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

Verapamil is considered by many investigators to be the drug of choice for the acute management of uncomplicated PSVT. Several clinical investigators have demonstrated termination of PSVT in more than 90% of their patients within minutes following IV drug administration. The incidence of reported severe adverse reactions has been less than 1%. PSVT may be complicated by underlying heart disease, or by antegrade accessory pathway conduction in individuals with pre-excitation syndrome. Such conditions, or the prior use of beta-blocking agents, may contraindicate the use of verapamil. However, the history of recent myocardial ischemia or the prior use of digitalis does not appear to contraindicate verapamil therapy. Guidelines for the emergency management of the patient in PSVT are presented.
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PMID:Verapamil in the treatment of PSVT. 702 10

Changes in the exercise ECG caused by five different drugs are presented. Analysis of these changes indicate that these are related to the hemodynamic effects of the drugs, rather than to reduction of myocardial ischemia. Calcium antagonists (Verapamil) as well as drugs which reduce heart rate (Alinidine, Propranolol) do not change the relation between ST depression and heart rate in a given patient. Drugs which lower ventricular volume (Molsidomine, Nitroglycerine) reduce the amount of ST depression at the same heart rate during exercise.
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PMID:The effects of drugs on the exercise electrocardiogram. 731 92

The hemodynamic effects of verapamil in conditions of myocardial ischemia and its influence on the atrio-ventricular conduction were investigated in 13 dogs with transient repeated occlusions of the anterior descending coronary artery. Verapamil 0.25 mg/kg was administered after control determinations of heart rate, LV dp/dt, systolic and diastolic arterial pressure and the mean sum of S--T segment elevations recorded by means of 9 epicardial electrodes. Comparison of the differences between the control data and those after occlusion, on the one hand, and those before and after occlusion + verapamil, on the other hand, showed that the drug did not induce significant hemodynamic changes. Arterial pressure was slightly lowered; the increase of LV dp/dt noted after occlusion without verapamil did not occur any more and the S-T segment and T wave disturbances were also less marked, suggesting a protective effect on the ischemic lesion. Larger doses of verapamil (0.50-0.75 mg/kg) induced second and third degree A-V blocks in three animals. These effects could be controlled in two animals by previous or subsequent administration of Carbocromen.
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PMID:Effects of verapamil on the acute experimental myocardial ischemia. 745 81

Twenty-two patients with coronary heart disease (CHD) were examined for pain threshold and pain tolerance by a tourniquet test. The relationships between pain and ST segment depression were studied simultaneously during bicycle exercise. Pain sensitivity was measured in response to action of various antianginal drugs (isosorbide dinitrate, verapamil, nifedipine, diltiazem, propranolol, atenolol) and placebo. Reproducibility of the tourniquet test proved satisfactory. There were significant correlations between tourniquet test evidence and clinical patterns of ischemic myocardial episodes: significant differences in the values of pain threshold and pain tolerance in patients with painful myocardial ischemia, in combination of angina of effort with painless myocardial ischemia (p < 0.0001). Significant were also correlations between tourniquet test findings at bicycle exercise and value describing the proportion of ST depression to pain. As for the drugs, verapamil appeared most active in the tourniquet test (p < 0.02 and p < 0.05 for pain threshold and pain tolerance, respectively). Pain tolerance changes due to isosorbide dinitrate were somewhat greater than for placebo (p = 0.06). The study provided evidence in support of the adequacy of the tourniquet test for assessment of general pain sensitivity and pain sensitivity to myocardial ischemia as well as of analgetic effects of the drugs. Verapamil and isosorbide dinitrate are suggested to have analgetic activity.
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PMID:[The tourniquet test in evaluating the analgesic action of antianginal preparations]. 805 6

Congestive heart failure (CHF) due to idiopathic cardiomyopathy is reviewed. CHF in dilated cardiomyopathy (DCM) is caused mainly by myocardial systolic dysfunction. Diuretics, angiotensin-converting enzyme (ACE) inhibitors and digitalis are the first choice drugs. ACE inhibitors have been shown to be effective in prolonging life and improving quality of life. Recently, long-term beta-blockade therapy has been shown to be useful. CHF in hypertrophic cardiomyopathy (HCM) is caused by decreased myocardial compliance. The beneficial effect of verapamil in HCM is related to improved relaxation and diastolic filing. Verapamil is also effective in relieving myocardial ischemia. Beta-blockade decreases pressure gradient and oxygen consumption. Idiopathic restrictive cardiomyopathy is a very rare disease and decreased myocardial compliance is responsible for CHF.
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PMID:[Pathophysiology and current therapy of congestive heart failure due to idiopathic cardiomyopathy]. 810 Dec 39

The effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated by exercise myocardial 201Tl SPECT (EX-Tl). EX-Tl was performed before and after 8.1 +/- 6.1 weeks of oral administration of verapamil (240 mg/day) on 20 patients with HCM who showed transient 201Tl perfusion defects under control conditions. SPECT images were divided into nine segments. The 201Tl perfusion defect was visually scored and evaluated for four grades in each segment and the sum total grade was calculated as the defect score. Transient dilation index was calculated as a reflection of subendocardial ischemia. Improvements in defect score were demonstrated in 18 of 20 patients after administration of verapamil. The mean defect score decreased significantly from 5.1 +/- 2.3 to 2.5 +/- 2.4 (p < 0.001). Although 18 of 20 patients showed abnormal transient dilation index under control conditions, 16 showed improvement and 12 were normalized after verapamil therapy. Mean transient dilation index decreased from 1.24 +/- 0.19 to 1.08 +/- 0.10 (p < 0.01). Verapamil improves myocardial ischemia in patients with HCM.
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PMID:[Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy: evaluation by exercise thallium-201 SPECT]. 815 30

Many theoretical and experimental studies suggest that calcium antagonists drugs should be useful in pathological situations of myocardial ischemia or ischemia/reperfusion. This therapeutic model was tested in controlled trials of angina, post-infarction and cardiac surgery. The authors undertook a meta-analysis of these trials using the occurrence of myocardial infarction or death as criteria of judgement. No long-term benefits seem to be associated with the dihydropyridines such as nifedipine and nicardipine in anginal patients. In unstable angina, betablockers seem to be more effective but the difference is not statistically significant. In the post-infarction period, nifedipine does not reduce the risk of recurrence of myocardial infarction and may even increase the mortality by 15%, though this was not significant in the 9,055 patients studied (p = 0.08). Verapamil and diltiazem globally reduce the risk of recurrent infarction by 21% (p = 0.009) but not mortality (p = 0.52). Because of the small numbers of patients and the low prevalence of observed events, no useful conclusions can be drawn from studies of calcium antagonists in cardiac surgery. The results of the validation of the therapeutic model "calcium antagonists in pathological situation of myocardial ischemia or ischemia/reperfusion" does not justify the labels "anti-ischemics" or "cardio protectors" often applied to the calcium antagonists.
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PMID:[Calcium channel antagonists and myocardial ischemia or ischemia/reperfusion]. 830 18

Hypertensive emergency is a condition in which there is elevation of both systolic and diastolic blood pressure with the presence of acute target organ disease. Hypertensive urgency is a condition where the blood pressure is elevated (diastolic > 120 mmHg) with the absence of acute target organ disease. Hypertensive emergencies are best managed with parenteral drugs and careful intraarterial blood pressure monitoring. Hydralazine has been widely used in treatment of hypertension in eclampsia and preeclampsia, and its safety has been demonstrated in these patients. Sodium nitroprusside (SNP) has the most reliable antihypertensive activity, which begins immediately after its administration and ends when the infusion is stopped. As with diazoxide, it should be used with caution in patients with impaired cerebral flow. SNP is the preferred drug in obtaining controlled hypotension in patients undergoing neurovascular surgery. Intravenous nitroglycerin is useful in patients prone to myocardial ischemia, but should be avoided in patients with increased intracranial pressure. Esmolol is effective in controlling both supraventricular tachyarrhythmias and severe hypertension. Its short onset of duration of action make it useful in the emergent setting, but because of its negative inotropic effect its use should be avoided in patients with low cardiac output. Verapamil should not be used in patients with preexisting conduction abnormalities. Nicardipine is a potent arteriolar vasodilator without a significant direct depressant effect on myocardium. As with other afterload reducing agents, it should not be used in patients with severe aortic stenosis. Because angiotensin-converting enzyme (ACE) inhibitors generally cause cerebral vasodilatation, enalaprilat may be particularly beneficial for patients who are at high risk of developing cerebral hypotensive episodes secondary to impaired cerebral circulation. Fenoldopam, a selective post-synaptic dopaminergic receptor (DA1) has been shown to be effective in treating severe hypertension with a lower incidence of side effects than SNP. Hypertensive urgencies can usually be managed with oral agents. Oral nifedipine, captopril, clonidine, labetalol, prazosin, and nimodipine have all been shown to be effective in these situations.
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PMID:Management of hypertensive urgencies and emergencies. 852 30

