Postinfarction use of beta-blockers in elderly patients

Post-myocardial infarction beta-blocker therapy: the bradycardia conundrum. Rationale and design for the Pacemaker & beta-blocker therapy post-MI (PACE-MI) trial

Multiple clinical trials have demonstrated beta-blockers improving survival after myocardial infarction (MI). Patients with "bradycardia-related" contraindications to beta-blockers, such as those with asymptomatic bradycardia or AV conduction abnormalities, have been excluded from clinical trials of beta-blockers and continue to be excluded from post-MI beta-blocker therapy in routine clinical practice. These patients tend to be elderly and have a high 1-year mortality. If beta-blockers provide benefit to the post-MI patient independent of their heart rate-lowering effect, then these patients could benefit substantially from initiation of beta-blocker therapy. However, in this particular group of patients, beta-blockers can be safely initiated only if more severe or significant bradycardia can be prevented by pacemaker implantation. It is unclear whether adverse effects related to pacemaker implantation could also negate some or all of the hypothesized benefit of beta-blocker therapy. Although beta-blockers are particularly effective in the elderly, the benefit of beta-blocker therapy in patients with bradycardia-related contraindications to beta-blockers has not been established. The PACE-MI trial is a randomized controlled trial that will address whether beta-blocker therapy enabled by pacemaker implantation is superior to no beta-blocker and no pacemaker therapy after MI in patients with rhythm contraindications to beta-blockers or in those who have developed symptomatic bradycardia due to beta-blockers. The trial will randomize 1124 patients to standard therapy (not to include beta-blockers as patients must have a contraindication to be enrolled) or standard therapy plus pacemaker implantation and beta-blocker. The primary end point is the composite end point of total mortality plus nonfatal reinfarction.

Age-related differences in the management and outcome of patients with acute coronary syndromes

BACKGROUND

Age-related differences in patients with an acute coronary syndrome (ACS) have not been well characterized in prior observational studies that often included only certain age groups or subjects with myocardial infarction (MI).

METHODS

We stratified 4627 patients admitted with an ACS across 9 provinces between 1999 and 2001 enrolled in the Canadian ACS Registry into 3 age groups (< 65, 65-74, and > or = 75 years) to evaluate differences in clinical characteristics, management, and 1-year outcome.

RESULTS

Older patients more frequently had previous angina, MI, or heart failure and were less likely to have positive cardiac markers, ST elevation, and Q-wave MI or to receive thrombolytics, beta-blockers, and cholesterol-lowering and antiplatelet agents in hospital, at discharge, and at 1 year. In multivariable analyses controlling for patient factors, every decade increase in age was independently associated with reduced use of coronary angiography (odds ratio [OR] 0.79, 95% CI 0.74-0.84, P < .001) and percutaneous coronary intervention (OR 0.88, 95% CI 0.81-0.95, P = .001). When adjusted for validated clinical prognosticators and differences in management, every decade of age increment independently predicted an increased risk of death at 1 year (OR 1.87, 95% CI 1.66-2.12, P < .001).

CONCLUSIONS

Across the broad spectrum of ACS, elderly patients had more complex comorbidities and worse outcome, yet they were less likely to undergo revascularization or to receive acute and long-term evidence-based medications. Our findings emphasize the ongoing need to better define and promote optimal therapeutic regimens for elderly patients with ACS.

Beta-blockers after acute myocardial infarction in elderly patients with diabetes mellitus: time to reassess

Beta-blockers effectively reduce mortality and recurrent cardiovascular events in patients surviving myocardial infarction. However, these agents are underused in clinical practice, especially in older patients with diabetes mellitus. The current literature shows that beta-blockers are at least as effective in older diabetic patients as in other patients, without major safety concerns for their possible adverse effects. The use of these agents in clinical practice should therefore be encouraged, in order to reduce the burden of cardiovascular mortality and morbidity in older diabetic patients post-infarction.

Drug treatment of elderly patients with acute myocardial infarction: practical recommendations

Aspirin (acetylsalicylic acid) should be administered to patients on day 1 of an acute myocardial infarction (MI) and continued indefinitely. Early intravenous beta-blockade should be used during acute MI. beta-blockers should be continued indefinitely. Angiotensin-converting enzyme (ACE) inhibitors should be used in patients with acute MI with ST-segment elevation in two or more anterior precordial leads. ACE inhibitors should be used during and after acute MI in patients with chronic heart failure (CHF) or with a left ventricular ejection fraction < or =40%. There are no class I indications for using calcium channel antagonists during and after acute MI. Intravenous heparin should be used in patients with acute MI undergoing coronary revascularisation and in patients at high risk for systemic embolisation. Enoxaparin should be used in patients with non-Q-wave MI. Thrombolytic therapy should be considered in patients with acute MI with ST-segment elevation in contiguous leads of a 12-lead electrocardiogram or with left bundle branch block. Platelet glycoprotein IIb/IIIa inhibitors should be administered intravenously as an adjunct to heparin and aspirin in patients with non-Q-wave MI. Intravenous nitroglycerin should be used: (i) for the first 24 to 48 hours in patients with acute MI and CHF, large anterior MI, persistent ischaemia or hypertension; and (ii) continued beyond 48 hours in patients with recurrent angina pectoris or persistent pulmonary congestion. Long-acting nitrates should be given after MI, along with beta-blockers, to patients with angina pectoris. There are no class I indications for using intravenous magnesium during acute MI. The routine use of antiarrhythmic drugs other than beta-blockers during and after acute MI is not recommended.

Treatment of Hypertension in the Institutionalized Elderly

The goal of antihypertensive therapy in elderly institutionalized persons is to reduce the blood pressure to less than 140/90 mm Hg if possible. Elderly persons with diastolic hypertension should have their diastolic blood pressure lowered to 80-85 mm Hg. Elderly persons with stage 2 or 3 hypertension, stage 1 hypertension and target organ damage, evidence of clinical cardiovascular disease, or diabetes mellitus should be treated with antihypertensive drug therapy immediately in addition to lifestyle modification. The initial antihypertensive drug in elderly persons without associated medical conditions should be a diuretic or à -blocker because these drugs have been shown to decrease cardiovascular morbidity and mortality in controlled clinical trials. The initial antihypertensive drug in elderly persons should depend on the associated medical condition. If a second antihypertensive drug is indicated, a drug from another class should be administered. If a diuretic is not the initial drug, it is usually indicated as the second drug. If the antihypertensive response is inadequate after reaching the full dose of two classes of drugs, a third drug from another class should be added. Causes of secondary hypertension should be identified and treated. (c)2000 by CVRR, Inc.