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Background: The micro waveform of His bundle potential can't be recorded beat-to-beat on surface electrocardiogram yet. We have found that the micro-wavelets before QRS complex may be related to atrioventricular conduction system potentials. This study is to explore the possibility of His bundle potential can be noninvasively recorded on surface electrocardiogram.Methods: We randomized 65 patients undergoing radiofrequency catheter ablation of paroxysmal superventricular tachycardia (exclude overt Wolff-Parkinson-White syndrome) to receive "conventional electrocardiogram" and "new electrocardiogram" before the procedure. His bundle electrogram was collected during the procedure. Comparative analysis of PAs (PA interval recorded on surface electrocardiogram), AHs (AH interval recorded on surface electrocardiogram) and HVs (HV interval recorded on surface electrocardiogram) interval recorded on surface "new electrocardiogram" and PA, AH, HV interval recorded on His bundle electrogram was investigated.Results: There was no difference (P > 0.05) between groups in HVs interval (49.63 ± 6.19 ms) and HV interval (49.35 ± 6.49 ms). Results of correlational analysis found that HVS interval was significantly positively associated with HV interval (r = 0.929; P < 0.01).Conclusions: His bundle potentials can be noninvasively recorded on surface electrocardiogram. Noninvasive His bundle potential tracing might represent a new method for locating the site of atrioventricular block and identifying the origin of a wide QRS complex. [ABSTRACT FROM AUTHOR]

The diagnosis of myocardial infarction with left bundle branch block is difficult. We report a case of 56-year-old man with old extensive anterior myocardial infarction and left bundle branch block (masked each other). The recurrent myocardial infarction indicated right bundle branch block and first-degree atrioventricular block, making a clear diagnosis of complicated and interesting ECG. [ABSTRACT FROM AUTHOR]

Objective: To formulate the classification criteria of femoral intertrochanteric fractures based on irreducibility or not in order to predict the difficulty of fracture recovery., Methods: A clinical data of 244 patients with closed femoral intertrochanteric fractures admitted between January 2017 and March 2020 was retrospectively analyzed. There were 116 males and 128 females with an average age of 77.9 years (range, 45-100 years). The cause of injury included falling in 190 cases, traffic accident in 36 cases, smashing in 13 cases, and falling from height in 5 cases. The time from injury to operation was 1-14 days (mean, 3.6 days). According toAO/Orthopaedic Trauma Association (AO/OTA) classification, the fractures were classified as type 31-A1 in 38 cases, type 31-A2 in 160 cases, and type 31-A3 in 46 cases. According to whether the recovery difficulty occurred after intraoperative closed traction reset, the patients were divided into reducible-group and irreducible-group; combined with the literature and preoperative imaging data of two groups, the classification criteria of femoral intertrochanteric fractures was formulated based on the irreducibility or not. The 244 fractures were classified by the doctors who did not attend the operation according to the classification criteria, predicted the difficulty of fracture reduction, and compared with the actual intraoperative reduction situation., Results: The 244 patients were divided into reducible-group ( n =164, 67.21%) and irreducible-group ( n =80, 32.79%) according to the intraoperative difficulty of reduction. Comparing the imaging data and characteristics of the two groups, and formulating the classification criteria of femoral intertrochanteric fractures based on irreducibility or not, the fractures were mainly divided into two categories of irreducibility and reducibility. The fractures of irreducibility category was divided into typesⅠ-Ⅴ, among which type Ⅲ was divided into subtypes 1-4; the fractures of reducibility category was divided into typesⅠand Ⅱ. Compared with the actual intraoperative evaluation results, the total accuracy rate of the doctors who did not attend the operation was 81.15% (198/244) based on the classification criteria of femoral intertrochanteric fractures. The accuracy rate of irreducibility category was 65.74% (71/108), and the reducibility category was 93.38% (127/136). All patients were followed up 13-25 months, with an average of 17.6 months. All fractures healed except 2 cases died of infection., Conclusion: The classification criteria of femoral intertrochanteric fractures based on irreducibility or not can accurately predict the reducible cases preoperatively, and most of the irreducible cases can be correctly predicted in a wider way. But the classification criteria still need to be further improved and supplemented.