Silent myocardial ischemia during rehabilitation for cerebrovascular disease

In asymptomatic patients the importance of silent ischemic ST-T wave changes on Holter monitoring is known to be a significant predictive variable for one-year mortality of postmyocardial infarction patients. This case report represents the uses of ambulatory ECG to detect ischemic ST changes in patients who have had recent strokes. The cases reported here of silent myocardiac ischemia in stroke patients reflect previous reports in which 70% of the ischemic episodes in patients with symptomatic coronary artery disease are not associated with angina and in which approximately 10% to 15% of acute myocardial infarctions are silent. We now believe that the incidence of "silent" ischemia may be precipitated in poststroke patients during their rehabilitation program. This belief is supported by two main factors. First, a high level of personally relevant mental stress exists which activates the sympathoadrenal system, which may lead to myocardial ischemia. Second, some stroke patients become aphasic and are unable to communicate adequately even if they experience angina symptoms. We have found that poststroke, most patients could not undergo exercise treadmill testing secondary to a variety of factors: inability to coordinate limbs, poor endurance, inability to follow directions, and/or lack of attention. We now propose that 24-hour monitoring for ST-T wave changes poststroke should be considered as part of a vigorous investigation for myocardial ischemia during the rehabilitation of these patients because they have an increased risk of cardiac morbidity.     

Silent myocardial ischemia in patients with diabetes: who to screen.

OBJECTIVE: Silent myocardial ischemia (SMI) is more common in diabetic patients than in the general population. However, the exact prevalence of SMI is not known, and routine screening is costly. The purpose of this 1-year study was to estimate the prevalence of SMI and define a high-risk diabetic population by systematically testing patients with no symptoms of coronary artery disease (CAD). RESEARCH DESIGN AND METHODS: The criteria for inclusion in this study were age (between 25 and 75 years), duration of diabetes (>15 years for type 1 diabetes, 10 years for type 2 diabetes with no cardiovascular risk factors, and 5 years for type 2 diabetes with at least one cardiovascular risk factor), and absence of clinical or electrocardiogram (ECG) symptoms of CAD. For 1 year, 203 patients were screened, including 28 women and 45 men with type 1 diabetes (aged 41.5+/-10.9 years, mean duration of diabetes 20.9+/-7.7 years [mean +/- SD]) and 61 women and 69 men with type 2 diabetes (aged 60.7+/-8.7 years, duration of diabetes 16.5+/-7.1 years). Exercise ECG was the first choice for screening method. If exercise ECG was not possible or inconclusive, thallium myocardial scintigraphy (TMS) with exercise testing and/or dipyridamole injection was performed. If any one of these tests was positive, coronary angiography was carried out and was considered to be positive with a stenosis of > or =50%. RESULTS: Positive screening results were obtained in 32 patients (15.7%). Coronary angiography demonstrated significant lesions in 19 patients (9.3%) and nonsignificant lesions in 7 patients (1 false-positive result for exercise ECG and 6 false-positive results for TMS). Coronary angiography was not performed in six patients. All but 3 of the 19 patients (15 men and 4 women) in whom silent coronary lesions were detected presented with type 2 diabetes. The main differences between the 16 type 2 diabetic patients presenting with coronary lesions and the type 2 diabetic patients without SMI were a higher prevalence of peripheral macroangiopathy (56.2 vs. 15.1%, respectively, P < 0.01) and a higher prevalence of retinopathy (P < 0.05). No correlation was found between SMI and duration of diabetes, HbA1c level, renal status, or cardiovascular risk factors except for family history of CAD. CONCLUSIONS: The results of this study allowed us to determine a high-risk group for SMI in the diabetic population. SMI with significant lesions occurs in 20.9% of type 2 diabetic male patients who are totally asymptomatic for CAD. Based on these findings, we recommend routine screening for male patients in whom the duration of type 2 diabetes is >10 years or even less when more than one cardiovascular risk factor is present.     

