e; KO, knockout; SDNN, standard deviation of normal RR intervals; APC, %of animals with atrial premature contractions 17328890 during 10 min recording. P,0.05, P,0.05 by for x2 analysis. doi:10.1371/journal.pone.0033743.t001 Left Ventricular Histologic Alteration Routine histological stains did not reveal any structural difference between 4 month-old Fabry KO and wild type mice. Morphometric analysis showed identical myocyte diameters, and 22903131 electron micrographs showed occasional electron dense lamelated inclusion bodies, similar to previous descriptions . Statistical significance was determined by unpaired, two-tailed t-test: P,0.05: P,0.01. Abbreviations: LA, left atrium; LV, left ventricle; LV EDD, left ventricular end diastolic diameter; Vcfc, velocity of shortening of circumferential fibers; Sa, Spw: maximal systolic velocity of the mitral annulus and posterior wall; IVRT: isovolumic relaxation time; Ea and Epw: maximal diastolic velocity of the mitral annulus and posterior wall; E, maximal 
velocity of LV inflow. doi:10.1371/journal.pone.0033743.t002 Staining with Picrosirius Red showed no significant differences in non-vascular collagen staining in the myocardium of male Fabry KO mice compared to WT mice and no predominant area of fibrosis in Fabry KO mice. Systolic Blood Pressure, Heart Rate, ECG and Cardiac Weight Measurements: Effects of ERT The measurements of RR intervals with surface ECG recordings showed identical RR intervals and the standard deviation of the RR intervals, and the frequency of premature atrial contractions for Fabry KO mice compared to Fabry KO mice treated with 3 mg/kg intravenous ERT 3 weeks before. There were no significant differences in PQ, QRS, or corrected QT intervals. ERT had no effect 3 weeks after 50-57-7 injection on heart weight for Fabry KO mice, when normalized to body weight or tibial length. There was no effect 3 weeks after injection on heart weight for WT mice, when normalized to body weight or tibial length. LV Molecular Alterations in Fabry KO Mice We examined myocardial alterations that could be associated with cardiac remodeling and dysfunction by analyzing mRNA expression for atrial natriuretic factor brain natriuretic peptide, plasminogen activator inhibitor-1; connective tissue growth factor, thrombospondin 1, and thrombospondin 2. As shown in Left Ventricle and Aortic Structural Alterations with ERT The echocardiography results for 67 month-old Fabry KO mice are summarized in 4 Cardiomyopathy in Fabry Mouse Model age-matched controls according to a trend toward decrease in LV diameter after treatment without change in wall thickness. There was a significant decrease in the aortic diameter during diastole for Fabry KO mice treated with ERT compared to the age-matched KO controls. Left Ventricular Functional Alterations in Fabry KO Mice with ERT The heart rates obtained in 67 week old mice undergoing echocardiography with isoflurane anesthesia were the same for untreated Fabry KO mice compared to age-matched Fabry KO mice that had received ERT as a single IV injection 3 weeks before evaluation. LV systolic function, as assessed by echocardiography was similar in ERT-treated Fabry KO mice as compared to agematched untreated KO mice. ERT-treated Fabry KO WT Controls Myocyte diameter Collagen content doi:10.1371/journal.pone.0033743.t003 82.669.9 0.005660.0025 Fabry KOs 79.164.9 0.004660.0008 Cardiomyopathy in Fabry Mouse Model mice had similar diastolic LV function as the untreated KO controls. LV Mole
