Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diagnostic pacing has proven useful for the study of a great variety of clinical problems. Rapid atrial pacing is an excellent means of stressing the heart, particularly in patients with ischemic heart disease. Pacing-induced tachycardia has been used to provoke typical coronary pain and to produce hemodynamic, metabolic, and left ventricular contractile changes in patients with coronary artery disease. Because this heart stress is reproducible, it has also been valuable in assessing response to medical and surgic al therapy in patients with angina. Electrophysiologically, pacing has been used to clarify mechanisms of normal and abnormal function of the sinus node and A-V conduction. The pre-excitation states have been more precisely defined, and the introduction of programmed electrical stimuli into the cardiac cycle has helped elucidate the nature of re-entry supraventricular tachycardias.
Cardiovasc Clin 1975
PMID:Diagnostic uses of electrical pacing. 110 Feb 46

Phonocardiography provides one of a growing list of valuable intermediary studies between physical examination and cardiac catheterization. It not only provides a medium for instruction in physical examination, but also allows one to make certain diagnoses and assess severity of numerous cardiovascular lesions. It is especially valuable in the evaluation of all valvular stenoses, especially aortic stenosis. One can also use phonocardiography for screening and diagnosis of idiopathic hypertrophic subaortic stenosis. It is a helpful adjunct in the study of several congenital abnormalities as well as in the assessment of myocardial function in cardiomyopathies and ischemic heart disease, and may often be decisive in confirming the diagnosis of pericardial constriction.
Cardiovasc Clin 1975
PMID:Usefulness and limitations of precordial phonocardiography and external pulse recordings. 110 Feb 47

A series of nine dogs underwent 20 minutes of myocardial ischemia by cross clamping the aorta while total cardiopulmonary bypass. The four dogs that did not have subsequent left bypass all showed a deterioration of ventricular function curve 30 minutes after restarting the heart beat when compared to their own preischemic values. The five animals which were supported for 30 minutes in left heart after bypass all showed essentially unchanged cardiac function after bypass. This study suggests that an improvement of myocardial performance after ischemic damage can be achieved with left heart bypass.
J Cardiovasc Surg (Torino)
PMID:Effects of left heart bypass on cardiac performance following myocardial ischemia. 115 Jul 33

Four patients are reported in whom the aortic arch and variable portions of the ascending and descending aorta were replaced with a prosthesis. In three patients the preoperative diagnosis was dissecting aneurysm of the aortic arch and in one an arteriosclerotic aneurysm of the aortic arch was present. A combination of surface cooling and cardiopulmonary bypass was utilized to produce total body hypothermia. Arch replacement was carried out during a period of total circulatory arrest. Cardiopulmonary bypass was then utilized to warm the patient and resuscitate the heart. The average duration of cerebral ischemia was 43 minutes and the average duration of myocardial ischemia was 74 minutes. The average lowest esophageal temperature was 14 degrees C., and the average lowest rectal temperature was 18 degrees C. Three patients are alive and well 4 to 13 months following surgery. One patient died 4 days postoperatively of pulmonary insufficiency. This experience indicates that by utilizing total body hypothermia and circulatory arrest aortic arch replacement can be carried out with an acceptable mortality rate. Corrective surgery could be offered to patients with life-threatening enlarging aneurysms of the aortic arch.
J Thorac Cardiovasc Surg 1975 Dec
PMID:Prosthetic replacement of the aortic arch. 118 83

A special high viscosity preparation of water soluble radiopaque contrast media was explored in animals for its suitability in selective coronary angiography. The high viscosity required power injection to accomplish adequate filling during selective coronary arteriography. The anticipated angiographic advantages, such as prolonged visualization and coating of the vascular walls, were marginal. Comparison with conventional preparations of the same contrast agent suggests that the high viscosity itself exerts some protective effect with regard to the immediate side effects on the electrocardiogram and mechanical function of the myocardium. However, the high viscosity preparation induced electrocardiographic signs compatible with myocardial ischemia not usually seen to follow the injection of conventional contrast agents. These were followed by mechanical heart failure or ventricular fibrillation resulting in death of 6 of the 10 experimental animals. It was concluded that high viscosity contrast media preparations are unsuitable for use in clinical selective coronary arteriography as presently practiced.
Cathet Cardiovasc Diagn 1975
PMID:Evaluation of high viscosity contrast media in canine selective coronary arteriography. 122 26

