Response by Lubitz et al to Letter Regarding Article, “Stroke as the Initial Manifestation of Atrial Fibrillation: The Framingham Heart Study”

We thank Drs Sposato, Fridman, and Saposnik for their thoughtful comments. We agree that the relations between stroke and atrial fibrillation may be bidirectional and warrant further study. As the investigators mentioned, in some cases, stroke has been cited as a cause of atrial fibrillation. Clinical clues such as coronary artery disease status, cardiac dimensions and function, brain magnetic resonance imaging, and other characteristics of the stroke could also help in weighing the probability of whether atrial fibrillation detected after stroke is causal or a consequence of brain ischemia. We look forward to future results that might help distinguish the cause of atrial fibrillation after a stroke and inform patient management.