Incidence of Stroke or Systemic Embolism in Paroxysmal Versus Sustained Atrial Fibrillation

Abstract

A trial fibrillation (AF) is the most common cardiac arrhythmia in developed countries and increases the risks for stroke, heart failure, and death.1 Until 2 decades ago, the incidence and risk factors for stroke were less well characterized in patients with paroxysmal AF (PAF) when compared with those with persistent or permanent AF.2,3 Since then, several studies have reported that patients with PAF have a risk of thromboembolic events that was similar to that in persistent or permanent AF. [4][5][6][7] In accordance with the results from these studies, current guidelines worldwide recommend the use of oral anticoagulant (OAC) for the prevention of thromboembolism, irrespective of the type of AF. [8][9][10] However, more recent studies have reported that the patients with PAF had a lower rate of stroke/systemic embolism (SE). 11-13Also, patients with PAF are less likely to receive OAC therapy in the real-world clinical practice.6,14 However, limited data on stroke risk associated with PAF are evident in Asian populations with PAF because most studies were epidemiological studies on Western populations or selected clinical trial cohorts.Background and Purpose-There is controversy on the relationship of the type of atrial fibrillation (AF) to stroke.Although several studies show that patients with paroxysmal AF (PAF) have a stroke risk similar to those with persistent or permanent AF, recent studies suggest that PAF is associated with a lower rate of stroke. Limited data on stroke risk associated with PAF are evident in Asian populations. Methods-The Registry Study of Atrial Fibrillation Patients in Fushimi-ku (Fushimi AF Registry) is a community-basedsurvey of patients with AF in Fushimi-ku, Kyoto, Japan. Patients were categorized into 2 types of AF: PAF or sustained (persistent or permanent) AF. We compared clinical events between PAF (n=1588) and sustained AF (n=1716). Results-Patients with PAF were younger, had less comorbidities, and received oral anticoagulants (OAC) less commonly.A lower risk of stroke/systemic embolism during follow-up period in the patients with PAF was consistently observed (non-OAC users: hazard ratio, 0.45; 95% confidence intervals, 0.27-0.75; P<0.01 and OAC users: hazard ratio, 0.59; 95% confidence interval, 0.35-0.93; P=0.03). The composite end point of stroke/systemic embolism/all-cause mortality was also lower in PAF, whether among OAC users (hazard ratio, 0.77; 95% confidence interval, 0.59-0.99; P=0.046) or non-OAC users (hazard ratio, 0.59; 95% confidence interval, 0.46-0.75; P<0.01). On multivariate analysis, PAF was an independent predictor of lower stroke/systemic embolism risk. Conclusions-In this large cohort of Japanese patients with AF, PAF was independently associated with lower incidence of stroke/systemic embolism than sustained AF. This may aid decision making for anticoagulation, especially in those patients with AF with few stroke risk factors. Clinical Trial Registration

Current Status and Time Trends of Oral Anticoagulation Use Among Chinese Patients With Nonvalvular Atrial Fibrillation

“…The observation that persistent AF patients were more likely to have OAC has been seen in other studies. 29,30 Although the risk of stroke in paroxysmal AF is possibly lower compared with persistent or permanent AF patients, different studies reported conflict results, [31][32][33] and there is no evidence to recommend decision making for OAC in a patient by whether the subtype is persistent or paroxysmal AF. 4,5 For Nonadherence to guideline-directed OAC use may also be influenced by many variables, including the healthcare system, physician factor, and patient-level considerations.…”

Higher Risk of Ischemic Events in Secondary Prevention for Patients With Persistent Than Those With Paroxysmal Atrial Fibrillation

“…[6][7][8][9][10] Recently, data showing a higher risk for stroke or systemic embolism in patients with persistent or permanent AF than for those with paroxysmal AF has been accumulating, mainly from post hoc analyses of large randomized controlled trials (RCTs) of oral anticoagulants (OACs) or antiplatelets for AF patients and an AF registry. [11][12][13][14] Because previous reports mainly included primary prevention cohorts; the role of AF type in the risk stratification is still unclear in secondary prevention cohorts. Furthermore, there have been little data showing the effect of AF type on initial stroke severity and clinical independence after stroke/TIA.…”

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

“…The results are also reinforced by the evidence that the risk of stroke was lower in patients maintaining a paroxysmal AF pattern than those with paroxysmal AF at the baseline who progressed to a sustained AF during the 2-year follow-up (48).…”

“…A recent observational study conducted in Japan (48) found that paroxysmal AF was associated with a significantly higher risk of stroke than nonparoxysmal forms even after adjusting for a series of potential confounders, including oral anticoagulation. The results are also reinforced by the evidence that the risk of stroke was lower in patients maintaining a paroxysmal AF pattern than those with paroxysmal AF at the baseline who progressed to a sustained AF during the 2-year follow-up (48).…”