急性心肌梗死患者心肌复极异常心电图表现及其与恶性心律失常的关系研究

背景恶性心律失常可导致急性心肌梗死患者出现晕厥或猝死,因此探讨急性心肌梗死患者心肌复极异常心电图表现与恶性心律失常的关系具有重要意义。目的分析急性心肌梗死患者心肌复极异常心电图表现及其与恶性心律失常的关系。方法选取2016年10月—2018年9月湖北医药学院附属东风总医院收治的急性心肌梗死患者105例,根据恶性心律失常发生情况分为A组(发生恶性心律失常,n=41)和B组(未发生恶性心律失常,n=64)。分析所有患者心肌复极异常心电图表现及恶性心律失常发生情况,比较两组患者心肌复极异常心电图表现;急性心肌梗死患者心肌复极异常心电图表现与恶性心律失常的关系分析采用多因素Logistic回归分析。结果 (1)105例急性心肌梗死患者中出现ST段异常94例(89.5%),T波异常91例(86.7%),QT间期离散度(QTd)为(74.57±10.69)ms,校正的QT间期离散度(QTcd)为(84.63±12.79)ms,Tp-Te间期为(114.46±22.57)ms。(2)105例急性心肌梗死患者中发生恶性心律失常41例(39.0%),其中快速心室扑动/心室颤动10例,持续性室性心动过速10例、尖端扭转型室性心动过速5例、严重三度房室传导阻滞4例、单形性室性心动过速3例、多形性室性心动过速2例、其他7例。(3)A组患者中ST段异常、T波异常、QTd70 ms、QTcd80 ms、Tp-Te间期≥100 ms者所占比例高于B组(P0.05)。(4)多因素Logistic回归分析结果显示,ST段异常、T波异常、QTd70 ms、QTcd80 ms、Tp-Te间期≥100 ms是急性心肌梗死患者恶性心律失常的危险因素(P0.05)。结论急性心肌梗死患者心肌复极异常心电图表现主要包括ST段异常、T波异常、QT间期延长及Tp-Te间期延长,恶性心律失常发生率为39.0%;ST段异常、T波异常、QTd70 ms、QTcd80 ms、Tp-Te间期≥100 ms是急性心肌梗死患者恶性心律失常的危险因素。     

平板运动试验不同时段QT离散度变化的意义

目的探讨平板运动试验(TET)不同时段的QT离散度(QTd)和校正QT离散度(QTcd)变化的意义。方法选择38例TET阳性者不同时段记录的心电图用于测量、分析QTd、QTcd的变化,并与40例TET阴性者作对比分析。结果阳性组运动峰值心率时,运动中或后ST段下移最大时及运动后2、4、6分钟时的QTd、QTcd较运动前显著增大(P<0.01或P<0.05),尤以运动所致ST段下移最大时为明显,而阴性组运动相应时段的QTd、QTcd与运动前比较无明显增大(P>0.05)。结论QTd和QTcd增大,尤其ST段下移最大时的QTd,QTcd增大可作为TET结果判定的一项新的参考指标。     

前列地尔对急诊经皮冠状动脉介入治疗术后急性ST段抬高型心肌梗死患者室性心律失常的影响

目的探讨前列地尔对急诊经皮冠状动脉介入治疗(PCI)术后急性ST段抬高型心肌梗死患者室性心律失常的影响。方法选取2015年1月—2016年3月聊城市第二人民医院心内科收治的行急诊PCI的急性ST段抬高型心肌梗死患者100例,按照随机数字表法分为对照组和试验组,每组50例。两组患者入院后均进行常规处理并行急诊PCI,观察组患者于PCI术前30 min给予前列地尔治疗。比较两组患者室性心律失常发生情况、QT间期离散度及校正的QT间期离散度(QTcd)。结果试验组患者室性期前收缩发生率及非持续性室性心动过速+心室颤动发生率低于对照组(P0.05)。时间与方法存在交互作用(P0.05);时间在QT间期离散度、QTcd上主效应显著(P0.05);方法在QT间期离散度、QTcd上主效应显著(P0.05);试验组患者术后6、24、48、72 h QT间期离散度、QTcd均低于对照组(P0.05)。结论前列地尔对行急诊PCI术的急性ST段抬高型心肌梗死患者有一定的心肌保护作用,可有效降低患者PCI术后室性心律失常发生率,这可能与前列地尔抗炎、抗氧化及改善微循环等作用有关。     

