Development and validation of diagnostic criteria for atrial flutter on the surface electrocardiogram

Background: There are no universally accepted ECG diagnostic criteria for atrial flutter (AFL), making its differentiation from "coarse" atrial fibrillation (AF) difficult. Methods: To develop diagnostic criteria for AFL, we examined two sets of ECGs. Set 1 consisted of 100 ECGs (50 AF, AFL) with diagnoses confirmed by intracardiac recordings. Criteria evaluated were presence of F waves in the frontal plane leads, F waves in V₁, sawtooth F waves, rate, and regularity of ventricular response. Set 2 included 200 ECGs taken from the hospital database each of which had already been interpreted by a cardiologist as either AF (n = 100) or AFL (n = 100). Set 2 was blindly read by electrophysiologists whose consensus-diagnoses were compared to the diagnoses made by using the best criteria identified from the Set 1 data. Results: The criteria of frontal plane F waves, regular or partially regular ventricular response, and their combination had sensitivities of 92%, 98%, and 90% and specificities of 100%, 78%, and 100% in Set 1 for the diagnosis of AFL. In Set 2, concordance of electrophysiologist and cardiologist diagnoses was only 84%. The criteria of frontal plane Fwaves, regular or partially regular ventricular response, and their combination resulted in concordances with the cardiologist diagnoses of 85%, 85%, and 82% and with the electrophysiologist-consensus diagnoses of 90%, 89%, and 94% (P < 0.001). Conclusions: The criteria of frontal plane F waves and regular or partially regular ventricular response aid in the proper diagnosis of AFL. Because management strategies may differ for AF and AFL, it is important to adopt a more rigorous diagnostic approach.