Effect of metoprolol and diltiazem on the total ischaemic burden in patients with chronic stable angina: a randomized controlled trial

Long-term beta blockers for stable angina: systematic review and meta-analysis

Objectives: To assess the effects of long-term beta blockers in patients with stable angina.

Methods: We reviewed the literature up to June 2010 from CENTRAL, MEDLINE, EMBASE, CBM, and CNKI for randomized controlled trials. The appropriate data were meta-analysed using Revman 5.0.

Results: Twenty-six trials including 6108 patients were identified. The treatment with beta blockers has significantly decreased all-cause mortality when compared with no control (OR 0.40, 95% CI 0.20 to 0.79), but has had no statistically differences when compared with placebo (OR 0.92, 95% CI 0.62 to 1.38) and with calcium-channel blocker (CCB) (OR 0.84, 95% CI 0.49 to 1.44). This was similar in patients with fatal and non-fatal acute myocardial infarction when compared with placebo (OR 0.82, 95% CI 0.57 to 1.17) or CCB (OR 1.08, 95% CI 0.71 to 1.66); on revascularization and quality of life. The beta blockers reduced the incident of unstable angina compared to no treatment (OR 0.14, 95% CI 0.07 to 0.29), but increased unstable angina compared to placebo (OR 3.32, 95% CI 1.50 to 7.36). There was a significant reduction of nitrate consumption when beta blockers were compared with CCBs (OR −1.18, 95% CI −1.54 to −0.82), but not with placebo and trimetazidine. There was no significant difference in angina attack between each group. Side effects in beta blocker were similar with ones in controls.

Conclusions: Beta blockers may decrease the death and unstable angina when compared with no treatment, but no more effective than other anti-anginal agents on prophylaxis of myocardial ischaemia in stable angina patients.

Silent ischemic interval on exercise test is a predictor of response to drug therapy: a randomized crossover trial of metoprolol versus diltiazem in stable angina

BACKGROUND AND HYPOTHESIS

There is no method available to predict the relative antianginal efficacy of beta blockers and calcium-channel antagonists. The present study was undertaken to assess the role of silent ischemic interval (SII) on exercise treadmill test (ETT) as a predictor of response to therapy with metoprolol and diltiazem in patients with stable angina.

METHODS

Thirty-four patients with stable angina were divided into two groups depending upon the presence or absence of an SII gap of at least 1 min between onset of ST depression and appearance of angina on ETT. Metoprolol (50-100 mg twice daily) and diltiazem (60-120 mg three times daily) were randomly assigned for 6 weeks to patients in each group, and then patients were crossed over for further 6 weeks after a washout period of 2 weeks. Antianginal efficacy was assessed by clinical and exercise parameters.

RESULTS

In patients with SII, the clinical responder rate was better with metoprolol than with diltiazem (90 vs. 60%, respectively), and on ETT, metoprolol produced significant improvement in the total exercise time (p< 0.01), time to 1 mm ST depression (p <0.01), time to angina (p <0.01), and a significant decrease in peak rate-pressure product (p<0.001), whereas diltiazem had no significant effect on exercise parameters. However, in patients without SII, metoprolol and diltiazem had a similar clinical responder rate (57%), and both produced a significant increase in total exercise time (p < 0.01), time to 1 mm ST depression (p < 0.01), and time to angina (p < 0.01). In addition, metoprolol had a significant effect on peak rate-pressure product (p < 0.001).

CONCLUSION

Silent ischemic interval on ETT can be a predictor of response to antianginal therapy in stable angina, as patients with SII respond better to metoprolol and those without SII respond equally to both metoprolol and diltiazem.

Pharmacological rate control of atrial fibrillation

To control ventricular rate in patients with AF, physicians should seek to control heart rate at rest and with exertion. The goal has to be achieved while minimizing costs and adverse effects. For emergency use, i.v. diltiazem or esmolol are drugs useful because of their rapid onset of action. They have to be used with caution in patients with concomitant left ventricular failure symptoms, however. For most patients with AF, chronic control of the ventricular rate can be achieved with one drug. For the chronic control of ventricular rate in patients with AF and normal ventricular function, diltiazem, atenolol, are metoprolol are probably the drugs of choice. For patients with AF and structurally abnormal hearts, atenolol, metoprolol, or carvedilol are appropriate choices. Adequate ventricular rate control by pharmacological agents should be evaluated by either 24-hour Holter monitoring or a submaximal stress test to determine the resting and exercise ventricular rate. If the mean ventricular rate is not close to 80 beats per minute, or the heart rate on moderate exertion is not between 90 to 115 beats per minute, a second agent to control the rate should be added. Excessive reductions in ventricular rates that could limit exercise tolerance should be avoided.

Amlodipine reduces myocardial ischaemia during exercise without compromising left ventricular function in patients with silent ischaemia: a randomised, double-blind, placebo-controlled study

BACKGROUND

Left ventricular systolic function is reduced during episodes of silent ischaemia in patients with coronary artery disease (CAD). In most normal subjects left ventricular ejection fraction (LVEF) increases at least 5% during exercise whereas LVEF often remains unchanged or decreases in patients with CAD. The anti-ischaemic effect of calcium antagonists is well documented including a capability to reduce exercise-induced electrocardiographic ST-depressions, whereas the effect of these drugs on LV volume changes during exercise in patients with silent ischaemia is unknown.

