动态心电图检测老年冠心病无症状性心肌缺血探讨

采用动态心电图对300例老年冠心病患者,在日常活动状态下,连续检测24小时。结果表明:有215例(占71.7％)发生无症状心肌缺血,发作次数592次(81.8％),与老年前期冠心病者比较都有非常显著性差异;80岁以上年龄组的无症状性心肌缺血检出率明显高于其他2个年龄组;运动时出现的无症状心肌缺血明显多于休息时;白天发作次数多于夜间。提示:掌握老年冠心病患者无症状心肌缺血发生规律,对老年冠心病的防治及预防严重并发症的发生有极大意义。     

动态心电图诊断老年男性的无症状心肌缺血

目的探讨老年男性冠心病患者无症状心肌缺血的发作特点及动态心电图诊断的价值。方法选择行动态心电图检查的老年男性冠心病患者350例,按年龄分为Ⅰ组(年龄60～79岁,220例)和Ⅱ组(80～91岁,130例),对两组患者动态心电图结果进行对比分析,并与常规心电图结果进行比较。结果Ⅱ组患者的常规心电图及动态心电图的心肌缺血检出率及无症状心肌缺血平均持续时间均高于Ⅰ组,但差异无统计学意义(p0.05);Ⅰ组无症状心肌缺血发作有明显昼夜节律,Ⅱ组无明显昼夜节律;两组慢频率依赖型无症状心肌缺血持续时间均较快频率依赖型无症状心肌缺血延长(p0.05),且Ⅱ组较Ⅰ组明显;快频率依赖型无症状心肌缺血平均ST段压低幅度与慢频率依赖型无症状心肌缺血平均ST段压低幅度比较,以及Ⅰ,Ⅱ组无症状心肌缺血平均ST段压低幅度比较差异均无统计学意义(p0.05)。结论随着年龄增加,老年男性冠心病患者无症状心肌缺血发生率增高,且无症状心肌缺血持续时间延长;80岁男性冠心病患者无症状心肌缺血发作无明显昼夜节律,慢频率依赖型无症状心肌缺血持续时间较快频率依赖型无症状心肌缺血显著延长。动态心电图是检测和评估老年冠心病患者无症状心肌缺血的重要手段。     

冠心病患者无症状性心肌缺血的昼夜规律

我们对92例冠心病患者经24小时动态心电图监测到的191次无症状性心肌缺血进行了分析,结果表明:无症状性心肌缺血有明显的昼夜分布规律,白昼(占90.6％)明显多于夜间;全天发作高峰在上午6～12时(57％)。     

动态心电图对冠心病无症状性心肌缺血的诊断价值

作者应用动态心电图检测110例冠心病患者,结果发生缺血性ST段下移386次,其中无症状性心肌缺血(SMI)291次,占缺血总数75%。SMI发作时心率平均65±14.5次/分,有症状性心肌缺血(MI)发作时心率79.2±5.6次/分,两组比较有显著性差异。SMI发作频率以上午6～9时最高,占24小时发作总数的30%,而夜间10时～凌晨1时发作频率最低,占24小时发作总数的7%。提示动态心电图为诊断冠心病SMI的有效方法。     

12导联动态心电图对无症状性心肌缺血的诊断价值

目的探讨12导联动态心电图(ambulatory electrocardiogram,AECG)对无症状性心肌缺血(silent myocardial ischemia,SMI)的诊断价值。方法回顾性分析316例确诊的冠心病患者AECG检测结果。结果①AECG中ST段压低检出率高于常规心电图,差异有统计学意义(P<0.05);②无症状性心肌缺血时ST段压低持续时间在06:00～12:00时段最长,差异有统计学意义(P<0.05);③无症状性心肌缺血发作多呈快频率依赖性,与慢频率依赖性相比,差异有统计学意义(P<0.05)。结论 12导联动态心电图可以明确无症状性心肌缺血患者发作次数、持续时间及演变规律,为临床心肌缺血诊断及预后观察提供重要依据。     

无症状性与有症状心肌缺血的临床特征比较

对50例确诊为冠心病的病人进行了24小时动态心电监测。结果表明,无症状性心肌缺血次数明显多于有症状性心肌缺血次数(P<0.01);无症状性心肌缺血的病人明显多于有症状性心肌缺血的病人(P<0.01);有症状与无症状性缺血时的平均心率均明显快于缺血前的平均心率(P<0.01);6～12时及18～24时期间心肌缺血次数明显多于0～6时期间心肌缺血次数(P<0.05);有症状性与无症状性心肌缺血之间在平均缺血持续时间ST段下降幅度、缺血前及缺血时平均心率等方面无明显差异。     

