Ischemic cerebrovascular disease in children is relatively rare. To clarify the clinical features of ischemic stroke occurring in infants and children, we evaluated 54 cases of cerebral infarction, excluding cases of moyamoya disease, in patients < 16 years old at 24 clinics in the Tohoku (northeast) district of Japan. We observed two incidence peaks, one in little children and the other in junior high school students. Infection and minor head trauma were more frequently seen prior to ischemic strokes than was heart disease. The middle cerebral artery region, including the basal ganglia, was most commonly affected (49 patients, 91%) on computed tomograms. Angiography was performed in 48 patients (89%) and showed various types of occlusive lesions, mostly affecting the middle cerebral artery. Hemiparesls was the most common form of disability following ischemic strokes (48 patients, 89%). Surgical treatment was carried out in seven patients (13%). The clinical course of these cases showed that the recovery of children after a stroke tends to be better than that of adults, but that permanent disabilities, such as hemiparesis or mental retardation, occur commonly. Further investigation of juvenile cerebrovascular disease is important to prevent ischemic strokes in children. (Stroke 1991;22:586-589)

No abstract

No abstract

Ryanodine sensitive sarcoplasmic reticular function is probably involved in the mechanism for developing the myogenic response in rat skeletal muscle small arteries.

We examined the "vascular waterfall" hypothesis, which proposes that coronary flow is unaffected by elevations in outflow pressure until the latter reaches a critical threshold level, in 29 isolated canine hearts. In fibrillating hearts vasodilated with adenosine or carbocromen, coronary flow and the coronary pressure-flow relation were not affected by changes in great cardiac vein pressure (PGCV) below a threshold value of 11 +/- 0.9 (mean +/- SEM) mm Hg. Further elevations of PGCV reduced flow and shifted the pressure-flow relation to the right, increasing its pressure-axis intercept (Pf=0). When vasomotor tone was augmented with vasopressin, threshold PGCV increased to 25 +/- 2.7 mm Hg (p less than 0.001). Once again, the pressure-flow relation was unaffected by changes in PGCV below the threshold value and shifted to the right when this value was exceeded. The amount by which spontaneous values of Pf=0 exceeded threshold values of PGCV was greater when vasomotor tone was augmented than during vasodilation. Pf=0 continued to exceed PGCV when the latter was raised above the threshold level. Both Pf=0 and threshold values of PGCV were less during a long diastole than during ventricular fibrillation. We reached the following conclusions. 1) During changes in PGCV below a threshold value, the coronary circulation exhibits traditional waterfall behavior. 2) The threshold pressure for altering waterfall behavior is affected by vascular tone and mechanical activity. 3) Pf=0 remains above PGCV when the latter is increased above the threshold value needed to alter flow.

We studied the effects of the pericardium on diastolic left coronary pressure-flow relationships in heart-blocked and isolated canine preparations. In these preparations, the left and right coronary arteries were dilated with adenosine and perfused by means of a pressurized arterial reservoir. The diastolic left heart pressure (LHP) We hypothesized that the pericardium was one of several important factors affecting the diastolic coronary pressure-flow relationship for the following rea-

No abstract

inus arrest and sinoatrial block (sinus node disease: SND) decrease cardiac output and elicit AdamStokes syndrome. To improve the activities of daily life of patients with SND, pacemaker therapy is used, but because the incidence of SND increases with age, the number of the patients and cost of pacemaker therapy are increasing in developed countries.SND occurs because of either a decrease in the pacemaker potential to a level below the threshold of overshoot of the action potential or exit block of the pacemaker activity to the surrounding atrial muscle. Recently, an electroanatomical mapping technique demonstrated that structural and electrical abnormalities of the atrium characterized SND. 1 However, the properties of repolarization, based on structural differences of the right atrium (RA), have not been clarified in SND patients.The monophasic action potential (MAP) of the human heart enables us to estimate the repolarization of the human ventricle 2 and atrium 3 in the clinical setting. In this study, we developed a new technique of recording the MAP at the crista terminalis (CT) in the superior vena cava -RA junction. Using this method, we estimated the properties of the Circulation Journal Vol. 69, November 2005 MAP at the CT in the SND patients and compared it with the conventional indices of sinus node function. Also, we demonstrated the effect of adenosine triphosphate, known to enhance sinus arrest or sinoatrial block, 4 on the MAP at the CT in the SND patients. Methods Patient PopulationThirteen consecutive SND patients and 13 age-and sexmatched control patients were enrolled. All subjects underwent diagnostic electrophysiological studies (EPS) while in a postabsorptive nonsedated state. SND patients were defined as those having a ventricular pause lasting for more than 3 s because of either sinus arrest or sinoatrial block with symptoms related to a pause (Rubinstein type II or III). Control patients were defined as having none of those findings. Patients with (1) sinus bradycardia less than 50 beats/min in mean heart rate (Rubinstein type I), (2) atrial fibrillation, atrial flutter or atrial tachycardia during the monitoring described later, (3) a past history of heart failure and (4) ongoing cardiac ischemia were excluded because we wanted to focus on the characteristic of the MAP related to the particular type of ventricular pause. All patients underwent electrocardiography and ambulatory 24 h-Holter electrocardiogram (ECG) at least twice in the outpatient clinic. In addition, ambulatory monitoring by ECG for 24-48 h after admission and before the EPS was performed. All antiarrhythmic or cardioactive medications were ceased for at least 5 times the biological half-life of the drugs.Written informed consent from the patients and approval Monophasic Action Potential Duration at the Crista Terminalis in Patients With Sinus Node DiseaseHiroshi Katoh; Tsuyoshi Shinozaki, MD*; Shigeo Baba, MD*; Shoichi Satoh, MD**; Yutaka Kagaya, MD*; Jun Watanabe, MD*; Kunio Shirato, MD* Background The repolarizati...