Biomedical subjects
Publications and source records attributed to M Witsenburg.
We report 2 patients who developed severe scar contracture of a Microvel Hemashield valveless right-sided extracardiac conduit implanted 14 months earlier. In both cases, the diameter of the conduit was reduced along its entire length, with the prosthetic material plicated inward by retraction and organization of connective fibrous tissue on either side of the conduit.
Intraoperative two-dimensional contrast echocardiography was used to detect a residual shunt in 50 patients after surgical repair of ventricular septal defect. Contrast injections were performed following termination of the extracorporeal circulation. In the presence of a shunt the intensity of opacification of both left and right ventricular cavities was compared. In 40 patients no ventricular shunting was observed; insignificant shunting was noted in five patients. Follow-up of these 45 patients proved uneventful. Significant opacification of the right ventricle was noted in five patients. This finding, however, does not necessarily indicate a residual shunt of significant volume. In two patients the residual shunt was confirmed postoperatively by pulsed Doppler echocardiography but clinically there was no need for surgery. Three other patients subsequently required reoperation and partial patch dehiscence was confirmed in all. Thus, intraoperative two-dimensional contrast echocardiography is a sensitive technique to detect a residual ventricular septal defect, an observation which may warrant reoperation before chest closure.
Explore the source record for details and available documents.
During a 10-year period 16 children with acute Guillain-Barré syndrome were seen. Eleven were admitted to the Pediatric Intensive Care Unit, either because of difficulty of breathing and swallowing or because of symptoms of autonomic disturbance. Six patients were mechanically ventilated for a mean period of 17 days. Symptoms of autonomic disturbance were frequently seen especially in the mechanically ventilated patients. Two patients died because of cardiac arrhythmia. Methods of detecting patients at risk for cardiac dysrhythmia are suggested.
Intraoperative epicardial two-dimensional echocardiography was used in 195 patients undergoing surgery for congenital heart disease to evaluate its potential to identify new diagnostic information immediately before and after surgical correction. In 168 patients the preoperative diagnosis was confirmed by intraoperative echocardiography. In four patients, unsuspected findings were revealed, which resulted in modification of the surgical approach. In 18 patients additional morphologic information was obtained which contributed to alteration or refinement of surgical management. The adequacy of cardiac repair was assessed before closure of the chest in all patients. In six patients this information led to immediate reoperation and in four other patients to inotropic drug therapy. During congenital heart surgery, epicardial two-dimensional echocardiography may yield important information for surgical management. The technique is an essential adjunct when preoperative diagnostic studies are not conclusive or when the initial response to repair is unsatisfactory.
Explore the source record for details and available documents.
The usefulness of intraoperative epicardial two-dimensional (2D) echocardiography using a commercially available 5 MHz mechanical sector scanner was evaluated in 200 patients. The scanhead was inserted into a gas sterilized plastic bag and placed on the exposed heart. Unsuspected new diagnoses were made in 7 patients. In 68 patients additional morphologic information was obtained. This information influenced surgical management in 32 patients. Intraoperative echocardiographic analysis of the surgical correction revealed the expected results in 184 patients. In 16 patients the investigation provided important information in the decision of immediate reoperation. We conclude that epicardial two-dimensional echocardiography performed by the surgeon familiar with the interpretation of echocardiographic cross-sections yields important information for surgical management. The technique has become an important adjunct in our cardiac surgery department for immediate decision making and leads to optimal results.
The etiology of diastolic motion of the pulmonary valve seen on the M-mode echocardiogram has been the subject of much debate. To further investigate diastolic events in the pulmonary artery, the patterns of diastolic pulmonary artery blood flow velocity were studied using pulsed Doppler echocardiography in patients with a normal heart. Two diastolic waveforms were found, one in early diastole related to passive filling of the right ventricle and one in late diastole related to atrial contraction. These waveforms were also related to the two recognized phases of diastolic pulmonary valve motion detected by M-mode echocardiography. The presence of biphasic diastolic blood flow in the pulmonary artery was confirmed by electromagnetic flow velocimetry in four additional patients with various cardiac diseases and normal right heart pressures. It is concluded that both atrial contraction and passive right ventricular filling produce blood flow in the pulmonary artery.