Effect of Posture on Left Ventricular (LV) Transvenous Lead Capture Thresholds (EXPECT)

Study Overview
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Brief Summary
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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
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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.

Official Title
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Effect of Posture on LV Transvenous Lead Capture Thresholds (EXPECT)

Conditions
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Congestive Heart Failure

Intervention / Treatment
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* Device: Medtronic 4195 active fixation LV lead and Medtronic passive fixation LV lead


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Medtronic passive fixation LV lead<br>Medtronic 4195 Active Fixation LV lead and Medtronic passive fixation LV lead arms will both have same follow-up testing and schedule | Device: Medtronic 4195 active fixation LV lead and Medtronic passive fixation LV lead<br>* 1:1 randomization between Medtronic active fixation 4195 LV lead and another FDA approved passive fixation Medtronic LV lead. Fluoroscopic images will be taken at implant in a supine position and again at 3 month follow-up in different postural positions with capture thresholds of the LV lead taken at each postural position.<br>|
| Experimental: Medtronic 4195 Active Fixation LV Lead<br>Medtronic 4195 Active Fixation LV lead and Medtronic passive fixation LV lead arms will both have same follow-up testing and schedule | Device: Medtronic 4195 active fixation LV lead and Medtronic passive fixation LV lead<br>* 1:1 randomization between Medtronic active fixation 4195 LV lead and another FDA approved passive fixation Medtronic LV lead. Fluoroscopic images will be taken at implant in a supine position and again at 3 month follow-up in different postural positions with capture thresholds of the LV lead taken at each postural position.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evidence of Change in Threshold of >1 Volt With Posture Changes |  | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fraction, Congestive Heart Failure (CHF), Cardiac Resynchronization Therapy (CRT), BiVentricular Implantable Cardioverter Defibrillator (BiVICD)