Abstract
Clinical and hemodynamic characteristics of 7 patients with hyperdynamic β -adrenergic circulatory state were studied and the following results were obtained.
The subjects studied consisted of 7 patients with tachycardia and labile hyper-tension, 3 males and 4 females, ranging from 18 to 65 years old. The chief complaint was palpitation associated with tachycardia due to mental stress or following postural change. The results of laboratory examinations, including thyroid, liver and renal function and values for catecholamines in plasma and urine,. were normal, except high BMR in some cases.
In the hemodynamic studies, an increase of heart rate, cardiac index (measured by external counting method with RISA) and forearm muscle blood flow (measured by capacitance plethysmography) was observed in these patients. Following an intravenous infusion of isoproterenol (0.02 g/kg/min), the heart rate, cardiac index and forearm muscle blood flow were more remarkably increased than those observed in the control subjects. Following an intravenous injection of propranolol (10 mg), a decrease of the heart rate, cardiac index and forearm muscle blood flow was significantly larger in these patients. When the patients were tilted at an angle of 60°, the heart rate increased remarkably in most of the patients, the stroke volume index and cardiac index increased in 2 of the 5 cases, while these were reduced moderately in the control subjects. These abnormal responses to postural change were normalized by pretreatment with propranolol. Furthermore, the complaints and hemodynamic changes disappeared after the propranolol treatment (30-60 mg/day, orally).
In addition to the 7 patients described above, we observed 10 atypical or borderline patients. They were divided into two groups. The first group consists of7 patients in whom hemodynamic responses to isoproterenol were exaggerated while those to propranolol were normal. The second one consists of 3 patients in whom responses to propranolol were augumented while those to isoproterenol were in a normal range.
The cause of this state remains still unknown, and we discussed it by analyzing the patients' past history.