AIM

The aim of this study was to evaluate the effect of amlodipine on rest and exercise LVEF in patients with silent ischaemia.

METHODS

Twenty-one patients completed a double-blind placebo-controlled cross-over study. Conventional exercise test and radionuclide cardiographies during exercise were used for determining haemodynamic parameters.

RESULTS

Exercise-induced electrocardiographic ST-depressions were reduced in 83% of the patients having ST-deviations during placebo even though 10 patients were already treated with a beta-blocker. Amlodipine did not affect left ventricular systolic function compared to placebo, neither at rest nor during exercise.

CONCLUSION

The results indicated that amlodipine is a safe anti-ischaemic drug in patients with silent ischaemia concerning cardiac function.

Effect of metoprolol and amlodipine on myocardial total ischaemic burden in patients with stable angina pectoris

OBJECTIVE

A randomized double-blind cross-over study to assess the effect on myocardial total ischaemic burden and the anti-anginal efficacy of the beta-1-blocker metoprolol given as metoprolol CR/Zok versus the calcium channel blocker amlodipine, both given in the recommended and commonly used doses of 100 mg o.d. and 5 mg o.d., respectively.

METHOD

Fifty-two patients with a history of stable exercise-induced angina pectoris and at least six episodes of significant ST-segment depression during 24-h ambulatory electrocardiographic monitoring after 9 days of placebo were included in the study. The patients first completed a 9-day placebo run-in phase with additional administration of a long-acting nitrate during the first 7 days. They then received in a randomized sequence metoprolol CR/Zok and amlodipine each for 4 weeks. During placebo treatment and at the end of each phase of active treatment the patients' clinical progress was assessed and a 24-h ECG monitor performed.

RESULTS

Forty-seven patients completed the two 4-week treatment periods. Five patients withdrew from the study. The number of ischaemic episodes during 24 h was 30.4 at baseline with placebo, which was reduced significantly by both treatments (P<0.005) to 6.8 episodes after metoprolol and 15.8 episodes after amlodipine treatment (P<0.001 for the difference between the treatment groups). Metoprolol and amlodipine reduced the total duration of ischaemic episodes from 86.0 min to 15-1 and 48.3 min with a mean episode duration of 1.1 and 2.6 min, respectively. Twenty patients on metoprolol (42.6%) and four on amlodipine (8.4%) showed no ST-segment depression at the end of treatment. Baseline heart rate of 80 b.p.m. decreased by 11.1 b.p.m. after metoprolol and increased by 4b.p.m. after amlodipine. Anginal attacks were reduced from 14.8 attacks per week at baseline to 2.4 attacks on metoprolol and 4.4 attacks on amlodipine treatment. For all variables the observed changes from baseline were significant after either treatment (P<0.005) with a significantly more pronounced effect in favour of metoprolol (P<0.0001). Ten patients reported nine different adverse events during metoprolol treatment. On amlodipine, 12 patients were affected by 11 different symptoms leading to three treatment withdrawals. On metoprolol one patient withdrew due to adverse events.

CONCLUSION

Both drugs reduce total ischaemic burden by reducing ischaemic episodes and antianginal attacks, with a significantly greater effect from metoprolol 100 mg o.d. as compared to amlodipine 5 mg o.d.

Metoprolol abolishes exercise-induced left ventricular dysfunction in patients with silent ischemia

Left ventricular systolic function is reduced during episodes of silent ischemia in patients with coronary artery disease (CAD). Left ventricular ejection fraction (LVEF) is increased at least 5 absolute percent during exercise in most normal subjects; however, in patients with CAD, LVEF often remains unchanged or decreases. The anti-ischemic effect of beta-adrenergic receptor blockade is well documented, including a reduction of exercise-induced electrocardiographic ST depressions; however, the effect of these drugs on left ventricular volume changes during exercise in patients with silent ischemia is unknown. The aim of this study was to evaluate the effect of a cardio-selective beta-blocking agent, metoprolol, on rest and exercise LVEF in patients with silent ischemia, using radionuclide cardiography. Fifteen patients with silent ischemia completed a double-blind, placebo-controlled crossover study at rest and during submaximal exercise. LVEF remained unchanged during exercise in the placebo phase (56% to 58%; p = NS), but even though LVEF tended to decrease 56% during rest after metoprolol versus 52% after placebo (p = NS), the LVEF increase from rest to exercise resembled a normal LVEF response, 52% to 58% (p = 0.005). Exercise-induced electrocardiographic ST depressions were also reduced during metoprolol treatment. In patients with silent ischemia, the exercise-induced change in LVEF rises significantly during metoprolol treatment. The mechanism may be a reduction in myocardial ischemia as indicated by a reduction in ischemic electrocardiographic findings.