Exercise Training Following Cardiac Resynchronization Therapy in Patients With Chronic Heart Failure

Summary

Cardiac resynchronization therapy(CRT) is recommended to reduce mortality and morbidity in chronic heart failure(CHF) patients New York Heart Association(NYHA) class III-IV who are symptomatic despite optimal medical therapy, with a reduced left ventricular(LV) ejection fraction(LVEF) and prolonged complex QRS. CRT improves the prognosis however, despite the improvement, all major trials have demonstrated that one third of the patients are non-responders to CRT. Three months after the CRT implant, the responders have a significant increase in endothelial function(EntF), a decrease in the LV end-systolic volume, and increase in LVEF, 6 minute walk test(6MWT), improvements in NYHA class and quality of life. It is currently unknown if adding an exercise training(ExT) program following CRT provides better clinical outcomes than CRT alone. Prior studies on CRT and ExT have been preliminary in nature, but suggest small improvements in functional capacity(FC). The correction of endothelial dysfunction is associated with a significant improvement in exercise capacity evidenced by a 26%increase in peak oxygen uptake. These findings are important because CHF patients with the greatest sympathetic activation and the most reduced EntF have the poorest prognosis. Our experience with coronary artery disease patients, and most recently data in patients with CHF show that an ExT program that combines aerobic exercise(AE) and resistance exercise training are more effective than an AE program alone, and the aerobic interval training showed better improvements than continuous endurance training. It is unknown how CHF with more severe functional limitations responds to ExT and, more important, the explanation of the physiological mechanism that can explain the improvements as a consequence of ExT. This lack of scientific information is urgent since this is the group of patients that normally is targeted for CRT. The investigators propose to use a stratified randomized longitudinal study to determine the additional effects of a 6 month ExT in addition to CRT in NYHA stage III-IV HF patients. The aims of the study are:1-to determine whether a long-term ExT program follow the CRT provides better clinical outcomes than CRT alone and 2-To identify the mechanisms of the hypothesize improvement. The results of this project will represent an important contribution by understanding the role of ExT after CRT NYHA stage III-IV heart failure(HF) patients, an understudied population with poor clinical outcome. Understanding the potential mechanisms associated with clinical improvement and outcome is essential for the rehabilitative process to develop new innovative therapies in this high risk population. The investigators will use state-of-art methods including an integrated assessment autonomic nervous system(ANS) and arterial function using 123I-MIBG scintigraphy.

Conditions

• Cardiac Resynchronization Therapy
• Chronic Heart Failure

Interventions

BEHAVIORAL

Exercise training program

The exercise sessions will be hospital-based, 3 times a week for 60 minutes each, on non-consecutive days for 6 months. Selected the aerobic interval training (AIT) method for the development of cardiopulmonary system and the inclusion of resistance and sensorimotores exercises. The AIT comprises 4 interval training periods (high intensity) and 3 active pauses (moderate intensity) between interval training periods. The patient will warmup for 10 minutes at 50% to 60% of HRpeak from CPET, before walking to four 4 minutes intervals at 90 to 95% of peak HR. Each interval, including the last one, is separate by 3 minutes active pauses, walking at 60% to 70% of HRpeak. Total aerobic exercise time at this moment will be 28 minutes and will be maintain to the end of ExT intervention period.

DEVICE

Cardiac resynchronization therapy (CRT)

Implantation will be performed according to standard techniques of biventricular pacing. The CRT includes a generator and three leads, used to correct ventricular dyssynchrony.

Sponsors & Collaborators

• University of Lisbon

  lead OTHER

Principal Investigators

• Maria Helena Santa-Clara Pombo Rodrigues, PhD · University of Lisbon

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2012-01-31

Primary Completion

2015-07-31

Completion

2015-07-31

Countries

• Portugal

Study Locations