Active clinical trials for "Sick Sinus Syndrome"

Cardiac pacing is the only effective treatment for symptomatic bradycardia. The right ventricular apex (RVA) has become the most frequently used ventricular pacing site. However, RVA pacing has been shown to cause left ventricular (LV) dyssynchrony wich can lead to LV dysfunction and development of heart failure. Recent studies in animals have demonstrated that pacing at the LV septum induces significantly less ventricular dyssynchrony than RVA pacing and is able to improve LV function to a similar degree as biventricular (BiV) pacing. In addition it was shown that a LV septum lead can be placed permanently by driving a lead with extended helix from the RV side through the inter-ventricular septum into the LV endocardial layer. This was shown to be a feasible and safe procedure and lead stability was shown during four months of follow-up in otherwise healthy and active canines. LV septum pacing may therefore be a good treatment alternative in patients with symptomatic bradycardia, as well as patients with an indication for cardiac resynchronization therapy (CRT). The purpose of this study is to translate the findings from preclinical studies to the clinical situation by investigating the feasibility, long-term lead stability and safety of LV septum pacing by transvenous approach through the inter-ventricular septum in patients.

This study is a long-term, prospective, and controlled evaluation of the mechanical dyssynchrony induced by right ventricular apical pacing, both in acute (spontaneous and stimulated) and chronic (12 and 24 months); the study also evaluates the benefit of an alternative pacing site through measures of dyssynchrony in acute and chronic.

The purpose of this study is to determine the incidence of atrial fibrillation and heart failure in patients with pacemaker therapy with different pacing modes (AAI, DDD, and a novel algorithm to minimize ventricular pacing).

This is a pilot study into the effects on heart function when pacing the right ventricle (RV). This study aims to enrol a population who are clinically indicated to receive a pacemaker. When normal conduction within the heart fails, the treatment may be to implant a permanent pacemaker. Pacing involves passing a lead via a vein to the heart and using an electrical impulse to stimulate a beat. Increasingly the available evidence suggests that long term RV pacing is associated with complications - left ventricule (LV) dysfunction, heart failure, atrial fibrillation (AF) and death in some patients. What we do not see are a large proportion of all patients who receive pacemakers suffering pacing related adverse effects. If there could be a way of identifying those patients in the group who go on to develop pacing induced cardiomyopathy at the time of initial pacing implant, this would be a very valuable clinical measure. These patients could be identified from the outset and paced with a biventricular device to avoid the pacing induced cardiomyopathy. Whilst much energy has been directed towards the LV as a focus of the clinical markers of disease, little has been published looking at RV haemodynamics. We plan to study a cohort of patients who are clinically indicated to receive a pacemaker and study their RV in detail at the time of implantation. We will use conductance catheters and echocardiography to determine measures of pumping function. We will then follow them up for a period of six month using echocardiography and blood markers of heart dysfunction. In those patients who have a reduction in heart function we will then look for common patterns within their initial measurements.

A consequence of chronic RV pacing is a process of electrical remodeling that alters myocardial repolarization to reflect the altered depolarization induced by the RV lead. When RV pacing is discontinued, the altered repolarization persists for several weeks. This phenomena is traditionally described as "T-wave memory" based upon the 12-lead ECG appearance of inverted T-Waves. The investigators are using the ECGI technique to produce three dimensional electroanatomical images of this phenomena in patients with dual chamber pacemakers. Echocardiography will also be used to image the mechanical effects of RV pacing and T-wave memory. The images will show the spatial distribution of altered repolarization and allow us to correlate any mechanical consequences of this phenomena that may exist.

The main objective of this study is to verify the effectiveness of the new ACAP ® Confirm algorithm in the automatic management of atrial capture.

The objective of this trial is to show the therapeutic efficacy of the preventive pacing therapies of the Selection 9000 and Vitatron T70 DR pacemakers, dedicated to handle atrial fibrillation (AF). Two new algorithms (post-AF response and ventricular rate stabilization [VRS]) will be assessed in a combined pathway, compared to a control group. The efficacy of the overall available therapies to prevent AF and its symptoms will then be assessed also.

Registry to Improve the Adoption of Consensus Treatment Guidelines (IMPROVE Brady)

To generate a list of potential genetic markers that correlate with an increased risk of life-threatening arrhythmias. To evaluate ECG-based risk markers such as heart rate variability and T-wave Alternans for their association with arrhythmic events.

To construct a computerized database of national profiles and epidemiological data on patients wearing Medtronic implantable pacemakers and cardioverter defibrillators (both with or without cardiac resynchronization therapy), implantable loop recorders and leads used within their intended use. Clinical variables will be analyzed in relation to device-based data and diagnostics.