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Sample Size Formulas For Estimating Intraclass Correlation Coefficients In Reliability Studies With Binary Outcomes, Mengxiao Xu

Electronic Thesis and Dissertation Repository

Introduction: Measurement errors can seriously affect quality of clinical practice and medical research. It is therefore important to assess such errors by conduct- ing studies to estimate a coefficients reliability and assessing its precision. The intraclass correlation coefficient (ICC), defined on a model that an observation is a sum of information and random error, has been widely used to quantify reliability for continuous measurements. Sample formulas have been derived for explicitly incorporation of a prespecified probability of achieving the prespecified precision, i.e., the width or lower limit of a confidence interval for ICC. Although the concept of ICC is applicable …

Catheter Ablation For Atrial Fibrillation: Predicting Recurrence, Kendra Thomas

Electronic Thesis and Dissertation Repository

Background

Catheter ablation has emerged as treatment for atrial fibrillation (AF). Health care-related variables have not been explored as predictors of first ablation outcome. Determining factors associated with arrhythmia recurrence may help select patients likely to benefit. The objective was to identify variables associated with recurrence following AF ablation.

Methods

Retrospective cohort design of 314 AF patients who had undergone first ablation. Follow-up visits occurred at 3, 6 and 12 months. Variables and the outcome of recurrence were modeled with Cox proportional hazards analysis.

Results/Conclusions

After mean follow-up of 239+/-125 days, 110/314 patients (35.0%) experienced recurrence. Adjusted Cox proportional hazards …