运动试验无诱发胸痛或ST段压低患者运动后QT离散度预测明显冠脉狭窄的价值

踏车运动试验的心电图变化是检测冠心病最常用的无创伤性方法之一。然而,有些明显冠脉狭窄患者踏车运动试验时并未诱发胸痛或ST段压低。有研究报道应激期间因暂时心肌缺血的发生,从而增加了心室复极的不一致性,其表现为QT离散度(QTd)增大。作者计算运动试验无诱发胸痛或ST段压低患者运动试验前、后的QTd和QTcd,7d后做冠脉造影,旨在探讨运动试验无诱发胸痛或ST段压低患者运动试验后的QTd预测明显冠脉狭窄的价值。对象和方法研究对象为135例无心肌梗死史、运动试验时既无明显ST段压低亦无胸痛者。全部患者进行症状限止踏车运动试验,以50mm/S走纸速度记录运动试验前(基础值)、运动试验后(即刻)12导联心电图。自QRS波起点至T波终     

急诊经皮冠状动脉介入治疗对QT间期离散度的影响

目的探讨急诊经皮冠状动脉介入治疗（PCI）后对QT间期离散度（QTd）的影响。方法对70例ST段抬高的急性心肌梗死（AMI）患者行急诊PCI前和PCI后24h内12导联同步心电图QT间期、校正QT间期（QTc）、QTd及校正QT间期离散度（QTcd）4项指标进行对比分析。并监测严重心律失常发生情况。结果PCI后QT和QTc与术前差异无显著性,而QTd和QTcd则较术前明显减少,差异有显著性意义（P<0.01）。28例术前有恶性心律失常,其QTd明显高于无心律失常的患者[（70±18）msvs（52±15）ms,P<0.01];术后QTd降至（45±16）ms（P<0.01）,室性心律失常消失或减少。结论急诊PCI能显著减少AMI患者的QTd和QTcd,降低急性期恶性心律失常的发生。     

急性冠脉综合征病人PCI术后QT离散度相关影响因素分析

目的探讨急性冠脉综合征(ACS)病人PCI术后QT离散度(QTd)变化并分析相关影响因素。方法回顾性分析于我院就诊病人104例的临床资料,根据排除与纳入标准分为观察组:ACS病人74例(A组为不稳定型心绞痛26例,B组为非ST段抬高型心肌梗死31例,C组为ST段抬高型心肌梗死17例);对照组:非ACS病人30例。比较观察组与对照组、观察组各亚组发作时及围术期QTd及QT间期(QTc)离散度值(QTcd)。结果观察组QTc及QTcd较对照组明显升高;观察组QTc及QTcd水平升高程度为C组B组A组(P0.05)。单因素分析:ACS病人PCI术后QTc和QTcd与体质指数、日吸烟量、糖尿病史、心率有关(P0.05);Pearson相关性分析:ACS病人PCI术后QTc和QTcd与体质指数、日吸烟量、糖尿病史、心率呈正相关(P0.05)。结论 ACS病人QTc和QTcd与多因素有关,且PCI术后QTc降低,心肌血供改善。     

