Tada Yipintsoi

Effects of Respiration on the Hemodynamics of Hypertrophic Obstructive Cardiomyopathy

Abstract Marked respiratory variations in left ventricular outflow were noted in 8 of 9 patients with hypertrophie obstructive cardiomyopathy. Maximal systolic gradients were noted at the end of expiration, the smallest gradients at the end of inspiration. The reductions in left ventricular systolic pressures were accompanied by a rise in arterial systolic pressures and vice versa. These effects were not abolished by beta-adrenergic blockage and were exaggerated after “vensection.” The Valsalva maneuver resulted in increased obstruction during the period of peak strain, and after release the obstruction was diminished during the overshoot period. These responses persisted after beta-adrenergic blockade. The probable underlying mechanisms of varying obstruction observed with respiration and with the Valsalva maneuver are related to changes in volume of the left ventricle. The left ventricular outflow obstruction in hypertrophie obstructive cardiomyopathy is increased by a diminished ventricular volume, and relieved by an increased ventricular volume.

Mechanism of nitroglycerin effect in valvular aortic stenosis.

Abstract The hemodynamic effects of nitroglycerin taken sublingually were studied during cardiac catheterization in 10 patients with valvular aortic stenosis. Hemodynamics and cineangiographic left ventricular volumes were determined before administration of nitroglycerin and at peak nitroglycerin effect. Diastolic pressure-time and ejection pressure-time product were used to evaluate left ventricular energy supply and demand. Pressurevolume loops and left ventricular wall tension were calculated. There was a decrease ( P P It is concluded that sublingual nitroglycerin in aortic valve stenosis: (1) improves indirect indexes of left ventricular energy supply/demand ratio, (2) decreases left ventricular preload and afterload, and (3) does not change left ventricular contractility.

Effects of moderate uremia on cardiac contractile responses

We have previously reported results of studies on the hearts of rats with two types of uremia (1, 2): (1) severe acute uremia created by bilateral nephrectomy, and (2) moderate uremia created by 5/6 nephrectomy. In the former case hearts were studied 24 hr after nephrectomy and in the latter, 2 weeks after surgery. When hearts of rats with severe acute uremia were studied in an isolated heart apparatus, their performance was the same as control hearts. Under the same conditions, hearts of rats with moderate uremia show enhanced contractile responses. On the other hand, hearts of acute uremic rats studied in vivo were found to have greater contractile responses to gradual aortic occlusion than did hearts of sham operated animals (2). The present investigation was designed to determined if hearts from animals prepared with 5/6 nephrectomy show the same increased responses in vivo that they do in vitro, and to study the time course of the effect of uremia on the heart. Methods. Male Wistar rats weighing 250-300 g were anesthetized with ether, and 5/6 nephrectomy was performed taking care not to remove the adrenal glands (1). Sham operated rats were used as controls. For the 24 hr prior to study the rats were fasted but allowed to drink water. For the study, the rats were anesthetized with intraperitoneal pentobarbital (60 mg/kg). Respiration was controlled via a tracheostomy by a Harvard small animal respirator. To study cardiac performance complete aortic occlusion was produced in the open chest animal as described previously (2). Left ventricular pressure was measured by a 17 cm long PE catheter which punctured the apex of the left ventricle, and low and high gain tracings for systolic and diastolic pressures were recorded with an Electronics for Medicine VR6 multichannel recorder.

Pulmonary capillary permeability to sodium in unilateral transplanted canine lungs

Abstract Five dogs with autotransplanted left lungs, four with allotransplants and immunosuppression, and five with allotransplants but without immunosuppression were studied 4 to 5 days after surgery. The indicator dilution technique was used to measure the pulmonary capillary permeability to sodium from the left and right lungs separately. The permeability in each lung was evaluated with the blood flow (using carbonized microspheres), the steady-state albumin and sodium spaces and the lung morphology. In the allotransplanted lung there was an increase in capillary permeability to sodium, an increase in both water and solid content and a reduction in blood flow. These alterations were most marked in the allotransplants with immunosuppression, but were also present in the contralateral right nontransplanted lung in which pneumonia was frequently present.