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W D Spotnitz

Publications and source records attributed to W D Spotnitz.

83 records · Page 5Linked to original sources
PubMed1985

Compliance, mass, and shape of the canine left ventricle after global ischemia analyzed with two-dimensional echocardiography.

End-diastolic pressure (EDP)-volume (EDV) curves were constructed for the left ventricle (LV) in 10 dogs on cardiopulmonary bypass before and after 45 min of normothermic ischemic arrest. LVEDV and mass were calculated from three perpendicular two-dimensional echocardiographic sections using a Simpson's rule algorithm. The echocardiographic method employed was specially developed in earlier work for physiologic studies in dogs. Postmortem pressure-volume curves were measured for comparison by direct saline infusion into sealed ventricles. LVEDV was plotted against LVEDP (0-20 mm Hg) and data were analyzed by two-way analysis of variance and also by exponential curve fitting to the relation EDP = alpha e beta EDV, where beta is the derived exponential constant reflecting slope and thereby ventricular stiffness. Postischemic EDP-EDV curves shifted to the left and the beta constant increased (beta = 0.02 +/- 0.005 (SE) vs 0.05 +/- 0.01, P less than 0.05). LV eccentricity, the ratio between long- and short-axis measurements, was unchanged (1.43 +/- 0.05 vs 1.46 +/- 0.06 postischemia, NS), but LV mass increased (105 +/- 7 vs 128 +/- 9 g postischemia, P less than 0.001). Postischemic LV mass by echo was not significantly different from measured postmortem LV mass (r = 0.87). The nonparallel alteration in the EDP-EDV curves, lack of change in LV shape (eccentricity), and increase in LV mass in the postischemic ventricle suggest that increased ventricular stiffness rather than direct encroachment by the edematous endocardium on chamber volume is responsible for postischemic changes in LV diastolic properties.

Animals↗
PubMed1985

Effects of simulated clinical cardiopulmonary bypass and cardioplegia on mass of the canine left ventricle.

Myocardial edema is a well-documented response to ischemia and reperfusion in dogs and can be detected as an increase in left ventricular (LV) mass measured echocardiographically. Investigation in human beings has failed to demonstrate similar increases in LV mass after routine cardiac operations. However, direct comparison of these observations is not possible, because dogs have not been studied under conditions of cardiopulmonary bypass (CPB) and global ischemia that rigorously reproduce those of a clinical operation. Accordingly, clinical CPB and global ischemia were simulated in 8 adult dogs. Multisection two-dimensional echocardiograms and a computerized light pen were used to calculate LV volume and mass. The data were analyzed during four periods: before CPB; CPB before cross-clamping; CPB after cross-clamping, and after CPB. Echocardiographic LV mass increased significantly from 89.5 +/- 7.4 gm (before CPB) to 94.6 +/- 8.5 gm (CPB before cross-clamping) (p less than 0.05) and from 94.6 +/- 8.5 gm to 100.4 +/- 8.1 gm (CPB after cross-clamping) (p less than 0.05). Overall, mass increased 13.9% (p less than 0.05). Mean wall thickness increased 0.08 cm (p less than 0.05) overall and correlated with the increase in mass (r = 0.79). Postmortem mass correlated well with late echocardiographic mass (r = 0.95). Interobserver correlation of 98 separate mass determinations was high (r = 0.84) with a coefficient of variation of 10.5%. We conclude that canine LV mass increases significantly with CPB and global ischemia maintained within clinical standards and that human beings and dogs may differ in extent of edema during CPB.

Animals↗
PubMed1984

Effect of cardiopulmonary bypass and global ischemia on human and canine left ventricular mass: evidence for interspecies differences.

