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Biomedical subjects

L M Shapiro

Publications and source records attributed to L M Shapiro.

At least 73 records · Page 4Linked to original sources
PubMed1992

Conservative surgery of the mitral valve: a report of the first 100 cases from one unit and one surgeon.

OBJECTIVE: To report the first 100 mitral valve repairs performed in a unit with an aggressive approach to conservative mitral valve surgery. DESIGN: Case notes were reviewed retrospectively and patients invited for clinical examination and cross sectional and Doppler echocardiography. SETTING: Tertiary cardiothoracic referral centre. PATIENTS: Between December 1985 and April 1991 mitral valve repair was carried out on 100 patients (66 males). Patients with pure mitral stenosis were excluded. Sixty seven had degenerative and 15 rheumatic mitral valve disease. Median age was 66 (range 12 to 79) years, with an interquartile range of 59 to 71 years. INTERVENTIONS: Operative procedures included annuloplasty ring in 97, resection of the posterior leaflet in 67, resection of endocarditic portion of posterior leaflet in four, commissurotomy in six, and correction of anterior leaflet abnormalities in seven. Thirty nine concomitant cardiac procedures were performed in 32 patients. Six operations were emergencies, and three of these required concomitant procedures. MAIN OUTCOME MEASURES: Mortality, operative failure rate, patients' functional state and degree of residual mitral regurgitation, incidence of thromboembolism, and endocarditis. RESULTS: Follow up ranged from one to 59 months, median 14 months, and an interquartile range of four to 23.5 months. Early mortality was 1%, late mortality 5%, and there was a 2% reoperation rate. Eighty four patients had moderate to severe mitral regurgitation preoperatively. At follow up mitral regurgitation was absent or mild in 78. Eighty six patients were in New York Heart Association (NYHA) class I-II at follow up compared with 80 in NYHA class III-IV preoperatively. There were no thromboembolic events. CONCLUSION: This study shows that satisfactory results can be obtained with mitral valve repair in a fairly elderly population with a high incidence of concomitant cardiac disorders. We suggest that these encouraging results will lead to earlier mitral valve repair in mitral regurgitation.

Adolescent↗
PubMed1992

Hemodynamic evaluation of the Monostrut and spherical disc Björk-Shiley aortic valve prosthesis with Doppler echocardiography.

A Doppler echocardiographic study was performed to assess whether the Monostrut model of the Björk-Shiley valve (Shiley, Inc., Irvine, Calif.) had an improved hemodynamic performance in comparison with the spherical disc model in the aortic position. Twenty retrospectively randomly selected patients were studied, 10 with each valve type. Within each valve type two sizes of valve were studied, 21 and 23 mm. The two groups were comparable with respect to age, postoperative time, fractional shortening, New York Heart Association functional class preoperatively, and body surface area. Pulsed and continuous wave Doppler measurements were recorded at rest. Continuous wave Doppler recordings were performed every 2 minutes after exercise with supine bicycle ergometry until 10 minutes after exercise. Peak and mean gradients across the aortic valve prostheses were estimated. Both groups achieved a significant and comparable rise in heart rate with exercise. The mean gradients +/- standard error of the mean at rest and 2 minutes after exercise were 19.7 +/- 1.9 mm Hg and 30.9 +/- 2.2 mm Hg, respectively in the spherical disc group compared with 14.9 +/- 1.1 mm Hg and 23.6 +/- 1.7 mm Hg in the Monostrut group (p < 0.05 and p < 0.025, respectively). Peak transvalvular gradient at rest was 30.7 +/- 2.7 mm Hg in the spherical group compared with 23.9 +/- 1.9 mm Hg in the Monostrut group (p < 0.05). We conclude that the Monostrut Björk-Shiley valve prosthesis has better hemodynamic performance than the spherical disc model in the aortic position.

Aortic Valve↗
PubMed1992

Morphologic consequences of systematic training.

The development of echocardiography in the 1970s led to the flourishing of the study of the athlete's heart. From the earliest studies it was apparent that athletes develop enlargement of the left ventricular cavity and thickening of myocardium in response to prolonged repetitive training. The changes in echocardiographic measurements are small and often within quoted normal ranges. By comparison to sedentary controls, however, left ventricular end-diastolic dimension is increased by approximately 10%, posterior wall dimension by 15% to 20%, and calculated mass by up to 45%.

Adaptation, Physiological↗
PubMed1991

Ambulatory electrocardiography in dogs.

Twenty-four hour ambulatory electrocardiographic recording using a Medilog tape recorder was attempted in 16 healthy pet dogs weighing between 18.4 and 34 kg, while they were living in familiar surroundings. Full 24-hour records were obtained from 10 of them and recordings of more than 10 hours duration from two others; and the findings in these recordings were similar. Maximum heart rates ranged between 110 and 300 beats/minute and the minimum rates ranged between 17 and 46 beats/minute. Intermittent ventricular premature complexes were recorded from these apparently healthy dogs and all but one dog demonstrated a sinus pause, longer than two seconds; the longest pause was 5.7 seconds. The pauses were associated with marked sinus arrhythmia and occurred in both brachycephalic and non-brachycephalic breeds.

