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Biomedical subjects

C Kamata

Publications and source records attributed to C Kamata.

8 recordsLinked to original sources
PubMed1979

Electrophysiologic study and prognosis of chronic bifascicular block.

Thirty patients (22 males and 8 females, aged 64 to 89 years) with chronic bifascicular block were studied electrophysiologically and prognosis was assessed. Three had RBBB with LPH, 17 had RBBB with LAH, and 10 had LBBB. AH interval was prolonged in 12 (43%) of 28 patients and HV interval was prolonged in 11 (37%) of 30 patients. Of 16 patients with first or second degree AV block, 11 (69%) had prolonged AH interval and 8 (50%) had prolonged HV interval. Effective refractory period of the right atrium was prolonged in 8 (50%) of 16 patients and that of atrioventricular node was prolonged in 9 (64%) of 14 patients. Second degree AV block was observed at lower rates of atrial pacing (130 beats/min or less) in 14 (74%) of 19 patients. Sinus node dysfunction was present in 16 (62%) of 26 patients. During the follow-up period (37.1 +/- 6.1 months), advanced or complete AV block developed in 2 of 27 patients (2.4% per year) and a patient died of acute myocardial infarction (1.1% per year). The present study showed that prolongation of AH interval was observed more frequently than that of HV interval, and the presence of widespread lesions in the conduction system was suggested in chronic bifascicular block, and in spite of these facts prognosis was not so unfavorable as reported previously.

Aged↗
PubMed1978

A study on the effects of nifedipine in hypertensive crises and severe hypertension.

Ten mg of Nifedipine, a Ca++ antagonist, was administered orally in 2 groups of patients; Group 1: 6 patients in hypertensive emergency and Group II: 12 patients with intractable, severe hypertension. Following results were obtained. 1) A marked hypotensive effect was observed in all patients of Group I. The maximum effect was observed within 30 to 60 min and lasted for approximately 180 min. Clinical symptoms also improved remarkably with the fall in blood pressure. Any side effect was not observed. 2) A marked hypotensive effect was observed in all cases of Group II. The blood pressure fell by 21.4% systolic (p less than 0.01) and 19.4% diastolic (p less than 0.02). The peripheral vascular resistance also showed the decrease by 26.2% (p less than 0.01). The heart rate and cardiac index increased slightly. It was suggested that the hypotensive mechanism of this preparation is due primarily to the peripheral vasodilation.

Adult↗
PubMed1978

Sinoatrial response to premature atrial stimulation during atrial pacing in aged patients with and without sinus node dysfunction.

Sinus node function was analysed in 15 aged patients, including 8 with sick sinus syndrome and 7 without apparent sinus node dysfunction, by rapid artial pacing and premature atrial stimulation during sinus rhythm and 5 beats of atrial pacing. Three patterns of sinoatrial response were identified by premature atrial stimulation during atrial pacing. Type I response (3 cases) represented approximately constant return cycles and type II (2 cases) represented a markedly prolonged return cycles following premature stimulation. Type III response was characterized by a progressive shortening of return cycles as the prematurity of atrial extrastimuli was increased. Underlying mechanisms responsible for these responses were discussed in relation to the sinus node automaticity and sinoatrial conduction.

Aged↗
PubMed1977

A study on sinoatrial conduction in the aged.

Sinus node response to premature atrial stimulation (PAS) was studied in 30 aged patients (group I:21 cases without sinus node dysfunction, group II:9 cases with sick sinus syndrome). Sinoatrial conduction time (SACT) was calculated according to the method reported by Strauss et al. As coupling interval of PAS decreased, there noted 5 patterns of sinus node response. In Type A, return cycle length (RC) initially increased (fully compensatory pause) and then became constant; RC progressively increased either along the compensatory reference line (Type B1) or along the less-than-compensatory line (Type B2) without being constant. In 2 other cases, RC showed similar pattern as in Type A up to 32-37% of sinus cycle length where they showed abrupt prolongation below or above the compensatory reference line (Types C and D, respectively). The incidence of abnormal response (Types B1, B2, C, and D) was high both in group I (38.0%) and group II (33.3%). The calculated SACT in group I showed a high correlation with basic sinus cycle length, while no correlation was observed in group II. The possible factors influencing return cycle length and significance of frequent observation of abnormal sinus nodal responses in the aged subjects were discussed.

