ECG diagnosis: flecainide toxicity.

Joel T Levis, MD, PhD, FACEP, FAAEM, is a Senior Emergency Physician at the Santa Clara Medical Center, and Clinical Instructor of Emergency Medicine (Surgery) at Stanford University. He is the Medical Director for the Foothill College Paramedic Program in Los Altos, CA. E-mail: [email protected]. Figure 1. 12-lead Electrocardiogram from a 46-year-old woman with fl ecainide toxicity. Demonstrates prolonged PR and QTc intervals with widened QRS complexes, right bundle branch block, and left posterior fascicular block patterns (flecainide level 2.0 μg/mL; normal range 0.20-1.0 μg/mL).