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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The administration of verapamil to patients receiving beta-adrenergic blocking drugs is reported to produce adverse circulatory reactions, but a systematic investigation of this potential drug interaction has not been performed in man. We administered 40-, 80- and 120-mg doses of verapamil orally to 15 patients with angina pectoris who were receiving high doses of propranolol or metoprolol. Verapamil produced dose-dependent decreases in cardiac performance: with 120 mg, cardiac index decreased by 0.38 l/min/m2, stroke volume index decreased by 2.8 ml/beat/m2 and heart rate decreased by 6 beats/min, associated with increases in pulmonary capillary wedge (2.2 mm Hg) and mean right atrial pressures (1.7 mm Hg) (all p less than 0.01); two patients had marked, but asymptomatic, hypotensive reactions. In contrast, repeat administration of 120-mg doses of verapamil 24--30 hours after withdrawal of beta blockade produced no significant cardiodepressant effects despite significantly higher plasma levels of verapamil than during propranolol therapy (383.1 vs 205.1 ng/ml, p less than 0.01). In conclusion, verapamil produces significant negative inotropic and chronotropic effects in patients treated with beta-adrenergic antagonists; combination therapy should therefore be used with caution in patients with angina pectoris.
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PMID:Hemodynamic consequences of combined beta-adrenergic and slow calcium channel blockade in man. 706 Feb 44

In the Danish Verapamil Infarction Trial II (DAVIT II), treatment with verapamil 360 mg/day improved reinfarction-free survival compared with administration of placebo. Verapamil appears to effectively prevent reinfarction and sudden death, i.e. sudden events (hazard ratio 0.78 compared with placebo, 95% confidence limits 0.62 to 0.99). In a retrospective analysis of data from DAVIT II, verapamil treatment in patients with systemic hypertension prevented reinfarction significantly better than placebo (15 of 149 verapamil recipients compared with 27 of 152 placebo recipients reinfarcted, p = 0.04). Similarly, first cardiovascular events, i.e. first reinfarction, first stroke or death, were prevented more effectively by verapamil treatment than by administration of placebo (29 verapamil recipients vs 42 placebo recipients had first cardiovascular events, p = 0.07).
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PMID:Postinfarct treatment with verapamil. Effect of verapamil in patients with hypertension. 751 83

Intravenous (i.v.) cocaine administration elicits a decrease in cardiac output (CO) in some but not all rats. In the present study, we examined the effects of L-type calcium channel antagonists on cardiovascular responses in conscious freely moving rats with a cocaine-induced decrease in CO. Arterial blood pressure (ABP), heart rate (HR), and CO (pulsed Doppler flowmetry) were measured, and estimates of changes in systemic vascular resistance (SVR), stroke volume (SV), and rate-pressure product (RPP) were calculated from these values. After recovery, rats were treated with cocaine (5 mg/kg, i.v.) to ascertain their myocardial responses. Some rats demonstrated a decrease in CO, usually during the peak pressor response after cocaine administration, whereas others experienced only slight increases in CO. Rats demonstrating a minimum 15% decrement in CO were pretreated with either verapamil or nifedipine before cocaine was readministered. Verapamil (150 micrograms/kg) or nifedipine (100 micrograms/kg) selectively reduced the peak fall in CO and the increase in SVR after cocaine administration, whereas nifedipine (25 micrograms/kg) had little effect on these parameters. Neither drug affected the pressor response to cocaine. These data suggest that calcium channel antagonists can selectively reduce cocaine-induced decreases in CO and increases in SVR without reducing afterload in a subset of rats sensitive to the cardiodepressive effects of cocaine.
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PMID:Calcium channel antagonists reduce the cocaine-induced decrease in cardiac output in a subset of rats. 768 99

The aim of the study was to evaluate the effects of verapamil sustained release (SR) 240 mg, enalapril and their combination on blood pressure (BP) and cardiac haemodynamics at rest and during exercise in 20 patients with moderate essential hypertension (seven men and 13 women, mean age +/- s.d. 53.7 +/- 15.8 years). After a 4 week placebo run-in period, patients were randomly allocated to received verapamil SR 240 mg once daily or enalapril 20 mg once daily for 4 weeks in a double-blind fashion. Patients whose diastolic blood pressure (DBP) was still > or = 95 mm Hg at the end of this period received verapamil SR plus enalapril for an additional 4 weeks. At the end of the placebo, single and combined treatment periods, resting and exercise (bicycle ergometry) haemodynamics were evaluated by radionuclide ventricular angiography (technetium-99m) and the following parameters were assessed: BP, heart rate, double product, systemic vascular resistances (SVR), cardiac output (CO), stroke volume (SV), ejection fraction (EF) mean ejection rate (mER) and peak filling rate (PFR). Both verapamil SR and enalapril monotherapies significantly reduced resting and exercise BP (P < 0.01), with a BP normalisation (DBP < or = 95 mm Hg) of five of 10 and 4 of 10 patients respectively. A greater BP fall and a normalisation of 11 of 11 patients was obtained in non-responders to monotherapy, when treated with verapamil SR and enalapril (P < 0.01). Verapamil SR also reduced heart rate at rest and during exercise (-11.8% and -18.4%, respectively, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Favourable interaction of calcium antagonist plus ACE inhibitor on cardiac haemodynamics in treating hypertension: rest and effort evaluation. 778 96