The usefulness and limitations of currently available techniques for quantitating coronary flow in ischemic heart disease are summarized. There are appreciable difficulties in assessing coronary flow solely from an arteriographic evaluation of the epicardial arteries. There is a considerable reserve mechanism for vasodilation at the arteriolar level, and a proximal occlusive lesion produces a reduction in flow only after this distal reserve has been exhausted. In addition, small increments in the severity of established lesions sometimes cause profound reductions in flow. The development of clinically useful flow measurements has been impeded by methodological problems related to nonuniformity of flow within the left ventricle in coronary artery disease. Validation of specific techniques for abnormal situations is difficult but possible and should probably be a prerequisite to the clinical application of any technique. When a methodologically appropriate technique is employed, average left ventricular flow per unit weight is found to be reduced systematically at rest in patients with double- and triple-vessel disease. This reduction is a group difference, however, and is not always evident in individual patients. Accordingly, more recent measurements have concentrated on the assessment of regional perfusion, and two general approaches, selective venous sampling and selective precordial sampling are illustrated. While only preliminary measurements of regional flow are available, it is clear that these measurements offer a more sensitive tool for detecting abnormalities of flow in individual patients and thereby for contributing to the management of specific clinical problems. Measurements of regional flow need to be performed during stress as well as at rest. For the future, there is also need for techniques which can assess transmural variations of flow in man and relate measurements of regional flow to regional oxygen demand. Because of the complexity of current techniques which are methodologically adequate, measurements of coronary flow will, for the immediate future, probably remain confined to clinical centers which have a special interest in them. The effort in these centers will hopefully include significant emphasis on the refinement of existing techniques so that they are more widely applicable.
Cathet Cardiovasc Diagn 1975
PMID:Quantitative evaluation of coronary perfusion in man. 122 32

Alterations in left ventricular end-diastolic pressure and in dp/dt observed in ten patients with coronary heart disease who developed angina pectoris following left ventricular cineangiography were compared with those of six other patients who developed angina spontaneously and with patients who underwent left ventricular cineangiography without experiencing angina. In the patients with post-angiographic angina there was a greater increase in end-diastolic pressure than that seen in the other patients, but there was no significant change in dp/dt. Changes in left ventricular pressure associated with post-angiographic angina would appear to reflect the combined effects of increased preload provided by the contrast material and of ventricular dysfunction including diminished compliance associated with angina. A rise in end-diastolic pressure greater than 20 mmHg following left ventricular cineangiography should alert the physician that the patient may be having myocardial ischemia.
Cathet Cardiovasc Diagn 1975
PMID:Left ventricular pressure responses in post-angiographic angina. 122 35

