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Biomedical subjects

D R Boughner

Publications and source records attributed to D R Boughner.

At least 73 records · Page 4Linked to original sources
PubMed1981

Rapid estimation of echocardiographic peak velocity of circumferential fibre shortening (peak Vcf).

A transparent grid for estimating peak Vcf directly from the echocardiograph recording is described. Estimates so obtained were compared with peak Vcf measurements made by an echocardiographic digitising technique and with the angiographic ejection fraction in 13 patients with normal left ventricular function and 17 patients with impaired left ventricular function. No patient had angiographic segmental wall motion abnormalities. Significant linear correlations were found between peak Vcf derived by the simple manual technique and peak Vcf determined by the digitising technique and also between peak Vcf derived by the simple manual technique and the angiographic ejection fraction. Peak Vcf derived by the simple manual technique was found to be a reliable predictor of ventricular function, being more than 1.4 circumferences/s in 11 of 13 patients with angiographic ejection fractions greater than or equal to 55% and less than 1.4 in 14 of 17 patients with angiographic ejection fractions less than 55% (sensitivity 82%, specificity 85%). Thus, peak Vcf is an echocardiographic index that can be estimated rapidly and accurately without the need for digitising equipment and is well suited to general clinical use.

Adolescent↗
PubMed1981

Aortic regurgitation. Detection of left ventricular dysfunction by exercise echocardiography.

Left ventricular performance was assessed in 20 symptom free patients and 10 with symptoms, all with isolated aortic regurgitation, by measuring the echocardiographic peak velocity of circumferential fibre shortening (echo peak Vcf) at rest and during graded bicycle ergometer exercise in the supine position. The normal left ventricular response during such exercise was first determined in 20 healthy controls. On the basis of their resting and exercise echo peak Vcf, the 30 patients with aortic regurgitation could be separated into three groups: Group 1 comprised 11 symptom free patients with a normal resting echo peak Vcf which increased normally with exercise; group 2 comprised nine symptom free patients with a normal resting echo peak Vcf but with a subnormal response to exercise; group 3 consisted of 10 patients with symptoms with a depressed resting echo peak Vcf which remained subnormal with exercise. Subsequent cardiac catheterisation disclosed normal ejection fractions in patients in group 1, borderline ejection fractions in those in group 2, and reduced ejection fractions in those in group 3. Echocardiographic assessment of left ventricular performance during supine isotonic exercise may provide a simple noninvasive method for the early detection of left ventricular dysfunction in symptom free patients with aortic regurgitation.

Adolescent↗
PubMed1981

Left ventricular function in marathon runners: echocardiographic assessment.

Cardiac alterations induced by chronic isotonic exercise were assessed echocardiographically in 8 active male marathon runners aged 29 +/- 7 yr (mean +/- SD) compared with 10 sedentary controls aged 27 +/- 5 yr. The runners had a significantly higher aerobic capacity than the controls (72.8 +/- 6 vs. 41.4 +/- 6 ml . kg-1 . min-1; P less than 0.001). Compared with the controls, the runners had a significantly lower heart rate at rest (49 +/- 3 vs. 73 +/- 9 beats/min; P less than 0.01) and during submaximal supine exercise at a similar absolute work load (115 +/- 11 vs. 124 +/- 12 beats/min; P less than 0.01). Similarly, the runners had a lower pressure-rate product both at rest (5.52 +/- 1.0 x 10(3) vs. 9.43 +/- 1.4 x 10(-3)) and during submaximal exercise (19.7 +/- 3.2 x 10(3) vs. 25.0 +/- 4.2 x 10(3); P less than 0.01). The left ventricular peak velocity of circumferential fiber shortening of the runners relative to that of the controls was significantly reduced both at rest (1.40 +/- 0.08 vs. 1.64 +/- 0.08 circ/s) and during submaximal supine exercise at a similar absolute work load (2.36 +/- 0.15 vs. 2.71 +/- 0.10 circ/s). However, this reduction in V cf was found to be directly related to the lower pressure-rate product of the runners and therefore did not reflect a decreased intrinsic myocardial contractility in the runners relative to the controls.

Adult↗
PubMed1981

Transcutaneous continuous wave Doppler ultrasound in the diagnosis of left atrial myxoma.

Six cases of left atrial myxoma were studied using transcutaneous, continuous-wave, low-frequency Doppler ultrasound. The recordings, made from the suprasternal notch and the cardiac apex, showed characteristic deflections that coincided with tumor motion and provided a useful ancillary technique for noninvasively confirming the echocardiographic diagnosis of atrial myxoma.