Transtelephonic electrocardiographic monitoring of an outpatient cardiac rehabilitation programme

OBJECTIVE: To address whether transtelephonic electrocardiographic monitoring (TEM) of patients with chronic cardiac diseases, being exercised in public gyms, is safe and efficacious. DESIGN: Data were obtained from 91 patients (72 men and 19 women; with a mean (SD) age of 56 (6) years and over a total of 11 820 exercise hours) with coronary heart disease and/or chronic heart failure (< or = stage III NYHA (New York Heart Association)), who were referred for cardiac exercise rehabilitation (phase III). METHOD: Twelve-lead electrocardiograms of indicated patients were transmitted from the qualified trainers in real time by standard telephone lines and were evaluated by the medical staff at the base. The TEM kits contain a telemedicine 12-lead electrocardiographic unit, a telephone modem, a computer receiver with special operating software and a laser printer. As soon as the ECG was monitored and diagnosed, the cardiologist contacted the exercise trainer and provided all the necessary instructions for intervention. RESULTS: In total, 280 cases were monitored. Successful TEM was reported in 99.3% of the cases. The mean (SD) time from ECG recordings to final interventions was estimated at 294 (13) s. The patients were referred for TEM during or soon after exercise sessions, because of chest pain (36% of the TEM cases), palpitations (33%), dizziness (12%), unexpected fatigue (9%), hypertensive crises (7%) and other disorders (3%). Ischaemic ECG changes were recorded in 14 cases with thoracic pain and arrhythmias in nine patients with palpitations. In only one case was a medical emergency reported and an ambulance response required. CONCLUSION: These data demonstrate that TEM provides a workable facility in cardiac rehabilitation for monitoring patients who are exercising in gyms.     

冠心病患者无症状性心肌缺血心电监护的分析及护理

无症状性心肌缺血(silentm，叉ardial ischemia，SMI)是 冠心病的预后不良的高危因素。冠心病患者的预后取决于 有无缺血而不取决于有无症状〔‘〕，高达60%一90%的冠心 病患者有SMI[z]。无症状性心肌缺血仍然是当今冠心病研 究的一个重要方面，因其缺血发生时不能被感知，难以     

急性心肌梗死早期T波改变的观察及护理

心肌梗死（MI）是冠心病中最严重、危害最大的疾病之一。近年来，心肌梗死的患病率和死亡率在不断上升，已成为威胁人类健康和生命的“第一杀手”，因此，及早诊断、心电监护，为抢救患者及患者预后的效果评价创造了良好的时机。我科收治急性心肌梗死患者5例，在早期均只有T波改变，由于护理得当，均获得较好的预后，现报道如下。     

Ambulatory monitoring of silent myocardial ischemia: what is its utility?

In patients with angina pectoris, ambulatory ST segment monitoring has documented that asymptomatic myocardial ischemic episodes occur with greater frequency than previously suspected. During such episodes, ischemia has been verified by nuclear, echocardiographic, and biochemical techniques. Painless ST segment depression is consistent with severe coronary artery disease when detected by ambulatory monitoring in patients with angina and portends a worsened prognosis in patients about to have vascular surgical procedures. On the other hand, ST depression without angina has a better prognosis than ST depression with angina during treadmill exercise testing. Silent ischemia of prolonged duration per 24-hour period suggests a poor prognosis in patients with a history of unstable angina or myocardial infarction.     

