MethodsIn this observational single-center study, consecutive ischemic stroke and transient ischemic attack (TIA) patients aged >18 years Background and Purpose-Whether newly diagnosed atrial fibrillation (nAF) after stroke reflects underlying heart disease and represents an increased risk of cardioembolic stroke, or whether it is triggered by neurogenic mechanisms remains uncertain. We investigated, whether cardiovascular risk factors and echocardiographic parameters in patients with nAF are similar to patients with known AF (kAF) and differ from patients without AF. Methods-Consecutive acute ischemic stroke patients were enrolled into a prospective stroke database. All patients with echocardiography were included and univariable and multivariable testing was applied to compare clinical characteristics and echocardiographic findings among patients with nAF, kAF, and no AF. Results-A total of 1397 patients were included (male, 62.3%; median age, 71 years). AF was present in 320 (22.9%) patients. Of those, nAF was present in 36.2% (116/320) and kAF in 63.8% (204/320). No clinical or echocardiographic factor was independently associated with detection of nAF compared with kAF but a trend toward larger left atrial diameters in patients with kAF was observed (P=0.070). In contrast, patients with nAF were more often female (P<0.001), older (P<0.001) and had a larger left atrial diameters (P<0.001) compared with patients without AF. While stroke severity in patients with nAF and kAF was similar, patients without AF had less severe strokes. Conclusions-Stroke patients with nAF and with kAF share common cardiovascular risk factors, have similar echocardiographic findings and suffer equally severe strokes. We conclude that preexisting heart disease is the major cause of AF that is first diagnosed after stroke.

ObjectiveAtrial fibrillation (AF) is frequently detected after ischemic stroke for the first time, and brain regions involved in autonomic control have been suspected to trigger AF. We examined whether specific brain regions are associated with newly detected AF after ischemic stroke. MethodsPatients with acute cerebral infarctions on diffusion-weighted magnetic resonance imaging were included in this lesion mapping study. Lesions were mapped and modeled voxelwise using Bayesian Spatial Generalised Linear Mixed Modeling to determine differences in infarct locations between stroke patients with new AF, without AF and with AF already known before the stroke. Results582 patients were included (median age 68 years; 63.2% male). AF was present in 109/582 patients [(18.7%); new AF: 39/109 (35.8%), known AF: 70/109 (64.2%)]. AF patients had larger infarct volumes than patients without AF (mean: 29.7 ± 45.8 ml vs. 15.2 ± 35.1 ml; p<0.001). Lesions in AF patients accumulated in the right central middle cerebral artery territory. Increasing stroke size predicted progressive cortical but not pontine and thalamic involvement. Patients with new AF had more frequently lesions in the right insula compared to patients without AF when stroke size was not accounted for, but no specific brain region was more frequently involved after adjustment for infarct volume. Controlled for stroke size, ConclusionsIn the search for brain areas potentially triggering cardiac arrhythmias infarct size should be accounted for. After controlling for infarct size, there is currently no evidence that ischemic stroke lesions of specific brain areas are associated with new AF compared to patients without AF. This challenges the neurogenic hypothesis of AF according to which a relevant proportion of new AF is triggered by ischemic brain lesions of particular locations.