Exercise-induced myocardial ischemia in patients with coronary artery ectasia without obstructive coronary artery disease

BACKGROUND: Aetiology, clinical significance and treatment options for coronary artery ectasia/aneurysm is not clear. OBJECTIVE: We sought to determine whether exercise can induce coronary ischemia in patients with coronary artery ectasia/aneurysm without significant coronary stenosis. METHODS: Coronary artery ectasia was defined as 1.5-2-fold, aneurysm as >2-fold luminal dilatation of the adjacent normal segment. The study patients could have irregularities with ectatic coronaries but they did not have stenotic lesions >50% with visual assessment of two blinded observers. Patients having coronary artery ectasia or aneurysm with prior myocardial infarction, dilated cardiomyopathy, valvular heart disease, bundle branch block, significant ST-T changes were excluded. The control group was formed from a well matched population of 32 patients with normal coronary arteries who have not performed a treadmill test before coronary angiography. The study group underwent a symptom limited treadmill test if they did not have one before coronary angiogram, all control patients underwent treadmill test. RESULTS: Thirty-three patients with coronary artery ectasia/aneurysm (ranging from one to three vessels) but without significant stenosis were derived from 4470 cardiac catheterization procedures between January 1998 and July 2000. In the study group, 17 of the patients had positive treadmill tests with respect to five patients in the control group (P = 0.004). In subgroup analysis, diffuse ectasia/aneurysm (involving 2-3 vessels) was found to be strongly related with ischemia (P = 0.005) with respect to local disease. CONCLUSION: Coronary artery ectasia/aneurysm may lead to exercise induced ischemia, especially in the diffuse form.     

Sleep-disordered breathing and myocardial ischemia in patients with coronary artery disease

STUDY OBJECTIVES: To examine the occurrence of nocturnal myocardial ischemia and its relationship to sleep-disordered breathing (apneas and oxygen desaturations) in randomly selected men and women undergoing coronary angiography because of angina pectoris. DESIGN: An observational study using an overnight sleep study and Holter recording to examine disordered breathing (oxyhemoglobin desaturations > or = 4% and apnea-hypopneas), heart rates, and ST-segment depressions (> or = 1 mm, > or = 1 min). SETTING: University Hospital, Ume?, a teaching hospital in northern Sweden. PATIENTS: One hundred thirty-two men and 94 women referred for consideration of coronary intervention were randomly included, by lot. RESULTS: ST-segment depressions occurred in 59% (134 of 226) of the patients, and nocturnal ST-segment depressions occurred in 31% (69 of 226). A ST-segment depression occurred within 2 min after an apnea-hypopnea or desaturation in 12% (27 of 226) of patients. This temporal association was seen in 19% of nocturnal ST-segment depressions (71 of 366), more frequently in men (p < 0.01) and in more severely disordered breathing (p < 0.001). Most of these ST-segment depressions were preceded by a series of breathing events: three or more apnea-hypopneas or desaturations or both in 70% (50 of 71). CONCLUSION: Episodes of nocturnal myocardial ischemia are common in patients with angina pectoris. However, a temporal relationship between sleep-disordered breathing and myocardial ischemia is present only in a minority of the patients, but occurs more frequently in men and in more severely disordered breathing.     

Variability of transient myocardial ischemia in ambulatory patients with coronary artery disease

