Acute Efficacy and Chronic Follow-Up of Patients with Non-Thoracotomy Third Generation Implantahle Defibrillators

Non-thoracotomy implantation of implantable cardioverter defibrillators (ICDs) has simplified the process of device inserfion, promising to decrease associated procedural coniplications while providing sudden death protection at least equal to epicardial systems. This study presents the acute and chronic results of 110 patients who underwent attempted non-thoracotomy ICD impiuntation wiih the Medtronic Transvene lead system and PCD model 7217 or 7219. Of the 110 patients attempted, 100 (91%) had the system successfully implanted without the need for an epicar-dial patch. One patient died 1 week postoperatively of septic shock related to the implantation (0.9% perioperative mortality). During folloiv-up of 16 ± 11 months, 45% of the patients had an event detected as ventricular tachycardia; 26% of these detections were felt clinically to be due to supraventricular rhythms. Of the remainder, 87% were successfully treated with the first VT therapy, and 98% were terminated by the final therapy; 66% of the patients had at least one episode of ventricular fibrillation, of which 5% were felt to be inappropriate detections; 65% of the appropriate episodes were successfully treated with the first VF therapy, and all were converted by the final therapy. Total mortality at 6, 12, and 24 months was 3%, 11%, and 19% respectively. Only one patient had sudden cardiac death, occurring at 13 months postimplant. Overall, the non-thoracotomy lead system for this ICD displayed infrequent implant complications and proved to be reliable ai terminating arrhythmias and maintaining a low rate of sudden cardiac death in this high risk popuiation.     

射频消融迷宫术治疗心房纤颤

作者采用射频消融迷宫术治疗心房纤颤２０例，其中１９例合并风湿性二尖瓣病的患者，同时行瓣膜替换术，１例合并房间隔缺损患者进行修复。射频消融的路线采用小板井嘉夫的手术径路。术后１６例恢复窦性心律，占８０％，未恢复窦性心律的４例，２例为房颤，１例为房扑，另１例为结性心律。射频消融迷宫术耗时短，仅增加钳闭主动脉时间平均２０．５分钟，无术后出血的潜在危险。但术后７～１０天之内，有１８例出现过房颤、房扑、房速等室上性心律失常，可能由于射频消融不均匀，干扰心房的心电活动所致。     

Quantification of the Modifications in the Dominant Frequency of Ventricular Fibrillation under Conditions of Ischemia and Reperfusion: An Experimental Study

The characteristics of ventricular fibrillatory signals vary as a function of the time elapsed from the onset of arrhythmia and the maneuvers used to maintain coronary perfusion. The dominant frequency (FrD) of the power spectrum of ventricular fibrillation (VF) is known to decrease after interrupting coronary perfusion, though the corresponding recovery process upon reestablishing coronary flow has not been quantified to date. With the aim of investigating the recovery of the FrD during reperfusion after a brief ischemic, period, 11 isolated and perfused rabbit heart preparations were used to analyze the signals obtained with three unipolar epicardial electrodes (E1-E3) and a bipolar electrode immersed in the thermostatizfid organ bath (E4), following the electrical induction of VF. Recordings were made under conditions of maintained coronary perfusion (5 min), upon interrupting perfusion (15 mini, and after reperfusion (5 min), FrD was determined using Welch's method. The variations in FrD were quantified during both ischemia and reperfusion, based on an exponential model AFrD = A exp (-t/C). During ischemia ΔFrD is the difference between FrD and the minimum value, while t is the time elapsed from the interruption of coronary perfusion. During reperfusion ΔFrD is the difference between the maximum value and FrD, while t is the time elapsed from the restoration of perfusion, A is one of the constants of the model, and C is the time constant. FrD exhibited respective initial values of 16.20 ± 1.67, 16.03 ± 1.38, and 16.03 ± 1.80 Hz in the epicardial leads, and 15.09 ±1.07 Hz in the bipolar lead within the bath. No significant variations were observed during maintained coronary perfusion. The fit of the FrD variations to the model during ischemia and reperfusion proved significant in nine experiments. The mean time constants C obtained on fitting to the model during ischemia were as follows: El =294.4 ± 75.6, E2 = 225.7 ± 48.5, E3 = 327.4 ± 79.7, and E4 = 298.7 ± 43.9 seconds. The mean values of C obtained during reperfusion, and the significance of the differences with respect to the ischemic period were: El = 57.5 ± 8.4 (P ± 0.01), E2 = 64.5 ± 11.2 (P0.01), E3 = 80.7 ± 13.3 (P < 0.01), and E4 = 74.9 ± 13.6 (P < 0.0001). The time course variations of the FrD of the VF power spectrum fit an exponential model during ischemia and reperfusion. The time constants of the model during reperfusion after a brief ischemic period are significantly shorter than those obtained during ischemia.     

