Abstract: Objective To explore the diagnostic values of Lorenz scatter plot in elderly patients with coronary heart disease and atrial fibrillation. Methods 102 cases of elderly patients with coronary heart disease who were diagnosed and treated in our hospital from June 2019 to June 2022 were selected as the study subjects. All patients were subjected to electrocardiographic examination, recorded the traditional electrocardiographic indicators and Lorenz scatter plot indicators in the all cases. Used the final clinical diagnosis as the gold standard, determined the diagnostic sensitivity and specificity of the electrocardiographic scatter plot. Results There were 42 cases (41.18%) were clinically diagnosed as atrial fibrillation in the 102 cases. There were no significant differences in heart rate, systolic blood pressure, body mass index, diastolic blood pressure, gender, and age compared between the atrial fibrillation group and the non atrial fibrillation group (P>0.05). There was no significant difference in QRS and QTs between the atrial fibrillation group and the non atrial fibrillation group (P>0.05). The P wave time limit and P wave amplitude were significantly higher than the non-AF group (P<0.05), and there was no significant difference between P wave dispersion and P wave index between AF group and non-AF group (P>0.05). The long axis and short axis of Lorenz scatter plot in atrial fibrillation group were lower than those in non atrial fibrillation group, and the vector angle index and vector length index were significantly increased compared with non atrial fibrillation group (P<0.05). In the 102 patients, there were 41 cases were diagnosed as atrial fibrillation by scatter plot. The sensitivity and specificity of scatter plot in the diagnosis of elderly patients with coronary heart disease and atrial fibrillation were 92.86%and 96.67%, respectively. The ROC curve shows that the area under the diagnostic curve of Lorenz scatter plot for elderly patients with coronary heart disease and atrial fibrillation were 0.951. Conclusion It is difficult to effectively distinguish between coronary heart disease and atrial fibrillation by relying on traditional electrocardiogram indicators. Scatter plots have high sensitivity and specificity in the diagnosis of elderly patients with coronary heart disease and atrial fibrillation, and are worthy of clinical promotion and application.

Key words: lorenz scatter chart, aged, coronary heart disease, atrial fibrillation, sensitivity, 24 hour ambulatory electrocardiogram, vector length index