平板运动试验前后Q-T_(cd)、J-T_(cd)变化的意义

本文观察了140例平板运动试验患者运动前后心电图Q-T_(cd)、J-T_(cd)的变化,结果:①运动试验阳性组运动前后2项指标差异显著(P<0.05),阳性组中有症状组与无症状组之间差异不显著(P>0.05);②运动前,阳性组与阴性组之间差异不显著(P>0.05),运动后2组之间差异显著(P<0.05)。提示:运动试验阳性患者运动后Q-T_(cd)J-T_(cd)延长,有症状组与无症状组心肌缺血程度相似。     

平板运动试验前后Q—Tc,J—Tc离散度的变化

为了解Q-T_(cd)、J-T_(cd)对活动平板运动试验结果判断的价值。对50例活动平板运动试验阳性者及51例阴性者运动前后的心电图Q-T_(cd)、J-T_(cd)进行对比观察。结果显示:运动前两组Q-T_(cd)、J-T_(cd)变化差异均无显著意义(P均>0.05);运动后2min运动试验阳性组与阴性组比较Q-T_(cd)、J-T_(cd)差异有非常显著意义(P均<0.01);阳性组运动后2minQ-T_(cd)、J-T_(cd)均较运动前显著延长(P均<0.01);阴性组运动后2minQ-T_(cd)、J-T_(cd)与运动前比较差异无显著意义(P均>0.05)。提示运动试验后Q-T_(cd)、J-T_(cd)延长可作为判断运动试验结果的指标。     

平板运动试验前后Q—T离散度的半随机对照研究

为探讨冠心病患者运动试验后Q-T_d 改变的规律, 观察508例患者平板运动试验前后Q-T_d、Q-T_(cd)变化.结果显示:阳性组运动后1、3min Q-T_(cd)(3293±1090、31.01±11.09ms)比阴性组(28.91±10.03、27.00±10.08ms)显著延长(P<0.01,P<0.05);且比运动前(26.30±10.53ms)显著延长(P<0.05),认为Q-T_(cd)可作为冠心病运动试验的一项有价值的参数.     

200例心电图Q—Tc离散度分析

为评价Q-T_c离散度(Q-T_(cd))的临床意义,观察100例正常人,50例冠心病和50例高血压心脏病患者12导联ECG的Q-T_(cd)。发现正常组男、女之间Q-T_c有显著性差异(P<0.001),平均女比男长18ms;但Q-T_(cd)无显著性差异(P>0.05)。冠心组和高心组的Q-T_(cmin)接近于正常组(395.9±24.6ms),而Q-T_(cmax)则均明显大于正常组(418.5±24.7ms);Q-T_(cd)冠心组和高心组(50.3±17.0ms、48.1±18.3ms)明显大于正常组(22.7±8.1ms,P<0.001)。在正常组由X、Y、Z导联测得的Q-T_(cd)(15.7±11.4ms)比12导联测值偏小。Q-T_(cd)增大多见于VCG中T环呈圆形或马蹄形患者,冠心组中有24例,其Q-T_(cd)平均达63.0±12.7ms。认为Q-T_d增大是预告严重室性心律失常简明有用的指标。     

冠心病Q—T离散度与△ST／△HR指数关系的研究

为探讨Q-T离散度(Q-T_d和Q-T_(ed)与凸ΔST/ΔHR指数的关系,观察57例平板运动试验阳性的冠心病患者(冠心病组)和60例运动试验阴性者(对照组)的心电图,比较运动前后Q-T_d和Q-T_(ed)及其与ΔST/ΔHR指数的关系.结果显示:两组运动前Q-T_d(20.35±10.34ms比16.17±10.27ms)、Q-T_(ed)(22.42±11.62ms比17.98±11.62ms)差异均有显著意义(P<0.05);两组运动后Q-T_d(22.11±9.40ms比15.17±94.8ms)、Q-T_(ed)(32.75±14.70ms比25.44±14.87ms)差异均有非常显著意义(P<0.01).冠心病组ΔST/ΔHR指数2.80±1.49μV/次/min,与运动前Q-T_d几和Q-T_(ed)均无关(P>0.05),与运动后Q-T_d和Q-T_(ed)均呈高度正相关(P<0.01).提示运动诱发的心肌缺血是加重心室肌复极不均一的重要因素,Q-T_d、Q-T_(ed)、ΔST/ΔHR指数可作为评定心电图运动试验心肌缺血严重程度的指标.     

