Relationship between R wave peak time and subclinical left ventricular dysfunction in patients with Diabetes mellitus

Objective: Diabetes Mellitus (DM) is a chronic metabolic disease characterized by defects in insulin secretion or insulin action. Type 2 Diabetes Mellitus (T2DM) is the most common form of this disease and has significant impacts on the cardiovascular system. Diabetic cardiomyopathy is a condition characterized by myocardial structural and functional abnormalities that develop due to T2DM, irrespective of coronary artery disease and hypertension. Diabetic cardiomyopathy typically begins with subclinical left ventricular dysfunction, representing the early stage of the disease. Subclinical left ventricular dysfunction is a condition in which left ventricular diastolic functions are impaired, but ejection fraction remains preserved. Early detection of this condition is critical to preventing disease progression. Therefore, developing parameters for the diagnosis of subclinical left ventricular dysfunction could significantly contribute to the prevention of heart failure and other cardiovascular complications in diabetic individuals. RWPT (R wave peak time) is a parameter measurable by electrocardiography (ECG) that reflects the duration of left ventricular myocardial activation. We designed a study to investigate whether RWPT is prolonged in diabetic cardiomyopathy patients as a result of increased ventricular mass and impaired electrical activity to examine its potential association with subclinical left ventricular dysfunction. The aim of this study is to investigate the relationship between prolonged RWPT and diabetic cardiomyopathy in diabetic individuals and to evaluate whether RWPT prolongation can be used as an electrocardiographic parameter for the early diagnosis of subclinical left ventricular dysfunction. Materials and Methods: This study included 75 T2DM patients who met the inclusion criteria. Participants' body mass index (BMI), diabetes duration, and HbA1c levels were recorded. Left ventricular functions were evaluated using conventional transthoracic echocardiography and tissue Doppler imaging. R wave peak time (RWPT) was measured in leads V5-V6 of a 12-lead ECG. Results: The 75 patients were divided into two groups based on the median RWPT value (35 ms): prolonged and normal RWPT groups. No significant differences were found between the groups regarding gender, height, weight, BMI, HbA1c, ejection fraction, LV mass index, and relative wall thickness. However, left atrial volume index (LAVI) was significantly higher in the prolonged RWPT group (30.05 ± 3.19 cm³/m²) compared to the normal RWPT group (27.91 ± 3.86 cm³/m², p = 0.01061). Additionally, the mitral annular e' velocity, a key indicator of diastolic dysfunction, was significantly lower in the prolonged RWPT group (8.71 4 ± 1.20 cm/s vs. 10.66 ± 1.29 cm/s, p < 0.0001). When participants were grouped based on the degree of diastolic dysfunction, RWPT values were found to increase significantly with higher grades of dysfunction. The RWPT was measured at 32.17 ± 2.79 ms in the group with normal diastolic function, 34.33 ± 3.35 ms in Grade 1 dysfunction, and 37.44 ± 1.54 ms in Grade 2 dysfunction (p = 0.00007). In univariate regression analysis, age, HbA1c, diabetes duration, and LAVI were correlated positively with RWPT, while mean mitral annular e' velocity was correlated negatively. The relationship between grade 2 diastolic dysfunction and RWPT was evaluated using multivariate logistic regression analysis, which identified RWPT as a strong predictor. Each 1 ms increase in RWPT was found to be associated with a 1.59-fold increase in the odds of grade 2 diastolic dysfunction. Conclusion: This study evaluated the prevalence of subclinical left ventricular dysfunction in diabetic patients and its association with prolonged RWPT using transthoracic echocardiography and electrocardiographic measurements. The findings suggest that prolonged R wave peak time may serve as a potential marker for the early diagnosis of subclinical left ventricular dysfunction. These results contribute to the early recognition of diabetic cardiomyopathy and may facilitate the development of new approaches to improve patient prognosis. However, further studies with larger cohorts and longer follow-up periods are needed to validate these findings.