Adaptive Cardiac Resynchronization Therapy Study

The trial has 3 primary end points:

- to demonstrate that over 6-month follow-up, the proportion of the patients improved in
the aCRT arm is at least as high as in the Echo arm

- to demonstrate that cardiac function is similar when using aCRT versus echo-optimized
settings

- to demonstrate that aCRT does not result in inappropriate AV or VV delay settings

Inclusion Criteria:

- Subject is willing to sign and date the study Informed Consent form

- Subject is at least 18 years of age (or older, if required by local law)

- Subject is expected to remain available for at least six months of follow-up visits

- Subject is indicated for a study device that will be implanted within 30 days after
signing the Informed Consent form

- Subject has an intrinsic QRS duration greater than or equal to 120 milliseconds
(documented within 30 days prior to enrollment)

- Subject has a left ventricular ejection fraction less than or equal to 35 percent
(method per physician discretion) (documented within 180 days prior to enrollment)

- Subject is diagnosed with New York Heart Association (NYHA) class III or IV (within 30
days prior to enrollment) despite optimal medical therapy which is defined as:
ACE-inhibitor (Angiotensin-Converting Enzyme) or Angiotensin II Receptor Blocker
(ARB), if tolerated, for at least one month prior to implant, AND beta-blocker for at
least three months preceding implant, if tolerated, and stable for one month, OR
subject has an urgent medical need for an implantable cardioverter defibrillator (ICD)
that precludes waiting the one or three months for the medication requirements for ACE
inhibitor, ARB or beta-blocker

Exclusion Criteria:

- Subject has chronic (permanent) atrial arrhythmias for which pharmacological therapy
and/or cardioversion have been unsuccessful or have not been attempted

- Subject has existing CRT system

- Subject has non-intact or unstable leads

- Subject has medical conditions that would limit study participation (per physician
discretion)

- Subject is enrolled in one or more concurrent studies that would confound the study
results of this study as determined by Medtronic

- Subject has unstable angina, or experienced an acute myocardial infarction (MI) or
received coronary artery revascularization (CABG) or coronary angioplasty (PTCA)
(documented within 30 days prior to enrollment)

- Subject has a mechanical right heart valve or is scheduled to undergo valve repair or
valve replacement during the course of the study

- Subject is post-heart transplant (subjects on the heart transplant list for the first
time are not excluded)

- Subject has a limited life expectancy that would not allow completion of the 6 month
visit

- Subject is pregnant (In the United States, all women of child-bearing potential must
undergo a pregnancy test within seven days prior to aCRT download into device)

- Subject meets the exclusion criteria required by local law