Silent myocardial ischemia: an update

Silent myocardial ischemia is diagnosed by several different techniques and has been documented in all the anginal syndromes. In addition to other factors, its presence may be related to increased pain threshold and increased pain tolerance. Although some patients with painless ischemia may have less extensive coronary artery disease, cumulative evidence indicates that silent myocardial ischemia does not necessarily signify a lesser degree of cardiac ischemia or a less severe coronary abnormality. As judged by ambulatory monitoring studies, it shows circadian variation; occurs more frequently than symptomatic ischemia; and appears to depend, in large part, on activation of the sympathetic nervous system. Frequent silent ischemic events during ambulatory monitoring are worrisome because they reflect the disease "activity" of single or multiple coronary atherosclerotic lesions. Thus, there may be a direct association between the severity of ischemia seen during Holter monitoring, the extent of underlying coronary artery disease or disease activity, and prognosis. When diagnosed by exercise testing, silent myocardial ischemia may be associated with significant coronary involvement. In this regard, patients with three vessel coronary disease, impaired left ventricular function, and silent ischemia during stress testing should benefit from coronary revascularization. Compared with symptomatic patients, other evidence suggests that patients with exercise-induced asymptomatic ischemia have at least the same or perhaps even a worse outlook; this may be related to the lack of symptoms that would prompt evaluation and therapy. Awareness of the possibility of silent myocardial ischemia and use of commonly available tests, both to establish its presence and severity and to guide treatment, are emerging as new clinical goals. Further data, however, are necessary to determine how vigorously this should be pursued in different patient subgroups. In association with unstable angina or post-myocardial infarction, the added risk of silent myocardial ischemia warrants a more aggressive approach.     

Silent cardiac ischemia in cervical spinal cord injury: case study.

The management of ischemic heart disease in patients with chronic spinal cord injury (SCI) will become an increasingly major concern as this population ages. Although silent ischemia has become an important topic in the medical literature, the relationship with cervical SCI has not been adequately explored. A literature search revealed no case reports of documented asymptomatic cardiac ischemia in SCI patients. This is a case report of a 65-year-old patient with chronic C7 incomplete SCI who had multiple risk factors for coronary artery disease and an abnormal electrocardiogram. Despite being completely asymptomatic, the patient was found to have significant myocardial ischemia induced by minimal stress using atrial paced thallium scintigraphy. This finding led to the cancellation of an elective surgical procedure. This case illustrates the importance of suspecting silent myocardial ischemia in cervical SCI patients.     

Silent myocardial ischemia: improvement with nisoldipine therapy

Nisoldipine is a new calcium channel blocker of the dihydropyridine family with a high affinity for coronary vessels. We assessed the efficacy of nisoldipine in the treatment of asymptomatic ischemia in 12 patients with chronic, stable angina. Two to four weeks of daily therapy with prn nitroglycerin and placebo was followed by 24-hour ambulatory electrocardiographic recording for ST segment assessment. After two weeks of once-daily nisoldipine, 10 to 20 mg, the ambulatory recording was repeated. A significant difference was seen in ischemia-magnitude products of asymptomatic ischemic episodes in placebo versus active drug periods (P less than .05). When total ischemic burden was considered (ST segment depression during both painless and painful episodes), the difference was even more significant (P less than .02).     

Silent myocardial ischemia. Answers to frequently asked questions

Patients with coronary artery disease and silent myocardial ischemia have a prognosis similar to that of symptomatic patients. Screening of totally asymptomatic patients is not likely to identify many with silent ischemia. However, certain cohorts of patients--middle-aged men with two or more risk factors for coronary arteriosclerosis--are at risk of presenting initially with myocardial infarction or sudden death, and the screening of such persons is advised. Use of radionuclear imaging techniques during exercise stress testing appears to be helpful in identifying patients at high risk, who should then be offered coronary arteriography. An ideal treatment has not been established, but a treatment strategy based on symptom relief alone is suboptimal. Measures used for symptomatic ischemia are just as effective with silent ischemia. Treatment must be individualized, and ambulatory electrocardiographic monitoring appears useful in adjusting antiischemic therapy for a given patient.     

Twenty-four hours ambulatory monitoring: a new electrocardiographic tool.

In summary, this author has been able to assist in alerting the physician to the critical findings of his patients' cardiac analyses so that immediate medical intervention could be initiated. The implications for such a tool are far-reaching. Heart disease is still America's number one killer, but with devices such as this one, advances are being made to undermine its life-threatening effects.     

