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Biomedical subjects

M F Riley

Publications and source records attributed to M F Riley.

At least 37 records · Page 2Linked to original sources
PubMed1988

Prediction of severity of aortic stenosis: accuracy of multiple noninvasive parameters.

PURPOSE: As newer non-medical techniques are developed to treat older patients with severe aortic stenosis, reliable noninvasive diagnosis of the condition will become increasingly important. For this reason, the accuracy of multiple noninvasive indexes for quantitation of the severity of aortic stenosis was evaluated, relative to catheterization-determined aortic valve area. PATIENTS AND METHODS: To evaluate the accuracy of multiple noninvasive parameters in assessing the presence and extent of aortic valve narrowing, noninvasive and catheterization correlations of the severity of aortic stenosis were obtained on 121 occasions in 81 patients (mean age, 76 +/- 11 years). Forty patients had studies performed before and after valvuloplasty. Noninvasive studies included the time to one-half carotid upstroke and carotid ejection time, corrected for heart rate, measured from a carotid pulse tracing; M-mode echocardiographic aortic valve excursion; mean pressure gradient across the aortic valve assessed by Doppler technique; the ratio of the peak to mean pressure gradient by Doppler; and Doppler aortic valve area assessed using the following continuity equation: aortic valve area = A X V/V1, where A = left ventricular outflow tract area, V = peak left ventricular outflow tract velocity, and V1 = peak velocity in the aortic stenotic jet. Mean aortic valve gradients and area (calculated using the Gorlin formula) were also assessed at cardiac catheterization. RESULTS: The correlations between the catheterization measurement of aortic valve area and the various noninvasive measurements were as follows: time to one-half carotid upstroke (r = -0.32, p less than 0.001); corrected left ventricular ejection time (r = -0.24, p less than 0.05); aortic valve excursion (r = 0.51, p less than 0.001); mean gradient by Doppler study (r = -0.44, p less than 0.001); mean gradient by catheterization analysis (r = -0.55, p less than 0.001); peak to mean gradient ratio measured by continuous wave Doppler (r = 0.38, p less than 0.001); and aortic valve area assessed using the Doppler continuity equation (r = 0.85, p less than 0.001). CONCLUSION: Noninvasive determination of aortic valve area using the continuity equation is an accurate means of assessing the severity of aortic stenosis. Although multiple other noninvasive parameters also correlate with aortic valve area measured at catheterization, there is too much scatter of data points to permit accurate prediction of catheterization aortic valve area in any given patient.

Aged↗
PubMed1987

Dynamic left ventricular outflow tract obstruction when the anterior leaflet is retained at prosthetic mitral valve replacement.

Dynamic left ventricular outflow tract obstruction developed in a patient in whom the anterior leaflet was retained at mitral valve replacement. It was caused by systolic anterior movement of the native anterior leaflet. Reduced outflow tract diameter, resulting from both posterior displacement of the septum and anterior displacement of the native anterior leaflet by porcine stents, was likely instrumental in promoting dynamic obstruction.

Adult↗
PubMed1987

Two-dimensional and Doppler echocardiographic diagnosis of an aortic to right atrial fistula complicating aortic dissection.

A 60 year old woman presented with massive aortic root dilation and sudden cardiovascular collapse 10 years after aortic valve replacement. An aortic to right atrial fistula was diagnosed by echocardiographic imaging and Doppler ultrasound. At operation, the patient was found to have chronic aortic dissection with aneurysm formation. Rupture of the aneurysm into the right atrium was confirmed.

Aortic Dissection↗
PubMed1987

Echocardiographic assessment of aortic valve area in elderly patients with aortic stenosis and of changes in valve area after percutaneous balloon valvuloplasty.

Echocardiographic studies, adequate for analysis of aortic valve area using the continuity equation, were obtained in 31 patients aged greater than or equal to 60 years who were undergoing catheterization for assessment of suspected aortic stenosis. Catheterization-determined aortic valve area was 0.74 +/- 0.30 cm2 (mean +/- SD) and Doppler-determined aortic valve areas were 0.68 +/- 0.27 and 0.65 +/- 0.27 cm2, depending on whether peak or mean velocities, respectively, were entered into the continuity equation. There were significant correlations between both of the Doppler-derived and the catheterization-determined aortic valve areas (r = 0.86, p less than 0.001 for both the continuity equation employing peak velocities and the continuity equation employing mean velocities) which were demonstrated to be linear by F test (catheterization area = -0.03 + 1.13 X Doppler area determined using peak velocities, SEE = 0.163 cm2, p less than 0.001; and catheterization area = -0.02 + 1.16 X Doppler area determined using mean velocities, SEE = 0.165 cm2, p less than 0.001). Both sets of correlations had linear regression parameters meeting the conditions for identity. Significant linear correlations were also noted between the non-invasive measurements of aortic valve excursion, ventricular ejection time, time to one-half carotid upstroke, maximal Doppler velocity and maximal Doppler gradient and catheterization aortic valve area, but the correlations were less tight than those between valve areas determined by catheterization and by Doppler continuity equation. Ten of the patients underwent percutaneous balloon aortic valvuloplasty. There were significant linear correlations between aortic valve areas determined by Doppler and catheterization methods both before valvuloplasty (r = 0.77, p = 0.01; p less than 0.001 by F test, SEE = 0.134 cm2) and after valvuloplasty (r = 0.85, p less than 0.01; p = 0.0001 by F test, SEE = 0.161 cm2). Linear regression parameters met the conditions for identity. There was also a significant linear correlation between catheterization and Doppler measurements of absolute change in aortic valve area (r = 0.79, p less than 0.01; p less than 0.001 by F test, SEE = 0.11 cm2). Aortic valve area can be determined reliably by continuity equation in elderly patients. In addition, results of balloon valvuloplasty, measured by changes in catheterization-determined aortic valve area, are accurately reflected by changes in aortic valve area determined using the continuity equation.

