Exercise testing in the diagnosis of coronary heart disease: a perspective.

The methods of assessing the diagnostic usefulness of exercise testing in detecting coronary obstructive disease are examined. The limitations of long-term clinical follow-up and coronary angiography as standards for the determination of disease are described as are the effects of test methodology, criteria for positivity, prevalence of disease in the study population, reliability of the standard and recognition of false positive and false negative results in determining reliability of such testing. High values were found for sensitivity and specificity for exercise testing of patients with coronary artery disease referred for consultation to medical center cardiology services. Maximal exercise testing and consideration of symptomatic and hemodynamic as well as electrocardiographic criteria for identification of myocardial ischemia are helpful in improving reliability. Diagnostic accuracy is greatly enhanced by recognition of known causes for false positive and false negative results.

Treadmill walking protocol for the diagnostic evaluation and exercise programming of cardiac patients.

This study (1) describes a treadmill walking protocol which has been used safely in over 40,000 tests since 1960, (2) presents normative data on oxygen consumption (VO2) so that it may be determined from work load without direct measurement, and (3) demonstrates simple techniques for early activity prescription or later therapeutic walking programs for patients after myocardial infarction (MI) based on this treadmill test. Normative data are presented on 131 subjects. There were no significant differences in VO2 values at the various work loads dependent on age, gender, fitness level, familiarity with the test procedure, clinical status, or the presence or absence of beta blockade. The protocol was then applied in cardiac rehabilitation of 25 patients. As a low level test, in 2 to 9 minutes patients attained 56 to 83% of age-predicted maximal heart rate. The translation of these data into early activity guidelines is shown. For a walking program, the maximal speed attained at 10% grade on the treadmill when walked on level ground put patients in the target heart rate zone for cardiovascular conditioning.

Comparison of atenolol and nifedipine in chronic stable angina pectoris.

The antiangina effects of atenolol, 50 to 200 mg once daily, or nifedipine, 10 to 30 mg 3 times daily, were evaluated in a multicenter, randomized, double-blind, parallel study of 39 patients with known symptomatic coronary artery disease. Treatment was titrated to produce at least a 30% increase in treadmill exercise duration over placebo baseline and then maintained at that dosage for an additional 3 weeks. Both treatments produced significant (p less than 0.001) increases in duration of exercise, total work and exercise capacity when compared with placebo baseline. These improvements in exercise performance were obtained with significant (p less than 0.001) reductions in both ST-segment depression and rate-pressure product for atenolol compared with nifedipine. Furthermore, the total angina attack rate and rate at rest were significantly (p less than 0.01) less frequent with atenolol than with nifedipine. Hence, the antiischemic effects of atenolol exceeded those of nifedipine, based on ST-segment depression and rate-pressure product at comparable workloads.

Comparison of placebo, nitroglycerin, and isosorbide dinitrate for effectiveness of relief of angina and duration of action.

Each of 13 patients with angina had either chewable isosorbide dinitrate, nitroglycerin (sublingual therapy), or placebo administered on each of three different days when mild anginal pain had been induced by walking on a treadmill. Both therapy with isosorbide dinitrate and therapy with nitroglycerin were effective in bringing about complete relief of the angina in less than ten minutes of uninterrupted continuous walking on the treadmill in 11 of the 13 subjects, while administration of placebo afforded complete relief in none. The duration of action of the drug was determined by following the first effort (during which the tested drug was given) by successive ten-minute walks at the same workload that first induced anginal pain. Half-hour resting periods separated the repeated periods of exercise, and the duration of action was taken to be the time from administration of the agent to the return of angina on one of the repetitive efforts. No prolonged protection was afforded by administration of the placebo. Nitroglycerin protected for slightly longer than one hour, while isosorbide dinitrate protected for 2 1/2 to 3 hours.

Exercise testing for functional evaluation and exercise prescription.

Although radionuclide tests, despite their high cost, are being used with ever-increasing frequency in diagnostic testing, the ECG exercise stress test remains the best method for providing inexpensive, noninvasive information on how patients will function in vocational and recreational pursuits. This article explains the usefulness of respiratory gas analysis measurements in evaluating performance as well as providing some substitutes when direct measurement is not available. Various exercise test modifications that help in prescribing exercise for athletes, able-bodied cardiac patients, or the disabled are also described.

