View clinical trials related to Bundle-Branch Block.
Filter by:Heart failure (HF) affects 5 million Americans and is responsible for more health-care expenditure than any other medical diagnosis. Approximately half of all HF patients have electrocardiographic prolongation of the QRS interval and ventricular dyssynchrony, a perturbation of the normal pattern of ventricular contraction that reduces the efficiency of ventricular work. Ventricular dyssynchrony is directly responsible for worsening HF symptomatology in this subset of patients. Resynchronization of ventricular contraction is usually achieved through simultaneous pacing of the left and right ventricles using a biventricular (BiV) pacemaker or implantable cardioverter-defibrillator. Clinical trial evidence supporting the use of BiV pacing in patients with prolonged QRS duration was obtained almost exclusively in patients with a left bundle-branch block (LBBB) electrocardiographic pattern. Recent evidence suggests that resynchronization of ventricular contraction in patients with LBBB can be obtained by univentricular left ventricular pacing with equal or superior clinical benefits compared to BiV pacing. Animal studies suggest that ventricular resynchronization can be obtained in subjects with right bundle-branch block (RBBB) through univentricular right ventricular pacing. No clinical trial evidence exists to support the use of BiV pacing in patients with RBBB. Thousands of patients with symptomatic HF and RBBB currently have univentricular ICDs in place for the prevention of sudden cardiac death. Most of these devices are currently programmed to avoid RV pacing. We aim to determine if ventricular resynchronization delivered through univentricular RV pacing improves symptoms in patients with RBBB and moderate to severe HF who have previously undergone BiV ICD implantation for symptomatic heart failure. We further aim to determine if ventricular resynchronization improves myocardial performance and ventricular geometry as detected by echocardiographic measures and quality of life for patients with HF and RBBB. We hypothesize that RV univentricular pacing delivered with an atrio-ventricular interval that maximizes ventricular synchrony is equivalent to BiV pacing for improvement in cardiac performance, HF symptoms, and positive ventricular remodeling in patients with HF and RBBB.
Despite the dramatic effect of cardiac resynchronization therapy (CRT) on survival and morbidity in people with congestive heart failure, 50-70% of eligible patients do not respond to this intervention. There is retrospective evidence that placement of the left ventricular (LV) lead at the region of latest mechanical delay markedly improves response to CRT. However, there is no feasible way to gauge dyssynchrony at LV lead sites during CRT implantation. Impedance recordings from pacing lead tips allow for real-time assessment of mechanical motion and may represent a useful intraoperative tool to guide optimum placement of the LV lead during CRT implantation. This pilot trial will assess the use of intraoperative impedograms in humans to measure regional dyssynchrony at potential LV lead locations during CRT implantation.
A left bundle branch block (LBBB) is related to abnormal cardiac conduction and mechanical asynchrony and is associated with hypertension and coronary artery disease. Improved evaluation of left ventricular (LV) mechanical asynchrony is needed, because of the increasing number of patients with a LBBB and heart failure. A variety of patterns of mechanical activation can be observed in LBBB patients. Novel imaging modalities such as tissue Doppler imaging, real-time 3D echocardiography and cardiovascular magnetic resonance imaging provide information about regional and global LV function in healthy subjects, patients without a LBBB with heart failure, patients with a LBBB without heart failure, and patients with a LBBB with heart failure. The investigators want to evaluate the different patient groups with the novel imaging modalities and they want to compare the novel imaging modalities with each other. The investigators hypothesized that, between the groups, differences concerning regional and global LV function are measurable. Each novel imaging technique has its own advantages and limitations but are comparable in measuring regional and global LV function.
In patients with broad QRS complexes on electrocardiogram (ECG), the delayed electrical activation of the left heart chamber will cause abnormal contraction.This has been shown to be possible to treat by a special pacemaker treatment which includes pacing of the left heart chamber (= CRT treatment). In this study the researchers will investigate the effect of acute CRT treatment in the early phase after open heart surgery.
This study is to determine 1) the incidence of altered right bundle conduction, including CRBBB, IRBBB or rsR’ pattern in the Taipei city based on the school survey databank from 1999 to 2002, 2) the associated cardiac lesions, 3) clinical presentations relevant to the altered right bundle conduction, 4) the association with QTc prolongation and dispersion and HRV from a 5-minutes recording. Finally, molecular characterization for those with CRBBB or Brugada pattern EKG, especially those with positive family history will be studied.