Previous studies in dogs suggest that global ischemia with cardiopulmonary bypass causes increased left ventricular (LV) mass and water content. To investigate effects in humans, we developed a simplified method for mass determination by intraoperative two-dimensional echocardiography. LV mass was measured as echocardiographic short-axis myocardial area. This was validated by linear regression versus postmortem LV mass in 10 dogs (r = 0.89) and versus single-plane angiography in 18 patients (r = 0.73). According to this method, there was no change in LV mass (209 gm versus 208 gm; NS) at constant preload in 20 patients during routine operations (eight coronary revascularizations, 10 aortic valve replacements, and two mitral valve replacements). The same method used in 10 dogs after 2 hours of bypass, 60 minutes of normothermic global ischemia, and reperfusion revealed an LV mass increase from 113 +/- 13 gm (SE) to 150 +/- 16 gm (p less than 0.01) at matched preload. In addition, in 14 dogs after 2 hours of bypass alone, LV mass was unchanged (98 +/- 5 gm versus 101 +/- 5 gm; NS) at matched preload. Data recently derived from a separate study in our laboratory revealed a statistically significant increase in canine LV mass when conditions of human cardiopulmonary bypass and cardioplegic arrest were reproduced. We conclude that uncomplicated cardiac operations in humans do not alter LV mass. This supports the safety of crystalloid cardioplegia in humans. While present evidence is not conclusive, it appears that the threshold for edema formation after ischemic injury may be higher in humans than it is in dogs. The clinical relevance of studies of cardioplegia in edematous dog hearts thus deserves careful scrutiny.

Animals↗
PubMed1984

Pharmacologic antagonism of propranolol in dogs. III. Effects of dopamine-isoproterenol and glucagon on hemodynamics and myocardial oxygen consumption in ischemic hearts during chronic propranolol administration.

In 31 dogs chronically beta blocked with oral propranolol (12 to 14 mg/kg/day), glucagon (20 micrograms/kg) and combined dopamine (10 micrograms/kg/min) and isoproterenol (0.2 micrograms/kg/min) were given intravenously and tested for hemodynamic efficacy. Dogs were divided into four groups. Basal hemodynamics were obtained In Group I (n = 8) without cardiopulmonary bypass. In Group II (n = 8), hemodynamics were studied after 15 minutes of global ischemia during cardiopulmonary bypass. In Group III (n = 8), hemodynamics were studied after regional ischemia produced by ligation of the proximal left anterior descending coronary artery. In Group IV (n = 7), myocardial oxygen consumption and left ventricular mechanics were studied before and after 1 hour of cardiopulmonary bypass. Our results indicate the following: (1) Dopamine-isoproterenol improves hemodynamics in basal, post-global ischemic, and post-regional ischemic states. Glucagon improves hemodynamics either insignificantly or to a lesser extent than dopamine-isoproterenol. Furthermore, glucagon produces a larger increase in heart rate, which is not desirable. (2) Both dopamine-isoproterenol and glucagon increase myocardial oxygen consumption in comparison with control.

Animals↗
PubMedDate not supplied

Method for the quantitation of myocardial perfusion during myocardial contrast two-dimensional echocardiography.

This article describes the hardware and software components of two systems designed for quantitative analysis of data obtained during myocardial contrast two-dimensional echocardiography. One system is meant for off-line analysis of data, whereas the other is designed for on-line analysis, especially in the operating room. The algorithms used for data transfer, selection of appropriate frames, data alignment, derivation of time-intensity plots, and curve-fitting and parameter generation are described in some detail. It is hoped that this information will be of use to others who work in the field of myocardial perfusion imaging.

Algorithms↗
PubMedDate not supplied

Effects of fibrin sealant-containing antibiotics in a rabbit model of chronic sinusitis.

Postoperative complications of sinus surgery include bleeding, infection, and synechiae. Improved subjective outcomes in humans treated with fibrin sealant (FS) after endoscopic sinus surgery (ESS) have been reported. Streptococcus pneumoniae was used to initiate chronic sinusitis in occluded rabbit sinuses in order to evaluate the role of FS in mucosal healing. Six weeks later, all animals had maxillary antrostomies. Homologous FS-containing ciprofloxicin (100 mg/mL) and clindamycin (15 mg/mL) was applied topically to treatment rabbits (n = 9). Control rabbits (n = 10) received no antibiotics. Two weeks into the recovery phase after antrostomies, all animals were re-examined. Mucociliary transport velocity (mean +/- standard deviation in mm/minute) was measured in all sinuses (n = 38) during healthy (100% measurable, 13.82 +/- 4.16), infected (18% measurable, 4.74 +/- 0.42), and recovery phases (5% measurable, 6.30 +/- 4.67). In both groups, mucopurulent discharge was present in the majority of sinuses (control group 18/20, FS group 16/18). In addition, there was no significant difference in the recovery phase between the two groups when comparing changes in the size of antrostomies, light microscopy, or culture clearance. Scanning electron microscopy did suggest a possible improvement in ciliary regeneration in the FS group. Application of FS-containing antibiotics did not appear to improve healing after ESS in our rabbit model of chronic sinusitis.

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