Impaired HRT, abnormal TWA, and an EF <0.50 beyond 8 weeks after MI reliably identify patients at risk of serious events. (Assessment of Noninvasive Methods to Identify Patients at Risk of Serious Arrhythmias After a Heart Attack; http://www.clinicaltrials.gov/ct/show/NCT00399503?order=1; NCT00399503).

CSH is associated with a significantly increased risk of infection requiring hospitalization within 1 year following cardiac implantable electronic device surgery. Strategies aimed at reducing hematomas may decrease the long-term risk of infection. (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial [BRUISE CONTROL]; NCT00800137).

The expression of calreticulin, a Ca 2+ -binding chaperone of the endoplasmic reticulum, is elevated in the embryonic heart, and because of impaired cardiac development, knockout of the Calreticulin gene is lethal during embryogenesis. The elevated expression is downregulated after birth. Here we have investigated the physiological consequences of continued high expression of calreticulin in the postnatal heart, by producing transgenic mice that overexpress the protein in the heart. These transgenic animals exhibit decreased systolic function and inward I Ca,L , low levels of connexin43 and connexin40, sinus bradycardia, and prolonged atrioventricular (AV) node conduction followed by complete heart block and sudden death. We conclude that postnatal downregulation of calreticulin is essential in the development of the cardiac conductive system, in particular in the sinus and AV nodes, when an inward Ca 2+ current is required for activation. This work identifies a novel pathway of events, leading to complete heart block and sudden cardiac death, which involves high expression of calreticulin in the heart. G AC TAC AG C T C G T C C T T G G C C T G T C TAG -CATAGTCAGGAACATCATATGGGTAC-3′were annealed to create double strand DNA fragmentepitope is underlined followed by KDEL ER retrieval signal). cDNA encoding calreticulin was synthesized by a PCR-driven amplification (8) and cloned into SalI site of a plasmid containing the 5.5-kb mouse cardiac α-myosin heavy chain (α-MHC) (Figure 1a). Linearized pBS-α-MHC-CRT-HA was microinjected into the fertilized oocytes, which were transferred into the oviduct of pseudopregnant FVB/N mice. Transgenic mice were identified by PCR analysis of tail genomic DNA using a forward primer corresponding the 5′ end of the mouse the α-MHC promoter sequence (MHCf: 5′-TATCTCCCCCATAAGAGTTT-3′) and a reverse primer corresponding to the 5′ end of the calreticulin cDNA sequence (CRT-N3A: 5′-GTCAATCTTCACCTCAT-ACG-3′) (Figure 1a). Founder mice were identified, bred with wild-type FVB/N mice, and maintained in a pathogen-free environment.SDS-PAGE and Western immunoblotting. Proteins from mouse tissues including heart, brain, lung, liver, kidney, and thymus were lysed, separated by SDS-PAGE followed by immunoblotting (9). Protein assays were carried out using DC Protein Assay kit (Bio-Rad Laboratories Inc., Hercules, California, USA). Blots were probed with rabbit anti-HA antibodies, goat or rabbit anti-calreticulin antibodies (9, 10), rabbit anti-calnexin (Stress Gene, Victoria, British Columbia, Canada; 1:500 dilution), rabbit anti-BiP (1:2,000 dilution), rabbit anti-PDI (9) (1:500 dilution), rabbit anti-calsequestrin (10) (1:300 dilution), rabbit anti-Cx43 (1:20,000 dilution), or rabbit anti-SERCA2 antibodies (11) (1:1,000 dilution). Antibody binding was detected with appropriate peroxidase-conjugated secondary antibodies followed by a standard enhanced chemiluminescence development reaction.Northern blot analysis. Northern blot analysis was carried out as described elsewhere (10). The following c...

