LAUSR

Population studies of atrial fibrillation (AF) and randomized clinical trials of anticoagulation for stroke prevention have provided a wealth of information on the outcomes of patients with this arrhythmia. AF is associated with increased risks of stroke, heart failure, and death. AF as an independent risk for mortality was initially described in the Framingham studies. Adjusting for other cardiovascular diseases, AF conferred a 1.5 (men) to 1.9 (women) times increased risk of death in patients aged >55 years. Several subsequent population studies have confirmed this finding. The mechanistic explanation for this association is multifaceted. Lone AF, defined as AF in the absence of structural heart disease or co-morbidities such as diabetes or hypertension, has a survival that is not different from that of age-matched controls. However, lone AF is an uncommon entity. Over 70% of patients with AF will have associated morbidities, and a large proportion of the remaining 30% will have unrecognized risk factors such as sleep apnoea and obesity. Of the various co-morbidities, the relationship between AF and heart failure is perhaps the most intricate as it can be causal or the effect of progression of an underlying disease. Individuals with both AF and heart failure have a greater risk of death than those with either condition alone. There is increasing evidence that the adverse haemodynamic effects of AF in heart failure that promote ventricular remodelling can potentially be reversed by restoration of sinus rhythm. While early attempts at maintaining sinus rhythm were handicapped by the limited efficacy and toxic effects of antiarrhythmic drugs, catheter-based ablation is proving more effective, and did reduce mortality in a recent study. Ablation techniques, however, require expertise, and are associated with upfront risks including cardiac tamponade and stroke, and the need for repeat procedures in 30–40% of patients. Acceptance of this therapy therefore requires the demonstration of adequate safety. In this issue of the European Heart Journal, König and colleagues present data on mortality in hospitalized patients with AF or atrial flutter (AFL) from the Helios group of hospitals, one of the largest providers of healthcare in Germany. Using administrative database codes, patients who had a main or secondary discharge diagnosis of AF/AFL and those who were coded as having received an AF/AFL ablation procedure or a left atrial appendage closure procedure were identified, excluding those who received cardiac surgery. There are several interesting observations from this large data set. First >1.1 million patients during the 7-year period (from 2010 to 2017) had AF/AFL coded for their hospitalization, and it was the major discharge diagnosis in >160 000, i.e. 14%. Of those for whom it was a major discharge diagnosis, hospital mortality was 0.6%. Age, comorbidities, admission to a lower volume hospital, and emergency admissions were associated with greater mortality in multivariate analysis. Interestingly, 20% of patients with a primary AF/AFL discharge diagnosis received an ablation procedure. Thus, although ablation therapies are making great progress, the vast majority of hospitalized AF/AFL patients are managed with other strategies. Ablation tends to be an option more often for younger patients with fewer co-morbidities, and this is reflected in the data. Those receiving left atrial ablation are at least 6 years younger on average, with less congestive heart failure, diabetes, chronic kidney disease, and pulmonary disease compared with other patients hospitalized primarily for AF/AFL. AF/AFL ablations are almost always scheduled and not carried out as an emergency. The in-hospital mortality for 21 744 patients receiving left atrial ablation procedures was reassuringly low at 0.05%, consistent with the literature. The in-hospital mortality for patients who received only right atrial ablation procedures was slightly greater at 0.3%, probably reflecting the selection of a simple right AFL ablation as an option for some older, sicker patients, as is also suggested by these data. Left atrial appendage occlusion devices were coded in 1.4% of patients with a primary AF/AFL diagnosis. These