Laser Doppler anemometer studies in unsteady ventricular flows.

The laser Doppler technique was employed to obtain intraventricular velocity distributions on the basis of in vivo confirmation of previous in vitro flow visualization predictions. The quasi-steady assumption required for quantification of flow visualization results is unsatisfactory in regions of high acceleration and fluctuating velocities are unavailable via such techniques. Mean and fluctuating velocity profiles were obtained in a pneumatically driven prosthetic ventricle with the laser Doppler anemometer and stress levels estimated.

Total artificial heart implantation in calves with pump on an angled port design.

The APP was employed in our 21st TAH calf and has now been implanted in a total of 11 animals. The APP has a dynamic stroke volume of 105 ml, an ejection fraction of 75%, and a peak flow of 14 L/min. The TAH features 2 APPs which have polysulfone cases and contain smooth, seam-free polyurethane sacs.

Prolonged mechanical support of the left ventricle.

An interdisciplinary group has developed a left ventricular assist pump system composed of a modified sac type pump, a pneumatic power unit, and a synchronizer. The pump fills from the left ventricle and discharges into the aorta. The system was employed for left ventricular assistance in a series of 12 normal calves, with an average pumping period of 70 +/- 8 days.

Late results of the subclavian flap procedure in infants with coarctation of the thoracic aorta.

Persistent stenosis or recoarctation occurs in 16 to 33% of infants who undergo repair of coarctation of the thoracic aorta by use of end-to-end anastomosis. This report describes the results in 12 infants of repair of coarctation of the aorta using a left subclavian artery flap procedure. Cardiac catheterization and cineangiography performed in four patients from 4 to 66 months following repair showed a 10 mm systolic gradient in one patient and no evidence of significant stenosis in any patient.

The development of pulmonary vascular obstructive disease after successful Mustard operation in early infancy.

Pulmonary vascular obstructive disease developed postoperatively in an infant with aortopulmonary transposition and intact ventricular septum who underwent a Mustard operation in 3 months of age. Preoperative catheterization had shown normal pulmonary artery pressures. Four months after surgery, catheterization showed pulmonary artery systolic pressure above the systemic level and a tortuous, attenuated pulmonary vascular tree visualized angiographically.

A new prosthesis for reconstruction of the left ventricular outflow tract.

A new left ventricular outflow tract prosthesis is described. It consists of a tightly woven Dacron graft with one end modified by being wrapped around a thin perforated stainless steel tube to form a rigid left ventricular insertion port and the other end anastomosed to a Hancock xenograft valved conduit for suture to the arterial system. The prosthesis is simple in design and flexible enough to permit anastomosis to any portion of the abdominal aorta.

A technique to assess fibrinogen, platelet and red cell kinetics in calves with artificial hearts or circulatory assist devices.

1. Normal data for routine hematologic studies including fibrinogen, VIIIAHF, AT III, and circulating platelet aggregates are reported for Holstein calves. 2.

Similarity of clinical and laboratory results obtained with microporous teflon membrane oxygenator and bubble-film hybrid oxygenator.

For 80 elective clinical cardiopulmonary bypasses we alternately used either a commercial microporous Teflon membrane oxygenator or a commercial hybrid bubble-film oxygenator. Setup time was a little longer with the membrane unit (20 minutes), but priming volume (2,250 ml) was the same. No problems were encountered with the hybrid oxygenator.

Determining arterial pressure, left atrial pressure and cardiac output from the left pneumatic drive line of the total artificial heart.

These data presented here demonstrate how careful analysis of mock loop testing can lead to useful measurements for long-term calf experiments. The accuracy of the data rae primarily dependent upon a valid circulatory system analog and good experimental technique. These methods of determining arterial pressure, left atrial pressure and cardiac output have allowed us to obtain recordds of these important parameters for periods as long as 100 days in calves with total artificial heart implantation.

The artificial heart. Progress and promise.

A multidisciplinary group has designed, fabricated, and evaluated an artificial heart. The heart consists of two smooth-surfaced sac-type pumps, two pneumatic power units, and an electronic control system. The artificial heart has been employed in 22 calves.

The management of the lungs during cardiopulmonary bypass.

