Gordon S. Myers

Noninvasive evaluation of cardiac function in hypothyroidism. Response to gradual thyroxine replacement.

Left ventricular performance was studied in 15 patients with severe, primary hypothyroidism (mean serum total thyroxine of 0.8 mug per 100 ml and serum thyrotropin of 160 muU per milliliter). Pretreatment systolic-time intervals were characterized by prolongation of the pre-ejection period (delta PEP = +30) and reduction of the left ventricular ejection period (delta LVET = -23) with a resultant increase in the PEP/LVET ratio (0.47). Nine of 14 patients demonstrated pericardial effusions. These abnormalities were reversed with physiologic thyroxine replacement. Further reductions of the delta PEP and PEP/LVET ratio occurred with supraphysiologic doses (200 to 300 mug per day). During therapy, delta PEP was inversely correlated with serum thyroxine (P less than 0.001) and directly correlated with serum thyrotropin (P less than 0.001). Thus physiologic thyroid hormone replacement, appropriately adjusted to need, appears necessary in hypothyroidism for optimal left ventricular function.

Evaluation of Carotid Stenosis by Phonoangiography

Quantitative spectral (frequency) analyses were performed on 60 carotid bruits in 48 patients with suspected carotid stenosis. The technic was totally noninvasive. Bruits were recorded at the skin surface, analyzed by a minicomputer, and the degree of arterial stenosis estimated using a recently derived theory of sound production by turbulent blood flow. This method has been named phonoangiography. Fifty of the 60 bruits (83 per cent) had spectrums characteristic of turbulent blood flow, and a residual lumen diameter could be calculated. Results from the noninvasvie technic compared well with data obtained from radiographic carotid arteriograms in the 50 bruits with internal carotid artery stenosis. The residual lumen diameter estimated from phonoangiography differed from the radiographic value by less than 1 mm in 83 per cent and less than 1.5 mm in 92 per cent of the studies. Phonoangiography appears to be a useful method for assessment of carotid artery stenosis.

Detection of left atrial myxoma by gated radionuclide cardiac imaging.

SUMMARYGated radionuclide cardiac blood pool scans (GCS) of end-systole and end-diastole or eight images subtending the entire cardiac cycle were performed on seven patients with left atrial myxomas documented by pulmonary cineangiography with left atrial follow-through. The echocardiogram was either suggestive or diagnostic in all patients. In addition to demonstration of the tumor (6 patients), the GCS detected three patterns of tumor motion: 1) a defect which moved from the left atrium in end systole to the left ventricl in end diastole (2 patients); 2) a defect which remained within the region of the left atrium but decreased in size between end diastole and end systole (3); and 3) a defect which was observed within the region of the left ventricle in end diastole but disappeared in end systole (1). Thus, the GCS is a noninvasive method for detection and evaluation of motion of left atrial myxomas.

Atypical patent ductus arteriosus with absence of the usual aortic-pulmonary pressure gradient and of the characteristic murmur.

Abstract The clinical criteria for the diagnosis of patent ductus arteriosus are well known and are, in the vast majority of cases, sufficient to establish the diagnosis without recourse to cardiac catheterization or to angiocardiography. Of these criteria, a continuous machinery murmur best heard at the left of the upper sternum has been considered typical of patent ductus and is rarely of other origin (i.e., arteriovenous aneurysm in the same area). However, the earlier insistence that this typical murmur must be present in order to justify surgical exploration1,2 has proved untenable. Furthermore, it has been pointed out3,4 that in infancy or with congestive heart failure a patent ductus may be present with-out murmurs. Several proved cases3,5 have been reported in which only systolic murmurs not continuing into diastole were found. Why does a patent ductus arterious occasionally fail to give rise to a continuous murmur? Burchell5 suggested that in these cases the usual aortic-pulmonary pressure gradient may be absent during diastole or during the entire cardiac cycle. However, no data bearing on this point have thus far been available. In this paper we present two cases of patent ductus arteriosus in children who did not exhibit the classic machinery murmur. In the preoperative evaluation of these patients, cardiac catheterization was helpful in making the diagnosis and, in one of the cases, furnished data which satisfactorily explained the lack of typical physical signs.

Hypertrophic cardiomyopathy. Evaluation by gated cardiac blood pool scanning.

