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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Digitalis and diuretics constitute conventional therapy of congestive heart failure, but systemic vasodilators offer an innovative approach in acute and chronic heart failure of decreasing increased left ventricular systolic wall tension (ventricular afterload) by reducing aortic impedance and/or by reducing cardiac venous return. Thus, vasodilators increase cardiac output (CO) by diminishing peripheral vascular resistance (PVR) and/or decrease increased left ventricular end-diastolic pressure (LVEDP) (ventricular preload) by diminishing venous tone. Concomitantly, there is reduction of myocardial oxygen demand, thereby reliably reducing angina pectoris in coronary disease, and potentially limiting infarct size and ischemia provided systemic arterial pressure remains normal. The vasodilators produce disparate modifications of cardiac function depending upon their differing alterations of preload versus impedance: nitrates principally cause venodilation (decrease LVEDP); nitroprusside, phentolamine and prazosin produce balanced arterial and venous dilation (decrease LVEDP and increase CO) provided left ventricular filling pressure is maintained at the upper limit of normal; whereas hydralazine predominantly effects arteriolar dilation (increases CO). With depressed CO plus highly increased LVEDP and increased PVR, nitrates also induce some increase of CO by reducing PVR. Combined nitroprusside and dopamine synergistically enhance CO and decrease LVEDP. Mechanical counterpulsation aids nitroprusside in acute myocardial infarction. The 30-minute venodilator action of sublingual nitroglycerin is extended for 4 to 6 hours by cutaneous nitroglycerin ointment, by sublingual and oral isosorbide dintrate, and by oral pentaerythritol tetranitrate and sustained-release nitroglycerin capsules. Ambulatory oral vasodilator therapy is provided by long-acting nitrates (relieve pulmonary congestion); hydralazine (improves fatigue); prazosin alone, combined nitrate-hydralazine combined prazosin-hydralazine (improve both dyspnea and fatigue).
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PMID:Afterload reduction and cardiac performance. Physiologic basis of systemic vasodilators as a new approach in treatment of congestive heart failure. 9 30

The sensitivity of myocardial perfusion imaging (MPI) using thallium-201 injected both at rest and during peak exercise was compared to simultaneously recorded 12 lead electrocardiography (ECG) for the detection of transient ischemia in 20 normal subjects and 63 patients with coronary artery disease (CAD). No significant perfusion defects or ECG changes were seen on either the rest or exercise studies in any of the normal subjects. Fifty-six percent of patients with CAD developed new perfusion defects with exercise compared to 38% who developed ischemic ST-segment depression (P less than 0.02). However, when chest pain and/or ST depression were considered indices of ischemia, the sensitivity of exercise testing and thallium-201 MPI was similar. The increased sensitivity of MPI compared to ST-segment depression on the ECG was due to patients with baseline ECG abnormalities and those who failed to achieve 85% of predicted maximum heart rate with exercise. Analysis of the exercise results according to the extent of coronary artery disease revealed a progressive increase in both positive ECGs and MPI with the number of vessels involved. In patients with single vessel disease the MPI was more sensitive than the ECG (P less than 0.02). The combination of the rest and exercise ECG, MPI and chest pain during exercise failed to identify 11% of patients with CAD. Exercise thallium-201 MPI is a useful adjunct to conventional exercise testing particularly when evaluating patients with abnormal resting ECGs, those who develop ventricular conduction defects of arrhythmias during exercise, and those who fail to achieve their predicted heart rate because of fatigue or breathlessness.
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PMID:Thallium-201 myocardial perfusion imaging at rest and during exercise. Comparative sensitivity to electrocardiography in coronary artery disease. 83 Feb 22

Clinical predictors of in-hospital fatality were assessed in 191 persons admitted to the Yale-New Haven Hospital Intensive Care Unit with a diagnosis of congestive heart failure. In the 17 (8.9%) patients who died, the most important individual predictors among the presenting clinical features were absence of dyspnea, presence of anterior chest pain or jugulovenous distension, and cardiac severity due to ischemia, valvular disease, or arrhythmia. Two important predictors, largely neglected in previous literature, were a prior history of congestive heart failure and a poor clinical response after 24 h of therapy. Multivariable analysis led to the identification of 6 features (age greater than 70 y, prior history of congestive heart failure, jugulovenous distension, chest pain, cardiac severity, and poor early response to therapy) that could be combined into a simple clinical predictive index. The new index identified 5 prognostic groups with fatality rates of 0, 3.5, 7.4, 19.2, and 85.7 percent. An advantage of the clinical index is the identification of a subgroup of patients, with low risk for fatality, who may not need prolonged treatment in an intensive care unit.
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PMID:Response to initial therapy and new onset as predictors of prognosis in patients hospitalized with congestive heart failure. 159 94

