The pilot study aimed to analyze standard electrocardiogram (ECG) components in e-cigarette smokers and non-smokers. A lead II ECG test was performed on 10 e-cigarette users and a control group of 10 subjects (aged 18–23) under the rest stage and after the exercise stress test. We determined parameters, such as segments, intervals, and waves duration and amplitude, and further subjected them to statistical analysis using paired and unpaired t-tests and the Welch test. The results revealed a significant difference in T wave amplitude between smokers and non-smokers in both pre- and post-exercise states, with lower values in smokers, reflecting a trend of ischemic cardiomyopathy. Moreover, physical activity resulted in variations in heart rate (HR) and QT interval in smokers, which implies that e-cigarette-origin nicotine consumption may produce pathological arrhythmia. The study showed that e-cigarettes, promoted as a healthier substitute to traditional cigarettes, significantly affect heart health, even in young subjects. We also found that post-exercise ECG analysis provides a broader context of cardiac diagnosis in nicotine users.