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

To assess possible coronary vasoconstriction in patients with ischemic heart disease, we measured coronary vascular resistance in 12 patients with normal hearts and 12 with coronary disease before and during the initial 50 seconds of cold pressor test, a stimulus known to produce systemic vasoconstriction. Control coronary vascular resistance was similar in the two groups, and although it did not change in patients with normal vessels, it rose by 27 per cent (P less than 0.005) in the group with coronary disease during the cold pressor test. In three of 12 patients with coronary disease coronary flow actually declined despite an increase in arterial pressure; in four, angina was precipitated. Phentolamine abolished increases in arterial pressure and coronary vascular resistance during the test in three patients with coronary disease. Adrenergically mediated coronary vascular tone may be an important determinant of coronary blood flow and may contribute to ischemia in patients with coronary disease.
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PMID:Reflex increase in coronary vascular resistance in patients with ischemic heart disease. 1 May 27

In order to study the occurrence and frequency of ischemia-induced ventricular arrhythmias, we analyzed 105 episodes of spontaneous angina pectoris occurring at rest in 28 hospitalized patients with unstable angina pectoris and proved coronary artery disease. Of 24 patients with serious ventricular arrhythmias during pain, 17 (57%) were arrhythmia-free during monitoring. In the other four patients, 17 of 29 (59%) pain episodes were associated with serious ventricular arrhythmias, and three of these four had serious ventricular arrhythmias during pain-free periods. Each patient tended to manifest the same type of arrhythmia during repeat episodes of pain. It appears that continuous electrocardiogram (ECG) monitoring is important during the initial hospitalization of the patient with unstable angina. The presence of ventricular arrhythmias during pain-free periods indicates a high risk for serious ventricular arrhythmias during episodes of spontaneous pain. These patients should be considered for continued ECG monitoring and antiarrhythmic therapy.
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PMID:Ventricular arrhythmias during unstable angina pectoris. 5 51

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

Fifty-four patients with variant angina are described. They are divided into patients without hemodynamically (less than 50%) important coronary artery lesions (Group 1), patients with intermediate (greater than or equal to 50% and less than 90%) fixed obstruction (Group 2A), and patients with high grade (greater than or equal to 90%) fixed obstruction (Group 2B). Inferior ischemia occurred significantly more often in Group 1 (90% versus 33%. p less than 0.001), and exertional angina was more frequent in Group 2 (70% versus 36%, p less than 0.05). Maximum medical therapy with propranolol and nitrates failed to control angina in 55% of Group 1, 69% of Group 2A, and 63% of Group 2B. Twelve patients underwent intra-aortic balloon pumping (IABP), and in 10 there was complete control of variant angina. A total of 35 Group I patients underwent coronary artery bypass grafting (CABG), with a 2.9% mortality rate in patients without preoperative cardiogenic shock. Of these patients, 55% in Group 2A and 73% in Group 2B experienced marked improvement in their angina status. Therefore, we currently recommend bypass grafting for medically intractable variant angina in those patients with severely stenotic, fixed atherosclerotic lesions.
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PMID:Variant angina. Clinical spectrum and results of medical and surgical therapy. 11 30

Although acute infarction of the myocardium is known to accumulate 99mtechnetium pyrophosphate, it is not entirely clear that ischemia alone without necrosis does not result in abnormal uptake of 99mtechnetium pyrophosphate. The present study investigates whether transient myocardial ischemia is associated with localization of 99mtechnetium pyrophosphate by evaluating images obtained with the scintillation camera at rest and after exercise in 15 patients with unequivocal myocardial ischemia. All patients had angina pectoris, multivessel coronary artery stenoses by selective arteriographic studies, and electrocardiographic ischemic responses on treadmill exercise. Eleven of the 15 patients also underwent radionuclide imaging with 81rubidium at rest and after exercise; the results demonstrated scintigraphic ischemia. The scintiscans with 99mtechnetium pyrophosphate revealed no evidence of increased myocardial radioactivity after exercise compared to rest in 14 of the 15 patients. In contrast, myocardial activity was observed with 99mtechnetium pyrophosphate after treadmill exertion in the remaining patient, in whom a small subendocardial infarction appeared to have occurred with the exercise. It is concluded from these results that transient myocardial ischemia does not cause localization of 99mtechnetium pyrophosphate. These findings support the specificity of abnormal localization of 99mtechnetium pyrophosphate for acute myocardial infarction.
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PMID:Evaluation of myocardial uptake of 99mtechnetium pyrophosphate in clinical exercise-induced ventricular ischemia. 18 75

