Evaluation of QRS voltage variability (Shora sign) as a diagnostic criteria of atrial fibrillation

The study evaluates the diagnostic significance of QRS voltage variability (Shora sign) in identifying atrial fibrillation (AF) compared to conventional ECG criteria. It involves a case-control design with 200 AF patients and 200 non-AF patients, assessing QRS voltage changes in lead I, alongside clinical history, physical examination, and echocardiographic parameters. The primary endpoint is a QRS voltage change of more than 0.1mV in at least three successive beats. Statistical analysis will determine the sensitivity, specificity, and predictive value of this criterion using SPSS.