New image processing and noise reduction technology allows reduction of radiation exposure in complex electrophysiologic interventions while maintaining optimal image quality: a randomized clinical trial.

Background: Despite their carcinogenic potential, X-rays remain indispensable for electrophysiologic (EP) procedures.

Objective: The purpose of this study was to evaluate the dose reduction and image quality of a novel X-ray technology using advanced image processing and dose reduction technology in an EP laboratory.

Methods: In this single-center, randomized, unblinded, parallel controlled trial, consecutive patients undergoing catheter ablation for complex arrhythmias were eligible.

Cardiac resynchronization therapy cures dyssynchronopathy in canine left bundle-branch block hearts.

Aims: We investigated to what extent biventricular pacing (BVP) can normalize LV function and remodeling, induced by isolated left bundle branch block (LBBB).

Methods And Results: In 16 dogs LBBB was induced. Eight animals were followed for 16 weeks and in 8 animals BVP was started after 8 weeks.

Calculation of effective VV interval facilitates optimization of AV delay and VV interval in cardiac resynchronization therapy.

Background: In hearts with left bundle branch block (LBBB), both atrioventricular (AV) delay and interventricular (VV) interval determine left ventricular (LV) pump function in cardiac resynchronization therapy (CRT). The optimal combination of AV delay and VV interval currently is determined by extensive hemodynamic testing.

Objectives: The purpose of this study was to investigate whether the effective VV interval (VV(eff)) can be used to optimize AV delay and VV interval.

Tailoring cardiac resynchronization therapy using interventricular asynchrony. Validation of a simple model.

This study explores the use of interventricular asynchrony (interVA) for optimizing cardiac resynchronization therapy (CRT), an idea emerging from a simple pathway model of conduction in the ventricles. Measurements were performed in six dogs with chronic left bundle branch block (LBBB) and in 29 patients of the Pacing Therapies for Congestive Heart Failure (PATH-CHF)-I study. In the dogs, intraventricular asynchrony (intraVA) was determined using left ventricular (LV) endocardial activation maps.

Acute hemodynamic benefit of left ventricular apex pacing in children.

Background: Despite the fact that pacing at the right ventricular apex acutely and chronically decreases left ventricular contractile function, this pacing site is still conventionally used in adults and children. Because animal studies showed beneficial effects of left ventricular pacing, we compared the hemodynamic performance of left ventricular apex, left ventricular free wall, and right ventricular apex pacing in children.

Methods: Studies were performed in 10 children (median age, 2.

Left bundle branch block induces ventricular remodelling and functional septal hypoperfusion.

Aims: Left ventricular (LV) dilatation, hypertrophy, and septal perfusion defects are frequently observed in patients with left bundle branch block (LBBB). We investigated whether isolated LBBB causes these abnormalities.

Methods And Results: In eight dogs, LBBB was induced by radio frequency ablation.

The left ventricular apex is the optimal site for pediatric pacing: correlation with animal experience.

Pacing at the commonly used right ventricular (RV) apex results in impaired ventricular performance. Previous animal studies indicated that the left ventricular (LV) apex is a superior pacing site. The purpose of this study was to investigate in dogs whether this good performance is associated with a more synchronous electrical activation pattern of the LV and whether the LV apex is also a good pacing site in children.

Relation between abnormal ventricular impulse conduction and heart failure.

Ventricular pacing and left bundle branch block (LBBB) are two of the most common causes of asynchronous electrical activation of the ventricles. The sequence of activation is an important determinant of cardiac pump function. The sequence of activation during LBBB and during pacing at the conventional pacing site, the RV apex, is similar.

Intra-ventricular resynchronization for optimal left ventricular function during pacing in experimental left bundle branch block.

Objectives: We sought to investigate to what extent intra-ventricular asynchrony (intraVA) and inter-ventricular asynchrony (interVA) determine left ventricular (LV) function in canine hearts with left bundle branch block (LBBB) during ventricular pacing.

Background: Pacing therapy improves LV pump function in patients with heart failure and abnormal ventricular conduction supposedly due to resynchronization. However, the relationship between LV pump function and measures of asynchrony is not well established.

Quantification of interventricular asynchrony during LBBB and ventricular pacing.

The quantification of mechanical interventricular asynchrony (IVA) was investigated. In 12 dogs left bundle branch block (LBBB) was induced by radio frequency ablation. Left ventricular (LV) and right ventricular (RV) pressures were recorded before and after induction of LBBB and during LBBB + LV apex pacing at different atrioventricular (AV) delays.