The aim of the study was to investigate the combined influence of thiopental and antiarrhythmic drugs: procainamide, N-acetylprocainamide, verapamil or propranolol on hemodynamic parameters in rabbits: arterial blood pressure, heart rate, cardiac output, stroke volume, peripheral vascular resistance, renal and hepatic blood flows. Propranolol used during thiopental anesthesia deepened the decrease of hepatic and renal blood flow resulting from the action of the anesthetic drug. Verapamil in a dose that did not change hepatic blood flow caused significant decrease of that parameter during thiopental anesthesia. Other hemodynamic changes observed after administration of antiarrhythmic drugs during thiopental anesthesia are essentially similar to those resulting from the action of antiarrhythmic drugs alone. The administration of procainamide or N-acetylprocainamide during thiopental anaesthesia in rabbits had no significant influence on hemodynamic changes evoked by thiopental alone. Verapamil injected to rabbits together with thiopental caused a significant decrease of blood flow in the liver, which was not observed after thiopental alone or verapamil alone. Propranolol injection together with thiopental caused a decrease of blood pressure, heart rate, cardiac output but an increase of vascular peripheral resistance, which was similar to the action of propranolol alone. Propranolol administered during thiopental anesthesia caused a significant decrease of the renal and hepatic blood flow, more marked than after the injection of that beta-blocker alone.
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PMID:The influence of selected antiarrhythmic drugs on the hemodynamic parameters in rabbits during anesthesia. Part II. Thiopental anesthesia. 868 88

Hypertrophic cardiomyopathy (HC) is characterized by impaired diastolic function, and left ventricular (LV) outflow tract obstruction in about one-fourth of patients. Verapamil improves diastolic properties, but may have dangerous adverse effects. This study investigates the effects of diltiazem on hemodynamics and LV function in 16 patients with HC who were studied with cardiac catheterization and simultaneous radionuclide angiography. Studies were performed during atrial pacing (15 beats above spontaneous rhythm) at baseline and during intravenous diltiazem administration (0.25 mg x kg(-1) over 2 minutes, and 0.014 mg x kg(-1) x min(-1). Diltiazem induced a systemic vasodilation (cardiac index: 3.4 +/- 1.0 to 4.0 +/- 1.0 L x min(-1) x m(-2), p = 0.003; aortic systolic pressure: 116 +/- 16 to 107 +/- 19 mm Hg, p = 0.007; systemic resistance index: 676 +/- 235 to 532 +/- 193 dynes x s x cm(-5) x m(-2), p = 0.006), not associated with changes in the LV outflow tract gradient. The end-systolic pressure/volume ratio decreased (30 +/- 42 to 21 +/- 29 mm Hg x ml(-1) x m(-2); p = 0.044). Pulmonary artery wedge pressure (11 +/- 5 to 15 +/- 6 mm Hg, p = 0.006), and peak filling rate increased (4.1 +/- 1.3 to 6.0 +/- 2.4 stroke counts x s(-1), p = 0.004). The time constant of isovolumetric relaxation tau decreased (74 +/- 40 to 59 +/- 38 ms, p = 0.045). The constant of LV chamber stiffness did not change. Thus, active diastolic function is improved by the acute administration of diltiazem by both direct action and changes in hemodynamics and loading conditions. LV outflow tract gradient does not increase despite systemic vasodilation. In some patients, however, a marked increase in obstruction and a potentially harmful elevation in pulmonary artery wedge pressure do occur. Passive diastolic function is not affected.
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PMID:Effects of diltiazem on left ventricular systolic and diastolic function in hypertrophic cardiomyopathy. 875 92

To evaluate the effects on hemodynamics and the distribution of blood volume of various calcium entry blocker (CEB) agents, we invasively studied 24 hypertensive patients before and after treatment with isradipine, diltiazem, and verapamil. All three agents reduced arterial pressure through a significant fall in total peripheral resistance without causing reflex tachycardia, while preserving stroke volume and cardiac output. Verapamil reduced the central blood volume (CBV) and the ratio of CBV to total blood volume (TBV) in the supine position (P < .05), suggesting peripheral venodilatation. Isradipine and verapamil modified the responses to head-up tilt. The orthostatic decrease in stroke volume was accentuated following treatment, and it was associated with a greater fall in the ratio of CBV to TBV, suggesting that these two agents attenuate the reflex venoconstriction induced by postural change. In contrast to verapamil and isradipine, diltiazem did not affect volume distribution in the supine or head-up positions. These results suggest that the effect of CEBs varies in order of venodilatory effect from verapamil to isradipine to diltiazem, with verapamil having the greatest effect.
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PMID:Effects of calcium entry blockers on distribution of blood volume. 880 74