Exercise stress test interpretation for cardiac diagnosis and functional evaluation.

The physiatrist, with the assistance of the physical therapist, can be the appropriate individual to prescribe and supervise exercise training programs for cardiac patients, although exercise testing is probably best left to cardiologists. Exercise test data, as supplied by the cardiologist from a diagnostic test, are often not sufficient for exercise programming - since diagnostic and fitness type testing may be carried out on different modalities, with monitoring of different parameters, using different test patterns to different endpoints, and with the patient on medication rather than off. This article describes special test modifications which provide information useful in preparing exercise guidelines for individual patients. These include walk-through, second-effort testing, testing on medication and non-standard monitoring. Based upon results from the fitness type of test, it is possible to predict which exercise candidates will benefit most from exercise programming and which should be referred elsewhere for more intensive medical management or consideration of surgery.

The nitroglycerin exercise test.

The nitroglycerin (NTG) exercise test can help in detecting ischemia in the presence of right bundle branch block (RBBB), left bundle branch block (LBBB), or digitalis-induced exercise ST changes and in excluding ischemia when a falsely positive test is suspected. This treadmill test has 3-min stages at 10% grade starting at 1.5 mph and progressing in 0.5 mph increments until ST depression is observed. NTG is then given as exercise continues at the ischemia-provoking work load for up to 10 min. Among 3 patients with RBBB, 5 with LBBB, 1 on digitalis and 2 with presumed falsely positive tests, those whose ST depression lessened after NTG had ischemic thallium exercise scans; those with no change in ST depression after NTG had normal thallium images. Additional studies are needed to verify the consistency of these findings among a larger group of patients.

Intravenous dipyridamole thallium imaging V combined arm-leg cycle stress testing of patients unable to exercise on the treadmill.

UNLABELLED: Rehabilitation patients who will undergo noncardiac surgery or strenuous rehabilitation programs often cannot exercise to greater than 85% of predicted maximal heart rate as required for valid treadmill testing. Because many patients have known or suspected coronary artery disease, greatly increasing their risk for a cardiac event, dipyridamole thallium scans are usually performed, despite a cost of approximately $1400, patient radiation exposure, and the need for a gamma camera. Instead, arm-leg cycle stress testing can be continued to an appropriately high heart rate, is done in the physician's office with an electrocardiograph machine and a blood pressure cuff, and costs $250. This study describes nine patients who had both dipyridamole thallium scans and arm-leg cycle ergometry. Four awaited peripheral vascular surgery, one needed bilateral knee replacements, one was an amputee, and three had claudication. Six had documented and three had suspected coronary disease. RESULTS: In eight of nine patients, the electrocardiograms during both dipyridamole thallium imaging and ergometry were in agreement as to the presence or absence of ischemia (kappa statistic, 0.7273; P = 0.0117). In seven of nine patients, thallium images and ergometry agreed (78% concurrence). To achieve 90% agreement between dipyridamole thallium scans and cycle results, however, 68 patients would have to be studied. CONCLUSION: In this preliminary study, arm-leg ergometry was feasible in all patients and seemed cost-effective and useful for detecting myocardial ischemia. Clinically, if the ergometry were inconclusive, dipyridamole thallium scans could be performed subsequently to obtain the needed information.

Reduction of physiological, behavioral, and self-report responses in type A behavior: a preliminary report.

Recent reports indicate that Type A Behavior may be reducible by behavioral and other psychotherapeutic methods. To date, however, there has been virtually no demonstration of reduction of the actual, observed behavior. Furthermore, the physiologic hyperresponsiveness that seems to characterize many Type A individuals when under stress, has received relatively little therapeutic attention. This preliminary, uncontrolled report describes a cognitive-behavioral group intervention program, before and after which patients underwent assessment on physiologic, behavioral, and self-report assessments. These included heart rate and blood pressure responsiveness under stressful conditions, trained observer ratings of Type A Behavior, and a variety of subjective measures of Type A Behavior and psychological distress and symptoms. Results showed limited improvement on most behavioral and self-report indices. Relatively greater reduction of Type A Behavior was associated with higher pre-treatment levels of Type A Behavior, with the absence of coronary artery disease and with male gender.

