Improvement in Clinical Outcomes With Biventricular Versus Right Ventricular Pacing: The BLOCK HF Study.

Background: Sustained right ventricular (RV) apical pacing may lead to deterioration in ventricular function and an increased risk of heart failure, especially in patients with pre-existing systolic dysfunction. The BLOCK HF (Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block) trial demonstrated that biventricular-paced patients had a reduced incidence of a composite endpoint of death, heart failure-related urgent care, and adverse left ventricular remodeling.

Objectives: In a pre-specified analysis, this study examined clinical outcomes, including clinical composite score, quality of life (QOL), and change in New York Heart Association (NYHA) functional classification.

Left Ventricular Reverse Remodeling With Biventricular Versus Right Ventricular Pacing in Patients With Atrioventricular Block and Heart Failure in the BLOCK HF Trial.

Background: Biventricular pacing in heart failure (HF) improves survival, relieves symptoms, and attenuates left ventricular (LV) remodeling. However, little is known about biventricular pacing in HF patients with atrioventricular block because they are typically excluded from biventricular trials.

Methods And Results: The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) trial randomized patients with atrioventricular block, New York Heart Association symptom classes I to III HF, and LV ejection fraction ≤50% to biventricular or right ventricular pacing.

Heart failure decompensation and all-cause mortality in relation to percent biventricular pacing in patients with heart failure: is a goal of 100% biventricular pacing necessary?

Objectives: The goal of this analysis was to determine the appropriate biventricular pacing target in patients with heart failure (HF).

Background: Cardiac resynchronization therapy (CRT) decreases the risk of death and HF hospitalization. However, the appropriate amount of biventricular pacing is ill-defined.

Frequency, duration, and predictors of newly-diagnosed atrial fibrillation following dual-chamber pacemaker implantation in patients without a previous history of atrial fibrillation.

The Silent Atrial Fibrillation Detection With Stored EGMs (SAFE) registry is the first prospective study to characterize the incidence, duration, and predictors of atrial high-rate episodes (AHREs) in patients without previous clinically diagnosed atrial fibrillation after dual-chamber pacemaker implantation. Patients underwent in-clinic device interrogation at 2 weeks and then 3, 6, and 12 months after implantation. An AHRE was defined as an atrial tachyarrhythmia with an atrial rate > or =180 beats/min lasting > or =5 minutes.

Contributions of differential p53 expression in the spontaneous immortalization of a chicken embryo fibroblast cell line.

Background: The present study was carried out to determine whether the p53 pathway played a role in the spontaneous immortalization of the SC-2 chicken embryo fibroblast (CEF) cell line that has been in continuous culture for over three years.

Results: The SC-2 cell line emerged from an extended crisis period with a considerably slower growth rate than primary CEF cells. The phenotype of the SC-2 cells changed dramatically at about passage 80, appearing smaller than at earlier passages (e.

Modulation of p53 expression and its role in the conversion to a fully immortalized chicken embryo fibroblast line.

We have established a spontaneously immortalized chicken embryo fibroblast (CEF) cell line (SC-1) that has been in continuous culture for more than three years. This is only the second report of a spontaneously immortalized reverse transcriptase (RT)-negative chicken cell line. The SC-1 cells emerged from crisis (at about passage 29-31) with a slower growth rate than primary cells.

Events in the immortalizing process of primary human mammary epithelial cells by the catalytic subunit of human telomerase.

The in vitro immortalization of primary human mammary epithelial (HME) cells solely by the exogenous introduction of the catalytic subunit of human telomerase (hTERT) has been achieved. Early passage hTERT-transfected HME (T-HME) cells continuously decreased the length and density of telomeres even in the presence of telomerase activity, with a significant number of cells staining positive for senescence-associated beta-galactosidase (SA-beta-gal). Subsequently, with the increase in cell passages, the copy number of the exogenously transfected hTERT gene and the percentage of SA-beta-gal positive cells were found to decrease.

Expression profiles of p53-, p16(INK4a)-, and telomere-regulating genes in replicative senescent primary human, mouse, and chicken fibroblast cells.

Replicative senescence is known to be an intrinsic mechanism in determining the finite life span of in vitro cultured cells. Since this process is recognized as an evolutionarily conserved mechanism from yeast to mammalian cells, we compared the senescence-associated genetic alterations in the p53, p16(INK4a), and telomere regulatory pathways using replicative senescent human, mouse, and chicken fibroblast cells. Normal human diploid fibroblast (HDF; WI38) and chicken embryonic fibroblast (CEF) cells were shown to have a more extended in vitro proliferative potential than their mouse embryonic fibroblast (MEF) counterpart.