Aged↗
PubMed1986

Pulsed Doppler echocardiographic evaluation of valvular regurgitation in patients with mitral valve prolapse: comparison with normal subjects.

Pulsed Doppler echocardiography was used to determine prospectively the prevalence of mitral, aortic, tricuspid and pulmonary regurgitation in 80 consecutive patients with mitral valve prolapse and 85 normal subjects with similar age and sex distribution. Mitral valve prolapse was defined by posterior systolic displacement of the mitral valve on M-mode echocardiography of 3 mm or more (40 patients), the presence of one or more mid- or late systolic clicks (61 patients), or both. Mitral regurgitation, detected by pulsed Doppler techniques in 53 patients with prolapse, was holosystolic in 24, early to mid-systolic in 6, late systolic in 15 and both holosystolic and late systolic behind different portions of the valve in 8. Definitive M-mode findings were present in only 27 of the 53 patients, and only 21 had mitral regurgitation audible on physical examination. Tricuspid regurgitation was evident by pulsed Doppler echocardiography in 15 patients (holosystolic in 9, early to mid-systolic in 1, late systolic in 4 and both holosystolic and late systolic in 1); 12 of these 15 patients, including all with an isolated late systolic pattern, had an echocardiographic pattern of tricuspid prolapse, but none had audible tricuspid regurgitation. A Doppler pattern compatible with aortic regurgitation was recorded in seven patients, all without echocardiographic aortic valve prolapse and only two with audible aortic insufficiency. A Doppler shift in the right ventricular outflow tract in diastole, suggestive of pulmonary regurgitation, was recorded in 16 of the 78 patients with an adequate Doppler examination: only 1 of the 16 had audible pulmonary insufficiency. Of the 85 normal subjects without audible regurgitation, pulsed Doppler examination detected mitral regurgitation in 3 subjects (holosystolic in 1 and early to mid-systolic in 2), aortic regurgitation in none, tricuspid regurgitation in 9 (holosystolic alone in 8 and both holosystolic and late systolic in 1) and right ventricular outflow tract turbulence compatible with pulmonary insufficiency in 15. The prevalence of valvular regurgitation, detected by pulsed Doppler echocardiography, is high in patients with mitral valve prolapse. Regurgitation may involve any of the four cardiac valves and is clinically silent in the majority of patients. The prevalence rates of mitral and aortic regurgitation are significantly higher in patients with mitral prolapse than in normal subjects, suggesting that alterations in underlying valve structure in the prolapse syndrome may indeed be responsible for this regurgitation.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

Laser scanning phase modulation microscope.

We describe the concept and first implementation of an innovative new instrument for quantitative light microscopy. Currently, it provides selective imaging of optical path differences due to birefringence; with further development, it is also possible to selectively image several optical properties, including refractive path differences, optical rotation, and linear and circular dichroism, all with diffraction-limited resolution. An image consists of a 512 X 512 element array, with each pixel displaying one of 256 grey levels, linearly proportional to the specific optical property being observed. Additionally, conventional brightfield and polarized light microscopy are available, with the accompanying advantages of laser scanning and digital image processing. The microscope consists of three subsystems, representing three distinct technologies. The laser scanning subsystem moves a focused microspot across the specimen; the output of a photodetector is an electric signal corresponding to a scanned image. The image display subsystem digitizes this signal and displays it as an image on a video monitor. When used in conjunction with a phase modulation feedback loop, the image formed is of the specimen's birefringent retardation or other selected optical property. The digitized images are also available for computer enhancement.

Animals↗
PubMed1983

Roles of echocardiography and arrhythmia monitoring in the evaluation of patients with suspected systemic embolism.