Automated ambulatory blood pressure monitoring: clinical utility in the family practice setting

Although the percentage of patients who are treated for hypertension has increased, the percentage of those who demonstrate control of blood pressure has declined. As a result of this trend, clinicians may increasingly rely on ambulatory blood pressure monitoring to improve the diagnosis and treatment of hypertension. Studies confirm that ambulatory blood pressure monitoring devices more accurately reflect a patient's blood pressure and correlate more closely with end-organ complications than blood pressure levels measured in the physician's office. Discriminate use of this technology in specific clinical circumstances assists in identifying patients at risk for hypertension and may result in improved outcomes in this subset of patients. Ambulatory blood pressure monitoring may be particularly helpful in clinical situations such as borderline hypertension, white-coat hypertension, apparent drug resistance, hypotensive symptoms from medications or autonomic dysfunction, episodic hypertension, and evaluation of antihypertensive efficacy.     

Silent hypoxia: A harbinger of clinical deterioration in patients with COVID-19

Patients infected with the SARS-CoV-2 virus can present with a wide variety of symptoms including being entirely asymptomatic. Despite having no or minimal symptoms, some patients may have markedly reduced pulse oximetry readings. This has been referred to as “silent” or “apathetic” hypoxia (Ottestad et al., 2020 [1]). We present a case of a 72-year-old male with COVID-19 syndrome who presented to the emergency department with minimal symptoms but low peripheral oxygen saturation readings. The patient deteriorated over the following days and eventually died as a result of overwhelming multi-organ system failure. This case highlights the utility of peripheral oxygen measurements in the evaluation of patients with SARS-CoV-2 infection. Self-monitoring of pulse oximetry by patients discharged from the emergency department is a potential way to identify patients needing to return for further evaluation.     

Clinical utility of free drug monitoring.

Most drugs are bound to serum proteins to a various degree. Only unbound or free drug is pharmacologically active. Usually total drug is measured for therapeutic monitoring because there is equilibrium between bound and free drugs, and concentration of free drug can be predicted from total drug concentration. However, under certain conditions this equilibrium is disturbed and the measured free drug concentration can be significantly higher than expected from total drug concentrations, especially for strongly protein-bound drugs. In such case a patient may experience drug toxicity even if the total drug concentration is within the therapeutic range. Conditions like uremia, liver disease and hypoalbuminemia can lead to significant increases in free drug concentration. Therefore, monitoring free phenytoin and free valproic acid is recommended in these patients. Drug-drug interactions can also lead to a disproportionate increase in free drug concentration. One strongly protein-bound drug can significantly displace another strongly protein-bound drug if both drugs share the same binding site. Several over-the-counter pain medications such as salicylate, naproxen, and ibuprofen can cause significant displacement of both phenytoin and valproic acid from albumin binding site. Interestingly, such interactions are absent in uremic patients. Elderly patients may have increased free phenytoin or valproic acid due to hypoalbuminemia. Elevated free phenytoin concentrations have also been reported in patients with AIDS. Although digoxin is 25% bound to protein, monitoring free digoxin is useful in patients with elevated endogenous digoxin-like immunoreactive substances or in patients overdosed with digoxin and being treated with digibind. Monitoring free digoxin can also eliminate interference of Chinese medicines Chan Su and Danshen in serum digoxin measurement by certain immunoassays. However, free drug monitoring is not a routine procedure in clinical laboratories due to technical difficulties and lack of established reference ranges for free drugs.     

Extended field-of-view sonography: utility in clinical practice.

