Evaluate the Amount of Effective Cardiac Resynchronization Therapy (CRT) Pacing During AF

The CRTee study is an IDE, prospective, multi-center, randomized, controlled, crossover
clinical study, conducted worldwide and designed to demonstrate that the amount of effective
CRT pacing during AF (atrial fibrillation) when CAFRPlus (Conducted AF Response Plus) is
applied is not inferior to the amount of effective CRT pacing during AF when CAFR (Conducted
AF Response) is applied.

The study will be conducted at up to 20 centers located in the United States, Europe and
Middle East and Africa (MEA).

Inclusion Criteria:

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

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

- Subject is expected to remain available after enrollment to complete follow-up visits
in both arms of the study

- Subject has had a Medtronic Viva or Brava CRT-D device implanted at least 30 days
prior to enrollment.

- Subject has history of AF burden, of at least 6 days of at least 4 hours of AF over
any 4 week period within the last 90 days as documented in device diagnostic data OR
if subject has no atrial lead (therefore no device diagnostic data) but clinical
evidence of high AF burden.

- Subject has demonstrated history of being able to complete Left Ventricular Capture
Management (LVCM) documented in device data.

- Subject has a documented % V pacing during AF of less than or equal to 97% within 90
days prior to enrollment or within 10 days after enrollment.

Exclusion Criteria:

- Subject has undergone AV node ablation for treatment of AF.

- Subject has complete or 3rd degree AV block.

- Subject has had an MI within 30 days.

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

- Subject is enrolled in one or more concurrent studies that could confound the study
results as determined by Medtronic.

- Subject has a limited life expectancy for non-cardiac causes that would not allow
completion of the study.

- Subject is pregnant (in the US, all women of child-bearing potential must undergo a
pregnancy test within seven days prior to CRTee download).

- Subject meets the exclusion criteria required by local law.