Dual-Source Computed Tomography to Improve Prediction of Response to Cardiac Resynchronization Therapy

Study Overview
=================
Brief Summary
-----------------
Cardiac Resynchronization Therapy (CRT) is a widely accepted treatment that has led to improved clinical outcomes for patients with refractory congestive heart failure (CHF), systolic dysfunction, and wide QRS duration. However, it requires implantation of an expensive device ($30,000) and about 1/3 of patients do not have clinical improvement. Inadequate amounts of LV dyssynchrony or suboptimal lead placement may limit clinical response. Dual-Source computed tomography (DSCT) allows for subtle detection during myocardial contraction for assessing LV dyssynchrony, and can also assess coronary venous anatomy and scar burden. Thus DSCT may be the ideal noninvasive modality to predict response to CRT.

Official Title
-----------------
Dual-Source Computed Tomography to Improve Prediction of Response to Cardiac Resynchronization Therapy

Conditions
-----------------
Heart Failure - NYHA II - IV, Wide QRS Complex

Intervention / Treatment
-----------------
* Other: Randomization of Pre-knowledge of CT coronary venography


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Older than 18 years of age Ability to provide informed consent Planned CRT implantation NYHA Functional Class II-IV heart failure Echo Ejection Fraction less than or equal to 35% QRS duration greater than or equal to 120 ms Normal or mildly reduced kidney function (estimated serum creatinine less than or equal to 1.5 mg/dL or less than or equal to 1.3 mg/dL for diabetic subjects on metformin For diabetic subjects on glucophage (metformin) they will be required to stop glucophage (metformin) for at least 48 hours after the administration of contrast. Exclusion Criteria: Known allergy to iodine or iodinated contrast Chronic persistent atrial fibrillation Pregnancy or unknown pregnancy status Subjects on glucophage (metformin) therapy that are unable or unwilling to discontinue therapy for 48 hours after CT scan Known inadequate venous access for appropriate IV caliber placement Iodinated contrast administration within the past 48 hours Subjects who cannot hold their breath for 10-15 seconds

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Pre-procedural cardiac CT<br>CRT patients will undergo pre-procedural cardiac CT to assess for dyssynchrony, scar, and coronary venous anatomy. The CT venogram will be randomize to pre-knowledge to implanting physician or blinded. The CT dyssynchrony and scar assessment will remain blinded to caregivers and patients. | Other: Randomization of Pre-knowledge of CT coronary venography<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical Response to CRT | The clinical response to CRT will be adjudicated by two experienced cardiologists taking into account left ventricular ejection fraction, NYHA functional class, and patient global assessment score. | 6 months post implantation of CRT | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Major adverse cardiovascular events (MACE) | MACE defined as composite endpoints of death, cardiac transplant, left ventricular assist device, and HF hospitalization | 2 years | 
| Secondary endpoints | Change in NYHA Functional Class, Echo volumes and ejection fraction, Minnesota Quality of Life score, 6-minute walk distance, NT-proBNP levels, and hospitalization at 6 months | 6 months |