Clinical trial NCT01520714: Effect of Posture on Left Ventricular (LV) Transvenous Lead Capture Thresholds (EXPECT)
Official title: Effect of Posture on LV Transvenous Lead Capture Thresholds (EXPECT)
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: NA
Conditions: Congestive Heart Failure
Keywords: Congestive Heart Failure (CHF)
Cardiac Resynchronization Therapy (CRT)
BiVentricular Implantable Cardioverter Defibrillator (BiVICD)
Fraction
Lead sponsor: Baylor Research Institute
Sponsor class: OTHER
Collaborators: name: Medtronic
First posted: 2012-01-30
Enrollment: 11
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL

Brief summary: The purpose of this study is to determine whether changes in a patient's position affect LV capture thresholds in a clinically significant way.

Detailed description: Traditionally clinicians program the safety margins for the right atrial, right ventricular, and left ventricular leads two-times the capture thresholds. This safety margin is necessary for the right atrial and right ventricular outputs to prevent asystole during fluctuation of capture thresholds. This two-times safety margin may not be necessary for the left ventricular lead output and may be causing shorter device battery longevity. Newly implemented LV capture threshold management algorithms may help maintain a proper balance of safety margin and battery longevity. However, recent research conducted on automatic left ventricular capture measurement (LVCM) shows as much as 3.5 V daily variability in capture thresholds. In this same study, 18% of patients had \>1.5 V LV threshold variability. A possible explanation for the variability of LV thresholds is lead stability. Small movements of the lead electrodes associated with movement of patient posture may account for daily fluctuation of capture thresholds. As heart failure patient care and therapies improve, CRT patients may survive longer than the projected longevities of their device. In order to minimize patient risks associated with device change-outs, care must be taken to maximize battery longevity while maintaining CRT pacing. Examining patient posture changes as a possible cause of threshold variability may guide clinicians to program more appropriate LV outputs with patient safety and device longevity in mind.

Eligibility criteria: Inclusion Criteria:

* Greater than 18 years of age and able to provide informed consent
* Planned placement of a Medtronic LV pacing lead and a Medtronic ICD generator with LVCM technology
* Geographically stable and able to follow-up for a period of at least six months post-procedure at The Heart Hospital Baylor Plano
* Willingness to comply with the requirements of the protocol

Exclusion Criteria:

* Life expectancy of less than six months
* Plans for or significant possibility of pregnancy during the required follow-up window
* Significant cardiovascular surgery planned within six months following ICD implant

Primary outcomes:
measure: Evidence of Change in Threshold of >1 Volt With Posture Changes
timeFrame: 6 months
Secondary outcomes:
Other outcomes:
Locations:
city: Plano
country: United States
facility: The Heart Hospital in Plano
state: Texas
Study officials:
affiliation: Baylor Research Institute - The Heart Hospital Baylor Plano
name: James B DeVille, M.D.
role: PRINCIPAL_INVESTIGATOR
References: