[Idiopathic atrial fibrillation of recent onset and atrial stunning: the echocardiographic evidence after pharmacological cardioversion].

Successful cardioversion of atrial fibrillation may result in prolonged recovery of normal atrial mechanical function. This prolonged recovery of atrial contraction (so-called atrial stunning) might depend on: the amount of energy delivered during direct current cardioversion; the time course between the onset of atrial fibrillation and the conversion to sinus rhythm; the size of the left atrium; the underlying cardiac disease. The aim of this study was to evaluate, in subjects with normal atrial size and without heart disease, the phenomenon of atrial stunning soon after pharmacological cardioversion of an episode of atrial fibrillation of recent onset. Twenty-five patients with an acute episode of atrial fibrillation, without evidence of heart disease and M-mode left atrial dimension (< or = 40 mm received i.v. propafenone or flecainide 2 mg/kg/10 min in order to restore sinus rhythm. Atrial fibrillation lasted < 48 hours in all patients. Doppler echocardiography was used to assess atrial function, by recording the peak velocity of atrial contraction (A wave). An echocardiographic study was performed within 12 hours of successful cardioversion and was repeated on day 3, 12 and 30. The size of the left atrium (37 +/- 3.9; 37.57 +/- 2.9; 37.4 +/- 4; 37.82 +/- 3.7 mm) and peak E velocity (57.97 +/- 18.3; 59.4 +/- 18.3; 59.0 +/- 16; 59.07 +/- 16.7 cm/s) did not show any significant differences over the time, as demonstrated by the serial echocardiographic evaluations. In contrast, both peak A velocity (cm/s) and E/A ratio evaluated within 12 hours of cardioversion (60.29 +/- 12.3 and 1.0 +/- 0.37) and on day 3 (73.71 +/- 10.7 and 0.82 +/- 0.27) were statistically different (p < 0.000001 and p < 0.00001). No further statistically significant increase was found in subsequent examinations (respectively 76.31 +/- 12 and 0.78 +/- 0.24 on day 12, and 76.91 +/- 14.8 and 0.78 +/- 0.21 on day 30). In conclusion, this study suggests that patients with alone atrial fibrillation of recent onset have a delayed recovery of normal atrial systolic function even after pharmacological cardioversion.