ABC | Volume 112, Nº3, March 2019

Brief Communication Ribeiro et al Beta-blocker effect on substrate oxidation during exercise in heart failure Arq Bras Cardiol. 2019; 112(3):304-308 Table 1 – Baseline Clinical Characteristics according to the type of beta-blocker class Clinical Variables Beta-blocker class Non-vasodilating n = 10 Vasodilating n = 8 Age (years) 59.3 ± 9.8 58.0 ± 8.5 BMI (kg/m 2 ) 30.0 ± 4.0 28.0 ± 3.7 LVEF (%) 29 ± 7 27 ± 6 SBD (mmHg) 129 ± 20 108 ± 17* DBP (mmHg) 75 ± 10 61 ± 15* NYHA functional class I 1 (10%) 4 (50%) II 9 (90%) 3 (37.5%) III 0 1 (12.5%) Etiology of heart failure Ischemic heart disease 6 (60%) 4 (50%) Idiopathic dilated cardiomyopathy 4 (40%) 4 (50%) Medical history Diabetes mellitus 1 (10%) 3 (37.5%) Hypertension 6 (60%) 4 (50%) Medications ACE inhibitors or ARBs 10 (100%) 8 (100%) Digoxin 2 (20%) 4 (50%) Furosemide 8 (80%) 6 (75%) Spironolactone 4 (40%) 4 (50%) Devices ICD 7 (70%) 6 (75%) CRT 1 (10%) 3(37.5%) Maximal exercise variables Peak power output (Watts) 108 ± 33 110 ± 31 VO 2peak (L/min) 1598 ± 507 1478 ± 422 VO 2peak (% predicted) 63 ± 13 59 ± 12 VO 2peak (mL/min/kg) 17.3 ± 4.6 18.3 ± 4.6 Values are presented as means ± SDs, or numbers of patients (percentages). BMI: body mass index; LVEF: left ventricle ejection fraction; SBP: systolic blood pressure; DBP: diastolic blood pressure; ACE: angiotensin-converting enzyme; ARBs: angiotensin II receptor blockers; ICD: implantable cardioverter-defibrillator; CRT: cardiac resynchronization therapy; VO 2 : oxygen uptake; VO 2peak : peak oxygen uptake. * p < 0.05. Conclusion In short, according to our pilot data, carvedilol seems to facilitate CHO oxidation during HIIE and should be considered when possible, for patients under high-intensity exercise programs. However, how the use of different beta-blockers agents (ex: vasodilating) could impact muscle metabolism during various acute and chronic exercise training programs in these patients need to be better explored. Acknowledgement The authors are grateful to ÉPIC Foundation, Montreal Heart Institute Foundation andConselhoNacional deDesenvolvimento Científico e Tecnológico (CNPq– Brazil) for grant support. Author contributions Conception anddesignof the research: RibeiroPAB, JuneauM, White M, Nigam A, Gayda M; acquisition of data: Normandin E, Meyer P; analysis and interpretation of the data: Ribeiro PAB, Normandin E, Meyer P, White M, Nigam A, Gayda M; statistical analysis: Ribeiro PAB; obtaining funding: Ribeiro PAB, Juneau M, GaydaM;writing of themanuscript: RibeiroPAB, GaydaM; critical revision of the manuscript for intellectual content: Ribeiro PAB, Normandin E, Meyer P, Juneau M, White M, Nigam A, Gayda M. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. 306