Effect of beta-blockade on exercise capacity in hypertensive subjects: a one-year double-blind study of celiprolol and metoprolol

Candesartan improves maximal exercise capacity in hypertensives: results of a randomized placebo-controlled crossover trial

Cardiac hypertrophy and remodelling in hypertension has been associated with impaired exercise capacity. The authors tested whether an angiotensin receptor blocker, candesartan, improved exercise peak oxygen volume (VO2) in this population. A total of 154 untreated hypertensive patients, aged 40 to 66 years, with World Health Organization stage I or II hypertension and left ventricular hypertrophy, were randomized to receive placebo, candesartan (32 mg), each of these plus aspirin (300 mg/d), or the same preparations in a reverse order, for 3 weeks, with a 3-week washout period between treatments. The authors measured maximal workload and oxygen reserve with an exercise test, 24 hour-ambulatory blood pressure, and echocardiography at the end of each treatment. Hypertensive patients did not achieve the maximal workload (116 [99-133] W vs 132 (AMA style = no period on vs) [116-149] W; P=.01). This impaired exercise capacity was in a multiple regression analysis related to lower oxygen reserve (r=0.49, P<.001), and the lower oxygen reserve to higher left ventricular hypertrophy by echocardiography (beta=-0.34), respectively. The use of candesartan alone or with aspirin resulted in an improvement of peak VO2 and exercise tolerance, when compared with controls. Patients with hypertension and cardiac hypertrophy cannot achieve a predicted maximal workload. The use of an angiotensin receptor blocker in therapy may represent a useful treatment in these patients for its effect on exercise peak VO2 and exercise tolerance. The use of aspirin did not affect outcome.

Do β-blockers prolong survival in heart failure only by inhibiting the β1-receptor? A perspective on the results of the COMET trial

Experimental and clinical studies indicate that carvedilol exerts multiple antiadrenergic effects in addition to beta(1)-receptor blockade, but the prognostic importance of these actions has long been debated. This controversy has now been substantially advanced by the results of the recently completed Carvedilol Or Metoprolol European Trial (COMET), which showed that carvedilol (25 mg twice daily) reduced mortality by 17% when compared with metoprolol (50 mg twice daily), P=.0017--a result that was consistent with the differences seen across earlier controlled trials with beta-blockers in survivors of an acute myocardial infarction and in patients with chronic heart failure. Questions have been raised about the interpretation of these findings in view of the fact that the trial did not use the dose or formulation of metoprolol that was shown to prolong life in a placebo-controlled trial (ie, Metoprolol CR/XL [Controlled Release] Randomized Intervention Trial in Heart Failure). Pharmacokinetic and pharmacodynamic analyses, however, indicate that the dosing regimen of metoprolol selected for use in the COMET trial produces a magnitude and time course of beta(1)-blockade during a 24-hour period that is similar to the dose of carvedilol targeted for use in the trial. These analyses suggest that the observed difference in the mortality effects of metoprolol and carvedilol is not related to a difference in the magnitude or time course of their beta(1)-blocking effects but instead reflect antiadrenergic effects of carvedilol in addition to beta(1)-blockade.

Influences of nonselective, beta(1)-selective and vasodilatory beta(1)-selective beta-blockers on arterial pulse wave velocity in normotensive subjects

beta-Adrenoceptor blockers with disparate properties may have differential influences on arterial pulse wave velocity (PWV). Therefore, influences of single medium doses of bisoprolol, propranolol and celiprolol on PWV were compared in healthy subjects. Arterial PWV was obtained from the time delay between flow pulses measured from the root of the aorta and the popliteal artery. Bisoprolol and propranolol decreased arterial PWV more than placebo (P less-than-or-equal to .002) and celiprolol (P<.0001). In conclusion, the acute effects of bisoprolol and propranolol on arterial PWV in normotensive subjects seem to differ from that of celiprolol.

Prescribing exercise training for patients with defibrillators

Patients with an implantable cardioverter defibrillator (ICD) often refrain from physical exercise for fear of precipitating a life-threatening arrhythmia or receiving an ICD shock. However, most of these patients are able to safely exercise if they are provided appropriate clinical guidelines. This review describes the factors that enter into the development of an exercise program for patients with an ICD.

Comparative effects of bisoprolol and nitrendipine on exercise capacity in hypertensive patients with regular physical activity