小剂量氨茶碱治疗缓慢室率性房颤的长期疗效观察

目的研究小剂量氨茶碱对老年缓慢心室率性心房纤颤的长期疗效。方法１５例有症状的老年缓慢心室率性房颤病人口服氨茶碱（１５０ｍｇ／ｄ）。治疗前及治疗后第７天、第１、３、６、９及１２个月行心电图及动态心电图检查。结果以均数±标准差表示，采用秩和检验分析差异显著性。结果治疗后第７天静息心率、２４小时平均心率、最慢心率及最快心率分别增加３８％（Ｐ＜０．０１）、２８％（Ｐ＜０．０１）、２６％（Ｐ＜０．０５）及１６％（Ｐ＜０．０１），２４小时＞２５００ｍｓ的心脏停搏次数减少９４％（Ｐ＜０．０１），室性早搏次数增加６％，但差异不显著。随访１２个月（中位数），各项参数与治疗后第７天的结果相似，临床症状明显减轻或消失。结论小剂量氨茶碱治疗老年缓慢心室率性房颤有效。     

Experimental studies of electroacupuncture on ventricular fibrillation threshold in rats with acute ischemic myocardium

Summary By ligating the proximate left anterior descend (LAD) of coronary artery and inducing the ventricular fibrillation with electrical stimulation, the preventive effects of electroacupuncture (EA) on ventricular fibrillation were observed. The results showed that the ventricular fibrillation threshold (VFT) of rats with acute ischemic myocardium was raised after acupuncturing some acupoints, which could prevent the occurrence of ventricular fibrillation. Furthermore, the combination of EA and propranolol could enhance the VFT effectively, and they showed a good synergistic effect. This project was supported by grants from National Natural Science Foundation of China (No. 3870563).     

二尖瓣病变伴左房血栓的外科治疗

本文报道了18例风湿性心脏病伴有左房血栓病人的手术治疗,其中瓣膜置换者5例,二尖瓣直视成形者13例。死亡4例中1例死于脑栓塞。血栓形成和房颤有直接关系。左房血栓术前诊断主要依靠心脏B超,血栓治疗以手术清除为主。为预防术后再发,应纠正房颤及适当应用抗凝血药物。     

The influence of intravenous magnesium sulphate on the occurrence of atrial fibrillation after coronary artery by-pass operation

To examine the influence of (Mg) on hypomagnesaemia and atrialfibrillation (AF) following coronary artery by-pass surgery,140 consecutive patients were randomized to receive 70 mmolof magnesium sulphate intravenously (n = 69) or placebo (n =71). Serum magnesium concentrations fell to 0.77 ± 0.10mmol. l^–1 in the control group but rose to 1.09 ±0.17 mmol. l^–1 in the Mg group (P <0.001). The incidenceof AF was 29% in the Mg group and 26% in the placebo group (NS).The AF patients were older, more of them had had prior AF episodes,their sinus rates (SR) were slower (78 ± 10 vs 86 ±12 beats. Min^–1; P <0.01) and serum Mg concentrationshigher (0.89 ± 0.21 vs 0.11 mmol. ^l–1; P <0.05)The incidence of AF was 43% in the highest quartile of serumMg and 23% among the rest (P = 0.056). In patients experiencingAF during the first three post-operative days, serum Mg concentrationswere higher and SR slower on each day compared with non-AF patients.SR increased post-operatively less with high Mg levels (P =0.044). In the Mg group, serum Mg and SR were the only independentpredictors of AF. In conclusion, the incidence of post-operativeAF is not decreased with magnesium. High Mg levels are likelyto provoke AF probably by mechanisms that modify SR.     

