Results following physiological repair for tricuspid atresia.

Fourteen patients underwent a physiological operation for tricuspid atresia. Seven patients survived up to 3 years after operation. Six patients underwent hemodynamic studies 2 to 34 months postoperatively (mean, 15 months). Average age at the time of operation was 14 years (range, 5 to 25 years). Postoperative studies showed 4 patients to be in sinus rhythm and 2 in junctional rhythm. Right atrial pressure was elevated an average of 17 mm Hg (range, 10 to 34 mm Hg). All patients showed good atrial transport function regardless of their rhythm. Two had a right atrium-left pulmonary artery gradient of 1.5 to 10 mm Hg across the conduit. Average arterial saturation was 92% (range, 87 to 97%), on improvement of 13% over preoperative values. Residual hypoexmia was due to pulmonary vein desaturation and to atrial right-to-left shunting early postoperatively and later, to atrial right-to-left shunting alone.

Anatomic variations in underdeveloped right ventricle related to tricuspid atresia and stenosis.

In the anatomy of 416 hearts, the seat of tricuspid stenosis or atresia is examined, with special reference to Fontan-like surgical procedures. A classification is offered which includes cases with and without regular or inverted transposition, and with decreased or increased pulmonary flow. The size and thickness of the right atrium, the size and architecture of the right ventricle, the size of the pulmonary tree, the types of atrial and ventricular septal defects, the condition of the mitral valve, and the size and thickness of the left atrium and left ventricle are analyzed. In addition the various intracardiac and extracardiac abnormalities are enumerated. Reference is also made to the tendency of the aorta and pulmonary trunk to override the septum, in some cases producing double-outlet left ventricle. It is considered that many cases of tricuspid valve atresia and stenosis with or without transposition may be amenable to Fontan-like procedures in the proper age group. All the above anatomic considerations have a bearing on the suitability and type of operative tricuspid bypass procedures, and they may influence the prognosis of surgical therapy.

Persistence of the third heart sound after resection of the native mitral and tricuspid valves. Evidence against the valvular theory of third sound origin.

A patient is described with severe rheumatic mitral and tricuspid insufficiency in whom both atrioventricular valves with their chordae tendineae and papillary muscles were resected and replaced with Hancock porcine grafts. This would appear to be the second such patient reported and the first described in detail in whom the third heart sound persisted postoperation. This occurrence documents the fact that a third heart sound can occur in the absence of native atrioventricular valve leaflets and the major portions of the subvalvular supporting apparatus, and argues against the theory that the third heart sound is generated by either the valvular leaflets of the subvalvular apparatus.

Operative repair for tricuspid atresia.

Twelve patients with tricuspid atresia underwent physiological operative repair. The criteria for their selection for operation included normal pulmonary vascular resistance and normal left atrial and left ventricular end-diastolic pressures. Four patients died (30% mortality). The 8 surviving patients developed pleural effusion, ascites, and hepatomegaly, which markedly improved in the subsequent weeks. Five of the 8 survivors underwent cardiac catheterization. The arterial oxygen saturation in these patients averaged 82% preoperatively, 89% immediately postoperatively, and 94% or better six months later. All had improved subjectively and developed increased exercise tolerance.

Factors influencing neurohumoral control of the heart in the newborn dog.

Several investigators have documented immaturity of cardiac autonomic innervation in neonates. To evaluate the integrity of afferent and efferent responses and to determine the role of circulating catecholamines in newborns, 50 puppies and 24 adult dogswere studied with the use of chloralose anesthesia. Interventions were: bilateralvagotomy, bilateral carotid occlusion, central vagus stimulation, stellate stimulation, bilateral adrenalectomy, infusion of norepinephrine or isoproterenol, and intravenoustyramine. Newborns exhibited supersensitivity to exogenous norepinephrine, isoproterenol, and stellate stimulation; responses to carotid occlusion and central vagal stimulation were comparable in both groups. Newborns had less resting vagal tone. After adrenalectomy, newborns exhibited a more marked decline in systemic pressureand heart compared to adults. Myocardial catecholamine content in newborns was 1/10 that in adults, whereas plasma catecholamine concentration in newborns was 30-fold greater than in adults. These data demonstrate functional integrity of afferent and efferent cardiac autonomic pathways in the newborn, define in vivo supersensitivity to the sympathetic neurotransmitter, and suggest a dominant role of circulating catecholamines in modulation of cardiovascular events in neonates.