Atrial fibrillation, not atrial cardiopathy, is associated with stroke: A single center retrospective study.

Background: Atrial fibrillation (AF) increases the risk of thromboembolism. Atrial cardiopathy, defined as structural left atrial enlargement (LAE), has been proposed to be a unifying risk factor for stroke, with or without atrial fibrillation (AF). We sought to understand the relative importance of LAE and AF as risk factors for stroke.

Methods: We performed a retrospective analysis of all patients who underwent echocardiography within the Henry Ford Health System between March and September 2016. Patients were categorized based on the degree of LAE (none, mild, moderate and severe). The diagnosis of prior stroke or AF was ascertained by the presence of these conditions in the electronic medical record (www.EPIC.com).

Results: Total of 8679 cases, 54% were female, 41% were African-American, and mean age was 65 ± 17 years. Fifteen percent had mild, 12% had moderate and 18% had severe LAE; the frequency of AF was 22%; and prior stroke was 18%. In multivariate analysis, the odds of AF increased progressively with severity of LAE (adjusted OR for mild 1.81, moderate 2.13 and severe 4.38, all P < .001) and AF was confirmed as a risk factor for prior stroke (aOR 1.34, CI 1.15-1.56, p < .001). By contrast, there was no association between LAE and stroke (aOR 0.98 CI 0.86-1.12, p = .74), regardless of the severity of LAE, and regardless of whether AF was present or not.

Conclusion: Structural LAE, found in almost half of this population, has a significant association with AF. While AF was confirmed to have a significant association with prior stroke, we found no association between stroke and LAE. AF, not LAE, appears to be the true atrial factor associated with stroke.