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Biomedical subjects

J K Perloff

Publications and source records attributed to J K Perloff.

At least 55 records · Page 3Linked to original sources
PubMed1989

Regional myocardial blood flow and metabolism at rest in mildly symptomatic patients with hypertrophic cardiomyopathy.

Previous observations and clinical manifestations suggest the presence of ischemia in the disproportionately thickened septum of patients with hypertrophic cardiomyopathy. Metabolic consequences of ischemia can be demonstrated with positron emission tomography. Therefore, 10 patients with hypertrophic cardiomyopathy and an echocardiographic septum to posterior wall thickness ratio of 1.8 +/- 0.4 cm (range 1.3 to 2.5) were studied with the use of nitrogen (N)-13 ammonia, carbon (C)-11 palmitate and fluoro (F)-18 2-deoxyglucose as tracers of myocardial blood flow, fatty acid metabolism and exogenous glucose utilization. The results of positron emission tomography in 9 patients with hypertrophic cardiomyopathy were compared with those in 10 normal volunteers. In the hypertrophic cardiomyopathy group, observed myocardial activity of N-13 ammonia and C-11 palmitate in the septum was similar to that in the lateral wall. Septum to lateral wall tissue activity ratios averaged 1.04 +/- 0.15 for N-13 ammonia and 1.04 +/- 0.18 for C-11 palmitate, and were similar to those in the normal volunteers (0.98 +/- 0.07 and 0.98 +/- 0.03, respectively; p = NS). Myocardial clearance half-time and residual fraction of C-11 palmitate did not differ significantly between the septum and lateral wall. However, F-18 2-deoxyglucose uptake was significantly lower in the septum than in the lateral wall (15,768 +/- 4,314 versus 19,818 +/- 5,234 counts/pixel; p less than 0.003). The mean septum to lateral wall activity ratio of 0.83 +/- 0.21 was less than that observed in normal volunteers (0.92 +/- 0.07; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Adults with cyanotic congenital heart disease: hematologic management.

Hematologic management of adults with cyanotic congenital heart disease has received little recent attention. The lack of practical therapeutic guidelines prompted us to consolidate our observations on 124 cyanotic adults for general physicians, cardiologists, and hematologists who care for these patients. Specific attention focused on regulation of erythrocyte mass and concepts of compensated and decompensated erythrocytosis, symptoms of deficient tissue oxygen transport, hyperviscosity and iron deficiency, the potential relation between elevated hematocrit levels and brain injury, hemostasis, urate metabolism, and renal function. Cerebral infarction was not seen in any patient. Phlebotomy is best reserved for treatment of symptomatic hyperviscosity. Iron therapy is indicated for symptomatic iron deficient erythropoiesis. Abnormal hemostatic mechanisms are the rule. Antithrombotic medications have little or no role in treatment. Hyperuricemia is the result of abnormal renal uric acid excretion not urate overproduction, and serves as a marker of abnormal renal function. Drugs that promote urate excretion are the preferred maintenance treatment in symptomatic hyperuricemic patients.

Adolescent↗
PubMed1988

Reassessment of echocardiographic criteria for diagnosis of mitral valve prolapse.

Commonly used echocardiographic criteria for mitral valve prolapse (MVP) include a sizable proportion of persons whose hearts are normal. Nevertheless, the echocardiogram is generally used as an independent standard for the diagnosis of MVP despite lack of consensus on the criteria to be used and the probability of interobserver variability. Conversely, there is a relatively uniform consensus that classic auscultatory signs establish the diagnosis of MVP beyond reasonable doubt. Accordingly, in 148 patients referred for evaluation of known or suspected MVP, the echocardiographic patterns that coincide with diagnostic auscultatory signs were studied prospectively to compare those patterns with criteria commonly used for the echocardiographic diagnosis of MVP and to determine interobserver variability in echocardiographic interpretation. Eighty patients (54%) had a classic mid- to late systolic click or an apical late systolic murmur, or both. Eleven patients (7%) had the apical holosystolic murmur of mitral regurgitation with no discernible clinical or echocardiographic cause other than the consideration of MVP. Doppler echocardiography was performed in 80 of the 148 patients. The degree of superior systolic bowing of each mitral leaflet and the location of leaflet coaptation relative to the presumed plane of the mitral anulus were graded on apical 4-chamber and parasternal long-axis views. The only patterns absolutely specific for auscultatory MVP were: severe bowing of the anterior or posterior leaflet; coaptation of leaflets on the left atrial side of the anular plane; moderate to severe Doppler mitral regurgitation accompanied by any degree of leaflet bowing; and mild Doppler mitral regurgitation accompanied by moderate bowing of a leaflet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Hemodynamic responses to isolated increments in heart rate by atrial pacing after a Fontan procedure.