The purpose of this study was to evaluate the usefulness of real-time extended field-of view sonography in clinical practice (i.e., the frequency of use in various body systems, the frequency of use by different sonographers, and the benefits and drawbacks in comparison to conventional real-time sonography). The use of extended field-of-view sonography was monitored for a 6 month period. The pattern of usage among different sonographers and for different body systems was documented. Extended field-of-view sonography was utilized in 26.5% of patients. In comparison, color Doppler sonography was used in 23.2% of patients. Utilization of extended field-of-view sonography varied significantly among sonographers and among different body systems. Extended field-of-view sonography allowed measurement of large structures and revealed the anatomic context of abnormalities in circumstances under which conventional real-time scans could not provide this information.     

Ⅱ型糖尿病患者无症状性心肌缺血及其相关因素分析

目的 了解Ⅱ型糖尿病(T2DM)患者无症状性心肌缺血(SMI)的发病情况,探讨与其相关的主要危险因素.方法 217例无心绞痛(或与心绞痛等同症状)的T2DM患者,根据心电图(静息、动态或负荷试验)诊断有无心肌缺血分为两组,对比观察心肌缺血与临床一股情况及各生化指标的相关性.结果 T2DM患者SMI发病率20.7%,其中女性与男性之比为3∶2,SMI组中年龄、血压、BMI、2hPG、HbAlc、TG、TC、LDL-C均高于时照组,而HDL-C低于对照组,且SMI组中吸烟者所占比例亦高于对照组.结论 T2DM患者中多种危险因子的集簇增加了心血管病变发生的机率,且女性患者心肌缺血的比例超过男性,提示对女性T2DM患者加强控制心血管危险因子的干预甚至比男性更重要.     

心电监护对急性心肌梗死患者负面影响的原因分析及对策

总结心电监护对急性心肌梗死患者的负面影响,提出护理对策.主要负面影响为患者产生焦虑和恐惧、体位受限制、睡眠障碍、上肢酸胀麻木疼痛、电极粘贴部位皮肤过敏、经济压力、对医护人员误解等.产生原因主要为环境、体位、操作等因素,加之患者对心电监护缺乏全面理解.重视行心电监护的解释指导,取得患者理解及配合,为患者营造安全、舒适的环境,做好心电监护相关护理,以防止心电监护对患者的负面影响.     

Aspiration in rehabilitation patients: videofluoroscopy vs bedside clinical assessment

This paper reports the results of a blinded study comparing videofluoroscopy with bedside clinical evaluations by speech/language pathologists in the diagnosis of aspiration. One hundred and seven inpatients from a general rehabilitation hospital were evaluated over a four-month period. Of the total patient population, 43 (40%) aspirated at least one consistency of food during videofluoroscopy. Bedside evaluation identified only 18 (42%) of these patients. The positive predictive value of bedside assessment was 0.75; negative predictive value was 0.70. Aspirators on videofluoroscopy were more likely to have brainstem or multilobe central nervous system involvement than nonaspirators. However, there was no statistically significant difference in lesion sites between clinically detected and "silent" aspirators. While the significance of aspiration noted on videofluoroscopy is debatable, it is clear that bedside evaluation alone underestimates the frequency of aspiration in patients with neurologic dysfunction.     

"Silent" myocardial ischemia and the activity of the sympathetic-adrenal system in hypertension patients

The aim of the study was to assess the sympathoadrenal activity at the time of silent ischemia event in hypertensive patients. In 15 hospitalized hypertensive patients having silent ischemia event during Holter ECG monitoring while walking, blood samples for catecholamines were taken at the time of silent ischemia event, pointed with alarm by the real time ECG "Q Med" monitor (USA). Control blood samples were taken under the same conditions without ST-segment depression. Plasma noradrenaline (NA) during silent ischemia was significantly higher than the control level without ischemia (458 +/- 71 ng/l vs 717 +/- 95 ng/l) (p less than 0.01). The changes in plasma NA correlated with left ventricular mass assessed by echocardiography (r = 0.70, p less than 0.01). The role of sympathoadrenal hyperactivity in the genesis of silent myocardial ischemia in patients with essential hypertension is discussed.