Therapeutic implications of ischemia in the ambulatory setting

Prognosis of patients with stable angina pectoris on antianginal drug therapy

Antianginal drug treatment reduces symptoms and ischemia but may also influence the prognosis of patients with stable angina pectoris. The Atenolol Silent Ischemia Study (ASIST) compared atenolol and placebo treatment (about 140 patient-years on each) in patients with mainly silent ischemia and found less aggravation of angina and a tendency toward fewer cardiac complications with atenolol treatment. The Total Ischaemic Burden European Trial (TIBET) compared slow release nifedipine, atenolol, or the combination (about 450 patient-years on each) and found no significant differences with regard to cardiac complications, a nonsignificant trend toward better prognosis on combined treatment, and more side effects on nifedipine alone compared with the other treatments. The Angina Prognosis Study in Stockholm (APSIS) compared metoprolol and verapamil (about 1,400 patient-years on each) and found similar effects on cardiovascular endpoints, tolerability, and psychosocial variables with the 2 treatments. Hypothesis-generating subgroup analyses in APSIS suggest that treatment effects may differ in hypertensive and diabetic subgroups. Beneficial effects in primary and secondary prevention, together with data from ASIST, suggest that beta 1 blockade influences prognosis favorably. The safety of short-acting nifedipine in ischemic heart disease is questioned, but TIBET data suggest that slow release nifedipine may be safe. Verapamil has beneficial effects after myocardial infarction (Danish Verapamil Infarction Trial II) and shows similar efficacy as metoprolol in the APSIS study. The paucity of placebo data (antianginal treatment cannot be withheld during long periods of time in symptomatic patients) precludes firm conclusions regarding effects of drug treatment on prognosis. It is argued that patients with stable angina pectoris do well on medical treatment, and that beta 1 blockers, verapamil, and, possibly, slow-release nifedipine may influence their prognosis favorably.

Asymptomatic Cardiac Ischemia Pilot (ACIP) study: effects of coronary angioplasty and coronary artery bypass graft surgery on recurrent angina and ischemia. The ACIP investigators

OBJECTIVES

The Asymptomatic Cardiac Ischemia Pilot (ACIP) study showed that revascularization is more effective than medical therapy in suppressing cardiac ischemia at 12 weeks. This report compares the relative efficacy of coronary angioplasty or coronary artery bypass graft surgery in suppressing ambulatory electrocardiographic (ECG) and treadmill exercise cardiac ischemia between 2 and 3 months after revascularization in the ACIP study.

BACKGROUND

Previous studies have shown that coronary angioplasty and bypass surgery relieve angina early after the procedure in a high proportion of selected patients. However, alleviation of ischemia on the ambulatory ECG and treadmill exercise test have not been adequately studied prospectively after revascularization.

METHODS

In patients randomly assigned to revascularization in the ACIP study, the choice of coronary angioplasty or bypass surgery was made by the clinical unit staff and the patient.

RESULTS

Patients assigned to bypass surgery (n = 78) had more severe coronary disease (p = 0.001) and more ischemic episodes (p = 0.01) at baseline than those assigned to angioplasty (n = 92). Ambulatory ECG ischemia was no longer present 8 weeks after revascularization (12 weeks after enrollment) in 70% of the bypass surgery group versus 46% of the angioplasty group (p = 0.002). ST segment depression on the exercise ECG was no longer present in 46% of the bypass surgery group versus 23% of the angioplasty group (p = 0.005). Total exercise time in minutes on the treadmill exercise test increased by 2.4 min after bypass surgery and by 1.4 min after angioplasty (p = 0.02). Only 10% of the bypass surgery group versus 32% of the angioplasty group still reported angina in the 4 weeks before the 12-week visit (p = 0.001).

CONCLUSIONS

Angina and ambulatory ECG ischemia are relieved in a high proportion of patients early after revascularization. However, ischemia can still be induced on the treadmill exercise test, albeit at higher levels of exercise, in many patients. Bypass surgery was superior to coronary angioplasty in suppressing cardiac ischemia despite the finding that patients who underwent bypass surgery had more severe coronary artery disease.

ST segment depression detected by continuous electrocardiography in patients with acute ischemic stroke or transient ischemic attack

BACKGROUND AND PURPOSE

Forty percent of patients with a history of ischemic stroke or transient ischemic attack (TIA) have concomitant coronary artery disease. ST segment depression, detected by continuous electrocardiography, is associated with increased cardiac morbidity and mortality in patients with known coronary artery disease. While electrocardiographic changes have been associated with acute stroke, the etiology and significance of these changes remain unclear. In this pilot study we report the prevalence of ST segment depression and ventricular arrhythmias in patients with acute ischemic stroke or TIA monitored by continuous electrocardiography. Clinical predictors of ST segment depression and ventricular arrhythmia are also identified.

METHODS

Consecutive patients presenting with acute ischemic stroke or TIA were enrolled within 72 hours of hospital admission and monitored by continuous electrocardiography for 48 hours. The electrocardiographic results were analyzed for periods of ST segment depression and ventricular arrhythmias.

RESULTS

Of 51 patients with ischemic stroke or TIA, 15 (29%) had episodes of ST segment depression (95% confidence interval, 15% to 43%), and 18 (35%) had ventricular arrhythmias (95% confidence interval, 21% to 49%). In logistic regression analysis, increasing age (P < .02) and a left-sided neurological event (P < .01) were significant predictors of ST segment depression. Increasing numbers of atherosclerotic risk factors, a history of cardiac disease, and increasing or decreasing mean arterial pressure were not predictive of ST segment depression.

CONCLUSIONS

Patients with acute ischemic stroke or TIA have a 29% prevalence of ST segment depression within the first 5 days after their event. In comparison, the prevalence of ST depression is 2.5% to 8% in asymptomatic adults and 43% to 60% in patients with symptomatic coronary artery disease. The association of ST segment depression with left-sided neurological events suggests that the electrocardiographic changes are in part neurologically mediated. Further study is necessary to better define the brain-heart interaction and to determine whether ST segment depression in patients with ischemic stroke or TIA reflects underlying coronary artery disease.