Search

Recent studies strongly support the prognostic importance of transient silent ischemia. Because patients with silent ischemia are at higher risk of a cardiac event, they are likely to benefit not only from control of symptoms, but also from treatment directed at prevention of ischemia. The efficacy of controlled-release metoprolol 200 mg once daily and diltiazem 60 mg 4 times daily was assessed in a randomized, double-blind, crossover study in 32 patients with proven coronary artery disease, predominantly asymptomatic myocardial ischemia, positive bicycle exercise test results, and [greater than or equal to] 5 minutes of asymptomatic ST-segment depression on a 24-hour screening ambulatory electrocardiogram (ECG). At the beginning and at the end of both 3-week treatment periods, an exercise test was performed and a 72-hour ambulatory ECG was recorded. Both active treatment periods were preceded by a 2-week placebo phase. Both treatments effectively reduced and postponed exercise-induced ST depression and reduced the total ischemic integral on the ambulatory ECG. Only metoprolol significantly reduced the mean number of ischemic episodes (54%, p = 0.0003, vs 31% for diltiazem, p = NS) and the mean duration of ischemia (51%, p = 0.012, vs 27% for diltiazem, p = NS) compared with baseline values. Metoprolol strongly blunted the morning and afternoon peak in the circadian distribution of ischemia, whereas diltiazem did not change the circadian distribution of ischemia at all. (Am J Cardiol 1994; 74:1095--1098)

Ventricular arrhythmias occur frequently in patients with hypertensive left ventricular (LV) hypertrophy and have been associated with increased incidence of sudden death. In this study, the effect of various antihypertensive medications on ventricular arrhythmias was evaluated in 31 hypertensive patients with moderate to severe LV hypertrophy. Patients were assessed at baseline (after 3 weeks of placebo treatment) and after treatment with each of 4 monotherapies: diltiazem 120 or 240 mg/day, metoprolol 100 or 200 mg/day, enalapril 10 or 20 mg/day and hydrochlorothiazide 50 or 100 mg/day. Each drug therapy was administered for 4 weeks. The sequence of each treatment was determined at random. Echocardiographic measurements and electrocardiograms were obtained only at baseline. Biochemical measurements and 48-hour Holter monitoring were obtained at baseline and at the end of each treatment. All treatments resulted in a significant but similar decrease in blood pressure. In the group as a whole diltiazem decreased ventricular premature complexes (VPCs) by 65% (p

One hundred thirty-one patients presenting with acute myocardial infarction (AMI) a mean of 3 hours after the onset of symptoms were treated with oral aspirin and intravenous thrombolytic therapy followed by heparin. One hundred eleven patients (85%) also received intravenous followed by oral [beta] blockers. Twenty-one patients (19%) discontinued the [beta] blocker because of complications. Five (4.5%) required the addition of diuretic drugs or converting enzyme inhibitors. Six patients (5%) discontinued the [beta] blocker after complete mechanical revascularization, and 1 patient was noncompliant. Long-term treatment continued in 90 patients (69%) over a 2-year follow-up period (average 13 months). There were 3 infarct extensions and 3 reinfarctions (5%). Overall mortality at 2 years was 10%. Intravenous [beta] blockers are well tolerated in most patients treated with thrombolytic agents, aspirin and heparin. They may further improve the survival benefit of chronic [beta] blocker therapy in the period after AMI. (AM J Cardiol 1992;69:1389-1382)

Hypertension, or high blood pressure, is often treated with drugs known as adrenergic beta blocking agents, or beta blockers. These drugs have been found to be quite effective in lowering blood pressure over the long term; between 40 and 50 percent of patients experience a normalization of blood pressure levels. The drugs do not produce postural hypotension (excessively low blood pressure when the patient stands), and most beta blockers have a relatively low rate of unacceptable side effects. However, beta blockers have been less effective than had been hoped in reducing overall cardiovascular disease and death. This most likely results from the adverse effects that many beta blockers have on lipid and carbohydrate metabolism; decreases in insulin sensitivity, high blood sugar levels, increased blood lipid (fat) levels, and decreases in high-density lipoprotein cholesterol (so-called ''good'' cholesterol) have been reported. This adverse metabolic side effect profile appears to be lacking in some beta blockers with intrinsic sympathomimetic activity (ISA; weak excitatory activity at the receptors they bind to). Bopindolol, a potent beta blocker with a prolonged duration of action and moderate ISA, has been used in some cases in the treatment of hypertension. To further characterize the effects of this drug on blood pressure and metabolism, several studies were carried out at two Czechoslovakian medical centers. The drug was found to be effective for 24 hours in reducing blood pressure in hypertensive patients; hence, once-daily administration was sufficient. Seventy percent of the patients experienced a return to normal blood pressure values. In a separate six-month trial, bopindolol was shown to have no significant effects on total cholesterol, low-density and high-density lipoproteins, and blood triglyceride levels. No adverse effects on carbohydrate metabolism were seen. An additional 12-month study revealed an improvement in the blood triglyceride and cholesterol profiles of hypertensive patients receiving bopindolol. (Consumer Summary produced by Reliance Medical Information, Inc.)