动态心电图对冠心病心肌缺血的分析

目的 评价动态心电图(DCG)对监测心肌缺血,特别是无症状心肌缺血(SMI)的价值。方法 对350例冠心病(CHD)患者行24h DCG监测。分析SMI与有症状心肌缺血的阵数,时间分布,缺血时伴发室性心律失常以及与年龄的关系。结果 检出心肌缺血248例,其中SMI 189例,有症状心肌缺血59例。缺血性ST段改变1 769阵,其中SMI 1 412阵,有症状心肌缺血357阵。两组比较有明显差异意义(P<0.05)。心肌缺血的发作及发作时伴发室性心律失常均以6∶00～12∶00为多见,以0∶00-6∶00最为少见。63例发作SMI 633阵,12例发作有症状心肌缺血131阵,两组比较有明显差异意义(P<0.05)。且随着年龄的增大,心肌缺血发生的比例也明显增高,以SMI更为明显。其中,41～51岁为247阵,而>61岁为763阵。两组比较有明显差异性(P<0.05)。结论 DCG对SMI的检测率高。SMI发作有明显的时间分布规律,随着年龄的增长,SMI发生率也明显增高。     

动态心电图与常规心电图对无症状心肌缺血的诊断价值分析

目的：探讨动态心电图与常规心电图对无症状心肌缺血的诊断价值。方法回顾性分析我院收治的205例冠心病患者十二导联动态心电图和常规心电图检查结果。结果动态心电图无症状心肌缺血异常检出率为87.32%,常规心电图为76.10%,两组比较差异有统计学意义（P〈0.05）。无症状心肌缺血发作阵次主要集中在06：00-11：59时间段,与其他时间段比较差异均有统计学意义（P〈0.05）。无症状心肌缺血快频率发作率为84.97%,显著高于慢频率发作率15.03%（P〈0.05）。结论动态心电图可显著提高 ST段压低的检出率,明确无症状心肌缺血患者持续时间、发作次数和演变规律。     

急性心肌梗塞后无症状性心肌缺血及其预后

报告对５７例急性心肌梗塞（ＡＭＩ）患者于病情稳定后４～６周内行２４小时动态心电图检测及１年随访结果。有缺血性改变者５１例，共发作１６８阵次。其中无症状组４４例（８６．３％）共发作１３５阵次（８０．４％），缺血性ＳＴ段压低的幅度和持续时间与有症状组无显著性差异。无症状性心肌缺血发作以６～１２时最频，０～６时最少。其发作高峰与血浆儿茶酚胺（ＣＡ）生理高峰浓度相一致。提示ＣＡ在无症状组发作中有重要作用，无症状性心肌缺血发作时，严重心律失常检出率为８６．４％，表明心律失常是ＡＭＩ后无症状性心肌缺血患者最主要的死因。因此，临床不能根据ＡＭＩ后心绞痛的有无决定治疗及判断预后，改善ＡＭＩ后心肌缺血状态，预防和及时控制心律失常，尤其是严重室性心律失常已成为提高ＡＭＩ后患者长期生存率的关键。     

动态心电图诊断无症状性心肌缺血的价值研究

目的：探讨动态心电图诊断无症状性心肌缺血的临床价值。方法：选取2012年10月～2014年8月在本院确诊为冠心病的患者90例,进行24小时动态心电图检测。结果：90例冠心病患者中检出心肌缺血75例(83.33％),48小时内发生缺血性ST段下移1075阵次。其中有症状性心肌缺血27例(36.00％),ST段下移155阵次(14.42％),平均ST段下移(0.17±0.03) mV;无症状性心肌缺血48例(64.00％),ST段下移920阵次(85.58％),平均ST段下移(0.16±0.02) mV。无症状性心肌缺血发作主要分布在6：00～18：00,其中6：00～12：00最多,白天发作时夜间发作的2.48倍。48例无症状性心肌缺血患者的平均心率为65/min,发作时心率＞65/min者36例(75.00％),≤65/min者12例(25.00％),伴有心律失常者41例(85.42％)。结论：动态心电图检测无症状性心肌缺血具有重要的临床诊断价值。     