Bidirectional transvenous/subcutaneous defibrillation of ventricular fibrillation in dogs: success rates, energy requirements, currents, voltages and impedance

Four hundred and thirteen defibrillations of alternating current-inducedventricular fibrillation were performed in 10 halothane-anaesthetizeddogs (body weight: 24.5–30.5 kg). Success rates, energydemands, currents, peak voltages and impedance were determined.A transvenous catheter electrode system (Medtronic 6880, rightventricular apex and superior vena cava, distance 100 or 150mm) and subcutaneous patch electrodes (Intec 67 L, 2nd/3rd and/or3rd/4th left intercostal space) were used for bidirectionaldefibrillation. Loading voltages ranged from 600 to 850 V. Withan electrode distance of 100 mm and a pulse duration of 2 msseparated by 1 ms, success rates were 100%, 40% and 0% for 850,650 and 600 V, respectively. With a 3-ms pulse duration, thecorresponding rates were 100%, 60% and 50%. With a 2-ms pulseduration, successful defibrillation was achieved with energieslower than 15 J in 27%, with energies between 15 and 20 J in77%, and 100% with energies higher than 20 J. Defibrillationcurrents were 4.4–9.3 A for pulse 1 (superior vena cava/ventricularapex) and 6.3–13.4 A for pulse 2 (patch/ventricular apex),respectively. Effective peak voltages ranged from 510 to 787V and from 514 to 777 V and averaged 89.6% of the loading voltages.Impedance values (peak voltage/current) were 75.5–117.7(pulse 1) and 51.7–94.9 Ohms (pulse 2). Fifty consecutivedefibrillations in one animal resulted in a decrease of impedance(114.6 to 84.9 Ohms, pulse 1; 75.4 to 53.0 Ohms, pulse 2). Defibrillationof ventricular fibrillation can be achieved with acceptablylow energies using a bidirectional transvenous/subcutaneoussystem, avoiding thoracotomy and general anaesthesia for implantationof the defibrillation system.     

中国肥厚型心肌病患者血栓栓塞事件风险预测模型的构建研究

背景 血栓栓塞（TE）事件是肥厚型心肌病（HCM）的重要并发症。目前针对HCM患者TE事件的风险预测,仅国外学者构建了两个模型：HCM Risk-CVA及French HCM score,然而,现有研究发现HCM Risk-CVA模型对于中国HCM患者的临床价值较为有限。目的 本研究拟构建适合中国HCM患者的TE事件风险预测模型。方法本研究系回顾性队列研究,收集2010—2018年在四川大学华西医院就诊的537例HCM患者的病例资料。本研究通过电话随访或电子病历系统查询患者就诊记录,每6～12个月随访1次,直至出现终点事件或死亡或研究拟定的评估日期（2019-12-31）,终点事件定义为复合性TE事件。采用单因素和多因素Cox回归分析构建风险预测模型,并使用自助重抽样的方法进行内部验证。结果 537例患者中,24例患者有不同程度的数据缺失,最终纳入513例患者。中位随访时间为4.2(1.3,6.2)年,随访过程中42例（8.18%）发生TE事件,年发病率为2.10%[95%CI(1.47%,2.73%)]。根据多因素Cox回归模型构建TE事件风险预测模型,最终纳入年龄、既往TE事件、心...