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Biomedical subjects

T Ohe

Publications and source records attributed to T Ohe.

At least 199 records · Page 11Linked to original sources
PubMed1986

Age-related changes of clinical features and prevalences of coronary risk factors in Japanese patients with vasospastic angina.

From among 899 consecutive patients who underwent their first coronary arteriography, we selected 147 pts with vasospastic angina (VA) and 356 pts with classic angina (CA) and divided them into three different age groups: -49 years old, 50 to 59, and 60-. In these 899 pts, incidences of VA showed no increase with aging. Prevalence of coronary risk factors in CA, such as diabetes, hypercholesterolemia, hypertension, and obesity, was higher than in VA, although prevalence of smoking in CA was lower than in VA. In VA, we found an age-related increase in the incidence of smoking only, in contrast to the other four risk factors. The VA showed no age-related increase in the incidence of complication of fixed coronary stenosis. These findings suggest that aging and atherosclerosis might not play a major role in pathogenesis of VA, although the mere presence of atherosclerosis irrespective of its severity could interact with local susceptibility to spasm, leading to coronary vasospasm.

Adult↗
PubMed1985

Poor responsiveness of heart rate to treadmill exercise in vasospastic angina.

Heart rate response to submaximal graded treadmill exercise was measured in 45 patients with vasospastic angina, 31 with effort angina, and 40 normal controls. There was no difference of resting heart rate among the three groups. Vasospastic angina showed significantly poor responsiveness of heart rate to exercise at every stage: stage 1, 2.5 km/h (10%), stage 3, 4.5 km/h (10%), stage 5, 5.5 km/h (14%), stage 7, 5.5 km/h (22%), when compared with those in normal controls. The effort angina group also showed lower heart rates at stages 3 and 5 than those in control subjects, although their heart rate at stage 1 was not different from that in normals. When abnormal response suggesting vasospastic angina was defined as heart rate at each stage lower than values of mean heart rate +/- 1 SD in normal controls, positive test results were obtained in 15 of 45 patients (33%). The use of heart rate criteria in addition to ischemic criteria raises sensitivity from 27 to 51% (p less than 0.02).

Adult↗
PubMed1985

Abnormal heart rate control in vasospastic angina: effects of calcium antagonists.

We examined the effects of administration of calcium antagonists on the heart rate response to treadmill exercise in 11 patients with vasospastic angina and 8 healthy young volunteers. The exercise test was performed by walking on a treadmill at a constant speed and grade according to a scheme of pseudo-randomized sequence for 19 min. The dynamic property of heart rate response to exercise was evaluated by using a frequency analytic procedure. The exercise test was also studied in 21 age-matched normal controls without drug administration. Administration of calcium antagonists revealed no significant effects on heart rate and blood pressure at rest in young healthy subjects or in patients with vasospastic angina. Young volunteers showed the same normal properties of heart rate response to exercise before and after calcium antagonists. Vasospastic angina showed abnormal heart rate response to exercise and revealed characteristically different transfer function from that in normal controls. These characteristics were not affected by treatment with calcium antagonists except for a slight, uniform decrease of gain of the system over the whole frequency range. Accordingly, the present exercise test can feasibly be used in the diagnosis and management of vasospastic angina even when calcium antagonists are administered to the patients.

Administration, Oral↗
PubMed1985

Cycle length change during reciprocating tachycardia in patients with Wolff-Parkinson-White syndrome.

UNLABELLED: Cycle Length (CL) changes during reciprocating tachycardia (RT) were examined in 82 consecutive patients with Wolff-Parkinson-White syndrome (WPW) during electrophysiological studies. The significant CL changes (sudden and greater than 30 msec.) were found in 21 of 82 patients (26%). Thirteen patients had a manifest WPW and eight had a concealed WPW. An accessory pathway (AP) was located in the left side in 14 patients, the right side in four patients and the septum in two patients. One patient had multiple AP's. The development of ipsilateral bundle branch block during RT was responsible for CL changes in 11 patients. The sudden shift between fast and slow pathways in atrioventricular node (AVN) during RT was responsible for CL changes in two patients. Alternating CL changes during RT were found in eight patients. In five of them, alternating CL changes could be explained by physiological properties of a single AVN pathway. In the remaining three patients, the onset of 2:1 block in a fast pathway with 1:1 conduction in a slow pathway of the AVN may be responsible for CL changes. In one patient with multiple AP's the shift from one re-entrant circuit to the other was responsible for CL changes. IN CONCLUSION: 1) CL changes during RT are not uncommon in patients with WPW. 2) Several different mechanisms are responsible for CL changes.

