Termination Of Sustained Tachycardia By External Noninvasive Pacing

Invasive cardiac pacing has proved useful in the induction and termination of reentrant sustained tachycardias. In one of our two cases, programmed ventricular extra-stimulation was used to induce sustained ventricular tachycardia from the endocardial surface of the right ventricle. Induced ventricular tachycardia was terminated by burst ventricular pacing with an external cardiac pacemaker. In our second patient, external pacing was effective at inducing and terminating sustained supraventricular tachycardia. These patients illustrate that the principles of terminating sustained reentrant tachycardia with invasive pacing may also apply to noninvasive external pacing. The usefulness of this approach in treating reentrant tachycardias needs further evaluation.     

Evaluation of left ventricular contractile performance from baseline stress-shortening data in humans: comparison with pharmacological afterload challenge

The purpose of this study was to evaluate whether the baseline stress-shortening data reflect the contractile state adequately and give results comparable to the evaluation of the end-systolic stress-shortening relationships using pharmacological manipulation of afterload. Five groups were studied (total 152 patients): a control group of 30 healthy volunteers, 32 patients after surgical correction of infantile tetralogy of Fallot, 50 patients treated for childhood malignancies with doxorubicin, 17 patients with left ventricular hypertrophy due to systemic hypertension, and 23 patients with congestive cardiomyopathy. In all patients except those with congestive cardiomyopathy, afterload was altered pharmacologically to evaluate the individual stress-shortening relationship. In all patients the baseline stress-shortening data were evaluated, as well as their relative positions to two predefined normal ranges for the relationship between end-systolic stress and shortening. Additionally, a slope value was calculated from the baseline data of the five groups studied and compared with the data obtained by pharmacological afterload increment. Our data show that the comparison of individual baseline data of end-systolic wall stress and fractional shortening with predefined normal ranges for the relationship between end-systolic stress and shortening is inadequate. The appropriate normal range to compare with is the 95% confidence interval of baseline stress-shortening data in normal subjects. Also the calculation of a slope value from the baseline stress-shortening data of a group of patients seems to be inappropriate. Such a slope value does not necessarily reflect the contractile state, as the specific conditions leading to variations of end-systolic wall stress are undefined and not standardized, and the correlation between baseline stress-shortening data depends largely on the influence of the end-systolic dimension on both parameters.     

无心肌梗死冠心病患者心功能变化与室性心律失常的关系

目的：探讨冠心病心力衰竭对各种室性心律失常的影响。方法：选择381例冠心病住院患者，根据心功能分级标准（NYHA）分为4组，检测24h动态心电图（Holter），分析室性心律失常类型及发生率，进行统计分析。结果：各级心功能组其室性心律失常发生率经x^2检验示，室性心律失常的发生率除联律和持续性或非持续性室性心动过速外各组间差异无显著性（P＞0．05）。结论：非心肌梗死冠心病患者室性心律失常发作频率与心力衰竭的程度无关，但联律和持续或非持续性室性心动过速在重度心力衰竭患者发生率增加。     

血管紧张素转换酶抑制剂在急性心肌梗塞早期的应用

对２５例急性心肌梗塞（ＡＭＩ）并左心功能不全患者早期应用血管紧张素转换酶抑制剂（ＡＣＥＩ）治疗的对照性临床分析，结果：用小剂量的ＡＣＥＩ治疗对患者心率、血压无显著的影响〔治疗前后心率分别为８９．９０±１０．２２次／分与８９．４２±８．１９次／分，血压分别为１５．３７±３．４６／９．７４±２．３２ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ）〕和１４．９６±２．６０／９．４６±１．７６ｋＰａ〕；对合并轻、中度泵衰竭患者的疗效显著，但对重度泵衰竭的疗效与对照组比较无显著性差异；治疗组恶性心律失常的发生率较对照组减低１３．３８％，警告性室早的发生率治疗组较对照组减少２６．３９％，但Ⅱ°～Ⅲ°房室传导阻滞的发生率治疗组高于对照组；两组４周病死率比较无显著性差异。作者认为：ＡＣＥＩ治疗ＡＭＩ并轻、中度泵衰竭安全有效；ＡＣＥＩ有一定抗心律失常作用，但应注意传导系统的并发症，使用中应注意各种副作用的发生。     

Left ventricular growth in a patient with critical coarctation of the aorta and hypoplastic left ventricle

An infant is presented who at birth met criteria consistent with hypoplastic left heart syndrome. He was followed clinically and by 11 weeks of age demonstrated substantial growth of the left ventricle. He underwent successful repair of coarctation of the aorta and continues to do well with moderate aortic stenosis. The difficulties of predicting left ventricular growth and function are discussed, and management options are reviewed.     

