Effects of ischemia on epicardial segment shortening

To evaluate the effects of nontransmural ischemia on epicardial contractile function, we implanted sonomicrometers in 15 open-chest, anesthetized (halothane) dogs. One cylindrical crystal (radiating ultrasound 360[deg]) was used as a transmitter for three conventional flat plate crystals arrayed to measure epicardial segment shortening along three different axes that were deviated 0[deg] (parallel), 45[deg] (oblique), and 90[deg] (perpendicular) from surface fiber orientation in the anteriorapical or posterior-basal left ventricle. During baseline conditions, epicardial shortening was maximal parallel with fiber orientation. Shortening decreased in a non-linear manner as deviation from fiber orientation increased, but there were significant differences between the two left ventricular regions suggesting that more substantial lateral strain occurs in the anterior-apical than the posterior-basal area. During coronary inflow restriction, changes in epicardial segment shortening also varied greatly depending on location and alignment. At levels of wall thickening impairment associated with normal subepicardial perfusion, changes in epicardial function were restricted to the segments aligned perpendicular to fiber orientation whereas the parallel and oblique segments displayed moderate dysfunction or none at all. Thus, transmural tethering modifies epicardial segmental motion during coronary inflow restriction, but the severity of the influence depends on the alignment and location of the epicardial measurements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29525/1/0000612.pd

Provocation of ventricular tachycardia by an automatic implantable cardioverter defibrillator

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28495/1/0000292.pd

Cardiac pheochromocytoma involving the left main coronary artery presenting with exertional angina

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26628/1/0000169.pd

Measurements of Inclusive W and Z Cross Sections in p-pbar Collisions at sqrt{s} =1.96 TeV

We report the first measurements of inclusive W and Z boson cross sections times the corresponding leptonic branching ratios for p pbar collisions at sqrt{s} = 1.96 TeV based on the decays of the W and Z bosons into electrons and muons. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 72.0 +/- 4.3 pb-1. We test e-mu lepton universality in W decays by measuring the ratio of the W->mu nu to W->e nu cross sections and determine a value of 0.991 +/- 0.004(stat.) +/- 0.011(syst.) for the ratio of W-l-nu couplings (g_mu/g_e). Since there is no sign of non-universality, we combine our cross section measurements in the different lepton decay modes and obtain sigma*BR(W->lnu) = 2.749 +/- 0.010(stat.) +/- 0.053(syst.) +/- 0.165(lum.) nb and sigma*BR(gamma*/Z->ll)=254.9 +/- 3.3(stat.) +/- 4.6(syst.) +/- 15.2(lum.) pb for dilepton pairs in the mass range between 66 GeV/c^2 and 116 GeV/c^2. We compute the ratio R of the W->lnu to Z->ll cross sections taking all correlations among channels into account and obtain R=10.84 +/- 0.15(stat.) +/- 0.14(syst.) including a correction for the virtual photon exchange component in our measured gamma*/Z->ll cross section. Based on the measured value of R, we extract values for the W leptonic branching ratio, BR(W->lnu) =0.1082 +/- 0.0022; the total width of the W boson, Gamma(W) =2092 +/- 42 MeV; and the ratio of W and Z boson total widths, Gamma(W)/Gamma(Z) = 0.838 +/- 0.017. In addition, we use our extracted value of Gamma(W) whose value depends on various electroweak parameters and certain CKM matrix elements to constrain the V_CS CKM matrix element, |V_CS| = 0.976 +/- 0.030.Comment: 88 pages, 37 figures, published J. Phys.

Comparison of polyclonal antibody sera for early prophylaxis following cardiac transplantation

In order to test different polyclonal antibody regimes as early prophylaxis against cardiac rejection, 42 patients (ages 30 to 60 years) transplanted at the University of Michigan from December 1986 to August 1988 were randomized to receive antithymocyte globulin (ATGAM, Upjohn, n = 19) or antilymphoblast globulin (MALG, University of Minnesota, n = 23). Cyclosporine (CYA), steroids, and azothiaprine (AZA) administration was similar in all randomized patients during early prophylaxis. CYA was begun preoperatively and maintained at a serum level of 250-300 ng/ml. After an initial steroid taper, patients were maintained on 0.3 mg/kg/day. AZA was begun after polyclonal prophylaxis at 1-2 mg/kg. All patients received either ATGAM or MALG for 7 days or until the serum CYA reached 250 ng/ml. Although sex, pretransplant hemodynamics, follow-up length, total drug dose, mortality (one per group), postoperative white blood cell and lymphocyte counts did not differ between groups, MALG significantly delayed the first rejection episode as compared to ATGAM (35 +/- 4 vs 22 +/- 3 days, P P < 0.05). The beneficial effect of MALG may be due to immune-specific differences in its polyclonal spectrum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27736/1/0000128.pd

Effect of Antiarrhythmic Drug Therapy on the Incidence of Shocks in Patients who Receive an Implantable Cardioverter Defibrillator after a Single Episode of Sustained Ventricular Tachycardia/Fibrillation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71851/1/j.1540-8159.1991.tb02733.x.pd