Strategic Management to Optimize Response To Cardiac Resynchronization Therapy

Comparing cardiac resynchronization therapy (CRT) response rates between AV Delay programming schemes defined by SmartDelay or a Fixed AV Delay of 120ms. A negative change in LVESV is considered an improvement; CRT response is defined by a change in Left Ventricular End Systolic Volume (LVESV) \< -15% at 6 months compared to pre-implant baseline.

Time frame: Pre-Implant baseline to 6 months

Population: A total of 130 randomized subjects did not contribute data to the primary endpoint analysis due to death or withdrawal prior to six months, missed six-month visit or incomplete/insufficient echocardiogram.

The KCCQ is a disease-specific instrument for monitoring the health status and quality of life of subjects with congestive heart failure. It includes a total of 23 items that assess quality of life in the following domains: physical function, symptom frequency and severity, symptom stability, self-efficacy and knowledge, social function, and overall quality of life. These domains can be combined into a functional status summary score (derived from the physical function and symptom scales) and an overall summary score which combines the physical function, symptom, social function and quality of life domains. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.

Comparing absolute changes in Left Ventricular Ejection Fraction from Implant to 6 Months between AV Delay programming schemes defined by SmartDelay or a Fixed AV Delay of 120ms. Change is defined as 6-Month measurement - Implant measurement, in % of blood ejected during LV contraction. A positive change in LVEF is considered an improvement.

Time frame: Implant to 6 Months

Population: A total of 129 randomized subjects did not contribute data to the secondary endpoint analysis due to death or withdrawal prior to six months, missed six-month visit or incomplete/insufficient echocardiogram.

Comparing relative changes in Left Ventricular Ejection Fraction from Implant to 6 Months between AV Delay programming schemes defined by SmartDelay or a Fixed AV Delay of 120ms. Change is defined as 100\*(6-Month measurement - Implant measurement)/(Implant Measurement), in %. A positive change in LVEF is considered an improvement.

Time frame: Implant to 6 Months

Population: A total of 129 randomized subjects did not contribute data to the secondary endpoint analysis due to death or withdrawal prior to six months, missed six-month visit or incomplete/insufficient echocardiogram.

Comparing absolute changes in Left Ventricular End Systolic Volume from Implant to 6 Months between AV Delay programming schemes defined by SmartDelay or a Fixed AV Delay of 120ms. Change is defined as 6-Month measurement - Implant measurement, in milliliters. A negative change in LVESV is considered an improvement.

Time frame: Implant to 6 Months

Population: A total of 130 randomized subjects did not contribute data to the secondary endpoint analysis due to death or withdrawal prior to six months, missed six-month visit or incomplete/insufficient echocardiogram.

Comparing relative changes in Left Ventricular End Systolic Volume from Implant to 6 Months between AV Delay programming schemes defined by SmartDelay or a Fixed AV Delay of 120ms. Change is defined as 100\*(6-Month measurement - Implant measurement)/(Implant Measurement), in %. A negative change in LVESV is considered an improvement.

Time frame: Implant to 6 Months

Population: A total of 130 randomized subjects did not contribute data to the secondary endpoint analysis due to death or withdrawal prior to six months, missed six-month visit or incomplete/insufficient echocardiogram.

Th CCS combines four metrics: all-cause mortality, heart failure hospitalization (HFH), New York Heart Association (NYHA) Class, and quality of life as measured with the patient global assessment (GA) instrument. The CCS categorizes each subject into one of three groups: Improved, Unchanged or Worsened. * Improved: Subjects that survived without a HFH through the 6-month visit window and had either an improvement in NYHA class or responded to GA with much better or very much better. * Unchanged: All patients that reached the end of 6-month visit window that were not categorized as either Improved or Worsened. * Worsened: Subjects that died or had HFH within 6-month visit window or had either a worsening in NYHA class or responded to GA with much worse or very much worse.

Time frame: Implant to 6 Months

Population: Subjects that were followed through the end of the 6-month visit window and those that died and/or or had a heart failure hospitalization within the 6-month visit window contributed to this endpoint. A total of 34 subjects did not meet these conditions are were therefore excluded from endpoint analysis.

KCCQ Physical Function Domain measures the limitations patients experience, due to their heart failure symptoms, in performing routine activities. Activities are common, gender-neutral, and generalizable across cultures, while also capturing a range of exertional requirements. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.

KCCQ Quality of Life Domain is designed to reflect patients' assessment of their quality of life, given the current status of their heart failure. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.

KCCQ Self-efficacy Domain quantifies patients' perceptions of how to prevent heart failure exacerbations and manage complications when they arise. This scale is not included in the summary scores. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.

The KCCQ Social Limitation Domain quantifies the extent to which heart failure symptoms impair patients' ability to interact in a number of gender-neutral social activities. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.

KCCQ Symptom Domain quantifies the burden of clinical symptoms in heart failure, including fatigue, shortness of breath, paroxysmal nocturnal dyspnea and patients' edema/swelling. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.

KCCQ Symptom Domain quantifies the frequency of clinical symptoms in heart failure, including fatigue, shortness of breath, paroxysmal nocturnal dyspnea and patients' edema/swelling. KCCQ scores have a minimum of 0 and a maximum of 100. Higher score indicates better quality of life.

Time frame: Implant to 6 Months

Population: Subjects that completed the KCCQ at both the implant and 6 month visits contributed to this endpoint. A total of 51 subjects did not contribute data to the endpoint.