ST segment analysis in 24-hour long-term ECG in patients with stable angina pectoris and angiographically detected coronary sclerosis

ST-segment analysis on 24-hour Holter ECG was performed in 64 patients with angiographically proven coronary artery disease, a positive exercise test and chronic stable angina. During 125 days of recording, 494 episodes of transient ST-segment depression were observed, at an average of 4.0 +/- 3.7 episodes (1-13 episodes, median: 3 episodes) per day. The duration of ST depression per episode was 13.2 +/- 14.4 min (1-90 min; median: 8 min). No episodes of ST-elevation were observed. Only 27 (5.5%) ischemic episodes occurred during the night, between midnight and 6:00 a.m., but they were frequently observed during the morning hours between 7:00 and 12:00 a.m. Nearly all episodes of ischemia were preceded by an increase in heart rate. However, heart rate at the onset of significant ST-segment depression was significantly lower during Holter monitoring than during exercise test (p less than 0.001); this indicates that factors additional to the increase in myocardial demand might be relevant for transient myocardial ischemia during daily life. 382 of the 494 episodes (77.3%) of ischemia were asymptomatic; heart rate at the onset of ST-segment depression was similar in symptomatic and asymptomatic episodes; however, in asymptomatic episodes, maximal heart rate was significantly lower (p less than 0.001) and the duration of the episodes significantly longer (p less than 0.001). The percentage of asymptomatic episodes was very high in patients with one-vessel disease, whereas the duration and amount of ST-segment depression, as well as heart rate, at the onset of ischemia, were not dependent on the extent of coronary artery disease.     

Silent myocardial ischemia during daily activities in asymptomatic men with positive exercise test responses

The usefulness of prolonged ambulatory electrocardiographic monitoring (AEM) for detecting ischemia was investigated in 17 asymptomatic men who had ischemic-type ST-segment depression (greater than or equal to 2.0 mm) during treadmill exercise testing. No patient took anti-ischemic medications and all patients underwent coronary angiography. A total of 1,154 hours (range 64 to 72 hours/patient) of high-quality AEM recordings was obtained. Silent ischemia (episodes of asymptomatic ischemic-type ST depression of 60 seconds or longer) occurred in 11 patients during daily activity detected by AEM. In 6 other patients, no myocardial ischemic episodes were found. But 1 of these patients withdrew after only 24 hours of AEM and the remaining 5 had no significant coronary artery disease (CAD). All 11 patients who had silent ischemia had significant CAD (at least 50% stenosis) on angiography. There was wide intrapatient variability in the frequency of silent ischemic episodes. Silent ischemia was identified in 6 of these 11 patients after 24 hours of AEM, in 2 after 48 hours and in 3 after 72 hours. Thus, asymptomatic men with positive exercise test responses and CAD have silent ischemic episodes during daily activity. AEM may be useful in helping to predict which patients with asymptomatic positive exercise test responses have CAD; however, extended AEM periods are required.     

Value of stress and long-term ECG in the diagnosis of silent myocardial ischemia in patients with coronary heart disease

Symptomatic and asymptomatic myocardial ischemia during exercise testing and during daily activities (ST-segment analysis on 24-h Holter ECG) was studied in 109 patients with stable angina pectoris and proven coronary artery disease (coronary stenoses greater than 70%) (group I) and in 20 patients with angiographically normal coronary arteries or minimal changes (group II). During exercise testing, 94/109 (86.2%) group I patients and 6/20 (30%) group II patients showed ST-segment depression greater than or equal to 0.1 mV. During Holter ECG, transient ST-segment depression (greater than or equal to 0.1 mV; greater than or equal to 1 min) was observed in 76/109 (69.7%) group I patients and in 5/20 (25%) group II patients; all patients with positive Holter ECG also had a positive exercise tests result. Heart rate and exercise duration at the onset of ischemia during stress testing were useful parameters to estimate the incidence of ischemic episodes during Holter ECG. Patients with asymptomatic positive exercise tests showed a significantly higher percentage of asymptomatic ischemic episodes during Holter ECG than patients with a symptomatic positive exercise test (89% vs. 68% asymptomatic ischemic episodes; p less than 0.001). Therefore, in patients with coronary artery disease and stable angina pectoris, the exercise test provides information also about the activity of ischemic heart disease during daily activities.     

