Electrocardiographic diagnosis of hyperkalemia in the presence of ventricular pacing and atrial fibrillation.

H yperkalemia has several electrophysiologic effects on cardiac tissues that allow for its ready detection on a standard electrocardiogram. The diagnosis is easiest when the baseline tracing is normal with sinus rhythm and a normal QRS duration. We report this case of hyperkalemia which was diagnosed in the presence of ventricular pacing and atrial fibrillation and which resulted in the conversion of the atrial fibrillation to normal sinus rhythm.