English to Swedish Medical Medical: Cardiology field study

The sample size is based on the primary endpoints and was calculated using exact binomial and normal theory methods, 80% power and á=0.05. Accounting for 25% attrition (10% for general attrition and 15% CS lead attrition), 170 patients are required to ensure 130 patients though 6 months of follow-up for the Primary Endpoint 1. To ensure 22 complete data sets for the Primary Endpoint 2 are available in each pacing group, 30 patients are required in each arm for Primary Endpoint 2. Based on clinical data from PATH-CHF II research study, it is expected that 20% of HF patients could be recommended for LV Only CRT pacing mode, an estimated 150 patients are required. Therefore, 170 patients is the enrollment ceiling for this study.