急性心肌梗死恢复期PTCA及支架置入术对QT离散度的影响

目的　观察急性心肌梗死 (AMI)恢复期 (2～ 4周 )行经皮冠状动脉腔内成形术 (PTCA)及支架置入术对QT离散度 (QTd)的影响。方法　选择 5 7例AMI恢复期的患者 ,分别记录PTCA及支架置入术前 1d ,术后 1h的 12导联同步心电图 ,测量QTd及校正的QTd(QTcd) ,并与 86例同期行冠状动脉造影结果正常者进行对照。结果　AMI组行PTCA及支架置入术前最大QT间期 (QTmax) ,最小QT间期 (QTmin) ,QTd及QTcd均较对照组明显增大 ,差异有显著性。前壁与下壁AMI之间上述指标差异无显著性。成功的PTCA及支架置入术后QTmax,QTmin,QTd及QTcd比术前明显缩短 ,两者相比差异有显著性。而单纯行冠状动脉造影对QT离散度无明显影响。结论　AMI患者QTd及QTcd显著高于正常人 ,而AMI恢复期成功的PTCA及支架置入术可使增加的QTd及QTcd显著缩短 ,从而减低AMI后恶性心律失常和心源性猝死的发生率 ,改善患者的远期预后。     

活动平板运动试验QT离散度对冠心病诊断的意义

目的:探讨活动平板运动试验的QT离散度对冠心病诊断的意义.方法:30例正常人和27例冠心病人进行活动平板运动试验,测定运动前和运动高峰的QT离散度(QTd)及校正QT离散度(QTcd).结果:正常人群运动前后QTd及QTcd无差别,而冠心病患者运动后QTd和QTcd较运动前明显增大.结论:运动后QT离散度增大是反映冠心病心肌缺血的重要指标,运动后QTd、QTcd增大结合ST段偏移可增加对冠心病诊断的敏感性.     

50例Ⅱ型糖尿病者QT离散度分析

QT离散度(QTd)是体表心电图(ECG)不同导联最长与最短QT间期的差值。QTd与急性心肌梗死、心肌病、室性心律失常者的关系研究报道较多,与糖尿病者的关系也有报道,但多以手工测定计算,用电脑自动测定QTd、QTcd报道极少。本文对电脑自动测定糖尿病者的QTd、QTcd报告如下。     

急性心肌梗死QT离散度的临床意义探讨

目的观察急性心肌梗死(AMI)QT离散度(QTd)的变化与心律失常的关系以及有效的溶栓治疗对QTd的影响。方法AMI病人42例与正常健康者50例进行对比,所有对象测量12导联心电图不同导联最长与最短的QT间期QTmax和QTmin,QTd=QTmax-QTmin,根据Bazett’s公式,校正QT间期QTc=QT/RR,校正QT离散度(QTcd)=QTcmax-QTcmin。结果AMI病人QTd、QTcd分别为(68.7±16.3)、(74.8±20.1)ms,对照组QTd(32.3±11.4)ms、QTcd(36.4±13.3)ms,P<0.01,有心律失常组QTd(70.4±19.5)ms、QTcd(79.4±22.5)ms,无心律失常组QTd(54.4±16.3)ms、QTcd(63.2±20.1)ms,P<0.01。溶栓有效者与无效者比较差异也有统计学意义(P<0.05,表1)。结论有效的溶栓治疗可使QTd明显减小,减少危险性心律失常的发生,降低AMI患者病死率。QTd对预测AMI患者溶栓疗效以及早期危险性心律失常和预后具有重要价值。     

Exercise performance-based outcomes of medically treated patients with coronary artery disease and profound ST segment depression

OBJECTIVES

We sought to determine the relationship between exercise duration and cardiovascular outcomes in patients with profound (≥2 mm) ST segment depression during exercise treadmill testing (ETT).

BACKGROUND

Patients with stable symptoms but profound ST segment depression during ETT are often referred for a coronary intervention on the basis that presumed severe coronary artery disease (CAD) will lead to unfavorable cardiovascular outcomes, irrespective of symptomatic and functional status. We hypothesized that good exercise tolerance in such patients treated medically is associated with favorable long-term outcomes.

METHODS

We prospectively followed 203 consecutive patients (181 men; mean age 73 years) with known stable CAD and ≥2 mm ST segment depression who are performing ETT according to the Bruce protocol for an average of 41 months. The primary end point was occurrence of myocardial infarction (MI) or death.