急性心肌梗死Q—T离散度的意义

为了解急性心肌梗死患者严重心律失常与Q-T延长的关系,观察32例急性心肌梗死、20例陈旧性心肌梗死及50例对照组的Q-T_a、J-T_d及Q-T_(cd)的变化,结果急性心肌梗死组的Q-T_d、J-T_d及Q-T_(cd)分别为65.6±22.7,59.4±22.6及70±25ms,均显著高于陈旧性心肌梗死组和对照组(P<0.01)。并发现急性心肌梗死组严重室性心律失常发生率、心功能状况与Q-T_d延长程度有关。揭示Q-T_d对判断心肌梗死病情程度有一定参考价值。     

老年人运动试验结果与Q—T离散度变化的关系

为探讨Q-T离散度(Q-T_d)变化的机制,观察39例老年人踏车运动试验前后心肌复极Q-T_d变化。结果显示:运动试验阴性组运动前Q-T_d、Q-T_(cd)及Q-T_d/R-R分别为38.6±9.9ms、43.6±12.1ms及4.95±1.55％,阳性组运动前为40.6±14.8ms、45.9±17.3ms及5.29±2.01％,两组均无显著性差异(P>0.05)。阴性组运动后上述3值为26.4±8.5ms,35.4±10.1ms及4.77±1.24％,其中Q-T_d及Q-T_(cd)显著缩短(P<0.001及0.05);阳性组为35.9±9.4ms、48.9±12.9ms及6.59±1.86％,其中Q-T_d/R-R显著延长(P<0.001),两组有显著性差异(P<0.01—0.001)。提示运动缩短健康老年人心肌复极离散度,但运动诱发的心肌缺血却使之延长。     

扩张型心肌病,高血压性心脏病心功能不全患者Q—Td,Q—Tcd观察

为评价心功能不全患者Q-T_d、Q-T_d的临床应用价值,观察扩张型心肌病心功能不全患者(n=19)和高血压性心脏病心功能不全患者(n=20)Q-T、Q-T_c,并与健康成人(n=30)作对比。结果显示扩张型心肌病组与高血压性心脏病组Q-T_d无显著性差异(P>0.05),Q-T_(cd)有显著性差异(P<0.05),但均显著高于对照组(P<0.01),认为Q-T_(cd)比Q-T_d更能准确反映心肌复极离散程度。扩张型心肌病心功能不全患者Q-T_d、Q-T_(cd)增加最显著可能与其预后不良有关。     

甲状腺功能亢进性心脏病的Q—T离散度分析

为探讨甲状腺功能亢进性心脏病的Q-T离散度(Q-T_d及Q-T_(cd))变化的意义,分析41例甲状腺功能亢进性心脏病患者的体表12导联心电图并与42例单纯甲状腺功能亢进症患者及42例正常人作对照.结果显示甲状腺功能亢进性心脏病组Q-T_d、Q-T_(cd)均显著高于其余两组(P<0.01).以Q-T_d>42ms判为异常,诊断甲状腺功能亢进性心脏病的敏感性、特异性及准确性分别为82.9%、86.9%及85.6%;以Q-T_(cd)>46ms判为异常,诊断敏感性、特异性及准确性分别为82.9%、89.3%及87.2%.提示甲状腺功能亢进性心脏病患者的Q-T_d、Q-T_(cd)延长可作为临床诊断的一项参考指标.     

索他洛尔对室性期前收缩患者Q-T离散度的影响

为研究索他洛尔对Q-T离散度的影响,测量良性室性期前收缩患者(n=19)应用索他洛尔(160—320mg/天)前后的Q-T。离散度(Q-T_(cd)),并与安慰剂组(n=15)作对照。结果发现索他洛尔用药后最大Q-T_c间期、最小Q-T_c间期显著延长,Q-T_(cd)显著缩小,但与安慰剂组比较差异无显著意义;安慰剂组上述3项指标各时期比较无显著变化。提示索他洛尔剂量在160—320mg/天范围内不增加Q-T_(cd)。     

运动诱导心肌缺血时QTc离散度变化的意义

目的 :探讨心肌缺血与 QTc离散度 (QTcd)的关系。方法 :测量 80例平板运动诱导的心肌缺血患者的QTcd并与 5 0例正常人作对照。结果 :缺血组运动后 QTcd显著高于正常对照组 (P <0 .0 0 1) ;而对照组运动前后QTcd变化无显著性差异 (P >0 .0 5 )。结论 :心肌缺血是 QTcd增大的重要因素 ,可作为判断运动试验结果的有意义的心电学指标     

