BENEFICIAL EFFECTS OF SINUS RHYTHM ON HEMODYNAMIC PARAMETERS

具体目的：1)确定心房颤动的化学或电复律（和长期药物抑制）策略对左心室功能、运动耐量和内在心脏收缩力的长期影响。2)如果心功能出现长期改善，确定这种改善的时间过程和机制。有待验证的假设：1)慢性心房颤动患者的内在心脏收缩力受损。2)这种损害的机制是：A)持续性心动过速。B)舒张充盈异常导致舒张功能障碍。3)如果慢性房颤得到成功的抑制，长期心室功能可以得到改善。

Specific aims: 1) To determine the long term effect of a strategy of chemical or electrical cardioversion (and long term pharmacologic suppression) of atrial fibrillation on left ventricular function, exercise tolerance, and intrinsic cardiac contractility. 2) If long term improvement in cardiac function occurs, to determine the time course and mechanism of that improvement. Hypotheses to be tested: 1) Intrinsic cardiac contractility is impaired in patients with chronic atrial fibrillation. 2) The mechanism of that impairment is: A) Persistent tachycardia. B) Abnormal diastolic filling leading to diastolic dysfunction. 3) Long term ventricular function can be improved if chronic atrial fibrillation is successfully suppressed.