AdaptResponse Clinical Trial

Inclusion Criteria:

   - Subject is willing to sign and date the study Patient Informed Consent Form.

   - Subject is indicated for a CRT device according to local guidelines.

   - Sinus Rhythm at time of enrollment

   - Complete Left Bundle Branch Block (LBBB) as documented on an ECG (within 30 days prior
   to enrollment). Strauss Criteria used for LBBB.

   - Intrinsic, normal AV conduction as documented on an ECG by a PR interval less than or
   equal to 200ms (within 30 days prior to enrollment).

   - Left ventricular ejection fraction less than or equal to 35% (documented within 180
   days prior to enrollment).

   - NYHA class II, III or IV (documented within 30 days prior to enrollment) despite
   optimal medical therapy. Optimal medical therapy is defined as maximal tolerated dose
   of Beta-blockers and a therapeutic dose of ACE-I, ARB or Aldosterone Antagonist.

Exclusion Criteria:

   - Subject is less than 18 years of age (or has not reached minimum age per local law).

   - Subject is not expected to remain available for at least 2 years of follow-up visits.

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

   - Subject is, or previously has been, receiving cardiac resynchronization therapy.

   - Subject is currently enrolled or planning to participate in a potentially confounding
   drug or device trial during the course of this study. Co-enrollment in concurrent
   trials is only allowed when documented pre-approval is obtained from the Medtronic
   study manager.

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

   - Subject has a mechanical tricuspid 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 due to non-cardiac causes that would not allow
   completion of the study.

   - Subject is pregnant (if required by local law, women of child-bearing potential must
   undergo a pregnancy test within seven days prior to device implant).

   - Subject meets any exclusion criteria required by local law.