The physiologic role of the right ventricle has long been a subject of interest to physiologists. The Fontan operation provides a human model for studying the circulation in series devoid of a subpulmonic right ventricle. The hemodynamic response to isotonic exercise in this setting has been established, and differs appreciably from normal. However, the physiologic response to an increase in heart rate (atrial pacing) as an isolated variable has not been examined and compared to atrial pacing in hearts with two concordant subarterial ventricles. Accordingly, we compared the supine bicycle exercise response to rate-equivalent right atrial pacing in nine patients after atriopulmonary anastomoses (the Fontan operation) for single ventricle or tricuspid atresia. Cardiac index increased 77% with exercise (rest 2.6 L/min/m2; exercise 4.6 L/min/m2) but decreased 12% with atrial pacing (rest 2.5 L/min/m2; pacing 2.2 L/min/m2). Pulmonary arterial oxygen saturation declined significantly during exercise (rest 68%; exercise 31%) and during atrial pacing (control 72%; pacing 64%). The mean increment in pulmonary arterial pressure was 1.3 times greater with exercise (rest 14 mm Hg; exercise 20 mm Hg) than with pacing (control 12 mm Hg; pacing 16 mm Hg). Peak systemic arterial systolic pressure increased 14% with exercise but was unchanged by pacing. Systemic and pulmonary vascular resistances fell with exercise but changed insignificantly during atrial pacing. Stroke volume rose slightly with exercise but fell significantly with pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Control of ventilation during exercise in patients with central venous-to-systemic arterial shunts.

The diversion of systemic venous blood into the arterial circulation in patients with intracardiac right-to-left shunts represents a pathophysiological condition in which there are alterations in some of the potential stimuli for the exercise hyperpnea. We therefore studied 18 adult patients with congenital (16) or noncongenital (2) right-to-left shunts and a group of normal control subjects during constant work rate and progressive work rate exercise to assess the effects of these alterations on the dynamics of exercise ventilation and gas exchange. Minute ventilation (VE) was significantly higher in the patients than in the controls, both at rest (10.7 +/- 2.4 vs. 7.5 +/- 1.2 l/min, respectively) and during constant-load exercise (24.9 +/- 4.8 vs. 12.7 +/- 2.61 l/min, respectively). When beginning constant work rate exercise from rest, the ventilatory response of the patients followed a pattern that was distinct from that of the normal subjects. At the onset of exercise, the patients' end-tidal PCO2 decreased, end-tidal PO2 increased, and gas exchange ratio increased, indicating that pulmonary blood was hyperventilated relative to the resting state. However, arterial blood gases, in six patients in which they were measured, revealed that despite the large VE response to exercise, arterial pH and PCO2 were not significantly different from resting values when sampled during the first 2 min of moderate-intensity exercise. Arterial PCO2 changed by an average of only 1.4 Torr after 4.5-6 min of exercise. Thus the exercise-induced alveolar and pulmonary capillary hypocapnia was of an appropriate degree to compensate for the shunting of CO2-rich venous blood into the systemic arterial circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The dilated cardiomyopathies: clinical aspects.

The dilated cardiomyopathies are characterized by an increase in left ventricular internal dimensions without an appropriate increase in ventricular wall thickness. The myocardial injury often goes unrecognized until the offending cause is no longer apparent. Although specific diagnoses and treatment can sometimes be established, the majority of cases are designated idiopathic but are believed to result from previous viral infections, autoimmune or genetic predisposition, or abnormalities of the coronary microvasculature. Despite impaired contractility and ventricular dilatation, compensated dysfunction may prevail for some time. Excessive fluid retention, neurohumoral activation, systemic vasoconstriction, and atrioventricular valve regurgitation promote progressive hemodynamic deterioration. The meticulous matching of diuretic and vasodilator therapy to specific hemodynamic goals, particularly the normalization of ventricular filling pressure, frequently allows restoration and maintenance of reasonable functional capacity even in patients with severe heart failure. Nevertheless, sudden death due to ventricular arrhythmias and occasionally to systemic emboli remains a major threat. Prophylactic use of antiarrhythmic agents and anticoagulant therapy is not of proven efficacy. Cardiac transplantation results in significant improvement in life expectancy for patients with dilated heart failure but is available only to a relatively small number of patients because of the limited donor supply. Accordingly, programs providing cardiac transplantation should be equally committed to providing optimal medical management that is the only option for the majority of patients with dilated cardiomyopathy.

Adolescent↗
PubMed1988

The restrictive cardiomyopathies.

In parallel with the rapidly developing interest in the diastolic properties of ventricular function in the 1970s, the restrictive cardiomyopathies have taken their place as the third major category of primary heart muscle disease. The restrictive cardiomyopathies are characterized by primary abnormalities of diastolic ventricular function with normal to near normal systolic performance and little or no increase in end-diastolic or end-systolic dimensions of either right or left ventricle. The restrictive abnormality of ventricular function can result from myocardial or endomyocardial disease, the etiologies of which may be known or unknown. Diastolic dysfunction that is essentially myocardial can be idiopathic (probably an enzymatic/metabolic disturbance), infiltrative (myocardial interstitium), or within myocardial cells (storage diseases). Diastolic dysfunction that results from endomyocardial disease is typified by endomyocardial fibrosis or the hypereosinophilic syndrome, although carcinoid, metastatic malignancies, radiation, and anthracycline toxicity may be accompanied by endomyocardial restriction. Echocardiography and Doppler ultrasound, MRI, and radionuclear techniques have been major advances in providing diagnostic precision, contributing materially to the clinical identification of the restrictive cardiomyopathies as well as discriminating certain of their etiologies.

