Clinical Trial: The Effect of Losartan on Atrial Fibrillation (AF) Burden and Pacemaker Dependence in Patients With Sick Sinus Syndrome

Study Status: Completed
Recruit Status: Unknown status
Study Type: Interventional

Official Title: The Effect of Losartan on Atrial Fibrillation and Pacemaker Dependence in Sick Sinus Syndrome (SSS) Patients Receiving Physiological Pacemaker - A Prospective, Randomized,

Brief Summary: This is a an investigator-initial, multicenter, open-label, randomized, parallel-group comparative study to evaluate the effect on the incidence of AF and pacemaker dependence in SSS patients receiving physiological atrial-based pacing alone or adding losartan 100mg to physiological atrial-based pacing treatment. The duration of the study will be approximately 13 months, comprising 4-week pre-study period, and 12-month treatment period.

Detailed Summary:

Sick sinus syndrome is a common indication for permanent cardiac pacing in the community. It results from disordered impulse generation within the sinus node or impaired conduction of the impulse to the surrounding atrial tissue, thus leading to the clinical manifestation of bradycardia. In patients with SSS, AF frequently develops after pacemaker implantation,and progresses to persistent AF over long term follow up.

The occurrence of AF have been shown to be an independent predictor for major cardiovascular events in SSS patients receiving physiologic pacing. Recent prospective clinical trials have demonstrated that physiologic pacing mode reduces the risk of AF compared to single chamber ventricular pacing in patients with SSS. However, the effectiveness of physiologic pacing in reducing the incidence of AF in patients with sinus node dysfunction is still incomplete.

One recent clinical study had reported that 68% of SSS patients with a DDDR pacemaker have atrial tachyarrhythmias detected by the pacemaker devices at median 718 days follow-up. Modern pacemakers have diagnostic features that permit the detection and storage of information about the date, time of onset, and duration of multiple, sequential episodes of atrial tachyarrhythmias. Since a high percentage of AF episodes may be asymptomatic, AF "burden" have been used as surrogate end points. Prolonged P wave, shortened refractoriness, or remarkably abnormal conduction disturbances in the presence of prolonged refractoriness limit the effectiveness of standard physiologic pacing in AF prevention. This could explain, at least in part, the tendency of SSS to develop AF as a part of its natural history. Clinical electrophysiology has focused the attention on the electrophysiological and structural properties of the atrial muscle in patients with SSS: shorte
Sponsor: Chung Shan Medical University

Current Primary Outcome: The proportion of patients who developed AF burden by pacemaker telemetry and developed permanent AF [ Time Frame: 12-month study period(2-week + 2-week + 4-week + 4-week + 3-month + 3-month + 3-month) ]

Original Primary Outcome: Same as current

Current Secondary Outcome: The time to first occurrence of AF lasting for at least 1 minute after pacemaker insertion, and the AF burden over time measured as the portion of AF per day (in hours/day) [ Time Frame: 12-month study period(2-week + 2-week + 4-week + 4-week + 3-month + 3-month + 3-month) ]

Original Secondary Outcome: Same as current

Information By: Chung Shan Medical University

Dates:
Date Received: March 26, 2008
Date Started: April 2008
Date Completion: December 2009
Last Updated: March 31, 2010
Last Verified: March 2010