SUMMARYThe gated radionuclide cardiac blood pool scan (GCS) can be used to visualize the entire profile of the interventricular septum and left ventricular contraction. Twenty-two patients with hypertrophic cardiomyopathy, nine with valvular aortic stenosis and six normals, underwent echocardiography and GCS. All patients with hypertrophic cardiomyopathy had asymmetric septal hypertrophy and 14 of 22 had resting systolic anterior motion of the anterior leaflet of the mitral valve on echocardiogram. In eight patients with aortic stenosis with adequate echocardiograms, two had asymmetric septal hypertrophy and none had systolic anterior motion. The GCS demonstrated disproportionate upper septal thickening in 11; septal flattening in 16; cavity obliteration in 17; and a filling defect in the region of the left ventricular outflow tract in 16 of the 22 patients with hypertrophic cardiomyopathy. In the nine patients with valvular aortic stenosis, two demonstrated septal flattening, two cavity obliteration, two an outflow tract defect, and none disproportionate upper septal thickening. Both patients with cavity obliteration demonstrated asymmetric septal hypertrophy on echocardiogram. One normal control patient had septal flattening.Thus the gated cardiac blood pool scan provides an atraumatic technique for the evaluation of patients with hypertrophic cardiomyopathy which complements the echocardiogram.

Respiratory and Circulatory Studies of Patients with Mitral Stenosis

Sixteen patients with severe mitral stenosis have been studied by means of cardiac catheterization, ventilatory and respiratory tests. A decrease in the oxygen diffusing capacity and an increase in venous admixture were observed in a majority of the cases. The degree of pulmonary arterial and arteriolar abnormality observed in lung biopsies failed to correlate with the pulmonary arteriolar resistances calculated from the hemodynamic data. It is suggested that reversible vasoconstriction plays an important role in the pathogenesis of the pulmonary hypertension associated with mitral stenosis.

The use of protoveratrine in the treatment of hypertensive vascular disease.

Abstract The purpose of this report is to present out experience with the use of protoveratrine in one hundred patients with hypertensive vascular disease. It is not possible to give a final answer as to the effect of this drug as a treatment of patients with hypertension. We cannot do this because the evaluation of any treatment of a chronic disease is hazardous and difficult unless the treatment is curative or unless improvement is prompt and sustained. This is particularly true of a disease such as hypertensive vascular disease which persists for a decade or more in a high proportion of patients and has a variable course. The natural history of hypertensive vascular disease has not been well delineated and the number of drugs and treatments which have been used in the past fifty years, only to be abandoned, is large. It is recognized that the final evaluation of any treatment of a chronic disease requires ten or more years and a large number of patients with adequate control study.

The value and limitations of echocardiography in recording mitral valve vegetations.

The echocardiographic findings and case reports of three patients with active Streptococcal endocarditis and severe congestive heart failure are presented. All three had pathologically proven vegetations on the mitral valve; however, only the two with calcification of the vegetations were successfully demonstrated on echocardiography. Clinical and pathological differences are highlighted and prior case reports in the literature are reviewed. The nonspecific nature of echoes recorded from valvular vegetation is stressed and factors in their echocardiographic detection are discussed.

THERAPY OF PRIMARY HYPOTHYROIDISM WITH L‐TRIIODOTHYRONINE: DISCORDANT CARDIAC AND PITUITARY RESPONSES

Cardiac systolic time intervals were studied in ten patients with primary hypo‐thyroidism before and during therapy with increasing doses of oral L‐triiodo‐thyronine (L‐T3). Therapy was increased sequentially from 10, 20, 25 to 50 μg of L‐T3 daily on a monthly basis. On L‐T3, 20 to 25 μg/day, cardiac systolic time intervals and other peripheral responses to thyroid hormone including serum cholesterol concentration, serum creatine phosphokinase (CPK) activity, and basal metabolic rate had normalized. However, serum thyrotrophin (TSH) levels and peak TSH responses to thyrotrophin‐releasing hormone (TRH) remained elevated on these doses of L‐T3. As the dose of L‐T3 was increased from 20 to 50 μg/day, mean basal serum TSH levels decreased from 55 to 16 μu/ml, and the peak TSH response to TRH decreased from 243 to 58 μu/ml (P < 0.001) while systolic time intervals did not decrease further. Changing to L‐thyroxine (L‐T4) therapy at this point resulted in further suppression of TSH secretion, without significantly altering systolic time intervals or the other peripheral responses to thyroid hormone. These data suggest (a) that some biological responses to thyroid hormone were normalized on lower doses of L‐T3 than were required to normalize TSH secretion, and (b) that higher doses of L‐T3 or substituting L‐T4 therapy could suppress TSH secretion further without altering the other peripheral responses to thyroid hormone.

The Electrocardiogram in Congenital Heart Disease A Preliminary Report

Adequate unipolar electrocardiograms have been recorded on 101 patients with congenital heart disease and the findings analyzed. It has been found that the chief value of such tracings rests in the determination of ventricular preponderance, the evidence being obtained from study of the QRS complexes in unipolar limb and multiple precordial leads, with relatively little help from the RS-T segments and T waves. Auricular hypertrophy, encountered chiefly in association with pulmonic stenosis and tricuspid valve disease, could be best detected by analysis of P waves seen in the right precordial leads rather than in the limb leads. Intraventricular block was observed both with auricular and with ventricular septal defects, and was also found in Ebsteins disease and with coarctation of the aorta. Auriculoventricular block and arrhythmias were rare.