Coronary heart disease and silent myocardial ischemia]

Silent myocardial ischemia was studied in 100 patients with coronary heart disease (CHD), proved by the coronary arteriogram (at least one major coronary artery narrowed by > or = 50%). The study demonstrated that 51 of 100 patients with CHD had episodes of myocardial ischemia by Holter monitoring. In the 51 patients, during daily activities, through 24-hour Holter monitoring, 239 transient episodes of ST depression were detected, 161 of the total were asymptomatic (67.4%). There were no statistically significant differences in the heart rate and the product of heart rate and systolic blood pressure before ST depression between asymptomatic and symptomatic episodes. The heart rate at the time of maximal ST depression during both asymptomatic and symptomatic ischemia increased by 13 and 22 beats/min, respectively, over those before ST depression (P < 0.01); whereas the increase in heart rate during symptomatic ischemia was more significant than during asymptomatic ischemia (P < 0.01). The increase of product of heart rate and systolic blood pressure at the time of maximal ST depression during asymptomatic and symptomatic ischemia were 22.2 and 35.4, respectively, over those before ST depression (P < 0.01). The incidence of silent ischemic episodes in patients with single vessel disease was 81.7% and those with multivessel disease was 61.3% (P < 0.01). The frequency of silent ischemic episodes was maximal (36% of total number of ischemic episodes) between 6 a.m. and 12 a.m. during 24-hour, whereas the incidence of silent ischemic episodes in patients with single vessel disease was similar to that in patients with multivessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characteristics of silent myocardial ischemia during out-of-hospital activities in asymptomatic angiographically documented coronary artery disease

Ambulatory electrocardiographic monitoring is useful in documenting characteristics of both painful and silent myocardial ischemia occurring during out-of-hospital activities in patients with angina and coronary artery disease (CAD), but few data are available concerning silent myocardial ischemia during ambulatory electrocardiographic monitoring in asymptomatic patients with CAD. Accordingly, 480 hours of ambulatory electrocardiographic monitoring were recorded in 10 asymptomatic patients with CAD not receiving cardiac drugs (48 hours/patient). All 10 patients had silent myocardial ischemia on treadmill exercise testing, with initial ST-segment depression at 2 to 6 minutes in 7 patients and more than 6 minutes in 3 patients. During ambulatory electrocardiographic monitoring, 64 episodes of silent myocardial ischemia (1 mm of ST-segment depression for at least 1 minute) were recorded, ranging from 1 to 17 episodes/patient/48 hours. Of the 64 silent myocardial ischemic episodes, 30 (47%) occurred between 6 am and noon. Duration of silent myocardial ischemia was 798 minutes (range 1 to 80). ST-segment depression ranged from 1 to 4.5 mm. Heart rate at onset of the episodes on ambulatory electrocardiographic monitoring ranged from 65 to 150 beats/min (mean 98), which was significantly less than that during treadmill exercise testing in the same patients (mean 120). At cardiac catheterization, 7 patients had 2- or 3-vessel CAD and 3 had 1-vessel CAD. Thus, silent myocardial ischemia is common during daily life in asymptomatic CAD patients with positive treadmill exercise tests.     

Circadian distribution of the characteristics of ischemic episodes in patients with stable coronary artery disease

To determine the circadian distribution of episodes of myocardial ischemia, studies were performed in 111 patients with chronic stable angina pectoris, positive exercise test results and angiographically proven coronary artery disease. During 24 hours of ambulatory electrocardiographic monitoring, 101 symptomatic and 298 asymptomatic ischemic episodes (ST-segment depression greater than 1 mm, duration greater than 1 minute) were observed. The number of ischemic episodes and the cumulative duration of ischemia showed a circadian variation with the highest values between 8 and 10 A.M. and between 4 and 5 P.M. associated with a similar circadian variation of heart rate. Mean duration of ischemic episodes, maximal amplitude of ST-segment depression during ischemic episodes and increase in heart rate before the onset of ischemic episodes showed no significant circadian variation. Heart rate at the onset of ischemic episodes and maximal heart rate during ischemic episodes were lower between midnight and A.M. than during other times of the day. The morning and afternoon increase in ischemic activity is not paralleled by changes reflecting a decrease in myocardial oxygen supply during these periods (heart rate at onset of ischemia, heart rate increase before onset of ischemia), but is paralleled by a similar circadian variation of heart rate. The circadian variation in ischemic activity is predominantly based on a comparable variation in myocardial oxygen requirements.     

