The study terminated due to significant delays in site start-up activities and enrollment in the setting of the ongoing COVID-19 pandemic.

The purpose of the BIO-AffectDX Study is to prospectively evaluate improvement from baseline in heart failure subjects with atrial fibrillation (AF) implanted with a two-lead CRT-DX system, with emphasis on a comparison of patient outcomes between AF subtypes.

There is a need for more evidence about the benefits of Cardiac Resynchronization Therapy (CRT) in a patient population with heart failure and atrial fibrillation. The BIO-AffectDX Study will gather information about adults with heart failure and atrial fibrillation who are treated with a CRT-DX device from many locations across the United States. The BIO-AffectDX Study will look at the results of treatment in participants with the primary goal to evaluate the improvement in overall health prior to device implant through 12 months. Overall health will be measured by your study doctor for AF improvement, physical fitness, and general quality of life.

Inclusion Criteria:

• Standard CRT-D indication according to current guidelines
• Patient has documented history of paroxysmal, persistent, or long-standing persistent atrial fibrillation
• De novo implant or upgrade from a DX implantable cardioverter-defibrillator (ICD) system
• Implant planned to occur within 30 days of consent
• Patient is able to understand English or Spanish
• Patient is able to understand the nature of the study and provide informed consent
• Patient is willing and able to complete all routine study visits at the investigational site for up to 12 months of follow-up
• Patient is willing to utilize BIOTRONIK Home Monitoring® via CardioMessenger
• Patient age is greater than or equal to 18 years

After consent has been signed, additional inclusion criteria must be fulfilled for study participation:

• Baseline subject assessment is evaluated as New York Heart Association class II, III or ambulatory IV heart failure at study Enrollment Visit
• Baseline subject assessment of six-minute walk test is completed at study Enrollment Visit and walk distance ≤ 450 meters (1,476 feet)

Exclusion Criteria:

• Contraindication to CRT-D/CRT-DX
• Patient has current or previous atrial pacing need
• Patient is considered for a His Bundle Pacing system
• Patient has current or previous pacemaker, non-DX ICD implant, or bi-ventricular pacing system prior to enrolling
• Patient is currently planned for a pulmonary vein isolation catheter ablation procedure within 3 months of consent
• Patient life expectancy is less than 1 year
• Patient is expected to receive heart transplantation or ventricular assist device within 1 year after implant
• Patient is expected to have a cardiac surgical procedure, such as coronary artery bypass graft or valve transcatheter replacement/repair or surgery, planned to occur within 6-months after implant (excludes atrioventricular node ablation procedures)
• Patient is currently on dialysis, or is expected to receive dialysis within 1 year of implant
• Patient is enrolled in any investigational cardiac device or drug trial that might significantly affect the studied outcomes
• Any condition (e.g. severe arthritis, wheelchair bound, etc.) preventing the patient from performing the required six-minute walk test
• Conditions that prohibit placement of any of the system leads
• Patient reports pregnancy at the time of consent

Patients selected for participation should be from the investigator's general patient population with standard CRT-D indication and according to the inclusion and exclusion criteria.

Applicable de-identified individual participant data will be made available to achieve aims in approved proposals, including but not limited to sub-analysis or meta-analysis that are not specifically pre-planned within the protocol.

Beginning no later than 12 months and ending no earlier than 3 years following study closure.

Proposals should be directed to BIOTRONIK Clinical Studies (BIOTRONIK Inc., Attn: Clinical Studies, 6024 Jean Road, Lake Oswego, OR 97035; 1-800-547-0394). BIOTRONIK, in consultation with the BIO-AffectDX Steering Committee, will review and evaluate proposals for scientific merit, fiscal feasibility, and logistical feasibility. They will additionally consider if the proposed publication fits into the overall BIO-AffectDX publication plan. If approved, the data requestors will need to sign a data use/access agreement prior to obtaining the data and agree to review and input from the BIO-AffectDX Steering Committee members.