Clinical Trial: AV Delay Optimization vs. Intrinsic Conduction in Pacemaker Patients With Long PR Intervals

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Evaluation of AV Delay Optimization vs. Intrinsic Conduction in Patients With Long PR Intervals Receiving Dual Chamber Pacemakers for Symptomatic Bradycardia

Brief Summary: This is a randomized, prospective clinical trial to determine the effects of two different pacemaker atrioventricular delay (AV delay) settings on heart function in patients with dual chamber pacemakers implanted for symptomatic bradycardia with long PR intervals (delayed conduction between upper and lower chambers of the heart). The study will compare a long, fixed AV delay (standard) with an optimized AV delay for each individual using echocardiography (experimental).

Detailed Summary:

Cardiac pacing is the only effective treatment for symptomatic sinus node dysfunction. Most patients with preserved left ventricular function receive dual chamber pacemakers; however, right ventricular pacing can have detrimental effects on left ventricular function due to the abnormal electrical and mechanical activation pattern of the ventricles.

Many patients receiving dual chamber pacemakers for symptomatic bradycardia have prolonged intrinsic AV conduction (first degree AV block), and as a result, will receive a significant amount of ventricular pacing if programmed at physiologic AV intervals. As an alternative, many pacemakers can be programmed to minimize ventricular pacing at the expense of allowing longer AV delays. However, these long AV delays may not be physiologic and may also lead to reduced cardiac output. At present the standard of care is either to program the pacemaker at an physiologic "natural" AV delay of about 160 msec or to program the pacemaker with a long AV delay to minimize ventricular pacing.

The main scientific questions being addressed in this study are to evaluate the acute and chronic effects on cardiac output, functional status, sense of well-being, and cardiac remodeling of a long AV delay allowing for intrinsic conduction as compared to an echocardiographically optimized AV delay during dual chamber pacing.

Patients enrolled in the trial will complete a run-in period of two weeks prior to randomization in which pacemakers will be programmed with a long-fixed AV delay to allow intrinsic conduction and minimize ventricular pacing (standard). At two weeks, patients will receive a baseline echocardiogram. To determine optimal AV delay, all patients will undergo echocardiographic analysis at varying AV delays. Optimal AV delay will b
Sponsor: University of California, San Diego

Current Primary Outcome: Change in cardiac output determined by echocardiography [ Time Frame: 6 months ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

• Changes in functional status determined by 6 minute walk. [ Time Frame: 6 months ]
  Measure distance walked in 6 minutes in meters.
• Changes in sense of well being as determined by Short Form - 36 Medical Outcomes Study Questionnaire [ Time Frame: 6 months ]
  Sense of well being score determined by answers to questions on Short Form - 36 questionnaire.

Original Secondary Outcome:

• Changes in functional status determined by 6 minute walk. [ Time Frame: 6 months ]
  Measure distance walked in 6 minutes in meters.
• Changes in sense of well being as determined by Short Form - 36 Medical Outcomes Study Questionnaire [ Time Frame: 6 months ]
  Sense of well being score determined by answers to quetions on Short Form - 36 questionnaire.

Information By: University of California, San Diego

Dates:
Date Received: May 28, 2014
Date Started: June 2013
Date Completion: June 2018
Last Updated: October 24, 2016
Last Verified: October 2016