Transient atrial mechanical dysfunction assessed in acute phase of embolic stroke of undetermined source

Background and Purpose: Paroxysmal atrial fibrillation (PAF) has been suggested as a major cause of embolic stroke of undetermined source (ESUS). Transient atrial mechanical dysfunction (stunning) frequently occurs after conversion of atrial fibrillation to sinus rhythm. The study aim was to determine if reversible atrial mechanical dysfunction in ESUS could help elucidate the mechanism of stroke. Methods: Eighty-five consecutive patients with acute ischemic stroke were enrolled according to the following inclusion criteria: [1] ≥55 years old; [2] normal sinus rhythm upon admission; [3] no apparent embolic source; and [4] transthoracic echocardiographic evaluation had been performed in both the early phase (7 days) after stroke onset. There were 27 patients in the lacunar or atherothrombotic infarction group (controls), 22 in the PAF group, and 36 in the ESUS group. To determine atrial stunning, transmitral flow velocity profiles (Doppler peak E- [early diastolic] and A- [atrial systolic] waves) were obtained. Results: In the early phase, an E/A velocity ratio ≥ 1.0 was less common in the control group (1 patient, 3.7%) than in the PAF group (19 patients, 86.4%; p