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Biomedical subjects

Y Koh

Publications and source records attributed to Y Koh.

At least 91 records · Page 5Linked to original sources
PubMed1990

Septation and Fontan repair of univentricular atrioventricular connection.

From April 1986 to September 1988, 12 patients with double- or common-inlet left ventricle and left anterior rudimentary right ventricle underwent septation while 17 patients with double- or common-inlet left or right ventricle underwent the Fontan operation. In the septation group, three patients who had pressure gradients ranging from 10 to 85 mm Hg between the left ventricle and the aorta underwent enlargement of the outlet foramen, and all survived. One of the 12 patients had a common atrioventricular valve that was repaired by separating the atrioventricular valve by the procedure used for atrioventricular septal defect. One had complete heart block before septation and the other one had it after separation. One 17-year-old woman, who had the smallest left ventricle (168% of normal), died in the hospital (mortality, 8.3%). In the Fontan group, one patient who died in the hospital (5.9%) had high pulmonary resistance of 4.4 U/m2, and one late death (5.9%) occurred in a patient who had complete heart block and a high mean pulmonary arterial pressure of 20 mm Hg. Because of suprasystemic pressure in the pulmonary ventricle, two patients had immediate takedown of the septation repair and substitution of the Fontan repair. Although right atrial pressure was almost equal in both groups after operation, the cardiac index was significantly higher in the septation group than in the Fontan repair group (p less than 0.01). These data suggest that patients who are candidates for either septation or Fontan repair might fare better with septation.

Adolescent↗
PubMed1990

[Radical correction of paracardiac type IIb of total anomalous pulmonary venous connection using pedicled flaps of right atrium and atrial septum].

Surgical results of total anomalous pulmonary venous connection (TAPVC) has been improved in recent years, however, late development of pulmonary venous obstruction was our concern in its total correction in early infancy. In the cardiac type of TAPVC, in which the pulmonary veins were connected to the right lateral wall, prosthetic patch is conventionally used in diversion of pulmonary venous flow into left atrium. It seemed favorable to repair this subset without using prosthesis. A 3-month-old female with TAPVCIIb according to Darling's classification underwent total correction on September 22th, 1988. Two pedicled flaps were developed using the right atrial wall and the atrial septum to create a pulmonary venous channel to divert arterial blood into left atrium and absorbable sutures were used throughout. Right atrium was entered through a vertical incision in its body and all the pulmonary veins were found in a recess in the lateral wall of the right atrium. Atrial septal defect in the cranial aspect of the fossa ovalis was enlarged by cutting the primum tissue along the right limbus and its caudal margin so as to form a pedicled flap attached to the left limbic tissue. Then the flap was sutured along the limbus to create a roof of the fossa ovalis. The second flap was made in the middle of the lateral atrial wall and was used to create a tunnel from the recess to the atrial septal defect. The defect in the right atrial wall was closed directly and no prosthetic patch was used. Postoperative course was uneventful and echocardiogram showed wide pulmonary venous channel draining into the left atrium.

Female↗
PubMed1989

[Case of skeletal open bite treated with orthognathic surgery, with special reference to morphological and functional analysis of the tongue].

Malfunction and abnormal posture of the tongue has been thought to be one of etiological factors for skeletal open-bite at length. In this study, an adult female patient with anterior open-bite is reported, who has been treated by means of posterior maxillary osteotomy and has obtained a good occlusion and profile, which is stable throughout the retention period. Electromyography was obtained from the tongue muscles by surface electrodes and the tongue muscle activity during deglutition was measured before and after surgery. The tongue posture was also analyzed on the basis of the roentgen cephalogram with the mandible at the rest position. Larger tongue muscle activities during swallowing was revealed compared to the control subjects. In addition, anteriorly and superiorly positioned tongue was seen in the initial stage. The amplitudes of the tongue muscle had decreased and tongue posture had shifted posteriorly and inferiorly following surgery, which approximated to the those observed in the control subjects. These improvements of the abnormal activity and posture of the tongue and the stability of occlusion after surgery confirmed that posterior maxillary osteotomy is an effective surgical operation for the anterior open-bite patients in terms of prognosis.

Adolescent↗
PubMed1989

[A report of two cases of absent pulmonary valve syndrome].

Two infants, aged 8 and 18 months, with absent pulmonary valve syndrome unaccompanied by severe pulmonary symptoms or roentgenographic evidence of emphysema underwent a corrective operation consisting of infundibular muscle resection, patch closure for ventricular septal defect (perimembranous outlet type), and right ventricular outflow tract reconstruction with a monocusp patch. The patients tolerated pulmonary regurgitation relatively well, although aneurysmal dilatation of the pulmonary arteries was present preoperatively. Since the postoperative course was uneventful, we think that, in milder cases of this syndrome, a pulmonary valve prosthesis, the insertion of which is advocated by some authors, is not essential, and that right ventricular outflow tract reconstruction with a monocusp patch may suffice in selected cases.

Female↗
PubMed1989

[Successful recovery and long-term survival following postcardiotomy (mitral valve replacement) cardiogenic shock by means of a left ventricular assist device].

A 48-year-old woman who had had mitral regurgitation associated with hypertension and left ventricular hypertrophy underwent mitral valve replacement with a 29 mm xenograft. Following the uneventful procedure, she could not come off cardiopulmonary bypass for 6 times even with an aid of IABP and with re-replacement of the mitral valve using a 29 mm Duromedics prosthesis because of the fear of xenograft malfunction. A left ventricular assist device (LVAD) was then utilized with a resultant dramatic recovery from profound postcardiotomy cardiogenic shock, and cardiopulmonary bypass was successfully terminated. Postoperatively, her hemodynamics were maintained with a LVAD and IABP. Heparin was used to keep the prosthesis from blood clotting by monitoring the ACT. The heart recovered gradually from intraoperative myocardial damage and the LVAD was successfully removed at the 5th postoperative day. Postoperative cardiac catheterization studies showed decreases in left ventricular wall motion and ejection fraction, although improvements of pulmonary hypertension and left ventricular end-diastolic pressure at rest were observed. At present, 1 year and 9 months after the use of LVAD, she is leading nearly normal life of NYHA grade 1. Because of the excellent present clinical condition of this patient, the benefit of a LVAD in perioperative cardiogenic shock is stressed.

Female↗
PubMed1987

Electrophysiological effects of flecainide on guinea pig ventricular muscle in high [K+]o, acidosis and hypoxia.

The electrophysiological effects of flecainide on the action potential were examined in guinea pig ventricular muscles using microelectrode recording methods. Under the control conditions, flecainide (0.5-1 microgram/ml) did not alter the resting potential, action potential duration (APD) or effective refractory period (ERP). The major effect of flecainide was on maximum upstroke velocity (Vmax), which was depressed in a dose-dependent manner. In high [K+] medium (potassium concentration = 10 mM), Vmax was depressed by 16.8% at a concentration of 1.0 microgram/ml (8.8% in normal [K+]o). In metabolic acidosis (pH = 6.89), it was depressed by 15.7% at the same concentration of the drug (8.3% in normal condition). The changes in ERP and ERP/APD90% in high [K+]o and metabolic acidosis were not significantly different from the normal condition. After hypoxic perfusion for 15 min, Vmax depression by flecainide was 16.3% (7.4% in control medium). The increase of ERP/APD90% was also greater in hypoxia. These data indicate that the most prominent effect of flecainide is Vmax depression which is enhanced under the high K+, acidic and hypoxic conditions. Therefore, it is suggested that flecainide may be most effective for ventricular arrhythmias occurring in myocardial ischemia.

Acidosis↗