The aim of this study was to evaluate the long-term effects of administering bisoprolol compared with nitrendipine on the duration of the exercise tolerated by male and female patients, aged 18-65 years, having mild to moderate hypertension and taking regular exercise. In this double-blind, randomized prospective study, 96 patients (85 men and 11 women, 48+/-10 years) formed two groups: 49 in the bisoprolol group, and 47 in the nitrendipine group. After a washout period of 14 days, either 10 mg of bisoprolol or 20 mg of nitrendipine was given daily over a treatment period of 12 weeks. During the treatment period, the stability of the physical training was monitored weekly by using a questionnaire. The results of two maximal triangular exercise tolerance tests (ETTs) on an ergometric bicycle performed at D0 under placebo and at D84 under active treatment were compared. No statistical difference was observed between both groups, concerning age, gender, morphologic characteristics, resting cardiovascular parameters, or physical training. Both groups maintained the same training level throughout the study. No significant differences between the groups were noted for duration of ETT [D0 892+/-284 s, D84, 919+/-267 s (NS) vs. D0 929+/-290 s, D84 904+/-324 s (NS)], or maximal work load [D0 190+/-49 W, D84 197+/-48 W (NS) vs. D0 198+/-49 W, D84 196+/-55 W (NS)]. On the other hand, both groups differed in maximal systolic blood pressure [D0 239+/-24 mm Hg, D84 215+/-22 mm Hg (p<0.001) vs. D0 237+/-24 mm Hg, D84 222+/-27 mm Hg (p<0.05)] (p = 0.05), and maximal pulse rate during exercise [141+/-18 vs. 163+/-17] (p<0.001), albeit not in maximal diastolic blood pressure [D0 113+/-13 mm Hg, D84 106+/-17 mm Hg (p<0.05) vs. D0 112+/-13 mm Hg, D84 104+/-15 mm Hg (p<0.05)]. The patient's own perception of the maximal effort (Borg scale) was not significantly different in either of the groups (placebo vs. treatment). Overall, in a population of hypertensive patients taking regular exercise, long-term treatment with bisoprolol produced no significant changes in the duration of peak effort, maximal workload, or the effort perceived by the patients themselves. The effects of regular exercise were comparable in both groups (bisoprolol or nitrendipine). Because previous studies have shown that dihydropyridines do not modify exercise performance in hypertensive patients, it may be concluded that the antihypertensive therapy with bisoprolol is well tolerated in a population of active hypertensive patients during dynamic exercise.

Different effects of the beta-adrenoceptor antagonists celiprolol and metoprolol on vascular structure and function in long-term type I diabetic rats

An intriguing problem of diabetes mellitus is the development of generalized angiopathy and concomitant hypertension. However, there is still a controversy whether beta-adrenoceptor antagonists can be used as antihypertensive agents in diabetes. Four groups of rats were investigated: nondiabetic controls, diabetes mellitus, diabetes + celiprolol (250 mg/kg body weight/day), diabetes + metoprolol (125 mg/kg body weight/day) after 6 months. Diabetes was induced by i.v. streptozotocin injection. We examined vascular structure and function histologically and by an in vitro microvideoangiometry of isolated perfused mesenterium. Additionally, we investigated the effects of hyperglycemia and celiprolol on NO release in cultivated aortic endothelial cells and the effect of celiprolol on transendothelial paracellular permeability. Diabetes resulted in endothelial dysfunction, characterized by a reduced response to acetylcholine and L-N(G)-nitro-arginine and an unchanged response to sodium nitroprusside (SNP). These effects were significantly antagonized by celiprolol but were not influenced by metoprolol treatment. This was supported by the finding of typical vascular changes associated with diabetes like media thickening, reduced cardiac capillary/muscle fiber ratio, and glomerulosclerosis, which were significantly reduced by celiprolol but not influenced by metoprolol treatment. Ketonuria improved after celiprolol treatment, whereas blood glucose, lipids, and body weight were not different between the diabetic groups. In cultured cells, celiprolol did not induce direct NO release but reversed the impairment of stimulated NO release caused by hyperglycemia. Furthermore, celiprolol reduced endothelial paracellular permeability. We conclude that celiprolol can exert antiangiopathic effects in diabetic rats and that both beta-adrenoceptor antagonists did not aggravate diabetic angiopathy and metabolic derangement.

Aerobic endurance training program improves exercise performance in lung transplant recipients

STUDY OBJECTIVE

To determine whether an aerobic endurance training program (AET) in comparison to normal daily activities improves exercise capacity in lung transplant recipients.

PATIENTS AND STUDY DESIGN

Nine lung transplant recipients (12+/-6 months after transplant) were examined. All patients underwent incremental bicycle ergometry with the work rate increased in increments of 20 W every 3 min. Identical exercise tests were performed after 11+/-5 weeks of normal daily activities and then after a 6-week AET. The weekly aerobic training time increased from 60 min at the beginning to 120 min during the last week. Training intensity ranged from 30 to 60% of the maximum heart rate reserve.

RESULTS

Normal daily activities had no effect on exercise performance. The AET induced a significant decrease in resting minute ventilation from 14+/-5 to 11+/-3 L/min. At an identical, submaximal level of exercise, a significant decrease in minute ventilation from 47+/-14 L/min to 39+/-13 L/min and heart rate from 144+/-12 to 133+/-17 beats/min, before and after the AET, was noted. The increase in peak oxygen uptake after AET was statistically significant (1.13+/-0.32 to 1.26+/-0.27 L/min).

CONCLUSIONS

These data demonstrate that normal daily activities do not affect exercise performance in lung transplant recipients > or = 6 months after lung transplantation. An AET improves submaximal and peak exercise performance significantly.