Can we predict stroke in atrial fibrillation?

Stroke prevention with appropriate thromboprophylaxis still remains central to the management of atrial fibrillation (AF). Nonetheless, stroke risk in AF is not homogeneous, but despite stroke risk in AF being a continuum, prior stroke risk stratification schema have been used to 'artificially' categorise patients into low, moderate and high risk stroke strata, so that the patients at highest risk can be identified for warfarin therapy. Data from recent large cohort studies show that by being more inclusive, rather than exclusive, of common stroke risk factors in the assessment of the risk for stroke and thromboembolism in AF patients, we can be so much better in assessing stroke risk, and in optimising thromboprophylaxis with the resultant reduction in stroke and mortality. Thus, there has been a recent paradigm shift towards getting better at identifying the 'truly low risk' patients with AF who do not even need antithrombotic therapy, whilst those with one or more stroke risk factors can be treated with oral anticoagulation, whether as well-controlled warfarin or one or the new oral anticoagulant drugs. The new European guidelines on AF have evolved to deemphasise the artificial low/moderate/high risk strata (as they were not very predictive of thromboembolism, anyway) and stressed a risk factor based approach (within the CHA(2) DS(2)-VASc score) given that stroke risk is a continuum. Those categorised as 'low risk' using the CHA(2) DS(2)-VASc score are 'truly low risk' for thromboembolism, and the CHA(2) DS(2)-VASc score performs as good as-and possibly better--than the CHADS(2) score in predicting those at 'high risk'. Indeed, those patients with a CHA(2) DS(2)-VASc score = 0 are 'truly low risk' so that no antithrombotic therapy is preferred, whilst in those with a CHA(2) DS(2)-VASc score of 1 or more, oral anticoagulation is recommended or preferred. Given that guidelines should be applicable for >80% of the time, for >80% of the patients, this stroke risk assessment approach covers the majority of the patients we commonly seen in everyday clinical practice, and considers the common stroke risk factors seen in these patients. The European guidelines also do stress that antithrombotic therapy is necessary in all patients with AF unless they are age <65 years and truly low risk. Indeed, some patients with 'female gender' only as a single risk factor (but still CHA(2) DS(2)-VASc score of 1, due to gender) do not need anticoagulation, especially if they fulfil the criterion of "age <65 and lone AF, and very low risk". In the European and Canadian guidelines, bleeding risk assessment is also emphasised, and the simple validated HAS-BLED score is recommended. A HAS-BLED score of ≥ 3 represents a sufficiently high risk such that caution and/or regular review of a patient is needed. It also makes the clinician think of correctable common bleeding risk factors, and the availability of such a score allows an informed assessment of bleeding risk in AF patients, when antithrombotic therapy is being initiated.     

Can we predict outcomes in atrial fibrillation?

Atrial fibrillation (AF) is the most common arrhythmia encountered by generalists and cardiologists alike. Much of the attendant morbidity from AF arises from systemic embolic complications which are effectively reduced with utilization of anti-platelet and/or anticoagulant therapy. The systemic embolic complications of AF and the medical therapy to attenuate these risks are very well established. Through the course of this review, we aim to highlight the complex relationship between AF and other, "non-embolic" outcomes. The presence of AF has been demonstrated to be associated with a 1.5 to 2-fold increase in mortality across numerous observational cohorts. Still further, AF frequently coexists with heart failure, whether as a causative factor or a consequence of underlying structural heart disease or neurohumoral derangement, where its presence is associated with worse clinical outcomes. Whether AF is an independent risk factor for acute coronary syndromes (ACS) remains controversial, though its occurrence in patients with ACS has been shown to be associated with adverse outcomes both in observational cohorts as well as clinical trial populations. Individuals with AF have a 1.5 to 3-fold increase in the rate of hospitalization and are at elevated risk for other arrhythmic disorders including both bradyarrhythmias as well as tachyarrhythmias. AF leads to considerable morbidity and mortality for patients and exacts a tremendous financial toll on the healthcare system-estimated to range from $6.0 to $26.0 billion. Given the current demographic transition in developed countries, the prevalence of AF will continue to increase and the need for refined approaches to risk stratification and pharmacotherapeutic interventions to attenuate the burden on patients will only become more important.     