A simple walk test to guide exercise programming of the elderly.

Exercise training programs are usually based on a maximal exercise stress test; however, this test is often difficult and sometimes frightening to older persons. This preliminary study reports on a fixed-distance, submaximal walk test and compares its usefulness for exercise prescription to that of the traditional maximal stress test. Ten cardiac patients, with an average age of 72 years (4 men), had recently clinically indicated maximal graded stress tests. Within one week, each had the walk test, which consisted of walking three times up and back 100 feet in the hospital corridor (total of 600 feet) as rapidly as possible, with a blood pressure cuff on their arm and carrying the electrocardiogram cable. Resting and peak heart rate, blood pressure, symptoms, and exercise electrocardiograms were compared for the walk test v the maximal stress test. Oxygen consumption was calculated from the peak workload on the maximal stress test and from walking speed on the walk test. The peak heart rates after the walk test were within the target heart rate zone (70-85%) for exercise programming, as obtained from the maximal stress test, in all patients except one. The calculated peak oxygen consumption from the walk test was also within the training zone (60-80%) obtained from the maximal stress test in all patients except one. This pilot study shows that a submaximal, steady state timed walk of 600 feet can be a feasible method of providing the information for exercise programming, possibly avoiding the need for a maximal stress test. This walk test can be performed easily by health-related staff without sophisticated facilities in an inpatient rehabilitation unit or nursing home; however, further study with a larger number of patients is necessary before this method of exercise prescription can be recommended.

Exercise stress testing and risk factor assessment among offspring of cardiac patients.

As we learn more about the origins of coronary artery disease, research has begun to focus on its prevention. The purpose of this study was to determine if exercise stress testing of the offspring of our cardiac rehabilitation patients would be a useful adjunct to their general cardiac risk factor assessment. In addition, we sought to quantitate the number of cardiac risk factors they might have already accumulated. We determined the lifestyle and lipid profiles of 22 young, healthy subjects. Subjects underwent maximal multistage exercise stress tests. Eighty-six percent of subjects had two or more major risk factors for CAD, and 73% had contributory risk factors. Seventy-three percent of subjects also demonstrated hypercholesterolemia. Exercise testing did not induce ischemic changes on electrocardiography of any subject. Our research revealed that these offspring demonstrate an alarming number of coronary artery disease risk factors, even though exercise stress tests were negative.

A controlled trial of cardiac rehabilitation in the home setting using electrocardiographic and voice transtelephonic monitoring.

OBJECTIVE: The goal of this study was to compare the effectiveness of home-based, transtelephonically monitored cardiac rehabilitation with standard, on-site, supervised cardiac rehabilitation. BACKGROUND: Participation in cardiac rehabilitation has been demonstrated to increase exercise capacity, decrease cardiovascular symptoms, improve psychosocial status, and decrease total and cardiovascular mortality rates in patients with coronary heart disease. Because of multiple factors, national overall participation is only at 15% of eligible patients. METHODS: Effects of a 3-month home-based, transtelephonically monitored rehabilitation program (n = 83 patients) with simultaneous voice and electrocardiographic transmission to a centrally located nurse coordinator were compared with effects of a standard on-site rehabilitation program (n = 50 patients). The study design was a multicenter, controlled trial. Primary outcome variables were peak aerobic capacity and quality of life, as measured by the Health Status Questionnaire. RESULTS: Patients in the home-based monitoring program increased peak aerobic capacity to a similar degree as patients who exercised on site (18% vs 23%). Quality of life domains of physical functioning, social functioning, physical role limitations, emotional role limitations, bodily pain, and energy/fatigue improved similarly in both groups. There were no circulatory arrests or other major exercise-related medical events in either group. A total of 3100 hours of home exercise were transtelephonically monitored. CONCLUSIONS: Patients with coronary heart disease can effectively participate in home-based, monitored cardiac rehabilitation, with exercise and quality of life improvements comparable to those demonstrated at on-site programs.