beta-Blockers are known to suppress exercise-induced ischemia but give rise to such problems as fatigue or dyspnea on effort and also bradycardia. In a series of double-blind, placebo-controlled studies of celiprolol (a cardioselective beta 1-blocker with beta 2-agonist and vasodilatory properties) in patients with hypertension and angina and in normal volunteers, it was found that celiprolol did not produce bradycardia when given in combination with verapamil. Celiprolol did reduce exercise-induced ischemia, but there was no reduction in cardiac output at rest or on exercise compared with placebo. Compared with atenolol, celiprolol produced less dyspnea and fatigue at submaximal levels of exercise. It is concluded that celiprolol possesses certain differences, compared with conventional beta-blockers, that may be of direct clinical benefit.
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PMID:Angina, ischemia, and effort tolerance with vasodilating beta-blockers. 167 26

The prognosis of coronary patients in terms of the mortality of coronary heart disease shows a positive relation to the severity of clinical and functional diagnostic parameters. Thus exercise therapy should be monitored by criteria that take ischemia, the myocardial situation and rhythm disorders into account. These criteria should be reliable and should be easy to determine as well as to apply. For pragmatic reasons the non-invasive evaluation of findings and the diagnostic symptom-limited ergometer test are especially significant for dosage and monitoring of exercise therapy. Monitored exercise therapy is here understood to mean individually adjusted exercising by patients, and training thus has to be based on diagnostic findings. First existing complaints have to be analyzed and such findings as size of infarction in the ECG, heart volume in the X-ray, size and function of the left ventricle by echography, etc. checked. Afterwards maximum physical work capacity on a multistage bicycle ergometer test is measured with respect to the following termination criteria: a) subjective reports by the patient during exercise (e.g. onset and severity of angina pectoris, dyspnea and/or fatigue of the leg muscles) and b) objective criteria such as significant ischemic ST-depression, exercise-hypertension, age-related submaximal heart rate and significant rhythm disorders. An inverse correlation is found between measured maximum symptom-limited physical performance and the frequency of cardiac termination criteria; a comparable inverse correlation exists with heart volume: max. O2 pulse.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Can the training of coronary patients be monitored by readily measurable parameters?]. 191 21

From April 1980 to January 1990, among 2,576 percutaneous transluminal coronary angioplasty (PTCA) procedures, 100 patients (82 men and 18 women; mean age, 54 +/- 10 years [3.9%]) underwent emergency coronary artery bypass graft surgery. Before PTCA 56 had unstable angina, 34 had prior myocardial infarction, and 60 had single-vessel coronary artery disease. The mean time period from the onset of ischemia to surgical reperfusion was 147 +/- 16 minutes; 155 grafts were placed (1.5 grafts per patient). In-hospital mortality was 19%; operative mortality was significantly related to older age (59 +/- 9 versus 53 +/- 10 years, p less than 0.05), presence of unstable angina (74% versus 53%, p less than 0.05), and development of cardiogenic shock or necessity of cardiac massage before surgery (53% versus 16%, p less than 0.0001). In addition, 57 patients developed a Q wave myocardial infarction. For hospital survivors, overall survival at 7 years was 94% (Kaplan-Meier method), with three cardiac deaths during follow-up; two additional patients had late myocardial infarction, and four had late PTCA. At a mean follow-up of 55 +/- 38 months, 78% of the patients had no chest pain, and 80% reported no dyspnea. All patients received antiplatelet agents or oral anticoagulants; 34% had no antianginal medications. Among the 40 previously employed patients, 73% resumed work after surgery. All patients with cardiogenic shock or cardiac massage who survived the initial hospital period were alive at follow-up. After an initial critical period, the long-term clinical outcome of patients with emergency coronary bypass surgery after failed PTCA is satisfactory.
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PMID:Early and long-term outcome after emergency coronary artery bypass surgery after failed coronary angioplasty. 193 17

