BACKGROUND: This study explores the relationship between angiotensin-converting enzyme (ACE) gene polymorphisms and early diastolic dysfunction in patients with hypertension utilizing four-dimensional echocardiography and assesses the prognosis. METHODS: This study consecutively selected 470 patients with hypertension who visited the Fourth Affiliated Hospital of Soochow University between September 2021 and August 2022, with 274 meeting the inclusion criteria. Hypertension gene testing was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques, and the Hardy-Weinberg equilibrium test was used to confirm genetic equilibrium. Patients were categorized into the D allele group (n = 163) and the non-D allele group (n = 111). Diastolic function was assessed using four-dimensional echocardiography, which included averaging the E/e' ratio over three cardiac cycles, measuring the left atrial (LA) maximum volume index (LA volume), tricuspid regurgitation velocity (TR velocity), LA strain, and left ventricular isovolumic relaxation time (IVRT). Patients were subsequently classified into the diastolic dysfunction group (n = 133) and the normal diastolic function group (n = 141). Chi-square tests were used to analyze differences in diastolic function indicators between the groups, Logistic regression was applied to control for potential confounding factors, and receiver operating characteristic (ROC) curves were plotted to assess the predictive value of different ACE alleles for diastolic dysfunction in patients with hypertension. RESULTS: The genotype distribution in both the D allele group and the non-D allele group was consistent with Hardy-Weinberg equilibrium (P >
0.05). Compared to the non-D allele group, echocardiographic indicators in the D allele group showed a decline in diastolic function: the average E/e' ratio over three cardiac cycles (14.67 [13.82, 15.80] vs. 9.30 [8.12, 12.00]), LA volume (32.76 [29.34, 34.61] vs. 25.61 [22.63, 29.64] ml/m CONCLUSIONS: The ACE-D allele is associated with early diastolic dysfunction in hypertension. ACE gene testing can enhance the predictive value for diastolic dysfunction in patients with hypertension.