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Biomedical subjects

T Iwa

Publications and source records attributed to T Iwa.

At least 253 records · Page 14Linked to original sources
PubMed1981

Surgical treatment of the Wolff-Parkinson-White syndrome in infants and children.

Eleven pediatric Wolff-Parkinson-White (WPW) syndrome patients underwent surgery. Four had left, 5 right cardiac type and 2 had right septal type WPW syndrome. Two patients had 2 accessory conduction pathways (ACP). Ebstein's anomaly and secundum type atrial septal defect were the association congenital cardiac diseases in one patient each. Indications for surgery included repeated and/or long-lasting paroxysmal supraventricular tachycardia (PSVT), ineffective drug therapy, cardiac failure due to frequent tachycardia, short effective refractory period of the ACP, and simultaneous surgery for associated congenital cardiac diseases. Pre- and intra-operative examinations, including ECG, VCG, UCG, body surface mapping, intracavitary recording by catheter electrodes, computerized epicardial mapping, and endocardial mapping, were performed for the precise localization of the ACP. The surgical method was basically the same as is used for adults. Anterior median stermotomy was used primarily in right cardiac and right septal type and left anterior thoracotomy was used in 3 of 4 cases of the left cardiac type. Eight of 11 cases, two of which had 3 ACPs, were completely cured and in 3 there was evidence of postoperative pre-excitation. However, the PSVT attacks disappeared almost completely and drug therapy is not required at present.

Adolescent↗
PubMed1981

Correlation between localization of accessory conduction pathway and body surface maps in the Wolff-Parkinson-White syndrome.

Body surface maps were recorded in 26 patients with Wolff-Parkinson-White syndrome, who underwent successful localization and interruption of the accessory conduction pathway. Five types of body surface maps were classified according to the location of the potential maximum and minimum in the delta wave. These 5 types were left free wall type, left posterior septal type, right posterior septal type, right anterior septal type and right free wall type. Each type correlated well with the location of the accessory pathway, which was determined intraoperatively through epicardial and/or endocardial maps or surgical interruption. The potential minimum zone at 40 msec after the onset of the delta wave appeared at limited areas on the body surface, and this zone was divided into 7 areas which correspond to the location of the accessory pathway.

Adolescent↗
PubMed1981

Experimental and clinical study of the pre-excitation syndrome.

Ventricular pre-excitation was experimentally produced in mongrel dogs. Their ECG and epicardial maps were analyzed. Forty-two cases of W-P-W syndrome were operated on between 1969 and May, 1980. The relationship between ECG, particularly the delta wave and localization and meaning of pre-operative examinations such as vectorcardiography, echocardiography, body surface mapping, intracavitary potential study, and cardiac pacing, were presented and discussed. As an intraoperative study, epicardial mapping was indispensable and was the most accurate method in determining the ACP. Endocardial potential study was another meaningful method in certain cases. Detachment of the atrium from the ventricle with an incision along the annulus and at the opposite of the pre-excitation area resulted in complete correction in 32 out of 34 cases between 1973 and May, 1980. Six cases of multiple ACPs were also corrected, although 4 needed a second operation. Indications for surgery of the W-P-W syndrome should be extended further in view of the high success and safety rate of the surgery.

Animals↗
PubMed1981

[The computerized display of epicardial mapping (author's transl)].

UNLABELLED: The epicardial mapping is necessary for the surgical treatment of drug-resistant cardiac arrhythmia. The procedure for the epicardial mapping consists of three stages: 1) recording of heart potentials, 2) extraction of excitation transmission time, and 3) display of epicardial mapping. In this paper, our new microcomputer-based system was discussed. It was achieved by this system to simplify the method for the extraction and to make the colorgraphic display of epicardial mapping. Two methods for extraction were used in this study to compare with manual operation: 1) D method; extracting the time, when the differentiated wave takes maximal potential, and 2) Wi method; extracting the time of (Formula: see text). RESULTS: 1) similar epicardial excitation maps were obtained by these computerized methods, and 2) the most approximate values of the transmission time was obtained by Wi (i=2) method.

Computers↗
PubMed1980

Interruption of multiple accessory conduction pathways in the Wolff-Parkinson-White syndrome.

Of 35 patients with Wolff-Parkinson-White syndrome operated on, 5 were seen with two accesory conduction pathways each; all of these were successfully interrupted. In one patient, one accessory conduction pathway each was located in the right and left side of the heart; in the other 4, both pathways were confined to the right side. In 2 patients with unilateral (right side) multiple accessory conduction pathways, Ebstein's anomaly was also present. In 1 patient with Ebstein's anomaly, the second unilateral accessory conduction pathway was discovered intraoperatively and was successfully interrupted. The remaining 4 patients required a second operation to interrupt the other pathway. A delta wave completely different from the preoperative one appeared 4 to 10 days after interruption of the first major pathway, and the second operation was performed 14 days, 42 days, four months, or five years after the first operation. All 5 patients survived, and long-term follow-up revealed no signs of morbidity.

Adolescent↗