Dofetilide is a potent and selective class III antiarrhythmic agent that is under development for the treatment of re-entrant tachyarrhythmias (ventricular tachycardia/ventricular fibrillation, atrial fibrillation/atrial flutter, and paraoxysmal supraventricular tachycardia). In animal studies, dofetilide selectively inhibits the rapid component of the time-dependent outward potassium current (IKr) and therefore increases the effective refractory period and action potential duration without affecting the fast inward sodium current. Studies in dogs have shown that dofetilide (a) prolongs the effective refractory period in a dose-dependent manner, (b) elevates ventricular fibrillation threshold, (c) facilitates conversion of electrically induced ventricular fibrillation or fibrilloflutter to sinus rhythm, (d) does not influence conduction within the His-Purkinje system or within the myocardium, (e) does not impair cardiac contractility, and (f) reduces dispersion of ventricular repolarization. Dofetilide has been administered to healthy volunteers as well as to patients with ischemic heart disease or with supraventricular arrhythmias; the compound has generally been well tolerated. Side effects have occasionally been reported, but have generally been transient and mild and occur in placebo-treated subjects as well. No clinically significant changes in laboratory safety tests have been detected. The pharmacokinetic profile of dofetilide both in healthy volunteers and patients includes a linear dose-plasma concentration relationship and also a linear plasma concentration-QTc relationship. The terminal plasma elimination half-life is approximately 9-10 h and systemic bioavailability in the region of 100%. The elimination pattern is balanced, with 50% being excreted unchanged via the kidney, the remaining 50% being metabolized in the liver to inactive metabolites, with greater than 90% of circulating drug-related material being unchanged dofetilide. After intravenous administration of the compound, a slight hysteresis in the plasma drug level-QTc relationship has been detected. Pharmacodynamic data demonstrate dose- and concentration-dependent effects on myocardial repolarization as evidenced by prolongations of the QTc interval. This is reflected in significant prolongations in the effective and functional refractory periods and monophasic action potential duration throughout the myocardium. No effects on sinus node function, conduction parameters, or cardiac contractility have been detected in any of the clinical studies, supporting the contention that dofetilide is a highly selective class III antiarrhythmic agent.
J Cardiovasc Pharmacol 1992
PMID:Dofetilide, a novel class III antiarrhythmic agent. 127 16

During recent years, understanding of the basic pathology, pathophysiology, and morbid risk of ischemic heart disease has increased immensely, but a wide gulf still exists between such knowledge and its practical application to the individual patient. Although the treatment of ischemic heart disease continues to pose many dilemmas for the physician in the 1990s, the key issues are easy to define, particularly with regard to pharmacotherapy. The basic pathologic processes and their rate of development and progression, their pathophysiologic consequences, and their morbidity and mortality risks are becoming increasingly clear. Until methods are developed to reconstitute the obstructed coronary arteries, clinical attention must be directed primarily to alleviating symptoms and ECG signs of myocardial ischemia and improving the deranged hemodynamic disorder. These primary objectives are now achievable with modern anti-ischemic drugs such as nicorandil. With the availability of efficacious drugs against clinical symptoms, ECG signs, and hemodynamic associates of ischemic heart disease, clinical attention must be redirected to retardation or even regression of the primary myocardial ischemic syndrome. This therapeutic goal can be achieved only by correction of the secondary risk factors that are present in many patients with ischemic heart disease. Only by such a comprehensive approach, namely, that of treatment allied to prevention, can the gap between knowledge and its practical application to the individual patient be narrowed.(ABSTRACT TRUNCATED AT 250 WORDS)
J Cardiovasc Pharmacol 1992
PMID:Treatment of ischemic heart disease in the 1990s: key issues for the physician. 128 69

Nicorandil is a potent vasodilator with antianginal and anti-ischemic properties that acts on both the coronary and the peripheral vascular bed. Because of its dual vasodilatory mechanisms mediated by an increase in cyclic GMP similar to that of nitrates and by a selective increase in the K+ conductance of the smooth muscle cell membrane, nicorandil unloads the right and left ventricles at rest and during exercise. Thus, compared with the classic nitrates, nicorandil is a more balanced vasodilator, i.e., it affects not only the venous capacitance vessels (as predominantly affected by nitrates) but also the arterial resistance vessels. In clinical pharmacologic trials, nicorandil has been administered intravenously (2 to approximately 14 mg) as well as sublingually and orally in single doses of 10-60 mg. In patients with coronary artery disease and impaired left ventricular function, the decrease in preload resulted in a significant improvement of cardiac output. Depending on the doses applied and the patient populations studied, observed decreases in systemic blood pressure were consistent with decreases in peripheral vascular resistance. The effect on heart rate was small, and no influence on atrioventricular conduction could be detected. Nicorandil enhanced exercise capacity in patients with ischemic heart disease. This benefit can be attributed to the reduction in loading of the right and left ventricle as well as to an improvement of regional wall motion abnormalities secondary to the coronary dilatory properties of the drug. Nicorandil appears to be a valuable additive to the antianginal and anti-ischemic management of coronary artery disease.
J Cardiovasc Pharmacol 1992
PMID:Acute hemodynamic effects of nicorandil in coronary artery disease. 128 76


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>