Atrial fibrillation (AF) is a common arrhythmia encountered in clinical practice, which contributes to hemodynamic abnormalities, thromboembolic events, cardiomyopathy, hospitalizations, and mortality.1 Coexistence of congestive heart failure (HF) and AF was not uncommon in the clinical practice.2 AF could be identified in up to 50% of patients who present with new-onset congestive HF; conversely, congestive HF could be diagnosed among those patients with new-onset AF.2 In patients with coexistence of AF and HF, randomized controlled trials of amiodarone and dofetilide have shown inadequate rhythm control effect and limited efficacy in improvement of left ventricular function, rate of hospitalization for HF or in all-cause mortality.3,4
The data from the previous large clinical trials studying the nonvitamin k antagonist OAC (NOAC) demonstrated that the paroxysmal AF (PAF) was associated with a lower stroke risk and lower all-cause mortality compared with non-paroxysmal AF (N-PAF).5–8 Of note, these numbers were observed in subjects who were all undergoing oral anticoagulation therapy. This probably foremost reflects the fact that patients with permanent AF have more advanced heart disease and more comorbidities. In contrast, Mogensen et al demonstrated the PAF was associated with a greater risk of stroke and HF hospitalization than in patients with N-PAF.9 The study demonstrated that the anticoagulant was less prescribed in the patients with PAF (only 53%) and new-onset AF (16%), which might be associated with higher stroke incidence in this subgroup.
In the current issue of the Journal of the Chinese Medical Association, Chang et al present the data from the Taiwan Society of Cardiology-Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry specifically enrolled decompensated hospitalized patients with left ventricular ejection fraction (LVEF) <40%.10 The TSOC-HFrEF registry was a prospective, multicenter, observational survey of patients from 21 hospitals between 2013 and 2014 in Taiwan. HF patients coextended with AF (393 AF patients from 1509 HF patients) were extracted for analysis in this study. The patients were divided into two groups according to their AF status: PAF in 117 patients and n-PAF in 276 patients. Patients with PAF more frequently presented with a history of myocardial infarction, peripheral arterial disease, chronic kidney disease, higher CHA2DS2-VASc score, and higher HASBLED score. At discharge, patients with PAF were more likely to receive treatment with more amiodarone but less likely to receive renin–angiotensin system blockers and anticoagulants compared with patients in the N-PAF group. The one-year all-cause mortality and non-HF-related mortality rates were significantly higher in patients with PAF, and equivalent HF-related mortality rates in both groups.
Although oral anticoagulants effectively reduce the risk of AF-associated stroke, the underuse of warfarin is a global issue, especially in Asia. The safety of convivence of NOACs compared with warfarin would improve the prescription rate and low the risk of ischemic stroke, and mortality in AF patients decreased.11 Especially, the present study by Chang et al demonstrated the patients with PAF and HFrEF were less prescribed than in the patients with PAF (67%) and non-PAF (50%), and far less than patients of previous studies. It is difficult to assess the effect of under-usage of guideline-recommended anticoagulation from this study, from the Taiwan National Health Insurance Research Database. The one-year risk of ischemic stroke and mortality after AF diagnosis was lower in the era of NOACs compared to the era without NOAC.11 The usage of oral anticoagulant was generally low in this relatively high-risk HF population and NOAC era, which confound the study endpoint. The increased one-year mortality might be contributed to higher CHA2DS2-VASc score, more chronic kidney disease, less anticoagulant agent, and less guideline-recommended HF therapy. There was no available information regarding drug-adjustment after discharge, status of sinus rhythm maintenance, change of LVEF, number of patients receiving catheter ablation, which might confound the long-term outcome.
Despite the study limitations, the current study reminds the clinical physician to carefully evaluate the medication in the patients with coexistence of AF and HF. The risk of stroke or bleeding should be routinely evaluated. Guideline-recommended HF therapy should also be checked at the same time. Generally, the N-PAF was associated with more advanced heart disease and more comorbidities in comparison to the PAF.6,8 In the era of NOAC, the N-PAF remained to be associated with more cardiovascular events. The higher incidence of cardiovascular events from PAF patients in the present study could be due to difference of baseline characteristics and medication.10 Further studies were needed to evaluate the impact of AF type in patients with HF under the optimal management.
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