Stimulus Intensity in Left Ventricular Leads

Study Overview
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Brief Summary
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Cardiac resynchronization therapy (CRT) is a device implanted to improve the function of some people's hearts. CRT involves the placement of 3 wires in the heart through a vein near the front of your left or right shoulder into three pumping chambers of the heart, the most important being the left lower chamber, left ventricle (LV).

Detailed Description
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The purpose of Cardiac resynchronization therapy (CRT) is to send small amounts of energy (called pacing) through the wires to both the left and right lower chambers of your heart at (or near) the same time. This helps the heart pump in a more coordinated way and send more blood to your body with each beat. How much energy is used for pacing is called the stimulus intensity. Increasing the pacing stimulus intensity of the left ventricular wire can lead to an increase in the volume of heart muscle directly stimulated. This has previously been shown to produce beneficial effects on the heart function, like strength of contraction and increased volume of blood pumped. The purpose of this study is to determine if pacing the wires in the left ventricular chamber of the heart using higher stimulus intensity improves the strength of the heart's contraction.

Official Title
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Stimulus Intensity in Left Ventricular Leads and Response to Cardiac Resynchronization Therapy

Conditions
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Congestive Heart Failure

Intervention / Treatment
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* Other: LV stimulus intensity


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults who fulfill approved criteria to receive a cardiac resynchronization device. Exclusion Criteria: -Adults who are unable to give informed consent.

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

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: LV lead low output<br>Low output on left ventricular pacing lead. Intervention: LV stimulus intensity | Other: LV stimulus intensity<br>* The voltage and pulse duration used for programmed LV pacing Arm 1: LV lead low output Arm 2: LV lead high output<br>|
| Other: LV lead high output<br>High output on left ventricular lead Intervention: LV stimulus intensity | Other: LV stimulus intensity<br>* The voltage and pulse duration used for programmed LV pacing Arm 1: LV lead low output Arm 2: LV lead high output<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ejection Fraction |  | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quality of Life |  | 6 months | 
| Six minute hall walk |  | 6 months | 
| End diastolic dimension |  | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cardiac resynchronization therapy, congestive heart failure