Calcium antagonists are effective in lowering blood pressure, relieving anginal symptoms and improving exercise tolerance in older and younger patients with coronary artery disease. Verapamil and diltiazem are effective in slowing ventricular response rates to supraventricular arrhythmias in both older and younger patients. Although they belong to at least 3 distinct chemical classes, a moderate decrease in the clearance of all calcium antagonists occurs with aging. Most clinical trials of these drugs have used the same dosages in older and younger patients, confounding analyses of sensitivity in older compared with younger patients. Greater reductions in blood pressure usually occur in older compared with younger patients receiving the same dosages of calcium antagonists; similarly, the dosage required to reduce blood pressure to a certain level is usually lower in older compared with younger patients. Drug acquisition costs are generally higher for calcium antagonists than for beta-blockers or diuretics. Compared with younger patients, greater heart rate suppression may be seen in older patients treated with verapamil and diltiazem; conversely, heart rate increases are usually seen with dihydropyridines. Calcium antagonists have not been shown to provide long-term benefits or decreased morbidity or mortality in elderly patients with hypertension. Verapamil, but not dihydropyridines, decreases mortality after myocardial infarction in patients without congestive heart failure. Calcium antagonists have not been shown to be beneficial in the treatment of acute stroke. Adverse effects, such as a postural hypotension, may be more frequent in elderly compared with younger patients. In addition, the elderly are at greater risk for drug interactions with calcium antagonists due to the higher likelihood that they are receiving other drugs.
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PMID:Calcium antagonists in the elderly. A risk-benefit analysis. 881 83

The Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) Trial is a randomized, prospective, double-blind, parallel-group, two-arm, actively controlled, multicenter, international 5-year clinical trial involving 15,000 patients. CONVINCE will compare the incidence of fatal or nonfatal myocardial infarction (MI), fatal or nonfatal stroke, or cardiovascular-disease-related death in two antihypertensive treatment regimens. One treatment arm begins with controlled onset-extended release (COER)-verapamil, which has its major antihypertensive effect 6-12 hours after administration. The other arm (standard of care (SOC)) begins with either hydrochlorothiazide (HCTZ) or atenolol, one of which is preselected by the investigator for an individual patient prior to randomization. Secondary objectives include comparisons of the regimens for each of the components of the primary endpoint (separately), death or hospitalization related to cardiovascular disease, efficacy in lowering blood pressure to goal, primary events occurring between 6 am and noon, all-cause mortality, withdrawals from blinded therapy, cancer, and hospitalizations due to bleeding. Patients may be enrolled if they are hypertensive and at least 55 years of age and have an established second risk factor for cardiovascular disease. Initial medications include COER-verapamil (180 mg/d), HCTZ (12.5 mg/d), or atenolol (50 mg/d). Initial doses are doubled if blood pressure (BP) does not reach goal (systolic BP < 140 mm and diastolic BP < 90 mm Hg). If BP is not controlled by the higher dose of the initial medication, HCTZ is added to COER-verapamil, or the SOC choice not initially selected is added in the SOC arm. An ACE-inhibitor is recommended (although nearly any open-label medication is allowed) as the third step for patients whose BP is not adequately controlled or who have a contraindication to one of the two SOC medications. Patients take two sets of tablets daily, one in the morning and one in the evening. Although most patients switch from an established antihypertensive medication to randomized treatment, untreated patients with stages I-III hypertension (SBP between 140 and 190 or DBP between 90 and 110 mm Hg) are eligible. Outcomes are monitored by an independent Data and Safety Monitoring Board. Enrollment began during the third quarter of 1996, and follow-up is to be completed in the third quarter of 2002.
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PMID:Rationale and design for the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) Trial. 968 12

Acute myocardial infarction (MI) is the leading cause of death around the globe. Advances in the field of cardiology have identified several effective treatments that have lead to decrease in mortality from this cause over the past 3 decades. The purpose of this article is to review the existing literature in regards to secondary prevention after acute MI. A search of MEDLINE through August of 1999 was carried out to identify any available publications on secondary prevention after MI. Evidence on the use of both pharmacological and nonpharmacological interventions that was shown to be effective in improving morbidity and mortality was sought. Recommendations for the treatment of patients with acute MI are made based on existing evidence. Betablockers, aspirin and lipid-lowering agents for patients with low density lipoprotein-cholesterol > 130 mg% should be used for all patients following a MI. Angiotensin converting enzyme inhibitors are indicated for patients with congestive heart failure and/or reduced left ventricular ejection fraction and are likely protective in most patients. Calcium channel blockers (Verapamil and Diltiazem) are indicated as second-line therapy for patients who have contraindications or are intolerant to betablockers. The routine prophylactic use of antiarrhythmic drugs to suppress ventricular ectopic beats should be avoided. Recommendations regarding diet, smoking cessation and achievement of ideal body weight should be an integral part of patient management. Referral for outpatient rehabilitation should also be strongly encouraged. Finally, adequate control of blood pressure and diabetes cannot be overemphasized. Adherence to these goals in patients with acute MI will lead to better long-term outcomes and reduction in cardiac death, recurrent MI, stroke, and need for coronary revascularization.
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PMID:Current concepts in secondary prevention after acute myocardial infarction. 1071 9


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