E lectrocardiogram (ECG) is still the most widely used tool for screening cardiac abnormalities, in particular, left ventricular hypertrophy (LVH) which is closely related to morbidity and mortality [1, 2]. Despite its low cost and widespread availability, ECG has many limitations concerning LVH assessment leading to the development of more than 30 different criteria, most of which have only modest sensitivities [3]. However, recently, a new criterion has been proposed by Peguero et al. [4] to identify LVH on ECG. Contrary to the previously described measurements, in which fixed leads are chosen for calculation. This new method incorporates the sum of S wave amplitude in lead V4 and the highest S wave in any lead. It is believed that selective measurement of the S wave of the QRS complex combined with the flexible lead selection improves sensitivity without hampering specificity. On the other hand, this new criterion has only been tested in a small number of patients. Thus, it is hard to implement it into clinical practice without validation. Therefore, in our study, we wanted to assess the sensitivity and specificity of ABSTRACT OBJECTIVE: Many criteria have been developed to predict left ventricular hypertrophy using an electrocardiogram (ECG). However, one major common limitation of all has been their low sensitivity. Based on that, recently, a novel criterion has been proposed, which is believed to have higher sensitivity without a compromise in specificity. Therefore, in our study, we aimed to test this novel ECG criterion prospectively in large, unselected cardiac patients. METHODS: Patients who were referred to our echocardiography laboratory due to various etiologies were prospectively enrolled. The novel Peguero-Lo Presti criterion was assessed along with other established ECG criteria. The left ventricular mass index was calculated using echocardiography. The performance of each index was evaluated. RESULTS: Overall, 767 patients were enrolled in this study. The sensitivity and specificity of the Peguero-Lo Presti criterion were 17.5% and 94.5%, respectively. Although the highest sensitivity belonged to the Peguero-Lo Presti criterion, in ROC analysis, it showed modest predictive capability, which was similar to the established Cornell voltage criterion (AUC=0.64 [0.56-0.68 95% CI], p<0.01). CONCLUSION: Although this novel criterion had higher sensitivity, the overall performance was similar to the current indices. Further adjustments, particularly based on age and body mass index, may yield better results.