This project used a ECG simulator built upon the Fourier series principle to study the patterns of normal and abnormal (defined as both above and below normal ranges) heart beats and other important ECG parameters for children of differing age groups. Across age groups with normal and abnormal settings, the heart rate is shown as positively correlated with R wave peaks, and inversely correlated with S curve minimums. In general, the higher the heart beat rate, the shorter the period for a complete ECG wave cycle (in milliseconds). Within each age group, the abnormal heart beat rates are observed to have extended or shortened wave durations. In addition to educational merits, studying ECG patterns via simulation for different types of patients is efficient and cost-effective before designing and implementing more adaptive and reliable interventions and biomedical technologies.