Adolescent↗
PubMed1985

Diagnosis of vasospastic angina by analysis of heart rate response to exercise: effects of different levels of work load.

To examine alterations in control functions of the heart, which may account for the pathophysiologic conditions precipitating coronary arterial spasm, heart rate response to exercise in vasospastic angina was evaluated by using our previously developed method of frequency analysis. We also examined the effects of three different levels of work load on the heart rate response to treadmill exercise in 9 patients with vasospastic angina and 7 normal controls: stage 1 (2.5 Km/h, 10%), stage 3 (4.5 Km/h, 10%), and stage 5 (5.5 Km/h, 14%). The transfer function of heart rate control in vasospastic angina was characteristically different from that in normal controls: lower gain and more delayed phase angle of the system. Although this abnormality was observed in every test at 3 different levels of work load, the abnormality was more striking in tests at lower levels of work load: stage 1 or 3. The moderately light exercise test at stage 3 is most suitable as a test for detecting abnormal heart rate response to exercise in vasospastic angina because the exercise test at stage 1 had a poor S/N ratio.

Adult↗
PubMed1985

Problems and anti-tachyarrhythmic effects of chronic atrial pacing.

Sixty-six patients in whom atrial pacemaker (AAI) were implanted were followed for one year to 5 years for the occurrence of pacing failure, sensing problems, and later AV block. Pacing failure occurred in only one patient and sensing problems occurred in 15 patients but 10 of them improved after a change of sensing. Temporal change of AV conductivity was not recognized in the majority of patients. Eighteen patients developed transient decrease in AV conductivity. Two patients developed persistent decrease in AV conductivity and ended in clinical AV block for which the pacemaker was implanted. Out of 66 patients, 22 had a history of paroxysmal atrial flutter or fibrillation (AFF) prior to AAI implantation. They were divided into two groups. Group I consisted of 20 patients in whom paroxysmal AFF disappeared after AAI implantation. Group II consisted of 22 patients in whom paroxysmal AFF persisted after AAI implantation. Electrophysiological studies prior to the AAI implantation showed that sinus rate at control was significantly slower (36.3 +/- 10.1 beats per min in Group I, 57.1 +/- 10.8 beats per min in Group II), atrial fragmented activity zone was significantly narrower (62.7 +/- 32.9 msec in Group I, 88.1 +/- 19.7 msec in Group II), and the occurrence of PAC was less at an atrial pacing rate of 70 beats per min (8% in Group I, 67% in Group II) in Group I compared to Group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Abnormal heart rate response to exercise in vasospastic angina: pathophysiologic mechanism in the provocation of coronary spasm.

To examine the alteration in control function of the heart, which may account for the pathophysiologic condition precipitating coronary arterial spasm, the dynamic property of heart rate response to exercise in vasospastic angina was evaluated by using our previously developed frequency analytic procedure. We studied 21 patients with vasospastic angina, divided into two groups (active angina and inactive angina) and 12 normal control subjects. When compared with the transfer function of the heart rate control system in normal control subjects, the transfer function in patients with active vasospastic angina showed moderately lower gain, especially in the middle frequency range, and significantly delayed phase angle over the whole frequency range, especially in the middle and high frequency ranges. These abnormalities were not observed in inactive vasospastic angina. The present exercise test to detect abnormal heart rate control can feasibly be used in the detection and management of vasospastic angina.

Adult↗
PubMed1984

Mutagenicity of photochemical reaction products of polycyclic aromatic hydrocarbons with nitrite.