运动试验PTFv1异常与超声心动图A／E的关系及临床意义

通过对148例运动试验PTFv_1改变与脉冲多普勒超声心动图A/E关系的对照研究,了解运动试验中出现PTFv_1异常的临床意义.结果在运动试验诱发PTFv_1异常合并ST异常组(n=19)及单纯PTFv_1异常组(n=31)中,超声心动图发生A/E异常者高达94.7%及90.3%,发生率均非常显著高于运动试验正常组(n=50)(P<0.001)及单纯ST异常组(n=48)(P<0.001).提示运动诱发PTFv_1异常与左心室舒张功能障碍有关,可作为早期反映左心室舒张功能异常的心电图指标.     

肝硬化患者心电图Q—Tc间期延长的临床意义

目的探讨肝硬化患者Q-Tc间期变化及相关影响因素。方法检测125例肝硬化患者与50例非肝硬化患者心电图Q-Tc、凝血酶原时间（PT）、血清白蛋白（Alb）、血清总胆红素（TBil）、血清钾、血清钙、丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、γ-谷氨酰转肽酶（GGT）和碱性磷酸酶（ALP）等指标,组间比较Q—Tc的变化及肝功能、不同Child分级间Q-Tc异常率,采用单因素直线相关回归分析探讨Q-Tc与各项相关指标的关系。结果肝硬化组Q-Tc为（440±15）ms,非肝硬化组为（405±13）ms,两组比较P〈O．001;以Q-Tc≥440ms为异常,肝硬化组异常率为37．90％（47／125）,非肝硬化组为12．00％（6／50）,两组比较P〈0．001。肝硬化组中ChildC级的Q-Tc异常率为72．50％（25／34）,B级为41．50％（19／45）,A级为28．37％（13／46）;A级与C级比较P〈0．01。单因素直线相关回归分析结果显示,Q-Tc与Child积分呈正相关,相关系数r=0．31（P〈0．01）;与腹水程度呈正相关,相关系数r=0．24（P〈0．05）;与血清总胆红素（TBil）呈正相关,相关系数r=0．23（P〈0．05）。结论肝硬化存在Q-Tc异常延长,病因是多因素性的,随肝硬化病情加重,Q-Tc异常率升高。Q-Tc延长是引起室性心律失常的常见诱因,可能也是肝硬化患者出现猝死的原因之一。     

Transient ischaemia after acute myocardial infarction: relationship to exercise ischaemia

To study the implications of transient myocardial ischaemia following acute myocardial infarction we compared ambulatory ST segment monitoring with exercise treadmill testing in 170 patients (mean age 58 years) at 4-8 weeks after admission. Ambulatory monitoring detected transient ischaemia (265 episodes; 249 (94%) silent) in 53/170 patients (31%) which was less frequent than ischaemia during exercise testing (90 patients; 53%) (P less than 0.0001). However, patients displaying transient ambulatory ischaemia (i) achieved less total exercise (248.7 +/- 17.2 vs 318.7 +/- 14.1 s; means +/- SEM) (P less than 0.006), (ii) developed exercise ST deviation earlier (172.4 +/- 14.3 vs 244.8 +/- 16.2 s) (P less than 0.0004) and (iii) had more widespread exercise ischaemia (3.8 +/- 0.3 vs 2.5 +/- 0.2 ECG leads) (P less than 0.005). Positive ambulatory ST segment monitoring was infrequently found (12/80 patients; 15%) in the presence of a negative exercise test but did identify the majority of patients (9/11 patients; 82%) with easily provoked exercise ischaemia and hence strongly positive exercise tests. These data suggest a limited role for routine 24 h ambulatory monitoring after myocardial infarction for the diagnosis of ongoing ischaemia but raise the possibility of an important place for this test in prognosis and risk stratification.     