Aged↗
PubMed1977

A clinicopathological study on the papillary muscle dysfunction.

A total of 11 cases of papillary muscle dysfunction (PMD) was found among 600 consecutive autopsy (1.8%). There were 5 men and 6 women, with their ages ranging from 64 to 92 years. Auscultation and phonocardiograms revealed holosystolic murmurs in 9 cases and early systolic murmurs in 2. There were accentuated 1st sound in 8 cases, 3rd sound in 7, and 4th sound in 5. PMD was classified into 3 types according to the clinical course and pathologic examinations. In type A (6 cases), myocardial infarction (MI) preceded the occurence of mitral regurgitation (MR) by 3 or 4 years, with pathological verification of old MI. In type B (1 case), MR developed during acute MI. In type C (4 cases), pathological examinations disclosed various degrees of myocardial fibrosis, in which clinical diagnosis was MR of unknown etiology. In a total of 113 cases of MI, 36 cases (32%) showed papillary muscle infarction (PMI), which occurred with significantly high incidence in (1) male, (2) large MI, and (3) subendocardial or lateral MI. Among 36 cases of PMI, 9 cases developed PMD, which showed high incidence in inferior MI and in female. Various other factors concerning PMD and PMI were examined, and it was pointed out that not only PMI but also severe lesions in corresponding ventricular wall were necessary for the development of PMD.

Aged↗
PubMed1977

Clinical and electrophysiologic studies on the Wolff-Parkinson-White syndrome in aged cases.

Clinical and electrophysiologic studies were performed in 10 aged cases (50-82 years of age) with WPW syndrome and following results were obtained: 1) Episodes of paroxysm of supraventricular tachyarrhythmias were observed in 7 and complication of sinus node dysfunction was noted in 3. 2) P-delta intervals on electrocardiogram exceeding 0.12 sec were observed in 4 cases. 3) Patterns of normalization of QRS complex in 4 cases were characterized by tachycardia-dependent in 2 and bradycardia-dependent in 2. 4) Effective refractory period of the accessory pathway (AP) in antegrade direction exceeded that of A-V node in 5 cases and the former exceeding 500 msec was observed in 2 cases. The relations between the changes of the electrophysiologic properties of the AP and altered clinical manifestations of the WPW syndrome in aged cases were discussed.

Age Factors↗
PubMed1976

Sinus node recovery time and abnormal postpacing phase in the aged patients with sick sinus syndrome.

The sinus node function was evaluated by rapid atrial pacing in 35 aged patients (mean age 78.2 years) including 10 aged controls, 12 cases with various degrees of AV block, 6 with bradycardia-tachycardia syndrome (BTS), and 7 with sinus bradyarrhythmia (SB). AV block was further divided into A-H block (7 cases) and H-V block (5 cases) by His bundle electrogram which was simultaneously recorded with 3 leads of surface electrocardiogram. Sinus node recovery time (SRT) was measured and its maximum value (SRTmax) was selected from SRTs obtained after pacing with various rates and durations in each patient. SRTmax was also expressed as percentage of the control P-P interval (%SRTmax). For patients in whom the study was repeated 3 to 8 months later, %SRTmax was reproducible in 9 of 14 instances. Prolongation of SRT was not always observed as the rate and/or duration of pacing was increased. SRTmax and %SRTmax were 1,363 +/- 188 msec and 147 +/- 19% (mean +/- SD), respectively, for aged controls, 1,597 +/- 442 msec and 156 +/- 31% for patients with AV block, 2,087 +/- 1,315 msec and 203 +/- 132% for those with BTS, and 3,069 +/- 1,287 msec and 247 +/- 115% for those with SB. SRTmax exceeding the range for aged controls was noted in 4 of 7 cases (57%) with A-H block, 2 of 6 (33%) with BTS, and 5 of 7 (71%) with SB; normal SRT was not infrequently observed in patients with sick sinus syndrome, especially in those with BTS. Analysis of 10 consecutive atrial cycles following cessation of pacing revealed that in 8 cases the first P-P interval (SRT) was followed by longer ones in some occasions (secondary suppression). It was observed almost exclusively in patients with sick sinus syndrome. The possibility of this phenomenon to reflect another feature of sinus node abnormality was discussed.

Aged↗