Adult↗
PubMed1987

Left ventricular geometry and function in adults with Ebstein's anomaly of the tricuspid valve.

We postulated that the abnormal shape, size, and function of the right heart and adjoining ventricular septum in adults with Ebstein's anomaly of the tricuspid valve might in turn alter the shape and function of the left ventricle. Seven adult patients with uncomplicated Ebstein's anomaly were studied. Left ventricular geometry was determined by two-dimensional echocardiography. Left ventricular function was assessed by treadmill exercise and radionuclide angiography at rest and with exercise. Paradoxic ventricular septal motion was consistently present. Left ventricular eccentricity (ratio of two minor axes in the short-axis view) was uniformly abnormal, averaging 1.35 +/- 0.23 (normal = 1.02 +/- 0.05). The ratio of right to left ventricular cavity size averaged 1.70 +/- 0.44 (normal 0.65 +/- 0.30), and tricuspid valve displacement into the right ventricular cavity averaged 52% (normal 8%). Functional right atrial size averaged 27.6 +/- 5.2 cm2 (normal right atrial area = 13.1 +/- 2.2 cm2). Resting left ventricular ejection fractions were below 50% in all but two patients. In response to Bruce protocol exercise stress, there were consistently appropriate increments in heart rate, blood pressure, and peak double product and, with one exception, radionuclide left ventricular ejection fraction. There were significant correlations between tricuspid valve displacement and functional right atrial size versus resting left ventricular ejection fraction and left ventricular eccentricity. These data support the hypothesis that derangements in right heart morphology and function in Ebstein's anomaly contribute to significant alterations in left ventricular geometry, but the geometric alterations are associated with tangible but less significant changes in left ventricular systolic function.

Adolescent↗
PubMed1986

Chronic hypoxaemia and decompensated erythrocytosis in cyanotic congenital heart disease.

Among forty adults with cyanotic congenital heart disease there was a subset of eleven patients with especially pronounced erythrocytosis, repeatedly rising haematocrit, recurring symptoms of hyperviscosity, and little or no shift of the haemoglobin/oxygen-dissociation curve. These patients were iron deficient as a result of many therapeutic phlebotomies; nevertheless their red-cell mass was comparable to that in iron-replete patients with similar, but stable, haematocrits. Iron repletion in the deficient patients resulted in rapidly increasing haematocrit and hyperviscosity. In one extreme case, erythropoiesis remained persistently iron deficient despite normal serum iron and ferritin levels. "Decompensated erythrocytosis" is an apt term for the excessive erythrocytic response and the associated phenomena.

Adolescent↗
PubMed1986

New guidelines for the clinical diagnosis of mitral valve prolapse.

Because the term mitral valve prolapse has pathologic connotations, considerable effort has been expended to establish acceptable diagnostic standards, but without general agreement. This report combines information from the history, physical examination, electrocardiogram, chest x-ray and 2-dimensional echocardiogram in an effort to avoid the artifice of using the 2-dimensional echocardiogram as a categoric reference standard and to establish new clinical guidelines that distinguish pathologic mitral valve prolapse--a primary connective tissue abnormality of leaflets, chordae tendineae and anulus--from normal superior systolic displacement of mitral leaflets. The objective is to avoid implications of heart disease in healthy young persons within the gaussian distribution of normal. To this end, and with the Jones criteria as a model, major and minor criteria are proposed for the clinical diagnosis of mitral valve prolapse as a pathologic entity.

Angiocardiography↗
PubMed1986

Cardiac involvement in Friedreich's ataxia: a clinical study of 75 patients.

To establish the prevalence and to characterize the types of cardiac involvement in Friedreich's ataxia, 75 consecutive patients (39 male and 36 female), aged 10 to 66 years (mean 24) were prospectively studied. Electrocardiograms were performed in all patients, vectorcardiograms in 34 and echocardiograms in 58. Electrocardiographic and vectorcardiographic abnormalities occurred in 69 (92%) of the 75 patients. Electrocardiograms revealed ST-T wave abnormalities in 79%, right axis deviation in 40%, short PR interval in 24%, abnormal R wave in lead V1 in 20%, abnormal inferolateral Q waves in 14% and left ventricular hypertrophy (voltage and repolarization criteria) in 16%. Echocardiograms revealed concentric left ventricular hypertrophy in 11%, asymmetric septal hypertrophy in 9% and globally decreased left ventricular function in 7%. Progression from a normal echocardiogram to concentric left ventricular hypertrophy, asymmetric septal hypertrophy or globally decreased left ventricular function was identified in one patient in each category, although the study was not designed for longitudinal follow-up. Two patients died, and necropsy revealed in both a minimally dilated but flabby left ventricle. On the basis of electrocardiographic and vectorcardiographic and echocardiographic data, 95% of patients had one or more disorders. The most common abnormality was segmental myocardial "dystrophy" (electrocardiographic QRS initial force abnormalities), but global left ventricular hypokinesia occurred more often than previously recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