Animals↗
PubMed1991

Experience of percutaneous transluminal coronary angioplasty in orthotopic cardiac transplant recipients.

We evaluated the role of percutaneous transluminal coronary angioplasty (PTCA) in a series of orthotopic cardiac transplant recipients with severe epicardial coronary occlusive disease. Ten orthotopic cardiac transplant patients treated by PTCA up to March 1990 were reviewed. All had significant epicardial coronary artery lesions (greater than 70% stenosis compared with the adjacent healthy artery) and exercise electrocardiogram or isotope perfusion evidence of myocardial ischaemia in the relevant region. Primary angiographic PTCA success was achieved in 12 of the 16 lesions attempted (75%). Mean stenosis improvement was from 80% of adjacent healthy artery (range 70-90%) to 12% (range 0-20%). Median angiographic follow-up of 9 months (2-25 months) is available for all patients. The mean recurrence rate is 33% (4 of 12 successfully treated lesions) defined as greater than 50% reduction in the original gain at the PTCA. We have shown that PTCA is technically possible in a series of cardiac transplant recipients. The primary success and recurrence rates are comparable to the use of PTCA in conventional atherosclerotic coronary disease.

Adult↗
PubMed1991

Histopathological validation of high frequency epicardial echocardiography of the coronary arteries in vitro.

The accuracy and reliability of measurement of coronary artery dimensions and detection of atherosclerotic lesions by high frequency epicardial echocardiography were compared with histopathological results. Ten pressure perfused human hearts were examined in vitro with a 10 MHz (Diasonics) transducer and a 7.5 MHz (Vingmed/Sonotron) transducer. There was close agreement between ultrasound and pathological measurements of coronary artery luminal diameter. Qualitative changes in wall structure such as diffuse wall thickening and calcification were readily identified; however, the resolution of the transducers was not high enough accurately to measure wall dimensions in normal coronary arteries. Coefficient of variation measurements for intra and inter observer variability (5.2% and 6.9% respectively) showed excellent reproducibility. The technique was accurate in identifying atherosclerotic lesions, imaging arteries distal to an occlusion, locating deeply sited arteries, and identifying complete obliteration of an artery. Intraoperative video playback and transducer miniaturisation may minimise problems caused by cardiac movement and restricted access. With these developments intraoperative assessment of coronary artery disease may become a real possibility.

Coronary Artery Disease↗
PubMed1990

Pituitary apoplexy following coronary artery bypass surgery.

Pituitary apoplexy is a syndrome with variable clinical manifestations depending on which parasellar structures (such as the optic nerves and chiasm, cavernous and sphenoid sinuses, or the hypothalamus) are compressed when the pituitary undergoes rapid enlargement. Factors associated with cardiopulmonary bypass that may lead to pituitary apoplexy include ischemia, hemorrhage, edema, and positive pressure ventilation. Seven cases of pituitary apoplexy following cardiopulmonary bypass have been reported, including the present case. Transsphenoidal surgical decompression in the present case and those previously reported appears to be safe after cardiac surgery and may be helpful in amelioration of compression of nearby structures. Pituitary apoplexy should be considered as a diagnostic possibility in patients who develop visual disturbances or ophthalmoplegia following open heart surgery.

Coronary Artery Bypass↗
PubMed1990

Familial restrictive cardiomyopathy with atrioventricular block and skeletal myopathy.

Five generations of an Italian family with an autosomal dominant restrictive cardiomyopathy are described. Members of four generations were examined. Symptoms usually developed in the third or fourth decade but the disease did occur in childhood. Initially the condition was characterised by normal ventricular size and systolic function with increased diastolic filling pressures in both ventricles and consequent bi-atrial enlargement. Cardiac catheterisation showed a left ventricular filling pattern of "dip and plateau". The electrocardiogram typically showed non-specific changes in the ST segment and T wave and changes indicating considerable atrial enlargement, which were confirmed by echocardiography. Light microscopy of two endocardial biopsy specimens showed no specific features but excluded the endomyocardial fibrosis of eosinophilic heart disease, amyloid, and specific heart muscle diseases. At necropsy in one case examined under light microscopy extensive patchy fibrosis was found throughout the endocardium, myocardium, and subepicardium, but there were no features typical of eosinophilic heart disease. Histopathological and biochemical examination of skeletal muscle identified no abnormality. The disease often had an insidious course over five to ten years after presentation. Bundle branch blocks, leading to complete atrioventricular block, however, often occurred and may be the first manifestation. Some individuals who survived into the fifth decade developed a progressive, non-wasting skeletal myopathy.