Circadian variation of transient myocardial ischemia in the early out-of-hospital period after first acute myocardial infarction

Circadian rhythms have been demonstrated in acute myocardial infarction (AMI) and in other clinical cardiac dysfunctions. The purpose of this study was to elucidate whether a circadian pattern of transient myocardial ischemia exists after first AMI. Prospectively, 24-hour ambulatory ST-segment monitoring was initiated at discharge on day 11 +/- 5 in 123 consecutive survivors of first AMI. A total of 93 ischemic episodes (91 asymptomatic) occurred in 21 of the 123 patients (17%) (mean duration of 30 minutes, range 4 to 292). A significant circadian rhythm of transient myocardial ischemia was found with a peak activity occurring in the evening hours (p less than 0.01). Thus, 43% of ischemic episodes and 42% of ischemic time occurred between 6 P.M. and 12 midnight. The characteristics of morning and evening episodes were similar, except for the heart rate at maximal ST-segment depression, which was significantly higher during morning episodes (p less than 0.02). Patients with transient myocardial ischemia had a diurnal distribution similar to the circadian variation displayed during ischemic activity. Thus, 16 of the 21 patients had ischemic episodes from 6 P.M. to 12 midnight versus 10 patients from 6 A.M. to 12 noon (p less than 0.01). The 24-hour mean minimal heart rate was significantly higher in patients with than without ischemic episodes (p less than 0.02). In conclusion, this study has established a significant circadian peak of transient myocardial ischemia in the evening hours in survivors of first AMI. Whether the pattern displayed is due to endogenous biologic functions or cyclic variations, or both, in the external environment needs to be clarified.     

Silent myocardial ischemia during Holter monitoring in ischemic heart disease

The purpose of this study was to investigate the frequency and characteristics of silent myocardial ischemia in patients with proven ischemic heart disease using ambulatory ECG monitoring, and to clarify possible mechanisms for the absence of symptoms during these attacks. A total of 182 patients, including 78 patients with stable effort angina (EA), 12 with unstable angina (UA), and 92 with prior myocardial infarction (MI), were examined. During daily activities, 43% and 56% of all transient ST-segment depression observed was asymptomatic in patients with EA and MI, respectively. In addition, 74% of all ischemic episodes were asymptomatic in patients with UA. In patients with EA, 35% exhibited both symptomatic and asymptomatic attacks, and the duration and magnitude of ST-segment depression were greater for symptomatic attacks than for asymptomatic attacks. On the other hand, in patients with MI, 55% had only asymptomatic attacks. When asymptomatic episodes in patients who had only asymptomatic attacks were compared with symptomatic episodes in patients who had only symptomatic attacks, asymptomatic episodes tended to be associated with a greater magnitude of ST depression. They were also significantly longer in duration than the symptomatic episodes. All patients with UA had both symptomatic and asymptomatic episodes, and the magnitude and duration were significantly greater during the former. These results lead us to conclude that: (1) silent myocardial ischemia is observed frequently in patients with EA and MI during daily activities. In particular, patients with MI tend to have more severe silent ischemia. (2) In patients with EA and UA, the severity of ischemia is a fundamental factor in determining the presence or absence of pain during an ischemic attack.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical evaluation of transient myocardial ischemia

Out of 432 patients with coronary heart disease, 106 (24.5%) were found to have transient myocardial infarction during ECG monitoring of ST segment for 10 hours of daily activity. High-grade ventricular arrhythmias were revealed in 74.6% of mainly male and middle-aged subjects. 63.4% of the patients exhibited congestive heart failure, 48.1% had postinfarct cardiosclerosis, and 25.5% presented with diabetes mellitus. Transient myocardial ischemia was more frequently detected during exercise and more rarely during emotional stress (21.7%), meal (19.8%), and smoking (7.8%). Asymptomatic episodes of ST segment elevation were recorded in 36.8%, while asymptomatic episodes of ST segment depression, in 29.2%. The duration of asymptomatic episodes of ST segment elevation and depression was twice and 1.5 times, respectively, less than that of symptomatic ones. Substantial myocardial perfusion and metabolic impairments were revealed with an asymptomatic ST segment depression frequency of at least one an hour, an amplitude of more than 2 mm, and a duration of no less than 40 min.