Left ventricular (LV) diastolic dysfunction (LVDD) is the result of impaired LV relaxation and identifies those at risk of developing heart failure [1]. Even evidence of mild or preclinical LVDD has been shown to predict all-cause mortality [2]. While the echocardiogram has long been used as the gold standard to diagnose LVDD, the accuracy of measuring multiple parameters such as the trans-mitral flow, left atrial (LA) volume, pulmonary artery pressures and tissue velocity has come under question [1,3]. Newer studies have focused on LA function to assess LVDD using standard and two-dimensional speckle-tracking echocardiography [[3], [4], [5]]. In a recent study by Brecht et al., LA function was shown to have a higher diagnostic accuracy than LA volume in detecting early LVDD [5]. Although cardiac magnetic resonance and computer tomography imaging can be used to measure the LA volume, the cost effectiveness and clinical utility of these modalities is yet to be established [6]. Therefore, echocardiography remains fundamental for the evaluation of LVDD. Certain electrocardiogram (ECG) parameters to diagnose LVDD have been presented [7,8] and recently the use of signal processed ECG (hsECG) to identify ECG abnormalities, has shown promise [9,10]. In a small study by Namdar el al. a novel calculation combining age with P-Q and T wave end to Q wave measurements was employed to demonstrate sensitivities (SN) and specificities (SP) of 82% and 93% respectively for the diagnosis of LVDD [7]. A recent study by Kagiyama et al. used machine learning hsECG to demonstrate similar SN and SP (82%, 96% respectively) to identify LVDD [9]. Potter et al. used hsECG in an elderly cohort (>65 years) to identify those with early LVDD (SN 88%, SP 70%) and demonstrated a 45% reduction in the need to perform echocardiography while only missing 12% of LVDD cases [11]. In a basic clinical setting, there are complexities in employing such calculations or specialised equipment to identify those that would benefit from an echocardiogram. If a more simplistic feature on the standard 12‑lead ECG was able to classify those requiring further testing, the need for such resources would be reduced. Therefore, the aim of this study was to evaluate the accuracy of the basic ECG parameter of ventricular repolarization, and the hsECG, to diagnose early LVDD (grade 1) in patients with presumed normal LV systolic function, an otherwise normal ECG, and no evidence of pre-existing heart failure or coronary artery disease.