Cardiovascular disease (CVD) and cognitive decline are common diseases among the elderly. In recent years, some works are dedicated to exploring the correlations between CVDs and dementia. This study investigated the potential of Electrocardiogram (ECG) patterns as early markers of cognitive decline in the elderly. Three age groups were examined, and three key ECG features—Left ventricular hypertrophy (LVH), Ventricular repolarization (QTc), and Resting heart rate (RHR)—were extracted from ECG signals. Statistical analysis, ANOVA, revealed significant differences (p<0.05) in these features across the different age groups, indicating a strong correlation between ECG patterns and aging. LVH, reflecting structural changes in the heart, was found to increase with age for both male and female subjects. Furthermore, QTc and RHR also showed age-related changes, especially an increase for the elderly people over 60 years of age, suggesting a link between heart function and cognitive health. The results of this study suggest that ECG patterns, particularly LVH, QTc, and RHR, may serve as early markers for cognitive decline in the elderly, providing a noninvasive and cost-effective approach for early detection and intervention.