Patients with suspected systemic embolism were evaluated for possible cardiac origin of emboli using echocardiography (280 patients) and prolonged arrhythmia (Holter) monitoring (150 patients). Echocardiography demonstrated cardiac abnormalities that might predispose to emboli in 47% of patients with and 14% of patients without clinically evident cardiovascular disease. Lesions that might be directly responsible for emboli, including thrombi, myxomas, and vegetations, were identified in only 11 patients (4%), all of whom had clinically evident disease. Patients less than 45 years of age with clinically evident cardiovascular disease were especially likely to have a potential source of embolism identified. Holter monitoring demonstrated atrial fibrillation in 15 patients. All 15, however, had known atrial fibrillation in the past or had atrial fibrillation detected on admission electrocardiogram, or both. The findings suggest that it is not cost effective to perform echocardiography and arrhythmia monitoring on all patients with suspected systemic emboli. Because echocardiographic identification of a likely responsible lesion was limited to those with clinically evident cardiovascular disease, a policy of performing this test only on such patients would have eliminated 38% of the echocardiographic studies in this series.

Adult↗
PubMed1982

M mode and cross-sectional echocardiographic recognition of fibrosis and calcification of the mitral valve chordae and left ventricular papillary muscles.

The echocardiographic appearance of fibrotic thickening and calcification of mitral valve chordae tendineae and left ventricular papillary muscles in 17 patients is described. Pathologic proof of excessive fibrosis or calcification was obtained in five patients. In a sixth patient, calcium was demonstrated on angiography to extend from the chordae into papillary muscle. The characteristic feature of chordal and papillary muscle fibrosis and calcification is the presence of highly echogenic densities best visualized within the left ventricle at a level below the mitral valve leaflets. The more inferior location of these densities, within the body of the left ventricle, enables them to be easily differentiated from densities indicating fibrosis and calcification of the mitral valve anulus. The pattern of chordal and papillary muscle fibrosis and calcification was frequently associated with mitral anular calcification, aortic valve fibrosis or calcification and left atrial enlargement. One patient had rheumatic mitral valve disease. Many patients had mitral regurgitation and most had a history, physical examination and radiologic findings compatible with congestive heart failure. Although the origin and importance of the chordal and papillary muscle changes reported are not known, their frequent association with mitral regurgitation and with congestive heart failure suggests possible interrelations.

Aged↗
PubMed1982

Diagnostic accuracy of M-mode echocardiography in active infective endocarditis and prognostic implications of ultrasound-detectable vegetations.

Sensitivity, specificity, diagnostic accuracy, and prognostic implications of the M-mode echocardiographic pattern of vegetations were examined prospectively in consecutive patients referred with potential active infective endocarditis (IE). A pattern of definite echo vegetations was present in 37% of 51 patients diagnosed clinically to have active IE. Specificity in 138 patients without IE was 96%. Diagnostic accuracy of a positive test was 76% and that of a negative test was 80%. Five of six false positive studies involved patients with prior IE or valvular thrombosis. If possible echo vegetations were included, sensitivity increased to 47% and specificity decreased to 89%. Echographic vegetations were significantly correlated with congestive heart failure and need for valve replacement and/or death. Seven of eight patients with definite aortic valve vegetations died or required surgery, compared with 1 of 11 patients with mitral or tricuspid vegetations alone. Prognostic importance of echocardiographically documented vegetations appears to depend upon their site within the heart.

Adult↗
PubMed1982

Hypertrophic cardiomyopathy. Disappearance of auscultatory, carotid pulse, and echocardiographic manifestations of obstruction following myocardial infarction.

Three patients with echocardiographically documented asymmetric septal hypertrophy and findings compatible with dynamic left ventricular outflow tract obstruction suffered acute myocardial infarction in regions remote from the interventricular septum. Following infarction, echocardiographic signs of dynamic left ventricular outflow tract obstruction were no longer apparent. No resting gradient was documented in either of the two patients undergoing cardiac catheterization following myocardial infarction. Valsalva's maneuver resulted, however, in a gradient of 20 mm Hg in one patient. It appears that myocardial infarction may cause loss of or marked lessening of dynamic left ventricular outflow tract obstruction, even when the infarction involves areas other than the septum.

Aged↗
PubMed1981

Limitations of echocardiographic techniques in evaluation of left atrial masses.

Four patients with large left atrial masses documented angiographically or pathologically, or both, were studied with M mode echocardiography (four patients) and two dimensional echocardiography (three patients) within 2 to 5 days of angiographic or pathologic diagnosis. The left atrium appeared clear of echos in two patients subsequently documented to have a left atrial thrombus weighing 35 and 100 g, respectively, and located within the body of the left atrium. Definitely abnormal echoes were visualized in a third patient only in the inferior aspect of the left atrium immediately beneath the posterior root of the aorta. Subsequently, a 70 g left atrial myxoma filling almost the entire left atrium was found. In the fourth patient, who had a 125 g left atrial myxoma, the two dimensional four chamber apical view demonstrated tumor filling almost the entire left atrium. Long axis cross-sectional and M mode echocardiograms less clearly demonstrated the extent of the mass. Even large left atrial tumors located within the body of the left atrium may not be apparent or may be underestimated in size by currently available ultrasonic techniques. The relatively homogenous nature of certain masses may be, in part, responsible for the inability to visualize some of them adequately with echocardiography.

Aged↗