Ambulatory electrocardiographic (ECG) monitoring of patients with chronic stable angina has demonstrated frequent and prolonged episodes of ischemic ST segment depression, but its clinical use requires an understanding of the components and extent of variability. Therefore, variations in the frequency and duration of episodes of ST segment depression were evaluated with ambulatory ECG recording at daily, weekly, and monthly intervals in 42 patients with chronic stable angina and known coronary artery disease. Data were analyzed with a nested analysis of variance design that yields estimates of variance components. From the estimates of variance components, power calculations and minimum significant percent reductions in frequency and duration of ischemia were derived. During 4,656 hours of ambulatory ECG monitoring, 1,262 episodes of ischemic ST segment depression were detected. The frequency of episodes was 6.3 +/- 0.45/24 hr (mean +/- SEM), and the duration of episodes was 18.3 +/- 2.8/24 hr. Because of variability over time, the ability to detect significant changes was dependent upon the number of subjects, length of monitoring period, and intervals between monitoring periods. In a clinical trial, for example, a sample size of 25 patients monitored for 48 hours with 1 week between control and test conditions would require a 65% reduction in frequency, whereas a sample size of 50 patients monitored under similar conditions would require a 46% reduction in frequency, to attribute the change with 90% power to a therapeutic intervention rather than to a spontaneous variation. When monitoring a single patient for 48 hours with 1 week or 1 month between control and repeat monitoring sessions, episodes of ischemic ST depression must be eliminated to detect significant therapeutic changes in ischemic activity at the 95% confidence level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Silent myocardial ischemia in diabetic and nondiabetic patients with coronary artery disease

Background: Patients with diabetes mellitus are at increased risk for CAD; silent ischemia is reported to be frequent in diabetic populations. The aim of the present study was to evaluate the prevalence of silent ischemia in diabetic and nondiabetic patients with assessed CAD. Methods and results: We recruited a total of 618 patients with CAD: 309 were consecutive diabetic patients and 309 were age- and gender-matched nondiabetic patients. Myocardial ischemia was evaluated both during daily life and during exercise testing. Angina pectoris during daily life was more frequent in diabetic than in nondiabetic patients (80% vs. 74%, P<0.05). The anginal pain intensity either during daily life or acute myocardial infarction (MI), the prevalence of a previous MI, the extent of CAD and ergometric parameters were similar in diabetics and nondiabetics. Silent ischemia during exercise was documented in 179 (58%) diabetics and in 197 (64%) nondiabetics (nonsignificant, ns). Both diabetics and nondiabetics with silent exertional myocardial ischemia differed from symptomatic subjects in higher heart rate values (P<0.01), systolic blood pressure (P<0.01), rate–pressure product (P<0.001), work load (P<0.01) and maximum ST-segment depression at peak exercise (P<0.05). Conclusions: The incidence of silent myocardial ischemia during exercise was similar in diabetic and nondiabetic CAD patients. Surprisingly, diabetics showed a higher prevalence of angina pectoris during daily activity than nondiabetics. A significant association between the presence of symptoms during daily life and exercise was observed in both groups. Our results may contribute to the planning of the clinical management of diabetic CAD patients and confirm the individual attitude to pain of CAD patients independent of the presence of diabetes.     

Mental stress-induced myocardial ischemia in coronary artery disease patients with left ventricular dysfunction.

BACKGROUND: Reduced left ventricular ejection fraction (LVEF) is a risk factor for poor outcomes in patients with coronary artery disease (CAD). Mental stress-induced myocardial ischemia (MSIMI) also identifies a subset of CAD patients at increased risk for future cardiovascular events. Susceptibility to MSIMI in patients with CAD and reduced LVEF is unknown. METHODS AND RESULTS: We enrolled 182 patients (67 women) with a mean age of 64 years and a documented history of CAD in this study. Baseline resting ejection fraction was determined by use of technetium 99m sestamibi gated single photon emission computed tomography. Abnormal LVEF was defined as less than 45% for men and less than 50% for women (based on published norms for our software [Cedars-Sinai Medical Center]). All participants underwent mental stress testing with a public speaking task. Rest/stress myocardial perfusion single photon emission computed tomography was performed via conventional methodology. Images were visually compared for number and severity of perfusion defects by use of a scoring method from 0 to 4. A summed difference score was calculated as the difference between summed stress and rest scores. A score of greater than 3 was considered abnormal. MSIMI developed in 19% of patients with normal LVEF and 31% of those with reduced LVEF. There is no statistically significant difference between the two groups (P = .11). CONCLUSIONS: CAD patients with left ventricular dysfunction are equally susceptible to MSIMI as those with normal LVEF.     

