Tilt testing is a commonly used diagnostic tool to evaluate syncope of undetermined etiology. We hereby describe a twelve year old male child who developed presyncope during provocative head up tilt testing along with ST segment elevation in cardiac monitor during presyncope. Patient underwent repeat head up tilt testing along with holter monitoring which showed a left bundle branch block escape rhythm. Hence development of ST elevation was due to the improper filter application in single lead ECG monitor. This case highlights the importance of filters in electrocardiographic monitoring.