Catheter ablation of arrhythmias in Ebstein's anomaly: a multicenter study

In patients with Ebstein's anomaly (EA) arrhythmias are frequently encountered. Although most arrhythmias can be targeted with catheter ablation, specific issues render the procedure more challenging in EA. This study examines the mechanisms of the different arrhythmias related to EA and the outcome after catheter ablation.

Evaluation of pulmonary vein stenosis after pulmonary vein isolation using a novel circular mapping and ablation catheter (PVAC)

Background—Pulmonary vein stenosis (PVST) is a well-known complication of pulmonary vein isolation (PVI). Specific anatomically designed ablation catheters for antral PVI have not been evaluated with regard to the incidence of PVST. We investigated the incidence, severity, and characteristics of PVST after PVI with the Pulmonary Vein Ablation Catheter (PVAC) and phased radiofrequency technology. Methods and Results A total of 100 patients (55 men) underwent PVI for atrial fibrillation using the PVAC. PVI was guided by selective angiography of each pulmonary vein (PV) in 70 (70%) patients and by reconstructed 3D atriography (ATG) in 30 (30%) patients. Gadolinium-enhanced MRI or multidetector CT was performed in all patients before treatment and 93±78 days after PVI. PVST was classified as follows: insignificant (<25%), mild (25%–50%), moderate (50%–75%), or severe (>75%). A total of 410 PVs were analyzed. Cardiac imaging demonstrated a detectable narrowing of the PV diameter in 23 (23%) patients and in 28 (7%) PVs. In detail, insignificant PVST was observed in 12 (2.9%) PVs, mild PVST in 15 (3.7%), and moderate PVST in 1 (0.2%). No instances of severe PVST were observed. The use of 3D-ATG was associated with a lower incidence of PVST (0.8% [95% CI, 0.0%–2.2%] versus 5.4% [95% CI, 2.7%–8.1%], P=0.027). Conclusions To our knowledge, this study is the first to report the incidence of PVST using the PVAC. In this regard, the PVAC seems to be safe if used in an experienced center. In addition, the use of 3D-ATG may decrease the risk of PVST.

Ablation of the tumor suppressor histidine triad nucleotide binding protein 1 is protective against hepatic ischemia/reperfusion injury

The identification of cellular pathways capable of limiting ischemia/reperfusion (I/R) injury remains a frontier in medicine, and its clinical relevance is urgent. Histidine triad nucleotide binding protein 1 (HINT1) is a tumor suppressor that influences apoptosis. Because apoptotic pathways are a feature of I/R injury, we asked whether Hint1 influences hepatic I/R injury. Hint1(-/-) and C57BL/6 mice were subjected to 70% liver ischemia followed by reperfusion for 3 or 24 hours or to a sham operation. The serum aminotransferase levels, histological lesions, apoptosis, reactive oxygen species, and expression of B cell lymphoma 2-associated X protein (Bax), heme oxygenase 1 (HO-1), interleukin-6 (IL-6), IL-10, tumor necrosis factor-a, Src, nuclear factor kappa B (p65/RelA), and c-Jun were quantified. The responses to toll-like receptor ligands and nicotinamide adenine dinucleotide phosphate oxidase activity in Kupffer cells were compared in Hint1(-/-) mice and C57BL/6 mice. After I/R, the levels of serum aminotransferases, parenchymal necrosis, and hepatocellular apoptosis were significantly lower in Hint1(-/-) mice versus control mice. Furthermore, Bax expression decreased more than 2-fold in Hint1(-/-) mice, and the increases in reactive oxygen species and HO-1 expression that were evident in wild-type mice after I/R were absent in Hint1(-/-) mice. The phosphorylation of Src and the nuclear translocation of p65 were increased in Hint1(-/-) mice, whereas the nuclear expression of phosphorylated c-Jun was decreased. The levels of the protective cytokines IL-6 and IL-10 were increased in Hint1(-/-) mice. These effects increased survival after I/R in mice lacking Hint1. Hint1(-/-) Kupffer cells were less activated than control cells after stimulation with lipopolysaccharides. CONCLUSION: The Hint1 protein influences the course of I/R injury, and its ablation in Kupffer cells may limit the extent of the injury.

Cardiac G-protein-coupled receptor kinase 2 ablation induces a novel Ca2+ handling phenotype resistant to adverse alterations and remodeling after myocardial infarction

G-protein-coupled receptor kinase 2 (GRK2) is a primary regulator of β-adrenergic signaling in the heart. G-protein-coupled receptor kinase 2 ablation impedes heart failure development, but elucidation of the cellular mechanisms has not been achieved, and such elucidation is the aim of this study.

Mitral isthmus ablation with and without temporary spot occlusion of the coronary sinus: a randomized clinical comparison of acute outcomes

To evaluate the safety and outcomes of mitral isthmus (MI) linear ablation with temporary spot occlusion of the coronary sinus (CS). Background: CS blood flow cools local tissue precluding transmurality and bidirectional block across MI lesion.