Adolescent↗
PubMed1990

Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.

A fatal case of Lyme carditis occurring in a Suffolk farmworker is reported. Post-mortem examination of the heart showed pericarditis, focal myocarditis and prominent endocardial and interstitial fibrosis. The additional finding of endodermal heterotopia ('mesothelioma') of the atrioventricular node raises the possibility that this could also be related to Lyme infection and account for the relatively frequent occurrence of atrioventricular block in this condition. Lyme disease should always be considered in a case of atrioventricular block, particularly in a young patient from a rural area. The heart block tends to improve and therefore only temporary pacing may be required.

Adult↗
PubMed1989

Diurnal variation of pulmonary artery pressure in chronic heart failure.

Variation in pulmonary artery pressure has important consequences for the interpretation of isolated pressure measurements in patients with chronic heart failure. To investigate the nature of diurnal variation in pulmonary artery pressure in chronic heart failure, eight angina-free men (aged 50-72 years) with treated chronic heart failure caused by ischaemic heart disease underwent continuous ambulatory pulmonary artery pressure recording by a transducer tipped catheter. The mean (1 SD) daytime pulmonary artery pressure was 29.6 (5.0) mm Hg systolic and 13.7 (5.6) mm Hg diastolic. The mean change in pressure from day to night was +5.1 (3.2) mm Hg systolic and +3.8 (1.7) mm Hg diastolic; and the mean change from standing to lying +9.3 (2.3) mm Hg systolic and +6.4 (2.1) mm Hg diastolic. In six of the eight patients there was considerable rise in pulmonary artery pressure at night, but in the two patients with the most severe symptoms there was no nocturnal rise. In patients with chronic heart failure, nocturnal pulmonary artery pressure is not determined by postural change alone. But interpretation of isolated pulmonary artery pressure measurements must take the posture of the patient into account.

Aged↗
PubMed1988

Detection of valvar obstruction by intracardiac masses using Doppler echocardiography.

The purpose of this paper was to examine valvar involvement in patients with intracardiac masses. Seven patients with intracardiac masses were studied by cross-sectional and Doppler echocardiography. In one, a candida vegetation on a mitral Starr-Edwards prosthesis obstructed the aortic valve with a peak transvalvar velocity of 2 m/sec and aortic regurgitation. Another patient with endocarditis demonstrated mitral stenosis as did two patients with left atrial myxomata. Tricuspid stenosis was demonstrated in three patients with right ventricular intracardiac masses (primary and secondary tumour and thrombus). By Doppler, the mitral and tricuspid stenosis was similar to from that seen in rheumatic heart disease with increased peak transvalvar velocity and prolonged pressure half-time. Because of the hazards associated with cardiac catheterisation in intracardiac masses, we conclude that Doppler ultrasound allows for the adequate assessment of the haemodynamic alterations so as to complement the images obtained by cross-sectional echocardiography.

Adult↗
PubMed1988

Unusual presentation of endomyocardial fibrosis.

A case of endomyocardial fibrosis in a Greek patient who had not visited the tropics is described. The patient suffered from an unusual form of the disease in that it was aggressive and recurrent (requiring three operative procedures) and presented with tricuspid stenosis, leading to syncope.

Adult↗
PubMed1988

Patterns of diastolic dysfunction in left ventricular hypertrophy.

The relative sensitivities of and interrelations between different measurements of diastolic function were studied in 50 patients with left ventricular hypertrophy diagnosed on anatomical grounds. Isovolumic relaxation time, the interval from minimum cavity dimension to mitral valve opening and relative dimension increase during this period, and the peak rate of dimension increase and wall thinning during rapid ventricular filling were measured by digitised M mode echocardiography. The relative heights of peak early diastolic and atrial velocities (a/E) and the time for decline of early diastolic velocity to half its peak value (velocity half time) were measured on continuous wave and pulsed Doppler and the relative height of the "a" wave was measured by apexcardiogram. All sets of values except those of the interval from minimum dimension to mitral opening were unimodally distributed, and all differed significantly from those in 20 age matched controls. The relative height of the "a" wave on the apexcardiogram (90% values were abnormal) was the most sensitive method of studying left ventricular diastolic function and peak rate of dimension increase was the least sensitive. Though none of the correlations was high, there were individual associations between peak rate of dimension increase, a/E, peak wall thinning rate, and velocity half time, and independently between delay in mitral valve opening and dimension change during this period. Other values seemed to be independent of one another, suggesting a different physiological basis. It is concluded that these various abnormal values do not reflect a single underlying disturbance of diastolic function. There are at least four possible discrete abnormalities: prolongation of isovolumic relaxation; incoordination during isovolumic relaxation; reduced rate of rapid filling; and an increase in the relative amplitude of the "a" wave probably caused by increased passive stiffness. These may be present singly or in combination in any patient.

Adolescent↗