RESULTS

Eight (20%) of 40 patients with an initial ETT exercise duration ≤6 min developed MI or died, as compared with five (6%) of 84 patients who exercised between 6 and 9 min and three (3.8%) of 79 patients who exercised ≥9 min (p = 0.01). Compared with patients who exercised ≤6 min, increased ETT duration was significantly associated with a reduced risk of MI/death (6 to 9 min: relative risk [RR] = 0.25, 95% confidence interval [CI] 0.08 to 0.76; >9 min: RR = 0.14, 95% CI 0.04 to 0.53). This protective effect persisted after adjustment for potentially confounding variables. We observed a 23% reduction in MI/death for each additional minute of exercise the patient was able to complete during the index ETT.

CONCLUSIONS

Optimal medical management in stable patients with CAD with profound exercise-induced ST segment depression but good ETT duration is an appropriate alternative to coronary revascularization and is associated with low rates of MI and death.     

Usefulness of Seismocardiography for the Diagnosis of Ischemia in Patients with Coronary Artery Disease

Background: Seismocardiography (SCG) is a useful method for the detection of exercise‐induced changes in cardiac muscle contractility which may occur during myocardial ischemia. The aim of this study was to compare the diagnostic accuracy of SCG with electrocardiographic exercise test (ETT) for diagnosis of ischemia in patients with angiographically proved coronary artery disease (CAD). Methods: Seventy‐seven male patients with CAD without myocardial infarction (MI), mean age 51 ± 9 years, were subjected to SCG and ETT. A gender‐matched control group consisted of 30 healthy volunteers aged 34 ± 7 years. SCG was done simultaneously with resting supine 12‐lead electrocardiography before and immediately after a symptom‐limited ETT. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of SCG were compared with ETT. Moreover, the diagnostic accuracy of both the methods was compared, with coronary angiography being the reference for the analysis. Results: SCG was more sensitive (61.1% vs 44.2%, P < 0.05) and accurate (70% vs 61%, P < 0.05) method for detecting ischemia caused by coronary stenosis ≥50%, at least in one coronary artery compared to the ETT. However, ETT had better specificity than SCG (82.4% vs 76%, P < 0.05). The PPV and NPV of SCG were significantly better than those obtained with ETT (77.9% vs 76%, P < 0.05 and 63.4% vs 53.8%, P < 0.05, respectively). Moreover, the concordant results of SCG and ETT improved the diagnostic accuracy of both methods. Conclusions: SCG appeared to be more sensitive for detecting ischemia caused by more than ≥50% stenosis of the main coronary artery compared to an electrocardiographic stress test. SCG was a useful ETT adjunct for selecting patients requiring coronary angiography.     

In search of the false-negative exercise treadmill testing evidence-based use of exercise echocardiography

BACKGROUND: Controversy exists regarding the role of exercise treadmill testing (ETT) versus exercise stress echocardiography (ESE) as the appropriate initial noninvasive test to risk-stratify patients with chest pain. The majority of studies to date that evaluated these methodologies included patients with poor functional status and baseline electrocardiogram (ECG) abnormalities, potentially limiting the sensitivity of ETT. HYPOTHESIS: We examined the hypothesis that given stringent standards of exercise duration and ECG interpretability, the ETT would have a high diagnostic sensitivity for the presence of significant coronary artery disease (CAD). METHODS: Results of concurrent ETT and ESE in 3,098 patients were examined, and the subset of patients with a negative ETT and positive ESE (-ETT/ + ESE) were reviewed for the presence of CAD as a function of exercise duration (< or > or = 6 min) and baseline ECG normality. RESULTS: In those patients with a - ETT/ + ESE who exercised > or = 6 min, 54 had a normal baseline ECG, 22 underwent angiography and 6 had CAD (all of whom had either small, grafted or collateralized vessels). Patients with a - ETT/ + ESE who were incapable of exercising 6 min were more frequently older and female. Mortality was significantly greater in the < 6 min exercise duration group (31.4 versus 3.1%). CONCLUSIONS: These findings support the use of the ETT without imaging as the initial test in patients with chest pain who have a normal baseline ECG and are able to exercise 6 min. Using these criteria, false negative findings are generally seen in patients without critical large vessel epicardial disease. The ESE should be reserved as the initial test for patients with an abnormal baseline ECG or reduced functional capacity.     

