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Biomedical subjects

S Aihoshi

Publications and source records attributed to S Aihoshi.

9 recordsLinked to original sources

Screening for QT prolongation using a new exponential formula.

We prospectively screened 14,227 school-aged children for evidence of QT prolongation using a exponential formula (eQTc = (QT interval)/(RR interval)0.31) and criteria (ie: abnormal eQTc was defined as being equal to or greater than 0.430 and 0.435 for male and female first-graders, respectively, and 0.440 and 0.445 for male and female seventh-graders, respectively). We previously reported that this new exponential correction of the QT interval may be useful for eliminating the effect of heart rate in school-aged children. Computer analyses detected 13 children with abnormally prolonged eQTc. All of the children who had abnormal QTc values by conventional QTc criteria also had abnormal eQTc values using the new criteria. Nine of these 13 children were ultimately confirmed to have a prolonged QT interval. Six cases of QT prolongation were detected that would not have been found if conventional screening criteria were used, since these cases had heart rates greater than 75 beats/min. One child had parents who were deaf. This case would not have been detected if only conventional screening were used. These results suggest that exponential correction of the QT interval (eQTc) is useful for prospectively screening large populations for evidence of QT prolongation.

Child↗

Correction of the QT interval in children.

We evaluated the usefulness of 11 formulas for correcting the QT interval in children, including the square root, cubic root, logarithmic, linear, exponential, and inverse formulas using the Mean-squared residual (MSR) values and Akaike Information Criterion (AIC) in 8,086 first-graders, 9,989 seventh-graders, and 5,786 tenth-graders. The subjects were divided into six groups according to age and sex. MSR and AIC values were lowest in all of the groups for the exponential formula (eQTc) and Fridericia's formula (fQTc). We then evaluated the relative usefulness of these two formulas by determining the optimal value for parameter k using the following exponential model: eQTc = (QT interval)/(RR interval)k. The best-fit value for k was different for each group. However, the tentative abnormal eQTc and fQTc values, determined by statistical analysis, were equivalent in all groups when 0.31 was used as the exponential parameter k. These results suggest that the exponential formula and Fridericia's formula are equally useful for screening for QT prolongation.

Adolescent↗

Effect of obesity on echocardiographic parameters in children.

We studied the effect of obesity on echocardiographic parameters in Japanese children. The subjects were 341 children: 106 first graders (age 6 years), 166 seventh graders (age 12 years), and 69 tenth graders (age 15 years). They were assigned to six groups according to school grade and sex. Echocardiographic parameters included thickness of the interventricular septum and of the posterior wall, end diastolic left ventricular internal dimension, and left ventricular mass. Left ventricular parameters were normalized for height, and for height to the power of 2.7. The obesity index as well as the body mass index were used to estimate obesity, because the obesity index is frequently used in Japan. There were significant correlations between the indices of obesity and left ventricular internal dimension or left ventricular mass in each group. The obesity index was more strongly correlated than the body mass index with posterior wall thickness and left ventricular internal dimension. For normalization of left ventricular parameters, correction for height was better for the first graders, whereas correction for height to the power of 2.7 was better for seventh and tenth graders. The most important finding was that the effect of obesity on left ventricular parameters was evident at 6 years of age.

Adolescent↗

Exponential correction of QT interval to minimize the effect of the heart rate in children.

The exponential correction of the QT interval (eQTc) was studied using 12,543 resting electrocardiograms obtained in children (first and seventh graders) who were screened for heart disease in Kagoshima City. The values of eQTc to minimize the effect of the RR interval were estimated using following exponential model, eQTc = (QT interval)/(RR interval)--k. The parameter k = 0.31 was found to be the most useful exponent. The distribution of eQTc values showed a hiatus or break at probability points near p < 0.001 or p < 0.0005. Tentative criteria for an abnormally long eQTc were selected using these points and the following convenient data: 0.430 and 0.435 for the male and female first graders, and 0.440 and 0.445 for the male and female seventh graders, increased by 0.005, respectively. Abnormal values must ultimately be selected using data on patients with the long QT syndrome; however, our findings suggest that the exponential correction of the QT interval may be useful in large-scale screening programs for detecting a QT prolongation in young school children.

Child↗

[Functional pulmonary atresia: a case report].

