患者男性,42岁,胸椎骨折。心电图发现:P波在Ⅱ,Ⅲ,avF等导联均为倒置,avR,V_1导联直立。P’—P’间距均齐,为0.25秒,心房率240次/分。P’—R间期为0.15秒。R—R间距不齐,平均心室率90次/分。以第Ⅱ导联为例,第1至20次p’波之间有3:1～2:1传导阻滞。第2、5、10、15、18个 P’波不能下传到心室,但P’波的激动深入到房室结(隐匿性传导)。因此,第3、 Male patient, 42 years old, with thoracic fracture. ECG found: P wave in Ⅱ, Ⅲ, avF and other lead are inverted, avR, V_1 lead upright. P’-P ’are evenly spaced, 0.25 seconds, atrial rate of 240 beats / min. The P’-R interval is 0.15 seconds. R-R gap between the average ventricular rate of 90 beats / min. Take the second lead as an example, there is a 3: 1 ~ 2: 1 block between the first and the 20th p ’waves. The 2nd, 5th, 10th, 15th and the 18th P ’waves can not be transmitted to the ventricle, but the P’ wave excites deeply into the AV node (occult conduction). Therefore, the 3rd,