Adult↗
PubMed1981

Mitral valve prolapse: a cause of stroke in children?

For a large proportion of children suffering a stroke, no specific cause can be found. Two cases with infantile hemiplegia are reported who subsequently were found to have mitral valve prolapse, which occurred as a familial trait in both cases. An association between stroke in childhood and mitral valve prolapse is suggested.

Adult↗
PubMed1980

Left atrial myxoma: report of six cases and review of the literature.

Six left atrial myxomas were detected at one hospital in a 15-month period. These tumours are not as rare as was once thought and they frequently cause systemic problems. The diagnosis may easily be missed, but echocardiography is a simple way of establishing the diagnosis. Excision of the tumour usually results in marked symptomatic improvement.

Adult↗
PubMed1980

Further evidence relating mitral-valve prolapse to cerebral ischemic events.

Echocardiography demonstrates prolapse of the mitral valve in at least 5 per cent of the population. Since some observations have linked this condition to stroke, we studied its incidence in two groups of patients with cerebral ischemia. The older group contained 141 patients over 45 years of age (mean, 64.7 years) who had transient ischemia or partial stroke. Prolapse was found in eight (5.7 per cent) of these patients and in 10 (7.1 per cent) of 141 age-matched controls. The second group contained 60 patients who had transient ischemia or partial stroke and were under 45 years old (mean 33.9 years). Prolapse was detected in 24 patients (40 per cent) but in only five (6.8 per cent) of 60 age-matched controls (mean age, 33.7 years). The odds ratio, 9.33, was highly significant (P less than 0.001). In six of the 24 patients there were other potential causes for cerebral ischemia leaving 18 whom the only recognizable potential cause was a prolapsing mitral valve (odds ratio, 7.00; P less than 0.001). This study suggests that this entity has a role in cerebral ischemia, at least in younger patients. (N Engl J Med 302:139-144, 1980).

Adult↗
PubMed1980

Familial stroke syndrome associated with mitral valve prolapse.

In a 27-member family, 8 individuals had mitral valve prolapse (MVP) by echocardiography. Four of them suffered a total of eight cerebral ischemic events in the first four decades of life. In none of these patients could risk factors for stroke, other than MVP, be found. Stroke did not occur in individuals free of MVP. This report draws attention to a previously unrecognized cause of familial stroke which strengthens the relationship between MVP and premature stroke.

Adult↗
PubMed1979

Ventricular response to isometric and isotonic exercise. Echocardiographic assessment.

The effects of supine isometric handgrip and graded isotonic bicycle ergometer exercise on left ventricular performance were studied echocardiographically in 20 normal subjects, aged 18 to 36. Measurements of the left ventricular minor axis diameter were taken from recordings performed at rest, during each form of exercise, and during recovery. At the completion of isometric exercise, the pressure-rate product increased significantly. There was no significant change in percentage of fractional shortening (%deltaD), while there was a small but significant fall in peak velocity of circumferential fibre shortening (peak Vcf). Isotonic exercise resulted in a significant increase in %deltaD and peak Vcf. The pressure-rate product also increased and showed a positive correlation with peak Vcf. Isotonic exercise produced a much greater stimulus to left ventricular contractility than isometric exercise and may be a useful means of detecting latent left ventricular dysfunction echocardiographically.

Adolescent↗
PubMed1978

Stress myocardial imaging in mitral leaflet prolapse syndrome.

Mitral leaflet prolapse syndrome has been associated with anginal chest pain, atypical chest pain, electrocardiographic abnormalities and positive stress electrocardiograms. These features overlap those of ischemic heart disease. Furthermore, coronary artery disease is frequently associated with mitral leaflet prolapse. This study evaluated the usefulness of stress myocardial scintigraphy in distinguishing these two disorders. Thirty-two patients with an angiographic diagnosis of mitral leaflet prolapse were studied. Of the 22 patients (8 men and 14 women, mean age 48 years) with a normal coronary arteriogram, 5 had "typical" angina pectoris, 6 had resting electrocardiographic abnormalities and 6 had a positive stress electrocardiogram; all 22 patients had a normal stress myocardial scintigram. Of the 10 patients (7 men and 3 women, mean age 55 years) with at least 70 percent stenosis of one coronary artery, 6 had "typical" angina pectoris, 1 had resting electrocardiographic abnormalities and 7 had a positive stress electrocardiogram. Nine of these 10 patients had one or more demonstrable perfusion defects on stress myocardial scintigrams. It is concluded that mitral leaflet prolapse syndrome is not associated with regional myocardial ischemia as demonstrated with stress scintigraphy, and that stress scintigraphy, a noninvasive technique, is useful in distinguishing the mitral prolapse syndrome from mitral prolapse associated with coronary artery disease.

