Background: Previous studies have evaluated average electrocardiographic (ECG) values in healthy subjects or specific subpopulations. However, none have evaluated ECG average values in not selected populations, so we examined ECG changes with respect to age and sex in a large primary population. Methods: From digitized ECG stored from 2008 to 2021 in the Modena province, 130,471 patients were enrolled. Heart rate, P, QRS and T wave axis, P, QRS and T wave duration, PR interval, QTc, and frontal QRS-T angle were evaluated. Results: All ECG parameters showed a dependence on age, but only some of them with a straight-line correlation: QRS axis (p < 0.001, R² = 0.991, r = 0.996), PR interval (p < 0.001, R² = 0.978, r = 0.989), QTc (p < 0.001, R² = 0.935, r = 0.967), and, in over 51.5 years old, QRS-T angle (p < 0.001, R² = 0.979, r = 0.956). Differences between females and males and in different clinical settings were observed. Conclusions: ECG changes with ageing are explainable by intrinsic modifications of the heart and thorax and with the appearance of cardiovascular diseases and comorbidities. Age-related reference values were computed and applicable in clinical practice. Significant deviations from mean values and from Z-scores should be investigated.

Background: The study aimed to compare the prognostic importance of the heart rate (HR) and QT—corrected (QTc) according to Fridericia, Framingham, and Bazett with respect to all-cause mortality in a large non-selected population. Methods: The analysis of digital electrocardiograms archived from 2008 to 2022 in the metropolitan area of Modena, Italy, was carried out. The population under study was divided into three groups based on age, and survival analysis was performed. Results: 131,627 patients were enrolled and, during the follow-up (mean 1641.4 days), all-cause mortality was 8.9%. Both HR and QTc were associated with mortality. All-cause mortality significantly increased with HR values greater than 81 BPM and QTc values greater than 440 msec in young subjects and 455 msec in old subjects (values of the 75th percentiles/optimal operating point). A Cox analysis confirmed the better prognostic value of Bazett’s QTc and HR in the whole population and in the three age-groups. Conclusion: Bazett’s method performed better than the others, but, unexpectedly, the HR had the same or an even better correlation with all-cause mortality. Since the HR is simple and readily available, its evaluation should be improved. However, QTC and HR values are difficult to define, causing many confounding factors, and further population studies are required.

Background: the study aimed at comparing the prognostic importance of Heart Rate (HR) and of QT corrected (QTc) according to Fridericia, Framingham and Bazett methods, in a large non-selected population. Methods: the analysis of digital Electrocardiograms archived from 2008 to 2022 in the metropolitan area of Modena, Italy, was made. The population under study was divided into three age-groups and survival analysis was performed. Results: 131.627 patients were enrolled and during the follow-up (mean 1641.4 days), all-cause mortality was 8.9%. Both HR and QTc were associated with mortality. All-cause mortality significantly increased from HR values greater than 81 BPM and from QTc values greater than 440 msec in young subjects and 455 msec in old subjects (values of the 75th percentiles/optimal operating point). Cox analysis confirmed the better prognostic value of Bazett’s QTc and of HR in the whole population and in the three age-groups. Conclusion: Bazett’s method performed better than other methods but unexpectedly HR had the same or a better correlation with all-cause mortality. Since HR is simple and readily available, its evaluation should be improved. However, reference values for QTc and for HR are difficult to define causing many confounding factors and further population-study are required.