Circadian variation of transient myocardial ischemia in patients with coronary artery disease

To examine whether a significant circadian variation of transient myocardial ischemia exists and to better understand the character of such variation, 32 patients with chronic stable symptoms of coronary artery disease underwent one or more days of ambulatory monitoring of ischemic ST segment changes during daily life. A total of 251 episodes of ischemic ST segment depression occurred in 24 (75%) of the 32 patients with a median duration of 5 min (range 1 to 253). A significant circadian increase in ischemic activity was found with 39% of episodes and 46% of total ischemic time occurring between 6 A.M. and 12 P.M. (p less than .05 and p = .02, respectively). In 21 patients with ST segment depression during the 6 hr after waking and the 6 hr before sleep, 68% of episodes occurred in the morning compared with 32% in the evening. There were no significant differences in heart rate at onset, heart rate at 1 min before onset, and activity score associated with ST segment depression. The proportion of minutes showing ST segment depression when the heart rate was above the lowest rate associated with ST segment depression was significantly greater in the morning compared with the evening (26% vs 15%; p = .03). Thus the early morning increase in ST segment depression does not appear to be explained by differences in extrinsic activity and/or stress measured by physical activity score and heart rate response. More importantly, this phenomenon is often ignored by the usual patterns of drug administration for angina.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of the Valsalva maneuver on myocardial ischemia in patients with coronary artery disease.

The influence of the Valsalva maneuver (VM) on myocardial ischemia was evaluated in 24 patients with coronary heart disease. Clinical and hemodynamic responses to the VM were studied during acute ischemia manifested by angina pectoris with transient left ventricular (LV) dysfunction and compared with responses during nonischemic intervals. In the absence of evidence for acute ischemia (angina and increased LV end-diastolic pressure), six patients had abnormal hemodynamic responses to the VM. Five had lack of systolic pressure overshoot and in one, systolic pressure did not decline during straining. When the VM was performed during an ischemic episode, 14 patients had abnormal responses (12 with lack of overshoot in phase IV and two with lack of systolic pressure decline in phase II). In 18 patients a prompt decline in LV end-diastolic pressure occurred with the disappearance of angina during the VM. These changes uniformly occurred during the latter part of straining (VM phase II) as cardiac size and systolic pressure declined. No adverse effects occurred when a VM was performed during acute ischemia. Our observations suggest that the VM abruptly reduces determinants of cardiac oxygen demand, relieving acute ischemia without harmful effects.     

Cholesterol lowering with statins reduces exercise-induced myocardial ischemia in hypercholesterolemic patients with coronary artery disease.

Coronary flow reserve is mainly influenced by the combination of luminal stenosis and vascular dilation capacity. Thus, after statin treatment, the reduction of ischemic threshold in patients submitted to exercise testing could be intensely influenced by angiographic severity. In this study, we verify the effect of statin treatment on exercise-induced myocardial ischemia in hypercholesterolemic patients with a broad range of coronary angiographic severities. Patients with 2 consecutive positive exercise tests, coronary stenosis > or =70%, total cholesterol > or =300 mg/dl, and triglycerides < or =200 mg/dl were randomly assigned to a 16-week treatment period with either diet alone (n = 39) or diet plus statins (simavastatin, n = 31 and pravastatin, n = 10). Statin-treated patients had a significant variation in total cholesterol (-46% vs -2.7%; p <0.01), low-density lipoprotein cholesterol (-58% vs 0.8%; p <0.01), and high-density cholesterol (+28% vs -6%; p <0.05) in comparison with the diet-only group. After 16 weeks of treatment, 36 patients (92%) in the diet group still had positive exercise tests, whereas only 7 patients (15%) of the statin group had a positive test (p <0.01). The proportion of positive tests was significantly reduced in subgroups of patients with 1-, 2-, or 3-vessel disease. Regarding the severity of coronary stenosis, the proportion of positive tests was significantly reduced in patients with stenosis between 70% and 90% and in patients with stenosis > or =90%. Moreover, the proportion of positive tests tended to decrease to a greater extent in patients with mild coronary disease. In conclusion, cholesterol-lowering treatment with statins reduces exercise-induced myocardial ischemia in hypercholesterolemic patients with mild or severe epicardial coronary stenosis.     