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Myocardial glucose oxidation is markedly reduced in the uncontrolled diabetic. We determined whether this was due to direct biochemical changes in the heart or whether this was due to altered circulating levels of insulin and substrates that can be seen in the diabetic. Isolated working hearts from control or diabetic rats (streptozotocin, 55 mg/kg iv administered 6 wk before study) were aerobically perfused with either 5 mM [(14)C]glucose and 0.4 mM [(3)H]palmitate (low-fat/low-glucose buffer) or 20 mM [(14)C]glucose and 1.2 mM [(3)H]palmitate (high-fat/high-glucose buffer) +/-100 microU/ml insulin. The presence of insulin increased glucose oxidation in control hearts perfused with low-fat/low-glucose buffer from 553 +/- 85 to 1,150 +/- 147 nmol x g dry wt(-1) x min(-1) (P < 0. 05). If control hearts were perfused with high-fat/high-glucose buffer, palmitate oxidation was significantly increased by 112% (P < 0.05), but glucose oxidation decreased to 55% of values seen in the low-fat/low-glucose group (P < 0.05). In diabetic hearts, glucose oxidation was very low in hearts perfused with low-fat/low-glucose buffer (9 +/- 1 nmol x g dry wt(-1) x min(-1)) and was not altered by insulin or high-fat/high-glucose buffer. These results suggest that neither circulating levels of substrates nor insulin was responsible for the reduced glucose oxidation in diabetic hearts. To determine if subcellular changes in the control of fatty acid oxidation contribute to these changes, we measured the activity of three enzymes involved in the control of fatty acid oxidation; AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), and malonyl-CoA decarboxylase (MCD). Although AMPK and ACC activity in control and diabetic hearts was not different, MCD activity and expression in all diabetic rat heart perfusion groups were significantly higher than that seen in corresponding control hearts. These results suggest that an increased MCD activity contributes to the high fatty acid oxidation rates and reduced glucose oxidation rates seen in diabetic rat hearts.

A line of nonobese diabetic (NOD) mice expressing the human diabetes-associated HLA-DQ8 transgene in the absence of mouse IA␤ failed to show spontaneous insulitis or diabetes, but rather developed dilated cardiomyopathy, leading to early death from heart failure. Pathology in these animals results from an organ-and cell-specific autoimmune response against normal cardiomyoctes in the atrial and ventricular walls, as well as against very similar myocytes present in the outermost muscle layer surrounding the pulmonary veins. Progression of the autoimmune process could be followed by serial ECG measurements; irradiation of young animals significantly delayed disease progression, and this effect could be reversed by adoptive transfer of splenocytes taken from older animals with complete heart block. Disease progression could also be blocked by cyclosporin A treatment, but was accelerated by injection of complete Fruend's adjuvant. The constellation of findings of spontaneously arising destructive focal lymphocytic infiltrates within the myocardium, rising titers of circulating anticardiac autoantibodies, dilation of the cardiac chambers, and gradual progression to end-stage heart failure bears a striking resemblance to what is seen in humans with idiopathic dilated cardiomyopathy, a serious and often life-threatening medical condition. This transgenic strain provides a highly relevant animal model for human autoimmune myocarditis and postinflammatory dilated cardiomyopathy.I diopathic dilated cardiomyopathy (IDCM) describes a condition whereby previously healthy individuals develop lifethreatening heart failure associated with enlargement of the heart, but with no apparent underlying cause (1, 2). The cardiac pathology seen in the majority of IDCM patients indicates a recent or more long-standing immune-mediated inflammatory process within the muscle tissue of the heart (i.e., myocarditis) (3,4). IDCM patients often demonstrate circulating anticardiac autoantibodies, and the myocarditis is generally thought to arise from an autoimmune response against cardiac tissues (5). Research on IDCM has been hampered by the lack of an appropriate animal model, that is, a model where animals develop disease spontaneously, show severe life-threatening pathology, and display an immunological and histological picture similar to that seen in humans with IDCM.The human MHC class II molecule DQ8 (i.e., haplotype DQA1*0301, DQB1*0302) is known to be associated with type 1 diabetes (T1D). To map DQ8-restricted T cell epitopes for T1D autoantigens we crossed DQ8 transgenic nonobese diabetic (NOD) mice with a NOD MHC class II ␤-chain knockout line (6). Because the resulting animals express the human MHC class II molecule but not the mouse, any CD4 ϩ T cells arising would be restricted to the human MHC molecule. We chose the NOD strain because it is known to have defects in self-tolerance, which we hypothesized would aid our efforts to induce immune responses against self-antigens such as GAD65. Although replacement of the murine T1D-asso...

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DDDR pacing compared with VDD pacing does not prevent paroxysmal AF over the long term in patients in the absence of antiarrhythmic drug therapy after total AV junction ablation. Many patients have permanent AF within the first year after ablation.