To analyze the prognosis of the sick sinus syndrome (SSS), we compared the clinical aspects among unpaced, ventricular paced, and physiologically paced patients who were followed over a long period. Unpaced intrinsic SSS was not always progressive and patients did not necessarily require permanent pacing. The incidence of concomitant AV conduction disturbance was 65.6% before pharmacologic autonomic block, (PAB), but this was significantly reduced to 31.7% after PAB. Follow-up study of the physiologically paced groups revealed no development of either new or more than second degree AVB. The VVI group had significantly more complications (68%) than the physiologically paced groups, mainly chronic atrial fibrillation (36%) and thromboembolism (20%). In addition, cardiothoracic ratio (CTR) in the VVI group was significantly greater compared with that in the physiologic groups. Nine deaths occurred during the follow-up period in the pacing groups, including six with VVI and three with physiologic pacing. In the VVI pacing group, heart failure and thromboembolism were most commonly the causes of death, while in the physiologic pacing groups, the causes of death were noncardiac. Although the survival rate in the ventricular paced group was not significantly different from that in the physiologic pacing groups, cardiac deaths were fewer in the latter group. Considering our clinical data, the decision to use ventricular pacing needs to be carefully weighed in patients with sick sinus syndrome, and physiologic pacing is more highly recommended.

No abstract

Abstract-The effects of DN-9693, a synthesized phosphodiesterase inhibitor, on the secretion of pancreatic juice were investigated in preparations of the isolated and blood-perfused dog pancreas. DN-9693 injected intraarterially caused a dose-dependent increase in the secretion of pancreatic juice and decrease in the perfusion pressure.The threshold doses to increase the pancreatic secretion and to decrease the perfusion pressure were about 100 ,ug and 1 ,cg, respectively. Thus, the secretory response was less effective than the vascular response.The secretory activity of was approximately equal to that of 0.03 mg of 3 isobutyl-1 -methylxanthine, 0.5 mg of papaverine, 5 mg of theophylline, 0.08 units of secretin and 0.2 units of cholecystokinin.The concentration of bicarbonate in the pancreatic juice induced by DN-9693 was increased, but protein concentration was not. DN-9693-induced pancreatic secretion was not modified by pretreat ments with phentolamine, propranolol, atropine, sulpiride and cimetidine. Secretin induced pancreatic secretion was significantly potentiated by infusion of DN-9693 (10 ,eg/min), but cholecystokinin-induced one was not. From these results, it is concluded that DN-9693 may produce an increase in pancreatic secretion by acting directly on the pancreatic exocrine gland of the dog, which might be mediated through an increase of intracellular cyclic AMP concentration by inhibiting phos phodiesterase activity.It was reported that adenosine 3",5 cyclic monophosphate (cyclic AMP) stimulated the pancreatic secretion of water and electrolytes in cats and dogs (1, 2). Additionally, secretin stimulated the pancreatic secretion concomi tant with the increase in the cyclic AMP con tent in the pancreas (3, 4). Phosphodiesterase inhibitors such as theophylline, papaverine and 3-isobutyl-1-methylxanthine (IBMX) were also shown to stimulate the pancreatic secretion (2, 5, 6). Thus, cyclic AMP may be an intracellular mediator in the process of pancreatic secretion. Along this line, it is of interest to investigate the effect of phospho diesterase inhibitors on pancreatic secretion. (1,5-dihydro-7-(1-piperidinyl) imidazo[2,1-b]quinazoline-2(3H)-one dihy drochloride hydrate) is a newly synthesized phosphodiesterase inhibitor and its potency was about 5 times as potent as papaverine in platelets (7). However, there is no available reports on the effect of DN-9693 on pancre atic exocrine secretion. The present experi ments were, therefore, undertaken to inves tigate the effects of DN-9693 on pancreatic secretion in isolated and blood-perfused day pancreas preparations in situ and to compare DN-9693 with secretin and cholecystokinin in the same preparations. Materials and MethodsTwenty-two mongrel dogs of either sex, weighing from 12-16 kg, were fasted 24 hr and anesthetized with sodium pentobarbital (30 mg/kg, i.v.). During the experimental periods, anesthesia was maintained by ad ditional injection of sodium pentobarbital (5 mg/kg, i.m.) at hourly intervals. The dogs

No abstract

No abstract