Stress testing predischarge and six weeks after myocardial infarction to compare submaximal and maximal exercise predischarge and to assess the reproducibility of induced abnormalities

Submaximal and maximal treadmill exercise tests were performed predischarge in 64 patients after acute myocardial infarction to assess the relative yield of residual ischaemic abnormalities. The reproducibility of individual abnormalities resulting from maximal stress tests performed predischarge and 6 weeks after infarction was also assessed in 55 of these patients. Compared with predischarge submaximal exercise testing, a maximal exercise test identified a significantly greater number of patients with residual myocardial ischaemia (26 vs. 15, P less than 0.05) and this was associated with a significantly longer average maximal exercise duration (P less than 0.001), and a higher rate-pressure product (P less than 0.001). Among the 55 patients who had maximal stress tests both predischarge and 6 weeks after infarction, there was a significant lack of reproducibility in the occurrence of exercise induced angina (P less than 0.01) and an abnormal blood pressure response (P less than 0.02). In contrast, exercise induced ST segment depression and elevation and ventricular arrhythmias were relatively reproducible. More patients had an ischaemic test result (ST depression or angina) at the later test compared to the predischarge test (33 vs. 25 patients) but this increase was not statistically significant. There were, however, significant increases at the later test in mean maximal exercise duration (P less than 0.001). mean maximal heart rate (P less than 0.001) and heart rate-systolic blood pressure double product (P less than 0.001). The majority of patients who had a cardiac event in the period between the two tests had a predischarge test abnormality. We conclude that a significantly greater number of patients with residual reversible myocardial ischaemia after infarction will be identified by symptom limited exercise testing compared with a submaximal predischarge test. Because ST depression and elevation appear reproducible, patients who develop these abnormalities during a predischarge test do not, for prognostic reasons, need retesting 6 weeks after infarction. Exercise induced angina pectoris and an abnormal blood pressure response, however, are highly variable and in these patients a repeat test may be useful.     

Prognostic value of exercise-induced QT dispersion in patients after acute myocardial infarction

BACKGROUND: Electrocardiographic exercise tests are widely recommended for patients before discharge after myocardial infarction, what justify the search for new variables which may improve their prognostic value. QT dispersion in 12 lead ECG reflects the heterogeneity of ventricular repolarisation. Increased QT dispersion is a noninvasive marker of ischaemia and electrical instability. AIM: Evaluation of the prognostic value of exercise-induced changes of QT dispersion in patients after an acute myocardial infarction. METHODS: Heart rate limited treadmill exercise test according to modified Bruce was performed 14+/-5 days after infarction in 77 patients (age 56+/-11,8 female). QT dispersion was measured at rest and on peak exercise. Patients were followed up for mean 88 months. RESULTS: QT dispersion was higher at peak exercise in those patients who died due to cardiovascular causes (n=8) or suffered from non-fatal myocardial infarction during follow-up (n=15), than in remaining group (71+/-20 vs 58+/-22 msec, p<0.01). At rest QT dispersion was similar in both groups (64+/-17 vs 66+/-20 msec, NS). CONCLUSIONS: The lack of an exercise-induced decrease in QT dispersion identifies a subgroup of patients after myocardial infarction with a poor long-term prognosis.     

Thrombolysis significantly reduces transient myocardial ischaemia following first acute myocardial infarction.

In order to investigate whether thrombolysis affects residual myocardial ischaemia, we prospectively performed a predischarge maximal exercise test and early out-of-hospital ambulatory ST segment monitoring in 123 consecutive men surviving a first acute myocardial infarction (AMI). Seventy-four patients fulfilled our criteria for thrombolysis, but only the last 35 patients included received thrombolytic therapy. As thrombolysis was not available in our Department at the start of the study, the first 39 patients included were conservatively treated (controls). No significant differences in baseline clinical characteristics were found between the two groups. In-hospital atrial fibrillation and digoxin therapy was more prevalent in controls (P less than 0.05). During exercise, thrombolysed patients reached a higher maximal work capacity compared with controls: 160 +/- 41 vs 139 +/- 34 W (P less than 0.02). Thrombolysis resulted in a non-significant reduction in exercise-induced ST segment depression: prevalence 43% vs 62% in controls. However, during ambulatory monitoring the duration of transient myocardial ischaemia was significantly reduced in thrombolysed patients: 322 min vs 1144 min in controls (P less than 0.05). Thrombolysed patients reached a higher heart rate during transient ischaemic episodes: 114 +/- 17 vs 93 +/- 11 b.min-1 in controls (P less than 0.001). In conclusion, thrombolytic therapy administered for a first AMI significantly reduces the burden of transient myocardial ischaemia. This may explain the improvement in myocardial function during physical activities, which was also observed in this study.