IJCS | Volume 33, Nº4, July and August 2020

DOI: https://doi.org/10.36660/ijcs.20200116 Hypertension is themainrisk factor for thedevelopment of cardiovascular diseases, such as cerebrovascular and ischemic heart diseases, as well as for premature death worldwide. The prevalence of this condition was about 30% in low-, middle- and high-income countries in 2010. Cardiovascular pharmacotherapy and lifestyle changes constitute important measures tomanage cardiovascular diseases, and the reduction of blood pressure is a fundamental strategy to prevent and treat them. Systemic arterial hypertension is a clinical multifactorial condition. The underlying mechanisms of hypertensive disease are complex, which is why it is essential to elucidate them. 1 Many animal models of hypertension can serve this purpose, most of which were developed considering the probable causes of this condition, such as high salt intake and renin-angiotensin-aldosterone system overactivity. It is important that each model exploit a single pathway to hypertension development. 2 Spontaneously hypertensive rats (SHR) are genetically modified animals commonly chosen for several studies, including antihypertensive drugs screening. They provide an inexpensive experimental model and have a hypertensive phenotype similar to human patients. There are also endocrinemodels of hypertension, including the administration of deoxycorticosterone acetate (plus salt) and N-ω-nitro-L-arginine methyl- ester (L-NAME). According to the literature, both SHR and L-NAMEmodels are related to sympathetic overactivity. 2,3 A hypertensive condition can affect cardiac electrical activity and, since electrocardiogram (ECG) techniques involve the recording of the heart's electrical activity, it seems to be a useful tool to evaluate high blood pressure-related cardiac impairment. These findings may explain the greater occurrence of arrhythmias and sudden death among hypertensive patients. ECG is considered a simple and inexpensive technique, being widely performed to diagnose cardiovascular diseases. 4,5 The manuscript published by Conceição-Vertamatti et al., 6 in the International Journal of Cardiovascular Sciences, proposes a comparative analysis encompassing two different experimental models of hypertension (endocrine/genetic) and their respective controls. Thus, the animals were divided into four experimental groups (6 animals/group): Wistar rats treated and untreated with L-NAME, Wistar-Kyoto rats and SHR. In brief, L-NAME treatment (40 mg / kg / day in drinking water) was performed between postnatal weeks 10 and 15. All assays were conducted under anesthesia. The four experimental groups were submitted to ECG recording, both at postnatal weeks 6 and 15, while non-invasive blood pressure measurements were carried out only at the end of the experimental period. Data normality was confirmed (Kolmogorov-Smirnov test) followed by unpaired Student's t-test or the Mann-Whitney. The authors observed higher systolic, diastolic, mean and mean diastolic pressures in L-NAME and SHR groups compared to their respective controls (Wistar and Wistar-Kyoto rats). In addition, SHR also presented higher time- to-peak values thanWystar-Kyoto rats.According to Conceição-Vertamatti et al., 6 these data are in agreement with the literature and validate the experimental models of hypertension used. No differences were observed between controls or hypertensive groups regarding the hemodynamic parameters. Several differences were noticed between SHR and Wistar-Kyoto rats regarding the ECG parameters, 329 EDITORIAL International Journal of Cardiovascular Sciences. 2020; 33(4):329-330 Mailing Address: Christianne Brêtas Viera Scaramello Rua Prof. Hernani Mello, 101. Postal Code: 24210-130, São Domingos, Niterói, Rio de Janeiro, RJ – Brazil. E-mail: chrisbretas@gmail.com Relevance of Animal Models and Echocardiogram for Hypertensive Disease Studies Karyne Pollo de Souz a and Christianne Brêtas Viera Scaramell o Universidade Federal Fluminense - Instituto Biomédico, Niterói, RJ - Brazil Editorial related to the article: Electrocardiographic Abnormalities in Hypertension Models Hypertension/complications; Blood Pressure; Cardiovascular Diseases/mortality; Electrocardiography/ methods; Rats; Animal Models. Keywords