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Biomedical subjects

J L Vanoverschelde

Publications and source records attributed to J L Vanoverschelde.

78 records · Page 5Linked to original sources
PubMed1990

Left ventricular filling in dilated cardiomyopathy: relation to functional class and hemodynamics.

Left ventricular systolic function does not correlate well with functional class in patients with dilated cardiomyopathy. To determine whether the correlation is better with Doppler indexes of left ventricular diastolic function, 34 patients with dilated cardiomyopathy (M-mode echocardiographic end-diastolic dimension greater than 60 mm, fractional shortening less than 25%, increased E point-septal separation) were studied. Patients were classified into two groups according to functional class. Group 1 consisted of 16 patients in New York Heart Association functional class I or II; group 2 included 18 patients in functional class III or IV. Left ventricular dimensions, fractional shortening, left ventricular mass, meridional end-systolic wall stress, peak early and late transmitral filling velocities and their ratio, isovolumetric relaxation period and time to peak filling rate were computed from pulsed wave Doppler and M-mode echocardiograms and calibrated carotid pulse tracings. Right heart catheterization was performed in 20 of 34 patients. No differences were observed between groups with regard to age, gender distribution, heart rate, blood pressure and M-mode echocardiographic-derived indexes of systolic function. Peak early filling velocity (72 +/- 13 versus 40 +/- 10 cm/s, p less than 0.001) was higher and atrial filling fraction (27 +/- 4% versus 46 +/- 8%, p less than 0.001) was lower in group 2 than in group 1. The ratio of early to late transmitral filling velocities was higher in group 2 patients (2.3 +/- 0.5 versus 0.7 +/- 0.2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Electrovectorcardiographic diagnosis of left ventricular hypertrophy in complete left bundle-branch block].

Diagnosis of left ventricular hypertrophy (LVH) in the presence of complete left bundle-branch block (CLBB) is difficult. The value of several electro-vectorcardiographic criteria were studied in a series of 71 patients with CLBB analyzed by echocardiography. Thirty nine of the patients (55%) had anatomical LVH defined as being a left ventricular weight (LVW) above 316 g. Twenty five of the 71 patients (35%) had dilated cardiomyopathy (dCMP). Of the hypervoltage indices, only the sum of RV6 + SV2 and the QRS spatial maximum vector (MAXQRSxyz) showed a significant difference between the group with LVH and the group without LVH. The duration of QRS and the average vector of spatial area (AQRSxyz) also differed significantly between the two groups and showed a good correlation with LVW. Of the various criteria for LVH, the best balance between sensitivity and specificity belonged to the criteria of duration of QRS greater than 150 msec and AQRSxyz greater than 140 mV.msec, with a merit ratio of 0.44 and a diagnostic accuracy of 72 per cent. In the dCMP subgroup, all the voltage and duration indices were significantly different between the two groups. The criterion AQRSxyz greater than 135 mV.msec obtained the best diagnostic score, with a sensitivity of 94 per cent, specificity of 100 per cent, and accuracy of 96 per cent. This parameter gave the best overall expression of the combination of hypervoltage and delay in ventricular depolarization produced both by hypertrophy/ventricular dilation and conduction disturbances.

Aged↗
PubMed1989

Influence of transmitral filling dynamics on continuous-wave Doppler assessment of aortic regurgitation by half-time methods.

The influence of transmitral filling dynamics on the evaluation of aortic regurgitation (AR) by continuous-wave Doppler pressure half-time was assessed in 30 consecutive patients in sinus rhythm with chronic moderate to severe AR. Pulsed-wave Doppler-derived regurgitant fraction (obtained from aortic and pulmonary stroke volumes) and color flow mapping relative regurgitant area (obtained from the parasternal short-axis view) were chosen as reference standards for the severity of AR. An excellent correlation was found between these 2 parameters (r = 0.98), while correlations were poor between pressure half-time and either regurgitant fraction (r = -0.74) or relative regurgitant jet area (r = -0.69). The ratio of early (E) to late (A) transmitral peak velocities was used to divide the study population into 2 groups: group A (n = 16) with E/A less than 1 and group B (n = 14) with E/A greater than 1. In patients with a similar degree of AR (estimated from Doppler regurgitant fraction or relative regurgitant jet area), the pressure half-time was found to be significantly shorter. Thus, the severity of AR in group A patients was overestimated (p less than 0.01). Compared to group B, group A patients were significantly shorter. Thus, the severity of AR in group A patients was overestimated (p less than 0.01). Compared to group B, group A patients were significantly older (p less than 0.02) and had a larger left ventricular mass (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMedDate not supplied

The use of carbon 11-labeled acetate for assessment of aerobic metabolism.

Carbon 11-labeled acetate has been validated as a tracer of citric acid flux and indirectly of oxidative metabolism. 11C-labeled acetate is predominantly metabolized to 11C-labeled carbon dioxide, which clears from the heart. The myocardial 11CO2 efflux rate that can be estimated by dynamic positron emission tomographic imaging closely correlates with myocardial oxygen consumption over a wide range of flow, substrate use, and metabolic conditions. 11C-labeled acetate clearance rates are indirect indexes of oxidative metabolism. To provide absolute mass fluxes, the 11C-labeled acetate approach would require biochemical validation and configuration of a tracer kinetic model. Clinically, estimates of myocardial oxygen consumption appear to be useful in assessing tissue viability, as shown in patients after acute myocardial infarction or with chronic coronary artery disease. In non-coronary artery disease, 11C-labeled acetate may provide measurement of cardiac efficiency and be useful for monitoring therapy.

Acetic Acid↗
PubMedDate not supplied

The pathophysiology of myocardial hibernation: current controversies and future directions.

It is now widely accepted that patients with chronic coronary artery disease can experience prolonged regional ischemic dysfunction that does not necessarily arise from irreversible tissue damage and, to some extent, can be reversed by restoration of blood flow. Recent clinical and experimental data suggest that this form of chronic but reversible left ventricular dysfunction represents a complex, progressive, and dynamic phenomenon. The initial stages of dysfunction are probably caused by chronic stunning. They are characterized by normal resting perfusion but reduced flow reserve, mild myocyte alterations, maintained membrane integrity (allowing the transport of both thallium and glucose), preserved capacity to respond to an inotropic stimulus, and no or little tissue fibrosis. After revascularization, functional recovery will probably be rapid and complete. On the other hand, the more advanced stages of dysfunction likely correspond to chronic hibernation. They usually are associated with reduced rest perfusion; increased tissue fibrosis; more severe myocyte alterations (degeneration[?], apoptosis); and a decreased ability to respond to inotropic stimuli. Nonetheless, membrane function and glucose metabolism may long remain preserved. After revascularization, functional recovery, if any, will probably be quite delayed and mostly incomplete.

Animals↗