醋柳黄酮治疗老年冠心病的疗效观察

目的：观察醋柳黄酮治疗老年冠心病心肌缺血的临床疗效。方法：78例冠心病，随机分为治疗组（40例）与对照组（38例）。对照组常规治疗应用硝酸异山梨酯与阿司匹林。治疗组在常规治疗基础上，加用醋柳黄酮15mg，3次／d，连续3个月。每例于治疗开始前1日与结束次日，进行血脂、血液流变学与动态心电图（Holter）检测。结果：服醋柳黄酮3个月，血清总胆固醇（TC），甘油三酯（TG），低密度脂蛋白-胆固醇（LDL—C）水平明显下降（P〈0．01），高密度指蛋白-胆固醇（HDL—C）水平明显上升（P〈0．05），较对照组显著（P〈0．01）；血液流变学指标如全血粘度、血浆比粘度等均显著下降（P〈0．01或〈0．05），且优于对照组（P〈0．05）。Holter监测示心肌缺血的发作次数及其持续时间，两组均明显减少（P〈0．01、〈0．05），但治疗组减少更著（P〈0．05）。醋柳黄酮治疗未见不良反应。结论：醋柳黄酮有调脂与改善血液流变性作用，治疗老年冠心病安全、有效。     

Clinical significance of exercise-induced silent myocardial ischemia in patients with coronary artery disease

Exercise-induced silent myocardial ischemia is a frequent feature in patients with coronary artery disease. The purpose of this study was to compare the clinical and angiographic characteristics of 269 patients who complained of chest pain during an exercise test (group I) with those of 204 who developed exercise-induced silent myocardial ischemia (group II). Group I patients more frequently had anginal symptoms of class III and IV of the Canadian Cardiovascular Society than did group II patients, who had milder symptoms (p less than 0.001). The only angiographic difference observed between the two groups was a slightly but significantly higher left ventricular end-diastolic pressure in group II patients (p less than 0.05), who also showed a longer exercise duration (p less than 0.01) with a higher heart rate-systolic pressure product (p less than 0.01) and more pronounced ST segment depression at peak exercise (p less than 0.001). Moreover, ventricular ectopic beats during exercise were more frequently observed in group II patients (p less than 0.05). Coronary bypass surgery was performed in 45% of patients of group I and in 24% of patients of group II (p less than 0.05). Survival curves of medically treated patients did not show any statistically significant difference between the two groups. Thus, although patients with a defective anginal warning system may have more pronounced signs of myocardial ischemia and a greater incidence of ventricular arrhythmias during exercise, their long-term prognosis is not different from that of patients who are stopped by angina from the activity that is inducing myocardial ischemia.     

Significance of silent myocardial ischemia during exercise testing in patients with coronary artery disease

To evaluate the significance of ischemic ST-segment depression without associated chest pain during exercise testing, data were analyzed from 2,982 patients from the Coronary Artery Surgery Study (CASS) registry who underwent coronary arteriography and exercise testing and were followed up for 7 years. Patients with proved coronary artery disease (CAD) (at least 70% diameter narrowing) were grouped according to whether they had at least 1 mm of ST-segment depression or anginal chest pain during exercise testing. Four hundred twenty-four had ischemic ST depression without angina (group 1); 232 had angina but no ischemic ST depression (group 2); 456 had both ischemic ST depression and angina (group 3); and 471 had neither ischemic ST depression nor angina (group 4). Sixty-three percent of patients in group 1 and 55% in group 2 had multivessel CAD (difference not significant). The 7-year survival rates were similar for patients in groups 1 (76%), 2 (77%), and 3 (78%), but were significantly better for patients in group 4 (88%, p less than 0.001). Among group 1 patients, survival was related to severity of CAD (p less than 0.001). The 7-year survival rate in group 1 was significantly worse than that in a separate group of 282 patients with ischemic ST depression without angina during exercise testing who had no CAD (95% survival, p less than 0.001). Thus, in patients with silent myocardial ischemia during exercise testing, the extent of CAD and the 7-year survival rate are similar to those of patients with angina during exercise testing. Prognosis is determined primarily by the severity of CAD. In patients without CAD, the survival rate is excellent.     

