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Biomedical subjects

L R Zohman

Publications and source records attributed to L R Zohman.

At least 19 recordsLinked to original sources

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.

Aged

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.

Adaptation, Physiological

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.

Adult

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.

Adult

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.

Aged

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.

Angina Pectoris

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.

Coronary Disease