BackgroundIn previous studies, faster heart rates in patients with atrial fibrillation combined with heart failure have been associated with poor long-term patient prognosis. However, the classical pharmacological regimen of beta-blockers has not reduced mortality in patients with atrial fibrillation combined with heart failure. Therefore, in patients with atrial fibrillation combined with heart failure with an ejection fraction >40%, we further screened patients with a diagnosis of atrial fibrillation cardiomyopathy and compared the combination of diltiazem with standard anti-heart failure drug therapy.Objective:To observe the effect of diltiazem hydrochloride on cardiac function and prognosis in patients with Atrial Fibrillation–Mediated Cardiomyopathy.Methods: A total of 186 patients diagnosed with atrial fibrillation–mediated cardiomyopathy who were admitted to the First Affiliated Hospital of Zhengzhou University from August 2018 to June 2020 were randomly divided into two groups: 93 cases in the experimental group and 93 cases in the control group, both groups were given standardized pharmacological treatment for heart failure (diuretics, digoxin, β-blockers, perindopril), and the experimental group was given diltiazem 30 mg on the basis of standardized treatment, 3 times a day. The patients were followed up for 30 days to observe the target heart rate <110 beats/min, left ventricular ejection fraction, proBNP, the rate of decrease in activity tolerance during the treatment period, and readmission rate within 30 days.Results:After the addition of diltiazem, the attainment rate of target heart rate was significantly higher in the experimental group than in the control group (p<0.05) . The improvement of left ventricular ejection fraction and proBNP was more significant in the experimental group than in the control group (p<0.05). The incidence of decreased activity tolerance during the follow-up period was higher in the experimental group than in the control group, but the difference was not statistically significant (p>0.05). The readmission rate for heart failure within 30 days was significantly lower in the experimental group than in the control group (p < 0.05).Conclusion：Diltiazem hydrochloride is effective in improving cardiac function and prognosis in patients with atrial fibrillation–mediated cardiomyopathy, and is a safe and effective method.