Cyrus Farrehi

Hypoventilation and cor pulmonale due to chronic upper airway obstruction

A syndrome of chronic upper airway obstruction, hypoventilation, and cor pulmonale seen in 2 patients is described. These children both manifested varying degrees of CO 2 retention, pulmonary hypertension, and right ventricular hypertrophy. Relief of the upper airway obstruction by tonsillectomy and adenoidectomy resulted in regression of the presenting symptoms and signs.

Left Ventricular Volume Measurements in Man by Thermodilution

A safe, rapid method for estimating left ventricular volume in man during the course of hemodynamic studies should prove helpful in the assessment of cardiac disease and useful in physiological research. It is the purpose of this report to present left ventricular volume measurements in man that were obtained by an indicator dilution method which employs cold as the indicator. This circulatory indicator has been studied by several workers (1-4) and has been used for left ventricular volume determinations in animals previously (5-10). The method employed was adapted from those used by Rapaport and his co-workers for left ventricular volume measurements in the dog (7) and right ventricular studies in man (11).

Idiopathic left ventricular hypertrophy: A hemodynamic reappraisal

Abstract Left ventricular end-systolic and end-diastolic volumes were measured by a thermodilution technic in four patients with idiopathic left ventricular hypertrophy. Two patients had no outflow tract obstruction at rest and the ventricular end-diastolic volumes were 90 and 107 ml. per M 2 . Two patients with idiopathic hypertrophic subaortic stenosis (IHSAS) with large gradients, had end-diastolic volumes of 69 and 67 ml. per M 2 . The lower limit of normal for this value in our laboratory is 90 ml. per M 2 . The low end-diastolic volumes in the two patients with IHSAS were associated with ventricular end-diastolic pressures of 18 and 20 mm. Hg, indicating that the diastolic compliance of the left ventricle was severely reduced. This low compliance produced a high mean left atrial pressure and a low stroke volume, due to inadequate ventricular filling. It is postulated that in some cases of IHSAS, such handicaps may be as important as outflow tract obstruction. When methoxamine was administered to two patients with IHSAS, the systemic pressure rose and the outflow gradient was lessened in both. However, in one case the ventricular enddiastolic volume rose from 69 to 79 ml. per M 2 ., and in the other it fell from 90 to 59 ml. per M 2 . Based on our data, and other studies from the literature, it is suggested that systemic diastolic pressure is an important determinant of the outflow gradient in IHSAS. A rise in systemic diastolic pressure may reduce, or even nullify, the effects of either a reduced ventricular systolic volume or positive inotropic stimulation, both of which have been shown to increase outflow obstruction. It is proposed that the gradient in IHSAS depends on a complex interplay of variables, some tending to increase the gradient, and some tending to decrease it. It may thus be difficult to predict the effect of any agent or maneuver in a given patient with IHSAS.

Clinical and Hemodynamic Observations After Combined Aortic and Mitral Replacement

Twelve patients have been observed from 6 to 19 months after combined aortic and mitral valvular replacement with Starr-Edwards prostheses. Eleven patients have had postoperative right- and left-heart catheterizations. The clinical and hemodynamic findings are described. Nine patients are well. Three others have less than satisfactory results, although one of these is improved. It is concluded that bivalvular replacement is now practical in selected patients and provides gratifying results in most individuals so treated.

The effects of supine exercise on left ventricular volume in heart disease

Abstract Left ventricular end-diastolic volume (EDV) was measured by thermodilution in 30 patients with heart disease. Those with little physiologic abnormality varied in their response to exertion. In some, EDV decreased while forward stroke volume (FSV) was maintained or increased. In others, EDV and FSV rose during exercise. Patients with aortic insufficiency usually had a decrease in EDV with exercise, whether FSV increased or decreased. In patients with other lesions, FSV and EDV tended to vary together. Changes in EDV and left ventricular end-diastolic pressure with exercise were usually not in the same direction, and the factors which may explain this unexpected finding are discussed. It is concluded that end-diastolic pressure, as usually measured in the left ventricle during cardiac catheterization, will not reliably describe EDV or its changes with exercise.

Left Ventricular Volume Studies in Tranquilized Dogs with Local Anesthesia

Left ventricular volumes were estimated by thermodilution in unanesthetized dogs given the tranquilizer, perphenazine. During systole, the left ventricle emptied an average of 40% of its end-diastolic volume. This is a significantly greater proportion than observed previously during general anesthesia with several different agents. Left ventricular mid-systolic wall force was calculated. Higher force values at a given end-diastolic volume occurred during intravenous infusion of norepinephrine. Methoxamine failed to change these relationships.