ABC | Volume 111, Nº4, Octuber 2018

Letter to the Editor Body Mass Index May Influence Heart Rate Variability Thalys Sampaio Rodrigues 1 and Levindo José Garcia Quarto 2 University of Melbourne Department of Medicine Austin Health, 1 Heidelberg, Victoria - Austrália Hospital Regional Norte, 2 Sobral, CE - Brazil Mailing Address: Thalys Sampaio Rodrigues • 145 Studley road. 3084, Heidelberg, Victoria – Australia E-mail: thalys.sampaiorodrigues@unimelb.edu.au Manuscript received August 01, 2018, revised manuscript September 12, 2018, accepted September 12, 2018 Keywords Hypertension/prevalence; Diabetes Mellitus, Type 2; Risk Factors; Cardiovascular Diseases; Autonomic Nervous Systems; Heart Rate. 1. Bassi D, Cabiddu R, Mendes RG, Tossini R, Arakilian VM, Caruso FC, et al. Effects of coexistence hypertension and type II diabetes on heart rate variability and cardiorespiratory fitness. Arq Bras Cardiol.2018;11(1):64-72. 2. Benichou T, Pereira B, Mermillod M, Tauveron I, Pfabigan D, Magdasy S, et al. Heart rate variability in type 2 diabetes mellitus: A systematic review and meta–analysis. PloSone. 2018;13(4):e0195166. 3. LiaoD,SloanRP,CascioWE,FolsomAR,LieseAD,EvansGW.Multiplemetabolic syndromeisassociatedwith lowerheartratevariability:theAtherosclerosisRisk in Communities Study. Diabetes Care. 1998;21(12):2116-22. 4. Vasconcelos DF, Junqueira Junior LF. Cardiac autonomic and ventricular mechanical functions in asymptomatic chronic chagasic cardiomyopathy. Arq Bras Cardiol. 2012;98(2):111-9. 5. Windham BG, Fumagalli S, Ble A, Sollers JJ, Thayer JF, Najjar SS, et al. The relationship between heart rate variability and adiposity differs for central and overall adiposity. J Obes. 2012;2012:149516. 6. Sacre JW, Franjic B, Jellis CL, Jenkins C, Coombes JS, Marwick TH, et al. Association of cardiac autonomic neuropathy with subclinical myocardial dysfunctionintype2diabetes. JACC:CardiovascImaging. 2010;3(12):1207-15. References Reply Dear Editor, We appreciate the authors’ interest towards our article, “Effects of Coexistence Hypertension and Type II Diabetes on Heart Rate Variability and Cardiorespiratory Fitness”. We also appreciate the opportunity to respond to their comments. Their critique of our study mainly focused on 3 issues: 1) lack of methodological attention in relation to the participants’ gender, BMI and insulin resistance; 2) lack of methodological details about the study population, regarding smoking habits and hyperlipidemia; and 3) lack of consistent investigation on ischemic and non-ischemic cardiomyopathy. We appreciate the authors’ concerns; however, we do not agree with many of their comments. The first issue was clearly acknowledged in our paper. Since cardiac variability dynamics differ between genders, with higher parasympathetic activity and overall complexity for women, gender distribution must be considered when investigating heart rate dynamics. 1 However, in our study, gender DOI: 10.5935/abc.20180201 We read with interest the article by Bassi et al., 1 titled “Effects of Coexistence Hypertension and Type II Diabetes on Heart Rate Variability and Cardiorespiratory Fitness”, published in the issue of July 2018. The authors investigated the influence of systemic hypertension on cardiac autonomic modulation in patients with type 2 diabetes mellitus (T2DM) and assessed the heart rate variability (HRV) on exercise capacity in these patients. They concluded that hypertension negatively affects cardiac autonomic function, with greater impairment in HRV, when compared to normotensive patients with T2DM. Several aspects of this study require discussion. As previously reported, numerous factors may have impact on HRV indices, including sex, insulin resistance, body mass index (BMI), hyperlipidemia, hypertension, ischemic and non-ischemic cardiomyopathy, and smoking status. 2-4 For instance, increased BMI can independently decrease HRV, particularly when central adiposity is present. 5 Indeed, the hypertensive group had a higher BMI when compared to the normotensive group (28 ± 4.4 vs 31 ± 3.8, p = 0.031). Given the lack of control for BMI between the two groups, the conclusions made by the authors should be regarded cautiously. Finally, it is known that subclinical myocardial dysfunction is highly prevalent in diabetic patients and is independently associated with cardiac autonomic neuropathy. 6 However, the authors only considered medical history consistent with ischemic heart disease for stratification/exclusion of patients for analysis. We believe that a more detailed cardiovascular assessment, including echocardiography to determine left ventricular mass and left ventricular diastolic dysfunction, would be important to better stratify the patients and strengthen their conclusions. 640