Combined pharmacologic and exercise stress myocardial scintigraphy: a practical method for assessment of potential cardiac ischemia in patients with limited exercise capacity.

A protocol for dipyridamole exercise stress testing with myocardial thallium scintigraphy has been used successfully for the evaluation of exercise or walking-impaired patients.

Detection of an abnormal plasma clot structure by a simple rigidity assay.

We report here on a patient whose abnormal fibrin clot was detected via the measurement of clot rigidity with a simple buoyant inner cylinder elastometer. The patient's clinical coagulation studies were all within normal limits except for prolonged thrombin and reptilase clotting times and high level of fibrin split products. The measured rigidity of the patient's clot was approximately ten times lower than that of a clot formed from normal pooled plasma. Light scattering studies indicated that this modified structure was not caused by a gross change in gel fiber morphology. Antithrombin activity was eliminated as a possible cause of the altered clot structure; this suggests the possibility of a modified fibrinogen. Abnormalities in the reptilase time and fibrinogen levels in two siblings support the hypothesis that the modification is an inherited defect. We suggest that the simple measurement of rigidity can be used rountinely to detect abnormalities in plasma clot structure. The screening for such disorders should be of importance to clinician, patient, and biochemical researcher.

Dose response effectiveness of propranolol for the treatment of angina pectoris.

Seventeen patients received placebo medication during a 12-week run-in period, followed by four double-blind study periods of six weeks each, during which time placebo, 80 mg, 160 mg and 320 mg propranolol dosages were administered. Examination of the frequency of angina episodes and nonprophylactic nitroglycerin consumption revealed significant beneficial clinical responses for both the 160 and 320 mg dosages. Exercise testing also demonstrated increased exercise tolerance (320 mg dose) with a shift of the exercise end point from pain to fatigue in seven of 17 patients. The interrelationships between propranolol daily dosage, clinical response assessed by percent reduction in anginal episodes, beta-adrenergic blockade measured by percent reduction in exercise heart rate and serum levels were examined. In general, serum levels of 30 ng/ml, when drawn 90 to 180 minutes following the last oral dose, were required to achieve a 25% or greater reduction in angina frequency. Serum levels above 30 ng/ml were similarly correlated with a 20% or greater reduction in exercise heart rate at equivalent levels of exercise. Detailed examination of different patterns of clinical response with respect to beta-blockade, serum levels and oral doses are presented.