A male neonate, two days of age, was admitted with cyanosis and tachypnea. Chest roentgenograms showed massive cardiomegaly and decreased pulmonary vasculatures. Echocardiographic and the right ventriculographic findings were interpreted as showing primary pulmonary atresia with secondary tricuspid incompetence. At a Brock operation, however, there was no resistance in passing the instrument through the pulmonary valve. The baby died twelve hours after surgery. Postmortem examination showed that the tricuspid regurgitation was a cause of the functional pulmonary atresia (FPA). It is important to distinguish FPA from pure pulmonary atresia because conservative therapy is the first choice for the FPA.

Diagnosis, Differential↗

[Nosocomial infections due to methicillin-resistant S. aureus (MRSA) at the Kagoshima University Hospital (1). Coagulase typing of MRSA].

Nosocomial infection due to MRSA at the Kagoshima University Hospital and their coagulase typing were examined using S. aureus (349 strains) clinically isolated in 1989. The results were as follows: 1) S. aureus consisted of 43.6% of MRSA and 56.7% of Methicillin-sensitive S. aureus (MSSA). 2) MRSAs were recovered most frequently from the specimens from the respiratory tract (47.8%). 3) The isolation of MRSA gradually increased in frequency from January to August; however, that of MSSA did not show a similar tendency. 4) The isolation of MRSA was higher in frequency in the surgical wards, the ICU and the pediatric ward. 5) When classified into 8 coagulase types, MRSAs (133 strains) consisted of only 3 types (54.1% of type II, 32.3% of type VII, and 12.0% of type IV), whereas MSSAs contained all coagulase types. As compared with the results of coagulase typing at other institutions, the incidence of type VII was much more frequent at our hospital. 6) A few coagulase types of MRSA appeared in each ward. Also, type II MRSA strains increased in June and July, and type VII MRSA increased in August. However, MSSA strains did not show any similar tendency.

Bacterial Typing Techniques↗

[Nosocomial infections due to methicillin-resistant S. aureus (MRSA) at the Kagoshima University Hospital (2). Susceptibility to antibiotics].

Susceptibility to antibiotics of 123 MRSA strains isolated at the Kagoshima University Hospital in 1989 was examined. The results were as follows: 1) Susceptibility of MRSA strains was excellent to VCM, MINO, and RFP, followed by IMP, CLDM, and CPFX. However, most strains were resistant to PCG, MPIPC, ABPC, CET, CMZ, CZON, GM, and AMK. 2) Five strains highly resistant to RFP were isolated. Three of these strains were isolated on the ward for tuberculosis. This suggests easy development of resistance to RFP by MRSA. 3) Differences in susceptibility to antibiotics between coagulase type II and type VII strains were examined. The cumulative percentage of type II strains susceptible to CLDM (MICs less than 0.5 microgram/ml) was 15.3%, and that of type VII was 45.2%. Strains resistant to CLDM were more frequently isolated among type II than among type VII strains (p less than 0.001). A similar relationship between strains and antibiotics was also found with EM and CPEX. On the other hand, the cumulative percentage of type II strains susceptible to AMK (MICs less than 25 micrograms/ml) was 89.7%, and that of type VII was 9.7%. Strains resistant to AMK were more frequently isolated among type VII than among type II strains (p less than 0.001).

Anti-Bacterial Agents↗

A simplified Master's two-step test for preschool children.

To investigate the usefulness of a simplified Master's two step test (s-MTT) for preschool children aged 4-6, s-MTT was carried out in our pediatric cardiology clinic using a new stair and connector for joining the leads from each child to the ECG machine. The subjects were 21 children with Kawasaki disease without coronary involvement and four children with arrhythmias. The treadmill exercise test (TET) was done on the same day to compare the exercise load of s-MTT with that of TET. Oxygen uptake during s-MTT was also examined using another group consisting of eight outpatients. There were no differences in indices such as peak heart rate (HR), HR immediately after exercise, and performance ratio between the outpatients in this study and kindergarteners in the preliminary report. The proportions of peak HR and HR immediately after exercise in s-MTT to those in TET were 91.1 +/- 7.9 (mean +/- SD)% and 91.1 +/- 8.6%, respectively. The average oxygen uptake of the eight outpatients in s-MTT was 23.2 +/- 4.1 ml/min/kg. These studies suggest that the simplified MTT is useful as a screening test, because it can be done for all children aged 4-6 in any laboratory.

Cardiovascular Diseases↗