This guide explains cardiac electrophysiology study (EPS), a diagnostic procedure that examines the heart's electrical activity to identify rhythm disturbances causing symptoms like dizziness, palpitations, or fainting. It covers the 1.5-2 hour procedure involving catheter insertion under X-ray guidance, potential radiofrequency ablation treatment to eliminate abnormal tissue, preparation requirements including fasting, potential risks, and post-procedure care with overnight hospitalization.