IJCS | Volume 33, Nº4, July and August 2020

especially at postnatal week 6. This pattern was not observed when comparing Wistar with L-NAME rats, which presented few differences, only at postnatal week 15. The highest parameters found for the L-NAME group were corrected QT, QT and JT intervals, which suggests changes in ventricular repolarization. SHR presented higher RR/PR intervals, S/P/Q amplitudes and P duration, while corrected QT/QT/JT intervals, R amplitude and heart rate were decreased. ECG parameters were not distinguished between controls, although differences were noticed when comparing SHR and L-NAME groups. Because L-NAME treatment began at postnatal week 10, it is important to highlight the differences between them, observed only at postnatal week 15 (increased RR interval and P amplitude, decreased JT interval for SHR). These findings altogether suggest that SHR developed cardiac dysfunction, whereas L-NAME rats presented alterations in ventricular performance. Thus, depending on the experimental model, the adaptive mechanisms triggered by hypertension may be distinct. 6 Previous researches have included these two hypertensive experimental models and the evaluation of ECG tracings. Scridon et al., 7 reported unprovoked atrial tachyarrhythmias in aging spontaneously hypertensive rats correlating them with changes in the autonomic nervous system. Abdel-Rahman et al., 8 in their turn, described differences between L-NAME and Wistar rats regarding the ECG parameters similarly to Conceição-Vertamatti et al., 6 However, the latter authors highlighted the fact that none of them compared two different models of hypertension with each other on this matter. Although of great importance, the manuscript published by Conceição-Vertamatti et al., 6 presents a few limitations that must be briefly discussed. More  accurate data could be obtained with a different strategy for oral administration of L-NAME, rather than the drinking-water approach. It is important to consider that the authors kept three rats in the same cage, so the gavage method should be preferred. In addition, since the authors performed multiple comparisons, one-way ANOVA and Kruskal-Wallis tests should also be preferred for the statistical analysis. Moreover, it would be interesting if the authors had included females in their study, since the literature describes that sex-related differences are observed in the progression of cardiovascular disease and survival. 9 S tudi es are requi red to t es t s t ra t eg i es for hypertension prevention and control, especially among low-income populations. Therefore, studies that allow for a better understanding of the hypertensive pathology are very welcome. 1. Mills KT, Stefanescu A, He J. The global epidemiology of hypertension. Nat Rev Nephrol. 2020;16(4):223-37. 2. Leong X-F, Ng C-Y, Jaarin K.Animal Models in Cardiovascular Research: Hypertension and Atherosclerosis. Biomed Res Int. 2015; 528757. 3. Lerman LO, Kurtz TW, Touyz RM, Ellison DH, Chade AR, Crowley SD, et al. Animal Models of Hypertension: A Scientific Statement From the American Heart Association. Hypertension. 2019;73(6):e87-e120. 4. Reichlin T, Abächerli R, Twerenbold R, Kühne M, Schaer B, Müller C, et al. Advanced ECG in 2016: is there more than just a tracing? Swiss Med Wkly. 2016; 28;146:w14303. 5. Vilas-Boas F, Lima AAC, Torreão J, Feitosa GS. Dispersão Temporal do QT em Pacientes com Hipertensão Arterial Sistêmica. Arq Bras Cardiol. 1997; 68(5):343-6. 6. Conceição-Vertamatti AG, Borghi F, Ishizu LY, Costa GT, Ramos LA, Areas MA, Grassi-Kassisse DM. Electrocardiographic Abnormalities in Hypertension Models. Int J Cardiovasc Sci. 2020; 33(4):321-328. 7. Scridon A, Gallet C, Arisha MM, Oréa V, Chapuis B, Li N, et al. Unprovoked atrial tachyarrhythmias in aging spontaneously hypertensive rats: the role of the autonomic nervous system.Am J Physiol Heart Circ Physiol. 2012;303(7):H386-H392. 8. Abdel-Rahman RF, Hessin AF, Abdelbaset M, Ogaly HA, Abd- Elsalam RM, Hassan SM. Antihypertensive Effects of Roselle-Olive Combination in L-NAME-Induced Hypertensive Rats. Oxid Med Cell Longev. 2017;2017:9460653. Doi:10.1161/JAHA. 119.014448. Epub 2019) Oct 30. 9. Siontis KC, Ommen SR, Geske JB. Sex, Survival, and Cardiomyopathy: DifferencesBetweenMenandWomenWithHypertrophicCardiomyopathy. J AmHeart Assoc. 2019;8:e014448 References 330 Souza e Scaramello Ecocardiogram and animal models of hypertension Int J Cardiovasc Sci. 2020; 33(4):329-330 Editorial This is an open-access article distributed under the terms of the Creative Commons Attribution License