Adult↗
PubMed1977

Strokes: A complication of mitral-leaflet prolapse?

During a prospective trial of platelet-inhibiting drugs in patients with transient ischaemic attacks (T.I.A.s), 14 patients had serious neurological dysfunction and normal cerebral angiograms. The patients (mean age 37 years) had neurological episodes over a period of 1-4 years consisting of acute non-progressive strokes with residual symptoms. In 3 patients, the two cerebral hemispheres were involved on different occasions. Cerebral angiograms showed no significant atheromatous disease in the intracranial or extracranial vessels. 3 patients had mid-systolic clicks, 5 had systolic murmurs, and 2 patients had both a click and a murmur. Holter electrocardiographic monitoring revealed atrial, junctional, or ventricular extrasystoles (5 patients), paroxysmal atrial fibrillation (3), and paroxysmal ventricular tachycardia (1). Left ventricular angiography confirmed mitral-leaflet prolapse in all the patients. The focal nature of the T.I.A.s suggests an embolic event, the embolus arising from the abnormal mitral valve. In a patient not included in this series, a small antemortem left atrial thrombus was found at necropsy.

Adolescent↗
PubMed1977

Dynamic elasticity of human mitral valve chorade tendinease.

Chordae tendineae are under constant dynamic stress and, therefore, measurements of static properties alone cannot provide a complete analysis of their mechanical response under stress. This study investigated the dynamic viscoelastic properties of human mitral valve chordae tendineae. The tissue was subjected to sinusoidal strain variations over a frequency range of 0.42 to 6.68 Hz. At a fixed strain, the storage modulus, E', was found to be independent of applied frequency but varied inversely with chordal thickness. Values in the order of 10(8) dyn cm-2 (1 dyn=10 muN) were found. E' also increased with strain level. The phase lag, phi, between stressing function and response was found to be small (0.2-0.058 rad) and decreased with frequency. Values of phi at each frequency were found to be independent of chordal size and strain level. This property would enable a smooth and even closure of the valve and provide a more rapid response at elevated heart rates. The loss modulus, E'', was found to be 18 to 50 times smaller than E'. This implied an almost complete recovery on removal of any stress on the tissue. E'', which also decreased with frequency, was found to be smaller for the larger chordae.

Adult↗
PubMed1977

Scanning electron microscopical study of human mitral valve chordae tendineae.

Scanning electron microscopy was used to examine the surface and internal structure of adult human mitral valve chordae tendineae. The endocardial cell surface of the tissue was found to be relatively smooth and even. Just beneath the endocardial surface, widely spaced collagen fibers were found. These were observed to be aligned at an angle to the chordal long axis and to wrap themselves around the central collagen core. The chordal core consisted of relatively straight collagen fibers that were arranged with their axis parallel to the long axis of the chordae. At the microstructural level, these collagen fibers were observed to consist of a network of collagen fibrils. This architectural arrangement is an advantageous feature for a tissue that is under constant dynamic stress. The scanning observations were confirmed by transmission electron microscopy.

Chordae Tendineae↗
PubMed1976

Cerebral ischemic events associated with prolapsing mitral valve.

Twelve patients who had no evidence of arteriosclerotic cerebral vascular disease, lacked hypertension or coagulation defect, and had not been receiving contraceptive therapy had recurrent transient cerebral ischemic attacks (TIAs) and partial nonprogressive strokes. All had prolapsing mitral valve proved by angiocardiography. The average age was 38 years, compared with 62 years in a larger series of patients with TIA associated with arteriosclerosis. We propose that the ischemic events are related to emboli emanating from the abnormal mitral valve with or without an associated paroxysmal cardiac arrhythmia.

Adult↗
PubMed1976

Parachute mitral valve: echocardiographic findings resembling idiopathic hypertrophic subaortic stenosis.

The echocardiographic features recorded in a patient with a congenital anomaly, single papillary muscle (parachute mitral valve), were identical with those seen in patients with idiopathic hypertrophic subaortic stenosis (IHSS). Asymmetric septal hypertrophy, mitral valve systolic anterior movement, aortic valve vibration, and midsystolic reclosure were all demonstrated. This congenital anomaly, should, therefore, be considered in any young patient before making the diagnosis of IHSS from the echocardiogram.

Cardiomyopathy, Hypertrophic↗