ABSTRACTS

Mucoid Degeneration of Heart Valves: “Blue Valve Syndrome”

LEO MCCARTHY, MD and PAUL L. WOLF, MD Palo Alto, California

We have studied several patients with symptoms of aortic or mitral insufficiency, or both, and heart failure who had histories suggesting rheumatic valvulitis as the diagnosis. There was no history of syphilis or bacterial endocarditis, and no evidence of Marfan’s syndrome. Gross and micro- scopic examination of the valves at surgery or autopsy revealed mucoid degeneration. At operation, all valvular annuli were moderately dilated, and there was prominent thinning of the cusps and valvular leaflets without intense

fibrosis or calcificat,ion. Sections demonst,rated pools of a mucoid substance without int,ense inflammation, fibrosis or calcification. Special stains, such as alcian blue, demon- strated increased mucopolysaccharides within the valves.

Thus, this abnormality may be responsible for significant’ numbers of patients presenting with valvular insufficiency simulating rheumatic disease. The lesion deserves con- sideration in the differential diagnosis of valvular in- sufficiency especially when the cause is obscure.

Cardiac Arrhythmias During Maximal Treadmill Exercise Testing

PAUL L. McHENRY, MD/OSCAR J. COGAN, MD and KERMIT R. BROWN, MD Indianapolis, Indiana

maximal exercise only in 69, during the last 3 minute stage The significance of arrhythmias occurring during exercise of maximal exercise in 86, and only during the 6 minute is of clinical importance. The frequency of cardiac ar- postexercise period in 16 subjects. Eight subjects demon- rhythmias during maximal treadmill exercise was studied strated ventricular tachycardia during exercise. Twenty- in 450 clinically normal male volunteers between the ages two (5% ) demonst,rated only supraventricular premature of 30 and 55 years. The program of graded exercise and contra.ctions, with 13 of these occurring only during the the technique of electrode application were designed to last stage of exercise. Three had supraventricular tachy- permit identification and interpretation of arrhythmias cardia. Of the 100 subjects who were 40 years of age or during exercise. The electrocardiogram was monitored older, 50y0 demonstrated arrhythmias with exercise. The continuously during exercise and was recorded on mag- incidence of arrhythmias in the 350 subjects between netic tape for subsequent study. 30 and 39 years was 41%.

A total of 171 men (38%) demonstrated ventricular This study suggests that arrhythmias appearing during premature contractions with exercise. The ventricular pre- strenuous exercise are not an indication of clinical organic mature contractions occurred at rest in 21, during sub- heart disease.

The Hemodynamic Response to Pulmonary Embolism in Previously Normal Patients

KEVIN M. MCINTYRE, MD and ARTHUR A. SASAHARA, MD, FACC West Roxbuty, Massachusetts

The degree of pulmonary arterial obstruction as deter- mined by selective pulmona.ry angiography ranged from 11 to 68y0 (mean 34yC) in 18 patients who had no prior cardiopulmonary disease. Systemic arterial hypoxemia was the most frequent abnormality, being observed in 17 (94v0). It occurred wit,h angiographic lesions as small as 10 to 15%. In 5 pa,tients, in whom obstruction ranged up to 25oJ,, hypoxemia was the only abnormality. Pulmonary arterial mean pressure (PA,) was elevated in 12 patients (66%); obstruction tended to exceed 25% in this group. A high degree of correlation was observed between the PA,,, and the angiographic defect (P = <O.Ol). Despite massive embolization, in no patient did the PA,,, exceed 40 mm Hg. Elevations in right atria1 mean pressure (RA,) were present in 8 patients (440/,), all of whom had hypoxemia. as well as pulmonary hypertension. Ele- vations in RA, were closely related to the level of PA, elevation. These increases in pressure tended to occur only

after the angiographic obstruction exceeded 30%. The cardiac index was characteristically elevated, av-

eraging 1 liter higher than normal (mean 3.4 + 1.1) and depressions were observed in only 2 cases (11%). The cardiac index did not fall as the pressure load increased; rather, it increased in direct relation to the degree of hypoxemia (P = <O.Ol ) and appeared to be a compen- satory mechanism by which peripheral tissue oxygen needs were supplied in the face of a falling ~0,. The increase in cardiac output was mediated by an increase in right ven- tricular stroke volume; no predictable alterations in heart rate were noted. A simultaneous increase in right ventric- ular stroke work and eject,ion rat.e in the face of increasing outflow obstruction attested to a compensatory enhance- ment of right ventricular performance, probably mediated by both the Frank-Starling mechanism and the positive inotropic influence of the sympathetic nervous system as a response to hypoxia.

VOLUME 25, JANUARY 1970 115