Life-threatening postoperative junctional ectopic tachycardia.

Junctional ectopic tachycardia developed in an infant after intraatrial repair of transposition of the great arteries. He failed to respond to medical management and, in moribund condition, underwent His bundle cryoablation. He survived and ultimately did well. Junctional ectopic tachycardia is not uncommon after open heart operations in children and may be lethal. Its genesis, diagnosis, and treatment are now well enough understood to allow successful treatment of nearly all patients.

Repair of supravalvar aortic stenosis: cardiovascular morphometric and hemodynamic results.

Supravalvar aortic stenosis is associated with normal systolic pressure in the aorta and its branches with the singular exception of the coronary arteries, which are hypertensive. This uncommon lesion has been treated by patch aortoplasty of several types. We examined hemodynamics and morphometrics in 13 patients who underwent operation for supravalvar aortic stenosis from 1979 through 1988. They ranged in age from 2 to 43 years (mean age, 14.5 +/- 3.8 years [+/- standard error of the mean]). There were no operative deaths. Preoperative and postoperative (1 to 5 years) catheterization or echocardiography or a combination of these was done in all but 3 patients (1 died late suddenly without a postmortem examination; 1 was lost to follow-up; and 1 has not yet been restudied). Pressure gradients across the stenosis in patients treated with a single-sinus patch (n = 4) were 65 +/- 18 mm Hg preoperatively and 5 +/- 3 mm Hg postoperatively (p less than 0.05) and in patients with a bisinus patch (n = 6), 83 +/- 15 mm Hg preoperatively and 6 +/- 2 mm Hg postoperatively (p less than 0.05); the two groups were not significantly different. Measurements of the diameters of the coronary arteries, aortic annulus, and descending aorta were made, and calculation of the ratio of the coronary artery and annulus diameters to the descending aortic diameters both preoperatively and postoperatively was possible in 5 patients. The left coronary artery was larger than normal before and after operation. Preoperatively there was a disproportionate increase in left coronary artery and annulus size during systole. Left ventricular wall thickness decreased significantly postoperatively (p less than 0.05). Repair of supravalvar aortic stenosis (localized and diffuse) by both single sinus and bisinus patch repair is safe and hemodynamic results are good.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental corticosteroid myopathy.

The steroids triamcinolone, dexamethasone, beta-methasone, and cortisone were administered i.p. to adult rats for 14-63 days. The extensor digitorum longus (EDL, white muscle) and soleus (SOL, red muscle) muscles were examined histologically and histochemically. Triamcinolone was the most potent lesion-producing drug. Selective involvement of muscles, and of the fiber types within them was observed: Necrotic changes were seen only in the type 1 fibers of the SOL; atrophic fibers were observed in the type 2 fibers of both the SOL and the EDL.

Platelets, fibroblasts, and inflammation: tissue reactions to platelets injected subcutaneously.

Evidence from the literature indicates that platelets contain (besides mediators of acute inflammation) factors capable of stimulating fibroblastic growth: namely, serotonin and "platelet factors" demonstrable by their effect on tissue cultures of fibroblasts. The purpose of this study was to find out whether an inflammatory and a fibroblast-stimulating effect could be demonstrated in vivo, in the rat, using a single subcutaneous injection of concentrated platelets (platelet pellet). For comparison, rat brain, heart, and kidney tissue were homogenized under sterile conditions, spun down, and injected subcutaneously. Platelet pellets caused intense edema and neutrophil infiltration; after 8 days they had assumed a spherical shape and were surrounded by typical myofibroblasts. The 30 pellets of tissue homogenates induced a much milder acute inflammatory reaction; only one (a heart pellet) induced a recognizable myofibroblast reaction. The delayed appearance of myofibroblasts around platelet pellets was probably mediated by the neutrophils, which accumulated in large amounts around platelet pellets. Using this in vivo model, a direct fibroblast-stimulating effect of platelets was not demonstrable. It is pointed out that there are analogies between cellular reactions induced by injected platelet pellets and by intravascular platelet thrombi.