT interval prolongation and torsade de pointes for a broad range of drugs: evidence for a provisional safety margin in drug development.

OBJECTIVE: To attempt to determine the relative value of preclinical cardiac electrophysiology data (in vitro and in vivo) for predicting risk of torsade de pointes (TdP) in clinical use. METHODS: Published data on hERG (or I(Kr)) activity, cardiac action potential duration (at 90% repolarisation; APD(90)), and QT prolongation in dogs were compared against QT effects and reports of TdP in humans for 100 drugs. These data were set against the free plasma concentrations attained during clinical use (effective therapeutic plasma concentrations; ETPC(unbound)). The drugs were divided into five categories: (1) Class Ia and III antiarrhythmics; (2) Withdrawn from market due to TdP; (3) Measurable incidence/numerous reports of TdP in humans; (4) Isolated reports of TdP in humans; (5) No reports of TdP in humans. RESULTS: Data from hERG (or I(Kr)) assays in addition to ETPC(unbound) data were available for 52 drugs. For Category 1 drugs, data for hERG/I(Kr) IC(50), APD(90), QTc in animals and QTc in humans were generally close to or superimposed on the ETPC(unbound) values. This relationship was uncoupled in the other categories, with more complex relationships between the data. In Category 1 (except amiodarone), the ratios between hERG/I(Kr) IC(50) and ETPC(unbound) (max) ranged from 0.1- to 31-fold. Similar ranges were obtained for drugs in Category 2 (0.31- to 13-fold) and Category 3 (0.03- to 35-fold). A large spread was found for Category 4 drugs (0.13- to 35700-fold); this category embraced an assortment of mechanisms ranging from drugs which may well be affecting I(Kr) currents in clinical use (e.g. sparfloxacin) to others such as nifedipine (35700-fold) where channel block is not involved. Finally, for the majority of Category 5 drugs there was a >30-fold separation between hERG/I(Kr) activity and ETPC(unbound) values, with the notable exception of verapamil (1.7-fold), which is free from QT prolongation in man; this is probably explained by its multiple interactions with cardiac ion channels. CONCLUSIONS: The dataset confirms the widely-held belief that most drugs associated with TdP in humans are also associated with hERG K(+) channel block at concentrations close to or superimposed upon the free plasma concentrations found in clinical use. A 30-fold margin between C(max) and hERG IC(50) may suffice for drugs currently undergoing clinical evaluation, but for future drug discovery programmes, pharmaceutical companies should consider increasing this margin, particularly for drugs aimed at non-debilitating diseases. However, interactions with multiple cardiac ion channels can either mitigate or exacerbate the prolongation of APD and QT that would ensue from block of I(Kr) currents alone, and delay of repolarisation per se is not necessarily torsadogenic. Clearly, an integrated assessment of in vitro and in vivo data is required in order to predict the torsadogenic risk of a new candidate drug in humans.

Comparison between biventricular pacing and single site pacing in patients with poor ventricular function: a hemodynamic study.

Biventricular pacing has been suggested as offering greater hemodynamic benefit than single site pacing in patients with advanced heart failure and left bundle branch block. This was tested using acute multisite pacing. Eighteen such patients were atrialsensed, ventricular multisite paced in random order for 5 minutes. The best achieved measure of cardiac output (CO), pulmonary capillary wedge pressure (PCWP) and left ventricular (LV) + dP/dtmax at RV, LV, and biventricular pacing sites compared. Baseline PCWP, CO, and LV + dP/dtmax were 20 +/- 10 mmHg 4.8 +/- 1.3 L/min and 680 +/- 173 mmHg/s respectively. In all 18 patients CO and in 17 of 18 patients LV + dP/dtmax and PCWP improved with pacing. In the group as a whole, no significant hemodynamic difference between pacing sites was observed in PCWP (pacing site RV 19 +/- 10 mmHg, LV 17 +/- 10, biventricular 18 +/- 11) or CO (RV 5.2 +/- 1.5 L/min, LV 5.1 +/- 1.5, biventricular 5.3 +/- 1.7). Increased stroke volume/PCWP with LV (5.6 +/- 3.7 mLs/mmHg) and biventricular pacing (5.4 +/- 4.0) were not significantly greater compared to RV pacing (4.7 +/- 3.0, ANOVA P = 0.20). Increase in LV + dP/dtmax with pacing at LV (814 +/- 190 mmHg/s) and biventricular (839 +/- 290) sites was not significantly greater than the increase with RV pacing (769 +/- 203 mmHg/s, ANOVA P = 0.30). Pacing in patients with heart failure and conduction delay can produce a hemodynamic benefit. There is individual variation in the pacing site that leads to the greatest improvement. In the group as a whole, biventricular and LV pacing produced only modest improvements compared to RV pacing.

Effect of multisite pacing on ventricular coordination.

OBJECTIVE: To determine the effect of multisite pacing on left ventricular function. DESIGN: Prospective observational study. PATIENTS: 18 patients with heart failure with a dilated poorly functioning left ventricle (LV) and left bundle branch block. INTERVENTIONS: Pacing for 5 minutes in random order at the right ventricle (RV) apex, RV outflow tract, mid posterolateral LV, RV apex and LV simultaneously, and RV outflow tract and LV simultaneously. The best achieved measurements with RV, LV, and biventricular pacing were compared. MAIN OUTCOME MEASURES: LV dimension, filling characteristics, and long axis indices were measured on echocardiography simultaneously with LV pressure. Cycle efficiency (%)--that is, the ratio of the area of the acquired pressure dimension loop to that of the ideal loop for that segment--quantified coordination. RESULTS: The pacing site that gave the best achieved cycle efficiency differed between patients (biventricular in five, LV in two, RV in seven, and no site in four). In patients with baseline incoordination (cycle efficiency < or = 72%, n = 12) cycle efficiency improved significantly with RV pacing (cycle efficiency 76%, p = 0.01) but not with LV (65%) or biventricular (67%) pacing. LV based pacing induced premature short axis contraction in a subset of patients (n = 4), which was associated with a prolonged time from the Q wave on the ECG to the onset of inward movement of the long axis (from apex to mitral ring): biventricular 145 ms, LV 105 ms, RV 85 ms (biventricular v RV, p < 0.05). Excluding patients with baseline incoordination in whom premature activation occurred, pacing at all sites led to a similar increase in cycle efficiency (RV 78%, LV 72%, biventricular 73%). CONCLUSIONS: Ventricular coordination can be improved with pacing in patients with baseline incoordination. Short and long axis fibres may be asynchronised in a subset of patients with LV or biventricular pacing, which may worsen coordination. The clinical significance of these findings remains to be defined.