Many factors that contribute to the postextracorporeal pulmonary insufficiency have been recognized over the years that extracorporeal circulation has evolved. It is evident that more than one factor is the cause. For the present, a complex multifactoral problem appears to exist.

Reconstruction of the right ventricular outflow tract with a conduit in congenital heart disease.

A series of five patients with complex cyanotic congenital cardiac malformations underwent surgical reconstruction of the right ventricular outflow tract using a Dacron conduit with a porcine aortic valve. All patients survived and all have shown clinical improvement. At cardiac catheterization postoperatively, a pressure gradient of between 20 and 50 mm Hg across the conduit was found in all patients.

Horizontal interventricular septum in congenital heart disease: surgical considerations.

A patient with complex congenital heart disease associated with a horizontal interventricular septum is described. In addition the ventricles were inverted, both great vessels arose from the left-sided right ventricle in the dextrotransposed position, and he had a ventricular septal defect of the type usually seen in endocardial cushion defect. Correction was performed using a Rastelli type procedure with good hemodynamic results.

Additional evidence that a new virulence-associated antigen of Neisseria gonorrhoeae is not of pilus origin.

Triton-X-100-treated pilus suspensions prepared from Neisseria gonorrhoeae produced a single line of precipitate in immunodiffusion tests. This line was distinct from that of the virulence-associated antigen.

A longitudinal study of Mycoplasma pneumoniae: infections in Navy recruits by isolation and seroepidemiology.

A longitudinal serologic study of M. pneumoniae infections in two recruit training centers with grossly different climates showed that the frequency of this infection peaks in the late summer-early fall and to a lesser degree in the spring at both training centers. Seroconversions (four-fold or greater increase in titer) were as high as 45-57% in some recruit companies during the late summer peak.

Quantitative evaluation of left ventricular bypass in reducing myocardial ischemia.

A controlled study was undertaken to evaluate the relationship between myocardial oxygen consumption (MVO2) and epicardial S-T segment improvement in an ischemic heart preparation during left ventricular (LV) bypass. Twelve mongrel dogs were prepared with left ventricular-aortic bypass, coronary sinus cannulation, and a multiple point epicardial electrocardiographic technique. The left anterior descending coronary artery was ligated low (Group I) or high (Group II) after baseline studies.

A pressure-measuring system for long-term in vivo pressure measurements.

A new balloon-tipped catheter has been developed for the purpose of making long-term vivo intravascular pressure measurements. Among its advantages are its ability to electrically isolate the subject from the pressure transducer and be rebalanced and calibrated while in situ. Experimental results in calves indicate that the system provides a very reliable means of calibrating implanted catheter tip pressure transducers in situ and can be used as the primary long-term pressure measuring device when high frequency response is not required.

A comparison of three ventricles used for left ventricular bypass in the calf.

Long-term synchronized left ventricular bypass has been performed in calves using pneumatically powered pumps having a smooth lining fabricated of segmented polyurethane. Three different pump designs have been employed: a) sac pump, b) longitudinal tethered sac pump, and c) transverse tethered sac pump. Sizeable thrombi occurred in the apex of the sac and longitudinal tethered sac pumps.

Automatic control of the artificial heart.

An automatic control system has been developed to balance and control the output of an artificial heart. The system consisted of 2 linked negative feedback loops. The left ventricle was controlled by a Servo-Stroke Optimizer, which insured complete filling and full stroke operation of the left pump with each beat and changed the beat rate in accord with changes in aortic pressure.

Design and evaluation of a percutaneous transthoracic cannula.

This investigation was designed to develop a satisfactory PTC for conveying large bore cannulae as required for current use with the artificial heart and left heart assist device. A total of 50 PTCs of varying designs and 6 controls were implanted in the dorsum of canines and goats. Observations with 6 initial designs indicated that necessary requirements in the design of a PTC, include adequate fixation and the use of dacron or nylon velour as the skin interfacing material.

Coarctation of the abdominal aorta with multiple aneurysms. Operative correction.

An 11-year-old asymptomatic girl with hypertension was found to have coarctation of the abdominal aorta with four aneurysms in or adjacent to the hypoplastic segment of aorta. Operative treatment included insertion of a thoracoabdominal aortic bypass graft and resection of the aneurysms. The association of abdominal coarctation and aneurysm formation is reviewed and the rationale for therapy discussed.