冠心病心电图心肌缺血与心率变异性的关系

为通过了解心肌缺血时心率变异性的改变，探讨冠心病自主神经失衡的状况，前瞻，顺序地观察静息心电图呈典型心肌缺血的冠心病患者２１例，心电图正常的冠心病患者１９例和健康人２２例ＨＲＶ时域，频域指标。     

Lack of ouabain effect on pacing-induced myocardial ischemia in patients with coronary artery disease

Sixteen patients with significant two and three vessel coronary artery disease but without clinical congestive heart failure were studied during rapid atrial pacing before and after infusion of 0.015 mg/kg of ouabain. Seven patients with a decreased (less than 50 percent) election fraction and nine patients with a normal election fraction had a significant (P < 0.05) increase in resting arterial systolic pressure after the administration of ouabain. However, resting values for coronary sinus flow, coronary vascular resistance, myocardial oxygen consumption and myocardial lactate extraction did not change significantly in either group. During pacing, patients with a decreased ejection fraction demonstrated more ischemia than patients with a normal ejection fraction; however, the administration of ouabain did not significantly alter pacing-related changes in coronary sinus flow, myocardial oxygen consumption, myocardial lactate extraction, ischemic electrocardiographic changes or onset of chest pain in either group. The administration of ouabain has a negligible effect on coronary hemodynamics, myocardial metabolism or clinical signs of ischemia in patients with coronary artery disease with normal or abnormal left ventricular function.     

动态心电图监测老年冠心病无症状心肌缺血的意义

目的:探讨24小时动态心电图(Holter)对老年冠心病患者无症状心肌缺血(SMI)的检出情况。方法:回顾分析我院门诊及住院336例老年冠心病患者的临床情况和Holter资料。结果:(1)常规心电图检出心肌缺血106例(31.55％),Holter检出心肌缺血220例(65.48％);SMI发生率为69.09％,有症状心肌缺血发生率为30.91％;(2)SMI发作有明显生物节律,以清晨6-12时发作频率最高;(3)SMI发作时心率减慢的比例明显低于有症状心肌缺血的(P<0.005);(4)SMI的心律失常检出率为93.4％。结论:Holter可早期发现老年人的无症状心肌缺血,有重要价值。     

Perioperative myocardial ischemia in coronary artery disease patients undergoing abdominal nonvascular surgery

BACKGROUND:

The incidence of perioperative myocardial ischemia (PMI) is the highest in patients who have coronary artery disease, and it is the best predictor of intrahospital morbidity and mortality.

OBJECTIVE:

To identify predictors of PMI in patients who have coronary artery disease and are undergoing abdominal nonvascular surgery.

METHODS:

A prospective, observational, clinical study of 111 consecutive patients with angiographically verified coronary artery disease, scheduled for open abdominal nonvascular surgery, was conducted. Patients received general anesthesia and were monitored by continuous electrocardiogram during surgery and immediately postsurgery (72 h period) in the intensive care unit at the University Clinical Center (Belgrade, Serbia). All of the patients had 12-lead electrocardiography immediately after the surgery, on postoperative days 1, 2 and 7, and one day before discharge from hospital. The patients were monitored until the 30th postoperative day.

RESULTS:

A total of 24 predictors for PMI were analyzed. The Pearson’s χ² test and a binomial logistic regression model were used for statistical analysis. A significant difference in the incidence of PMI was found in the coronary artery disease patients with an associated risk factor (14 of 24 risk factors) compared with those without the risk factor. In particular, a highly significant difference in the incidence of PMI was found in coronary artery disease patients with angina pectoris, compared with those without angina pectoris.

CONCLUSION:

Using the multivariate logistic regression analysis, angina pectoris was an independent predictor of PMI.     