Calcium channel antagonists can reduce calcium overload induced by myocardial ischemia and thereby protect against malignant arrhythmias. However, these drugs may also adversely affect cardiac contractile function. Mibefradil is a new calcium antagonist that can inhibit cardiac calcium current without reducing myocardial force development. The effects of mibefradil on the inducibility of arrhythmias both before and during ischemia were therefore evaluated in animals with healed infarctions. First, a 2-min coronary occlusion was made during the last minute of exercise (n = 48): 25 animals had ventricular fibrillation (susceptible), whereas 23 did not (resistant). On a subsequent day, programmed electrical stimulation (PES, 8 paced beats followed by two extrastimuli) induced ventricular tachycardia in 19 of 25 susceptible animals but in none of the resistant animals (chi square = 24.6, P < .001). Verapamil (n = 14), diltiazem (n = 13) and mibefradil (n = 14) elicited significant dose-dependent decreases in refractory period and in the Q-Tc interval (except mibefradil) yet failed to prevent PES-induced arrhythmias. Diltiazem and verapamil also increased P-R interval and reduced the maximum rate of change of left ventricular pressure, whereas mibefradil did not. However, all three drugs abolished arrhythmias induced by PES during ischemia. In contrast, lidocaine suppressed PES-induced arrhythmias but failed to prevent ischemically induced arrhythmias. Thus mibefradil can prevent ischemically induced ventricular fibrillation without adverse actions on either A-V nodal conduction or contractile function. These data further suggest that calcium entry may play a critical role in the initiation of ventricular fibrillation during ischemia, whereas other factors must be responsible for the extrasystoles induced by PES.
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PMID:The effects of mibefradil, a novel calcium channel antagonist on ventricular arrhythmias induced by myocardial ischemia and programmed electrical stimulation. 866 18

Angina pectoris is a significant risk predictor in patients with atherosclerotic heart disease. The major complications are myocardial infarction, heart failure, and arrhythmias. Plaque rupture turns stable angina pectoris into acute coronary syndrome by provoking platelet aggregation and thereby thrombus formation. Verapamil significantly inhibits platelet aggregation and thrombus formation, which may be one of several reasons for the protective effect of verapamil on reinfarction in patients recovering from myocardial infarction. Ischemia may lead to left ventricular dilation and diastolic dysfunction, and thereby heart failure. In postinfarction patients intervention with verapamil significantly reduced the use of diuretics compared with placebo, indicating that anti-ischemic intervention may prevent heart failure. Ventricular arrhythmias are significantly associated with arrhythmic as well as non-arrhythmic death. The lack of preferential association of ventricular arrhythmias with arrhythmic death rather than nonarrhythmic death may imply that arrhythmias are provoked by ischemia. Antiarrhythmic intervention in postinfarction patients significantly increases death and arrhythmic events compared with placebo, especially in patients with residual ischemia. This may be due to a significant slowing of conduction during ischemia in patients treated with antiarrhythmic agents. In animal studies anti-ischemic agents prevent or suppress ventricular arrhythmias during ischemia, whereas traditional antiarrhythmic drugs have no effect or even worsen the arrhythmias, especially during episodes with elevated sympathetic activity. Verapamil significantly reduces plasma norepinephrine levels and the norepinephrine release during ischemia, whereby ventricular arrhythmias may be prevented. Also, supraventricular arrhythmias are significantly associated with myocardial ischemia and are prevented by verapamil. In patients with atherosclerotic heart diseases, angina pectoris is a significant risk predictor, but anti-ischemic intervention should be considered even in patients in whom the major problem is heart failure or arrhythmias.
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PMID:Anti-ischemic intervention as prognosis improvement in patients with coronary artery disease, with special focus on verapamil. 867 96


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