• cavotricuspid isthmus-dependent flutter;
  • predictors;
  • unusual 12-lead ECG pattern;
  • ejection fraction

Background:An unusual 12-lead electrocardiographic pattern may be present in patients with cavotricuspid isthmus (CTI)-dependent flutter.

Objective:Using baseline patient characteristics and echocardiography, we sought to study predictors of unusual electrocardiogram (ECG) characteristics in patients with CTI-dependent atrial flutter.

Methods:This was a dual-center, retrospective cohort study of 147 patients undergoing electrophysiology study and ablation for CTI-dependent atrial flutter.

Results:Among this cohort, 23 patients (16%) had unusual 12-lead ECG characteristics. Using multivariate logistic regression, we found two clinical predictors for having an unusual ECG pattern. A clockwise (CW) pattern at time of electrophysiology study was the strongest predictor of an unusual ECG pattern (odds ratio 15.3, 95% confidence interval [CI] 4.0–59.4, P < 0.005). In addition, patients with decreased systolic function had a 3.5 greater odds (95% CI 1.1–11.5, P = 0.037) of having an unusual ECG pattern.

Conclusions:Our data demonstrate that among patients suffering from CTI-dependent atrial flutter who are referred for ablation, 16% will have unusual ECG patterns. Patients with CW atrial activation and left ventricle dysfunction have greater odds of manifesting unusual patterns by surface electrocardiogram. (PACE 2011; 34:1251–1257)