STUDY OF MORPHOLOGICAL CHANGES OF HEART IN VIRAL MYOCARDITIS CAUSED BY REPETITIVE INFECTION OF CVB3m

Objective To investigate the morphological changes of heart in viral myocarditis caused by repetitive infection of CVB3m. Methods 4-week-old mice were infected four times intraperitoneally with a timedependent dose and killed at the 10th, 30th and 60th day after the final infection respectively, then we examined the heart changes and collagen hyperplasia by HE, VG stain and 1HC. Results Heart damage appeared very serious at the tenth day, even there were small necrotic foci at the day of 30th, but we could not see any injury of heart 2 months later after final infection. Collagen turned up at the tenth day and there was much more collagen in heart and increased PCVA, CVF index at the sixtieth day. The 1HC of collagen demonstrated the collagen I hyperplasia was much obvious compared to collagen Ⅲ. Conclusion It strongly indicated that repetitive infection of CVB3m could lead to heart fibrosis and ventricular remodeling, which resulted in decreased systolic and diastolic function of heart.     

Modified Damus–Kaye–Stansel procedure using aortic flap technique for systemic ventricular outflow tract obstruction in functionally univentricular heart

Damus–Kaye–Stansel procedure is a useful method to relieve the systemic ventricular outflow tract obstruction in functionally univentricular heart. Regurgitation of pulmonary valve and recurrence of systemic ventricular outflow obstruction are the major concerns at the late phase of this procedure. Modification of original Damus–Kaye–Stansel procedure that can prevent the use of prosthetic materials is evaluated. The modified Damus–Kaye–Stansel procedure using aortic flap technique was performed in eight patients with functionally univentricular heart. Patients’ ages ranged from 3 to 28 months (mean 14 months). Follow-up period was 37 months as a mean (9–71 months), and the follow-up was complete. There was no operative mortality and no late death. In addition, there was no recurrence of systemic ventricular outflow tract obstruction throughout the follow-up period. Regurgitation of the pulmonary valve estimated by echocardiography at the latest follow-up was none to trivial in seven patients and mild in one. The modified Damus–Kaye–Stansel procedure using aortic flap technique is a safe, useful and reproducible technique to solve systemic ventricular outflow tract obstruction in functionally univentricular heart, and it can be an alternative for original technique or the so-called double-barrel modification.     

顽固性室性早搏的射频消融治疗

目的 :通过对 2 3例顽固性室性早搏 (简称室早 )的射频消融分析 ,探讨室早的心电图特点、消融方法及效果 .方法 :男性 16例 ,女性 7例 ,均为频发、药物难治、症状明显的顽固性单形性室早患者 ,年龄(4 4 4± 9 6 )岁 .采用起搏标测和激动顺序标测 ,前者以起搏时与室早QRS波形态完全相同点为消融靶点 ,后者以早搏时最早心室激动点为消融靶点 .2 3例中 17例室早起源于右室 ,4例起源于左室 .消融即刻成功率86 9% ,累积放电 (930 4± 72 5 )s,成功者行动态心电图检查记录消融前后室早数为 (5 6 71± 2 4 36 )次 / 2 4h和 (39± 5 2 )次 / 2 4h (P <0 0 1) .随访 (2 3 2± 12 3)月 ,未服任何抗心律失常药 ,无 1例复发及并发症发生 .结论 :射频消融可有效而安全地消除单形性室早 ,采用粗标激动顺序、精标起搏图形 ,多点、长时间、高功率放电可提高成功率 ,降低复发率 ,可作为症状严重、药物无效或不能耐受患者的治疗选择     

内皮素在评价不阻断升主动脉低温室颤对心肌保护作用中的应用

①目的探讨体外循环条件下低温室颤技术对心肌的保护作用。②方法14只健康成年犬随机分为两组，低温停跳组(n=7)与低温室颤组(n=7)，分别检测两组手术前、手术1、2小时和复跳后1小时4个时间点血内皮素(ET)的水平。③结果室颤组ET水平明显低于停跳组。④结论通过内皮素水平的变化，说明体外循环条件下低温室颤技术是一种安全、有效的心肌保护方式，优于传统低温停跳技术。     

慢性心房颤动患者心室率变化意义的探讨

目的分析探讨慢性心房颤动患者心室率变化的意义，为临如何预防心房颤动患者出现脑栓塞、心功能降低等并发症提供理论依据。方法将入院或门诊就诊病程超过1年的慢性心房颤动患者分为脑栓塞组和非脑栓塞组，各30例，观察比较两组患者临床特征，动态心电图计数比较两组患者最大心室率、平均心室率及最小心室率变化，超声心动图测定两组患者左房内径大小、左室射血分数变化，血浆凝血酶原时间凝固法测定两组患者血浆凝血酶原时间国际标准化比值（INR）变化。结果两组患者一般临床特征、左房内径大小、INR值比较。差异无统计学意义。脑栓塞组最大心室率、平均心室率及最小心室率均明显快于非脑栓塞组，左室射血分数明显低于非脑栓塞组。结论慢性心房颤动患者降低心室率对预防脑栓塞、左心功能降低有重要意义。