Six kinds of polycyclic aromatic hydrocarbons (PAHs) were subjected to ultraviolet light irradiation with nitrite for 1, 4, 8 and 24 h, and the irradiated samples were tested for mutagenicity towards Salmonella typhimurium TA 98, TA 100 and TA 1538. Irradiated samples of pyrene, fluoranthene and benzo[a]pyrene showed marked mutagen responses towards TA 98 and TA 1538, especially in the absence of S9 mix. The direct-acting mutagenic activity of these samples, showing high activities at 1-8 h, decreased greatly with the development of irradiation. Further, these direct-acting mutagens were mostly present in the neutral fraction. On the other hand, the mutagenicity of the irradiated sample of 5,6-benzoquinoline was high both with and without S9 mix, and was mostly present in the basic fraction because of its authentic characteristic. There was no correlation between the yield of 1-nitropyrene and the mutagenic activity of the photochemical reaction product of pyrene with nitrite. Further studies by TLC separation suggested that a considerable number of direct-acting mutagens formed in this experiment were more polar than nitrated PAH such as 1-nitropyrene.

Anthracenes↗
PubMed1983

Relation between the widening of the fragmented atrial activity zone and atrial fibrillation.

Fragmented electrical activity is often recorded by a local atrial electrogram in response to atrial extrastimuli. To assess the relation between fragmented activity and the spontaneous occurrence of atrial fibrillation or flutter (AFF), the fragmented activity zone was measured in 57 patients. The electrograms of the high right atrium, low right atrium and left atrium (through the coronary sinus) were recorded simultaneously during high right atrial stimulation. The fragmented activity zone was defined as the S1-S2 interval (S1 = stimulus of a basic beat, S2 = stimulus of a premature beat) during which a significant fragmented activity was recorded by a high right atrial electrogram after S2. Fifteen patients had neither sinoatrial disease nor atrial arrhythmias (Group I, controls), 16 had sick sinus syndrome (SSS) with a history of paroxysmal AFF (Group II), 14 had SSS without a history of paroxysmal AFF (Group III), and 12 had idiopathic paroxysmal AFF (Group IV). The fragmented activity zone was significantly wider in Group II (112 +/- 26 ms [mean +/- standard deviation], p less than 0.001), Group III (77 +/- 38 ms, p less than 0.001) and Group IV (86 +/- 19 ms, p less than 0.001) than in Group I (31 +/- 25 ms). Patients in Group II had a wider fragmented activity zone than those in Group III (p less than 0.01). Thus, the widening of the fragmented atrial activity zone is characteristic of AFF and may be a good index of a tendency to develop spontaneous AFF.

Adolescent↗
PubMed1983

Limiting factor for the initiation of reentrant tachycardia in concealed Wolff-Parkinson-White syndrome.

We studied the limiting factor for the initiation of reentrant tachycardia in 14 patients with concealed Wolff-Parkinson-White syndrome by comparing atrial refractoriness and echo times. When relatively late atrial premature beats (A2) were not accompanied by an atrial echo (Ae), the echo times were estimated from the antegrade A2-V2 conduction time of A2, since the retrograde conduction time via the accessory pathway remained constant regardless of the degree of prematurity. Thus, A2-Ae curves including the minimal echo time and the longest A2-Ae without Ae could be drawn in all patients. Then the curve was compared with the atrial effective refractory periods and the functional refractory periods of A2 in each patient. Atrial refractoriness which might limit the occurrence of an Ae is not that of basic beats (A1) but that of premature beats (A2). In all patients the atrial effective refractory periods of A2 were much shorter than the minimal echo time and the longest A2-Ae without Ae, suggesting that the atrial effective refractory period is not responsible for limiting the initiation of an Ae. Also in 13 of 14 patients, the atrial functional refractory periods were shorter than the minimal echo time and the longest A2-Ae without Ae. In one patient, the atrial functional refractory period was sandwiched between the minimal echo time and the longest A2-Ae without Ae suggesting the atrial functional refractory period of Ae might be responsible for limiting the occurrence of an Ae in this patient.

Adult↗