Cardiac Resynchronization Therapy, Dyspnea and Exercise Tolerance in Patients With Congestive Heart Failure (CHF)

Study Overview
=================
Brief Summary
-----------------
A new therapy for patients with advanced heart failure (HF) involves the implantation of a specialized pacemaker device (Cardiac Resynchronization Therapy, CRT) that attempts to restore the synchronized contraction of the ventricular chambers of the heart. In some people, CRT improves exertional breathlessness and allows them to exercise for longer periods. However, to date, the mechanisms by which CRT improves symptoms and exercise tolerance is unknown. This study will use in-depth cardiopulmonary exercise testing and pulmonary function testing to explore these mechanisms in greater detail.

Official Title
-----------------
Effects of Cardiac Resynchronization Therapy on Dyspnea and Exercise Tolerance in Patients With Congestive Heart Failure

Conditions
-----------------
Congestive Heart Failure

Intervention / Treatment
-----------------
* Device: Active Cardiac Resynchronization Therapy (CRT)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: clinically stable being considered for implantation of biventricular pacemaker for CRT LVEF <35% QRS duration >120 msec NYHA III-IV functional class optimized pharmacologic management of CHF no recent (<1 month) episodes of decompensated CHF Exclusion Criteria: inability to perform cycle ergometry or comply with testing uncontrolled ischemic heart disease coronary revascularization within 3 months of study entry concurrent primary lung disease current use of ambulatory oxygen rhythm other than sinus dependency on pacemaker therapy as a consequence of bradyarrhythmias severe valvulopathy

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 90 Years

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

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

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

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: CRT-ON/CRT-OFF<br>Group initially randomized to CRT-ON, then cross-over to CRT-OFF | Device: Active Cardiac Resynchronization Therapy (CRT)<br>* Initiation of active biventricular pacing/cardiac resynchronization therapy Devices by Medtronic: Insync Sentry 7298 & 7299 Concerto C174 ASK (Most frequently implanted) Insync III 8042 (PM) Devices by Guidant/Boston Scientific: Contak Renewal 4 H190 & H199 Contak Renewal 3 H127 Devices by ELA/Sorin: 1. Ovatio CRT 6750<br>* Other names: Received one of the above devices used in 2007-2008 at Kingston General Hospital.;|
| Active Comparator: CRT-OFF/CRT-ON<br>Group initially randomized to CRT-OFF, then cross-over to CRT-ON | Device: Active Cardiac Resynchronization Therapy (CRT)<br>* Initiation of active biventricular pacing/cardiac resynchronization therapy Devices by Medtronic: Insync Sentry 7298 & 7299 Concerto C174 ASK (Most frequently implanted) Insync III 8042 (PM) Devices by Guidant/Boston Scientific: Contak Renewal 4 H190 & H199 Contak Renewal 3 H127 Devices by ELA/Sorin: 1. Ovatio CRT 6750<br>* Other names: Received one of the above devices used in 2007-2008 at Kingston General Hospital.;|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise endurance time |  | 6 weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Congestive Heart Failure, Cardiac Resynchronization Therapy, Dyspnea, Exercise Tolerance