运动平板试验中收缩压异常反应的意义

目的:研究运动平板负荷试验(ETT)中收缩压异常反应的意义。方法:选择同时经ETT及冠状动脉造影(CAG)检查的可疑冠心病患者71例。分别用ST段偏移异常(公认指标)及收缩压反应异常(新指标)判断ETT结果,再分别与CAG结果进行统计学分析比较。结果:根据新指标判断的ETT阳性检出率与CAG的阳性率比较差异有统计学意义。结论:新指标不宜作为运动负荷试验阳性的独立判断指标。     

Exercise capacity and heart rate recovery as predictors of coronary heart disease events, in patients with heterozygous Familial Hypercholesterolemia

BACKGROUND: Several clinical and observational studies have established that exercise capacity and activity status are strong predictors of cardiovascular and overall mortality. We aimed to evaluate the relationship between exercise tolerance test (ETT) indices and occurrence of coronary heart disease (CHD), in patients with heterozygous Familial Hypercholesterolemia (eFH). METHODS: During 1987-1997, we enrolled 639 cardiovascular disease-free patients with heterozygous eFH; 58 (9%) patients were excluded since they had a positive ETT. A fatal or non-fatal CHD event was the end point. Cox proportional hazards models were applied to evaluate the association between the investigated outcome and ETT indices. RESULTS: During the follow-up (1987-2002), 53 (18%) men and 34 (10%) women developed a CHD event (11 were fatal). The age-adjusted event rate was 87 events per 2915 person-years (3%). Statistical analysis revealed that exercise capacity (hazard ratio = 0.82, P < 0.001), heart rate recovery at 1 min (hazard ratio = 0.91, P < 0.05), and peak pulse pressure levels (hazard ratio = 1.03, P < 0.001), were predictors of CHD, after controlling for several potential confounders. CONCLUSION: Decreased exercise capacity, a delayed decrease in heart rate during the first minute of graded exercise, and increased peak pulse pressure are strong predictors of coronary events in patients with eFH. Physical activity should be strongly recommended in these patients.     

Association of exercise capacity on treadmill with future cardiac events in patients referred for exercise testing

BACKGROUND: Little is known about the association between exercise capacity and nonfatal cardiac events in patients referred for exercise treadmill testing (ETT). Our objective was to determine the prognostic importance of exercise capacity for nonfatal cardiac events in a clinical population. METHODS: A cohort study was performed of 9191 patients referred for ETT. Median follow-up was 2.7 years. Exercise capacity was quantified as the proportion of age- and sex-predicted metabolic equivalents achieved and categorized as less than 85%, 85% to 100%, and greater than 100%. Individual primary outcomes were myocardial infarction, unstable angina, and coronary revascularization. All-cause mortality was a secondary outcome. RESULTS: Patients with lower exercise capacity were more likely to be female (55.38% vs 42.62%); to have comorbidities such as diabetes (23.16% vs 9.61%) and hypertension (59.43% vs 44.05%); and to have abnormal ETT findings such as chest pain on the treadmill (12.09% vs 7.63%), abnormal heart rate recovery (82.74% vs 64.13%), and abnormal chronotropic index (32.89% vs 12.20%). In multivariable analysis, including other ETT variables, lower exercise capacity (<85% of predicted) was associated with increased risk of myocardial infarction (hazard ratio [HR], 2.36; 95% confidence interval [CI], 1.55-3.60), unstable angina (HR, 2.39; 95% CI, 1.78-3.21), coronary revascularization (HR, 1.75; 95% CI, 1.46- 2.08), and all-cause mortality (HR, 2.90; 95% CI, 1.88-4.47) compared with exercise capacity greater than 100% of predicted. CONCLUSION: Adjusting for patient characteristics and other ETT variables, reduced exercise capacity was associated with both nonfatal cardiovascular events and mortality in patients referred for ETT.     