Hypertension, or high blood pressure, is a serious and widespread health problem. Drug treatment for hypertension is most commonly carried out through the use of vasodilator drugs, which cause relaxation of blood vessels and a subsequent drop in blood pressure. Drugs that block the entry of calcium into cells (calcium antagonists), those that block the formation of the vasoconstrictor substance angiotensin (angiotensin converting enzyme, or ACE, inhibitors), and drugs that block the vasoconstrictor activity of neurotransmitters and hormones (beta blockers) are used to produce vasodilation. These agents have been shown to reduce blood pressure, but the inaccuracies inherent in one-time office measurement of blood pressure have resulted in a dearth of knowledge concerning the comparative efficacy of these drugs in controlling 24-hour blood pressure. To investigate this, 201 patients suffering from hypertension were randomly assigned to receive either the calcium antagonist nitrendipine, the ACE inhibitor enalapril, the beta-1 selective blocker metoprolol, or the beta blocker mepindolol. Doses were customized so that each group of patients obtained similar reduction in blood pressure, as measured by the arm cuff method during an office visit. When therapy with one of these agents was unable to reduce blood pressure sufficiently, diuretic treatment (to increase urine output and decrease blood volume) was added to the drug regimen. Patients were then outfitted with an ambulatory blood pressure monitoring device that measured blood pressure 60 to 70 times per day as they went about their normal activities. The different drug regimens were not equally effective when blood pressures were measured in this way. Metoprolol was the most effective drug at reducing the peak (systolic) and trough (diastolic) blood pressures, and at reducing the number of blood pressure peaks above 180 millimeters of mercury. Both beta blockers (metoprolol and mepindolol) and the enalapril significantly reduced the morning increase in blood pressure, while nitrendipine did not. Hence, despite the similar efficacy of these four drugs in reducing ''office'' blood pressure, they affect 24-hour blood pressure quite differently. (Consumer Summary produced by Reliance Medical Information, Inc.)

TABULAR DATA OMITTED Cardiovascular and peripheral adaptations to an aerobic conditioning program were studied in 30 hypertensive adults taking either Placebo',[beta][.sub.1]-selective [beta]-adrenergic blocker (metoprdol) or [beta][.sub.1]-nonselective [beta]-adrenergic blocker (propranoid). The placebo group increased aerobic capacity (V0[.sub.2]max) 24% (p (Am J Cardiol 1990;66:591-596), Beta-adrenergic blocking agents prevent the activation of beta-adrenergic receptors, which are specialized cell membrane proteins that trigger specific cell processes such as heart rate and contraction. However, these drugs have been shown to decrease the capacity for exercise and to diminish conditioning response to aerobic exercise in healthy individuals. Studies have also shown that exercise conditioning normally increases aerobic capacity and decreases resting blood pressure in patients with high blood pressure (hypertension). Although beta-adrenergic blocking agents are commonly used to treat hypertension, the effects of these drugs on exercise conditioning in hypertensive patients are not known. However, a drug that selectively blocks the beta-1-type receptors may not affect the beta-2 receptor-mediated dilation of blood vessels during exercise. Hence, the effects of the beta-1 receptor blocking agent metoprolol and the nonspecific beta receptor blocker propranolol on exercise conditioning response were assessed in 30 patients with hypertension. Aerobic conditioning resulted in a 24 percent increase in aerobic capacity, reduced blood pressure, and decreased systemic resistance (the force against which blood flows in the peripheral circulation), in patients who were not treated with beta blocking agents. Aerobic capacity was increased by 8 percent and blood pressure decreased in patients treated with metoprolol. Patients treated with propranolol had no increase in aerobic capacity, no reduction in blood pressure, and no adaptation of the heart and blood vessels to exercise training. These findings show that selective beta-1 blocking agents such as metoprolol and nonspecific beta blocking agents such as propranolol can diminish the exercise conditioning effects in hypertensive patients to varying degrees. (Consumer Summary produced by Reliance Medical Information, Inc.)

Dilevalol combines vasodilation due to selective [[beta].sub.2] agonism and nonselective [beta] antagonism. We studied 311 patients randomized to dilevalol and 138 to metoprolol in a multicenter trial. After a 4-week placebo washout, dilevalol was titrated from 200 to 1,600 mg once daily and metoprolol from 100 to 400 mg to a goal supine diastolic blood pressure