We describe a 51-year-old man who came to our institution with cold cyanotic extremities. He was receiving radiation therapy for adenocarcinoma of the lung and superior vena cava syndrome. Findings on initial physical examination were notable for absent peripheral pulses and increased jugular venous pulsations. Shortly after admission, the patient experienced severe dyspnea and tachypnea. Arterial blood gas studies revealed mild metabolic acidosis. A chest roentgenogram showed an enlarged cardiac silhouette and the known mass in the right upper lobe of the lung. An electrocardiogram demonstrated no evidence of ischemia but low-voltage QRS complexes. An emergency echocardiogram disclosed a large pericardial effusion and evidence of hemodynamic compromise. With use of echocardiographic-guided pericardiocentesis, 600 ml of bloody fluid was removed; the pulses were immediately palpable in the patient's extremities. Although symptoms associated with the extremities are unusual as the initial complaint of patients with cardiac tamponade, we illustrate several key physical findings and abnormal results of laboratory test characteristic of this disorder. In addition, we underscore the importance of considering this diagnosis, especially in patients with a malignant tumor, and we describe the prompt response to therapy.
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PMID:A patient with pulseless extremities: an unusual manifestation of cardiac tamponade. 154 85

Impaired diastolic function of the hypertrophied and stiffened left ventricle is a characteristic feature of hypertrophic cardiomyopathy (Figure 1). Altered left ventricular filling dynamics and reduced left ventricular distensibility or increased left ventricular diastolic chamber stiffness are associated with reduced left ventricular stroke volume, increased left ventricular filling pressures and compressive effects on the coronary microcirculation. These factors contribute importantly to the clinical presentation of many patients, including symptoms of fatigue, dyspnea and angina pectoris. Reduced distensibility results both from factors determining the passive elastic properties of the ventricular chamber (including severity of hypertrophy, fibrosis and cellular disarray) and from factors influencing the rate and extent of active left ventricular relaxation (Figure 2). The factors contributing to impaired relaxation in hypertrophic cardiomyopathy are mediated via either inactivation dependent or load-dependent mechanisms. In laboratory animals, compromise of myocardial inactivation results in a persistent increase in intracellular calcium concentration and in prolonged interaction of the contractile proteins. Additionally, there is evidence for an increased number of active receptors for calcium antagonists and, lastly, for myocardial ischemia (Figure 3). Load-dependent mechanisms include diminished wall tension at the opening of the mitral valve, changes in afterload, contractility and coronary flow. Other factors are nonuniform and asynchronous regional ventricular function due to differing increases in thickness of the ventricular walls and ischemia (Figure 4). Calcium channel blockers exert a favorable influence on left ventricular relaxation and filling (Figure 5); verapamil and diltiazem are preferable to nifedipine. Verapamil increases left ventricular stroke volume without an increase in the end-diastolic pressure (Figure 6), reduces regional asynchrony if present, and leads to a more homogeneous regional diastolic filling (Figure 4).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Left ventricular diastolic function in hypertrophic cardiomyopathy. 202 81

The prevalence of silent myocardial ischemia was prospectively assessed in a group of 103 consecutive patients (mean age 59 +/- 10 years, 79% male) undergoing symptom-limited exercise thallium-201 scintigraphy. Variables that best correlated with the occurrence of painless ischemia by quantitative scintigraphic criteria were examined. Fifty-nine patients (57%) had no angina on exercise testing. A significantly greater percent of patients with silent ischemia than of patients with angina had a recent myocardial infarction (31% versus 7%, p less than 0.01), had no prior angina (91% versus 64%, p less than 0.01), had dyspnea as an exercise test end point (56% versus 35%, p less than 0.05) and exhibited redistribution defects in the supply regions of the right and circumflex coronary arteries (50% versus 35%, p less than 0.05). The group with exercise angina had more ST depression (64% versus 41%, p less than 0.05) and more patients with four or more redistribution defects. However, there was no difference between the two groups with respect to mean total thallium-201 perfusion score, number of redistribution defects per patient, multi-vessel thallium redistribution pattern or extent of angiographic coronary artery disease. There was also no difference between the silent ischemia and angina groups with respect to antianginal drug usage, prevalence of diabetes mellitus, exercise duration, peak exercise heart rate, peak work load, peak double (rate-pressure) product and percent of patients achieving greater than or equal to 85% of maximal predicted heart rate for age. Thus, in this study group, there was a rather high prevalence rate of silent ischemia (57%) by exercise thallium-201 criteria.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prevalence of and variables associated with silent myocardial ischemia on exercise thallium-201 stress testing. 235 86

Indications for a Holter-ECG-recording are dizzy-spells, syncopes, ischemic attacks, dyspnoea, ischemia of the myocardium, arrythmias after myocardial infarction and with different types of cardiomyopathies, the sick-sinus-syndrome and a-v-blocks; furthermore recording of cardiac situations and the effect of drugs. The report should mention the basic rhythm, ventricular and supraventricular arrhythmias as well as temporary blocks and pauses.
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PMID:[Long-term electrocardiography (quality standards and guidelines for the documentation of findings]. 245 58


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