Discordance of exercise thallium testing with coronary arteriography in patients with atypical presentations

Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with thallium-201. Results of these tests were in agreement in only 47 percent of the cases. Either exercise thallium or ETT was positive in 94 percent of patients with disease. Among a population with a disease prevalence of 67 percent, agreement between exercise thallium an ETT predicted disease in 92 percent of instances or excluded disease in 82 percent of instances. Frequent discordance between these two tests in 53 percent of the cases unfortunately limits this usefulness.     

Abnormal heart rate recovery after exercise: a comparison with known indicators of increased mortality.

BACKGROUND: Abnormal heart rate (HR) recovery at 1 min after exercise (< or =12 beats) was recently suggested to be a predictor of all cause and cardiac mortality. AIM: This study aimed to (1) correlate HR recovery at 1 min after exercise with known exercise and myocardial perfusion markers of increased cardiac mortality, and (2) compare the known exercise and myocardial perfusion markers of increased cardiac mortality between patients with a normal and abnormal HR recovery at 1 min after exercise. METHODS: One hundred patients with known or suspected coronary artery disease referred for exercise stress testing (ETT) were prospectively enrolled. Percent, ETT time peak HR, HR reserve, summed stress score (SSS), extent of stress (SE%) and reversible perfusion abnormalities (RE%) were recorded in every patient. RESULTS: There was poor correlation with markers of myocardial ischemia or infarction [SSS (r = 0.15), SE% (r = 0.05), RE% (r = 0.12), all p = n.s.] but highly significant correlation between HR recovery at 1 min after exercise and chronotropic variables [ETT time (r = 0.56), peak HR (r = 0.65), HR reserve % (r = 0.64), all p < 0.001]. Patients on beta-blockers had significantly more incidence of an abnormal HR recovery at 1 min after exercise, compared to patients not on beta-blockers (88 vs. 56%, p < 0.01). CONCLUSION: Abnormal HR recovery at 1 min after exercise has no correlation with known myocardial perfusion markers of increased cardiac mortality. Patients with an abnormal HR recovery do not appear to have an increased incidence or more severe myocardial infarction or ischemia. However, there is a strong correlation between HR recovery at 1 min after exercise and the chronotropic variables during exercise.     

平板运动试验阳性对冠状动脉造影正常患者的评价

为评价平板运动试验阳性而冠状动脉造影正常的胸痛患者的临床意义，对３６例平板运动试验阳性而造影阴性的患才与３６例运动试验和造影阳性的患者进行临床资料及平板运动试验参数的对照分析。     

Dobutamine stress echo is superior to exercise stress testing in achieving target heart rate among patients on beta blockers

Published guidelines recommend continuing beta-adrenergic receptor blockade in patients undergoing stress testing. We evaluated the role of pharmacological versus exercise stress testing in achieving target heart rate (THR) among patients on beta-adrenergic blockade. We compared data from 140 patients who underwent dobutamine stress echo (DSE) and 143 patients who underwent exercise treadmill testing (ETT). In both groups, beta-adrenergic blocker was continued at the time of stress testing. Overall, patients undergoing DSE achieved THR more frequently than ETT. With beta-adrenergic blockade, DSE patients met THR more frequently than ETT patients (p < 0.001). Without beta-adrenergic blockade, there was no difference between either modality in achieving THR. In both DSE and ETT patients, absence of beta-adrenergic blockade increased the odds of achieving THR [odds ratio (OR): 2.46, p = 0.042 and OR: 7.44, p < 0.001, respectively]. Atropine use with DSE increased the odds of achieving THR (OR: 3.76, p = 0.006). In conclusion, pharmacological stress testing appears to be superior to exercise stress testing in achieving THR among patients on beta-adrenergic blockade.