Biomedical subjects

R E Schumann

Publications and source records attributed to R E Schumann.

4 recordsLinked to original sources

PubMed1993

Prophylactic treatment of swine with bretylium for experimental cardiac catheterization.

We evaluated a cryothermic ablation catheter for potential use in treating supraventricular tachycardia by cardiac catheterization in miniature swine. Cardiac catheterization was performed on anesthetized miniature swine by using multiple catheters that were inserted bilaterally by either percutaneous or cutdown techniques into the femoral veins. We performed electrophysiologic tests according to standard atrial and ventricular electrical stimulation protocols. Manipulation of catheters in the tricuspid valve area and right ventricle was an essential part of the study. During an initial study of five swine, catheter manipulation produced sustained and nonsustained ventricular tachycardia and ventricular fibrillation. To prevent arrhythmias, bretylium (5 mg/kg) was administered intravenously 10 minutes before catheter manipulation and repeated every 30 minutes throughout the procedure. Since the use of bretylium was instituted, there have been no cases of ventricular fibrillation in a series of 20 animals. We determined that bretylium is effective in the suppression of ventricular arrhythmias in swine undergoing cardiac catheterization.

Animals↗

PubMed1991

Anesthetic and postoperative protocols for a canine model of reversible left ventricular volume overload.

The purpose of this study was to develop anesthetic and postoperative methods that could be used in a canine model of reversible left ventricular volume overload (LVVO). LVVO was created by inducing mitral regurgitation (MR) in adult conditioned dogs. Using fluoroscopy, MR was induced by passing urologic grasping forceps into the left ventricle through a carotid artery and rupturing one or more chordae tendinea. Cardiac catheterization was performed after significant cardiac dysfunction developed (3 months after creation of MR) in order to collect data to confirm reduced contractile function. The MR was repaired by replacing the damaged valve with a bovine pericardial xenograft. Dogs were followed with sequential cardiac catheterizations to determine if the valvular replacement reversed the cardiac dysfunction. To develop this model, unique anesthetic and post-operative care protocols had to be instituted. In order not to exacerbate the existing cardiac dysfunction, a high dose narcotic anesthetic regimen using a sufentanil infusion at 9-13 microgram/kg h-1 was developed in association with cardiopulmonary bypass and hypothermia for the mitral valve replacement surgery. Intensive postoperative care protocols that involved major personnel and pharmaceutic interventions were necessary. Using our methods 11/17 dogs survived the procedure and were included in the protocol for study of mechanisms involved in reversal of cardiac dysfunction.

Anesthesia↗

PubMedDate not supplied

High-dose narcotic anesthesia using sufentanil in swine for cardiac catheterization and electrophysiologic studies.

A protocol for high-dose narcotic anesthesia using sufentanil by intravenous infusion was developed in swine undergoing cardiac catheterization and intracardiac electrophysiologic studies. In experiments involving cardiac conduction system ablation, nine swine received intramuscular ketamine, 33 mg/kg, and intramuscular acepromazine, 1.1 mg/kg, as premedication. An infusion of sufentanil (15 mcg/kg/h) was started followed by a loading dose of sufentanil (7 mcg/kg) given as a bolus intravenously. A continuous infusion of sufentanil (15-30 mcg/kg/h) was used for maintenance anesthesia. Since the development of this protocol, we have been able to achieve stable hemodynamics and cardiac rhythms for intracardiac electrophysiologic studies.

Anesthesia, Intravenous↗

PubMedDate not supplied

Percutaneous serial catheterization in swine: a practical approach.

In a model designed for experimental cryoablation of the His bundle in swine, a study that required multiple and follow-up cardiac catheterizations, femoral percutaneous cannulations were successfully performed in 14 of 15 swine: 6/6 Yucatan miniature, 5/6 Hanford miniature, and 3/3 Yorkshire farm pigs, weight range 15-50 kg. A follow-up cardiac catheterization was performed in 10 of these animals: 5 Hanford and 5 Yucatan. Femoral percutaneous cannulation was successful in 6. A cutdown approach was successful in the remaining 4 after failed attempts at percutaneous vascular access. The results show that percutaneous femoral cardiac catheterization is a feasible and practical technique for cardiovascular studies in swine, especially those that require multiple and serial catheterizations.

Animals↗