Can we ablate permanent atrial fibrillation?

There is growing evidence of the benefit of ablation in the treatment of drug refractory atrial fibrillation.     

Does p-wave dispersion predict the atrial fibrillation occurrence after direct-current shock therapy?

Supraventricular tachycardia attacks, including atrial fibrillation (AF), occur after both external and internal cardioversions. These attacks of atrial fibrillation after direct-current (DC) shock may be related to hemodynamic impairment, thromboembolic events, or enhanced electrical instability of the ventricular and atrial myocardium, especially in predisposed patients. In this study, the authors aimed to show the importance of P-wave dispersion (PWD), which lead the atrium to fibrillate, in predicting post-DC shock AF after external cardioversion. Thus physicians may be able to choose the patients with high risk for AF occurrence and apply some other therapeutic modalities to those patients. The authors identified 18 patients in whom an AF attack was induced by urgent or elective cardioversion for a ventricular tachycardia attack and compared these patients with a control group composed of 40 patients without AF in regard to some clinical, echocardiographic, and electrocardiographic parameters. Left atrial diameters were greater (4.3+/-0.3 vs 3.5+/-0.5 cm, p = 0.001), left ventricular ejection fractions (LVEF) were lower (45.2+/-8.2 vs 54.9+/-7.5, p = 0.001), the energy needed for successful cardioversion was higher (166.6+/-59.4 vs 80.8+/-51.6 J, p = 0.001), and P max (135.2+/-7.4 vs 118.7+/-10.5 ms, p = 0.001) and PWD (53.8+/-12.2 vs 23.8+/-9.5 ms, p = 0.001) values were higher in patients with AF when compared to those without AF. Thus, the patients with higher PWD values had a greater risk for development of AF after a DC shock.     

Can short-long-short sequences predict atrial fibrillation in acute inferior myocardial infarction?

Short-long-short sequences (SLSS), related to atrial ectopic beats (AEBs), predict the recurrence of atrial fibrillation (AF) in some clinical situations. We investigated whether SLSS predict the occurrence of AF in acute phase of inferior myocardial infarction (MI). In patients who developed AF AEBs were more frequent. We concluded that the presence of frequent SLSS could be predictors or preceding factors of the occurrence of AF in acute inferior MI.     

Can we predict bleeding?

The prior identification of subjects who are likely to bleed excessively when subjected to operative surgery and other invasive procedures is desirable. Frequently, reliance is placed on laboratory-based screening tests of blood coagulation for this purpose. However, published evidence does not support this approach as the tests are not fit for purpose, and their sensitivity and specificity are low. Some more global assays may have use in the diagnostic workup in subjects with hemorrhage, but none has been established to date as an efficient method for prediction of bleeding in unselected populations. There is renewed interest in the use of the clinical history for the prediction of bleeding. Recent reports suggest that when a structured questionnaire is employed to derive a bleeding score, the positive predictive value of the approach for the detection of bleeding disorders is high.     

What have we learned of ablation procedures for atrial fibrillation?

Atrial fibrillation is a widespread disease of growing clinical, economic and social importance. Interventional therapy for atrial fibrillation offers encouraging results, with pulmonary vein isolation (PVI) as the established cornerstone. Yet, the challenge to create durable transmural lesions remains, leading to recurrence of atrial fibrillation in long‐term follow‐up even after multiple ablation procedures in 20% of patients with paroxysmal atrial fibrillation and approximately 50% with persistent atrial fibrillation. To overcome these limitations, innovative tools such as the cryoballoon and contact force catheters have been introduced and have demonstrated their potential for safe and effective PVI. Furthermore, advanced pharmacological and pacing manoeuvres enhance evaluation of conduction block in PVI.