To clarify the value of serum enzymes in the detection of intraoperative and postoperative myocardial injury associated with coronary artery bypass grafting, we evaluated 70 consecutive patients (151 grafts). We used electrocardiograms and serial determinations of serum levels: serum glutamic oxaloacetic transaminase (SGOT), creatinine phosphokinase (CPK), lactic dehydrogenase (LDH), and LDH isoenzymes on Days zero, 1, 3, 5, 7, and 10. Patency of all grafts 1 week postoperatively was 92 per cent. Fourteen patients (20 per cent) had ECG evidence of acute myocardial infarction (AMI) or ischemia lasting longer than 48 hours. This incidence of AMI was attendant with no deaths or discernible changes in postoperative ventriculography. LDH-1 (cardiac fraction) was elevated in all patients with myocardial injury. Late elevation of LDH-1 occurred in 2 patients at the time of postoperative catheterization, 1 of whom had negative findings on ECG. Diagnostic correlation was not observed with total LDH, CPK, or SGOT. Predisposing factors to AMI included preinfarction angina (4 of 14 patients), occluded grafts (4 of 14), and a bypass time greater than 120 minutes.
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PMID:Myocardial injury and bypass grafting. Value of serum enzymes in diagnosis. 24 Sep 85

In order to determine the natural evolution of different clinical types of "unstable angina", 167 patients were included in a prospective study. After angiography, 11 (6.5%) were excluded because they had no significant coronary lesions. The remaining 156 were sorted into different groups according to their clinical characteristics and were followed up for a period of 24 months at least. After that follow-up period, mortality and incidence of acute myocardial infarction (AMI) were as follows: angina of recent onset (Class III--IV NYHA): 8.5% (3/35) and 34.2% (12/35). Progressive angina: 7.4% (2/27) and 7.4% (2/27). Intermediate syndrome: 41.6% (10/24) and 37.5% (9/24). Prinzmetal's angina: 10% (1/10) and 10% (1/10). Post acute myocardial infarction angina: 35% (7/20) and 10% (2/20). Acute persistent ischemia: 2.5% (1/40) and 20% (8/40). Comparison of these figures pointed out significant differences (p less than 0.001 for mortality and p less than 0.03 for AMI incidence respectively). We conclude that it is clinically possible to identify different groups within the so-called unstable angina. Such a division not only allows for the creation of more homogeneous groups, but it contributes to a more rational therapeutic approach and also permits identification of high risk prodromes of greater complications, such as myocardial infarction or sudden death.
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PMID:Clinical spectrum of "unstable angina". 26 65

The study includes 50 patients with severe, stable angina who have undergone the saphenous vein bypass operation. Patients were evaluated preoperatively and postoperatively with regard to exercise tolerance, incidence of stress-induced agina, ST-segment changes of ischemia, and ventricular function as indicated by stroke work index (LVSWI) and ejection fraction. Comparisons were made between patients with complete revascularization (CR) and patients with postoperative residual ischemia (RI). Results revealed that exercise duration improved significantly in both the CR and RI groups. In the CR group, angina and ischemic ST changes were completely eliminated. In the RI group, there was a 25 percent incidence of stress angina and a 50 percent incidence of ischemic ST-segment changes. In neither group was the ejection fraction significantly different from preoperative values. LVSWI decreased significantly in both groups postoperatively.
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PMID:Evaluation of saphenous vein bypass surgery with multistage treadmill test and ventricular function studies. 30 89

A series of 188 patients who were operated on for left ventricular ischemia and dysfunction is presented. Angina was a prominent symptom in all patients, and a history of congestive heart failure could be elicited in 20%. Mean ejection fraction for the series was 0.35, with 67% having an ejection fraction of 0.35 or less 24%, 0.20 or less. Complete revascularization was accomplished whenever possible; more than 70% of the patients had triple-vessel disease, and single bypass was performed infrequently (5%). Factors thought to be important in achieving a low operative mortality (2.1%) were: precise prebypass monitoring, particularly with the V5 precordial lead; maintaining a low rate-pressure product (less than 12,000) prior to bypass; myocardial preservation with cold hyperkalemic or hyperkalemic-hyperosmolar solution; and careful titration of inotropic and vasodilator drugs. Inotropic drugs and intraaortic balloon pumping were used frequently in this series. The late mortality was 4.3%. Angina was completely relieved or improved in 94% of the patients. Those having a history of congestive heart failure had an increased late mortality rate, four times that of the entire series.
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PMID:Criteria for operability and reduction of surgical mortality in patients with severe left ventricular ischemia and dysfunction. 30 31

Early revascularization following myocardial infarction (MI) is reported to have a high risk of extension of and hemorrhage into infarction with resulting high mortality and morbidity. To evaluate this issue, 80 post-MI patients (aged 32-74 years) with unstable angina pectoris resistant to maximal medical therapy were reviewed. All patients underwent early uncomplicated angiography and subsequent revascularization; 55 (69%) were less than 10 days post-MI, and 25 (31%) were 10-30 days post-MI. Intraaortic balloon pumping was required in 72% for relief of intractable angina or hemodynamic instability. Of the 80 patients, 19% had single vessel disease (VD), 31% double VD, and 50% triple VD. The mortality rate from coronary bypass surgery was 7/80 (8.8%), with four cardiac and three noncardiac deaths. Two patients suffered a perioperative MI (2.5%). At a mean follow-up period of 33 months, there had been only one late death and one recurrent nonfatal MI; 96% of the patients had no significant angina. In patients with continuing ischemia immediately after MI, myocardial revascularization can be safely performed without further injury to the myocardium, and with excellent long-term results.
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PMID:Safe early revascularization for continuing ischemia after acute myocardial infarction. 31 12


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