目的探讨左、右心房肌复极,及其易损性与阵发性心房颤动(AF)的发生与维持机制。方法应用单相动作电位(MAP)技术记录14只犬左、右心房肌的复极达90%动作电位时程(APD90),通过S1S2程序刺激,同时记录心房有效不应期(ERP)及相对不应期(RRP),观察反复心房激动(RAF,在S1S2的早搏刺激后,发生2个以上的连续心房活动,从心房刺激到RAF第一个激动的间期必须小于250 ms)及AF的诱发。结果14只犬S1S2间期递减至130±32 ms时,可出现RAF,随后当S1S2间期缩短为110±28 ms时AF发作。AF发作前大多数可记录到RAF(66.7%);共诱发出15阵RAF,左房11阵,右房4阵,左房RAF的发生率明显多于右房(P<0.05);共诱发出18阵AF,左房诱发出12阵,右房诱发出6阵。左房的AF诱发率明显多于右房(P<0.05)。结论AF发作前多伴有RAF发作;RAF是易发生阵发性AF的特征性表现,代表心房的易损性;左右心房易损性不同。 Objective To investigate the repolarization of left and right atrial myocardium, its vulnerability and the mechanism of occurrence and maintenance of paroxysmal atrial fibrillation (AF). Methods Single-phase action potential (MAP) technique was used to record the APD 90% of the left and right atria of the right and left atriums stimulated by S1S2 program. Meanwhile, the atrial effective refractory period (ERP) and the relative Refractory period (RRP), repeated atrial activation (RAF, more than two consecutive atrial activities after S1S2 premature stimulation, and less than 250 ms between atrial stimulation and first RAF) and AF Induced. Results The reduction of S1S2 in 14 dogs to 130 ± 32 ms was associated with an appearance of RAF, followed by AF episodes when the S1S2 interval was shortened to 110 ± 28 ms. The incidence of RAF was significantly higher in the left atrium than in the right atrium (P <0.05), and most of them were recorded RAF before the onset of AF (66.7%). A total of 15 RAFs, 11 left atrium and 4 right atrium were found. Out of 18 AF, left atrium induced 12 array, right atrium induced 6 array. Left atrial AF induction rate was significantly more than the right atrium (P <0.05). Conclusions The onset of RAF is often accompanied by episodes of RAF. RAF is a characteristic manifestation of paroxysmal AF and represents the vulnerability of the atria. The vulnerability of left and right atria is different.