Hidden heart rhythm problem may underlie some strokes

Brain attacks tied to undiagnosed atrial fibrillation in two clinical studies

Monitoring stroke patients’ heartbeats after they leave the hospital reveals that some have atrial fibrillation that was previously undetected, two studies find. Atrial fibrillation, a heartbeat that’s occasionally out of rhythm, is itself a risk factor for stroke, but some people don’t know they have it.