Incidence of ventricular arrhythmias during transient myocardial ischemia in patients with stable coronary artery disease

To determine the incidence of ventricular arrhythmias related to episodes of transient myocardial ischemia during ambulatory electrocardiographic (ECG) monitoring, 97 patients with stable angina pectoris, angiographically proved coronary artery disease and an abnormal exercise test were studied. A total of 573 episodes with ST segment depression were documented: in 118 episodes (21%) the patients were symptomatic and in 455 (79%) they remained asymptomatic. Ventricular arrhythmias (greater than 5 premature ventricular beats/min, bigeminy, couplets or salvos of premature ventricular beats) occurred during 27 (5%) ischemic episodes in a subset of 10 patients (10%) (group A). The other 87 patients (90%) (group B) showed exclusively ischemic episodes without ventricular arrhythmias. Comparison of patients in group A and group B showed no differences in hemodynamic, angiographic, exercise testing and ambulatory ECG monitoring data. Ischemic episodes with and without ventricular arrhythmias showed a similar duration and amplitude of ST segment depression and a comparable heart rate at the onset of ischemia. Both types of ischemic episodes, with and without arrhythmias, occurred predominantly during the morning hours between 6:00 AM and noon, and both types remained asymptomatic to within similar percentages. The data demonstrate that ventricular arrhythmias are related to transient myocardial ischemia in only a few patients with stable angina pectoris; these arrhythmias are related neither to the degree of ischemia during ambulatory ECG monitoring nor to the occurrence of anginal symptoms.     

Characteristics of coronary artery lesions in patients with painless myocardial ischemia

AIM: To assess extent and localization of coronary artery lesions in patients with painless myocardial ischemia. MATERIAL AND METHODS: Tredmill stress-echocardiograghy, Holter ECG monitoring and coronary angiography were carried out in 59 male patients (age 30-72, mean 54.5 years) with either angina pectoris or painless ischemia. RESULTS: Among patients with painless ischemia 50% had 2-vessel disease, mostly with right coronary artery involvement (87.5%) and there was no case of left main stenosis. Patients with angina were characterized by significantly higher index of obstruction (p<0.005) and often had multivessel coronary artery disease (48.8%). CONCLUSION: Patients with effort angina compared with those with painless ischemia had more extensive and severe coronary artery involvement while the latter more often had right coronary artery stenoses.     

Reduction of myocardial ischemia with simvastatin in addition to conventional treatment in patients with chronic coronary artery disease.

BACKGROUND: Coronary artery disease is becoming more prevalent every day. We now know that controlling the risk factors for this pathology is of the utmost importance, not only to prevent the formation of atheromatous plaques (primary prevention), but also to slow its progression, or even promote regression of existing plaques (secondary prevention). There is no longer any doubt that an increase in serum cholesterol is essential for the development and progression of atherosclerosis. Therefore, lowering cholesterol levels is a key factor in controlling this disease. It has been shown that cholesterol reduction with statins is associated with a reduction in cardiovascular morbidity and mortality. It has also been demonstrated that reducing cholesterol restores peripheral and coronary vasodilation even in subjects with no angiographic evidence of the disease. OBJECTIVE: The present study aimed at assessing the effect of simvastatin in reducing myocardial ischemia in patients with chronic atherosclerotic coronary artery disease. PATIENTS AND METHODS: Twenty-five patients with stable angina and dyslipidemia undergoing clinical treatment were studied prospectively. Their lipid profile was analyzed and the diagnosis of effort-induced ischemia was confirmed by means of exercise testing. They were then randomly distributed in two groups: the simvastatin group and the placebo group. After a four- to six-month follow-up period (average of 5.72 months), they underwent new laboratory and exercise tests. RESULTS: A significant reduction in the variation of total cholesterol (p < 0.0002) and LDL-C levels (p < 0.001) was observed in the simvastatin group, compared to the placebo group. The parameters assessed during the exercise test revealed a significant improvement in ST-segment depression during effort (p < 0.046), as well as a decrease in precordial pain in the treated group during exertion, when comparing pre- and post-treatment periods. Patients receiving simvastatin also improved their functional capacity (p < 0.016), subjectively assessed by the angina pectoris classification of the Canadian Cardiovascular Society. CONCLUSIONS: These results suggest that the association of simvastatin and conventional treatment in patients with stable angina reduces effort-induced ischemia, and can be used with this group of patients, particularly those considered ineligible for invasive therapeutic intervention.