Salvador Manoel Serra

Cholinergic Stimulation Improves Autonomic and Hemodynamic Profile During Dynamic Exercise in Patients With Heart Failure

BACKGROUND Parasympathetic dysfunction is an independent risk factor for mortality in heart failure for which there is no specific pharmacologic treatment. This article aims to determine the effect of pyridostigmine, an anticholinesterase agent, on the integrated physiologic responses to dynamic exercise in heart failure. METHODS AND RESULTS Patients with chronic heart failure (n = 23; 9 female; age = 48 +/- 12 years) were submitted to 3 maximal cardiopulmonary exercise tests on treadmill in different days. The first test was used for adaptation and to determine exercise tolerance. The other tests were performed after oral administration of pyridostigmine (45 mg, 3 times/day, for 24 hours) or placebo, in random order. All patients were taking their usual medication. Pyridostigmine reduced cholinesterase activity by 30%, inhibited the chronotropic response throughout exercise, up to 60% of maximal effort (pyridostigmine = 108 +/- 3 beats/min vs. placebo = 113 +/- 3 beats/min; P = .040), and improved heart rate reserve (pyridostigmine = 73 +/- 5 beats/min vs. placebo = 69 +/- 5 beats/min; P = 0.035) and heart rate recovery in the first minute after exercise (pyridostigmine = 25 +/- 2 beats/min vs. placebo = 22 +/- 2 beats/min; P = .005), whereas peak heart rate was similar to placebo. Oxygen pulse, an indirect indicator of stroke volume, was higher under pyridostigmine during submaximal exercise. CONCLUSIONS Pyridostigmine was well tolerated by heart failure patients, leading to improved hemodynamic profile during dynamic exercise.

Reduction of QTc interval dispersion. Potential mechanism of cardiac protection of pyridostigmine bromide

OBJECTIVE Parasympathetic dysfunction is an independent risk factor in individuals with coronary artery disease, and cholinergic stimulation is a potential therapeutical option. We determined the effects of pyridostigmine bromide, a reversible anticholinesterase agent, on electrocardiographic variables of healthy individuals. METHODS We carried out a cross-sectional, double blind, randomized, placebo-controlled study. We obtained electrocardiographic tracings in 12 simultaneous leads of 10 healthy young individuals at rest before and after oral administration of 45 mg of pyridostigmine or placebo. RESULTS Pyridostigmine increased RR intervals (before: 886+/-27 ms vs. after: 1054+/-37 ms) and decreased QTc dispersion (before: 72+/-9 ms vs. after: 45+/-3 ms), without changing other electrocardiographic variables (PR segment, QT interval, QTc, and QT dispersion). CONCLUSION Bradycardia and the reduction in QTc dispersion induced by pyridostigmine may effectively represent a protective mechanism if these results can be reproduced in individuals with cardiovascular diseases.

Influence of skeletal muscle mass on ventilatory and hemodynamic variables during exercise in patients with chronic heart failure.

OBJECTIVE To assess the influence of skeletal muscle mass on ventilatory and hemodynamic variables during exercise in patients with chronic heart failure (CHF). METHODS Twenty-five male patients underwent maximum cardiopulmonary exercise testing on a treadmill with a ramp protocol and measurement of the skeletal muscle mass of their thighs by using magnetic resonance imaging. The clinically stable, noncachectic patients were assessed and compared with 14 healthy individuals (S) paired by age and body mass index, who underwent the same examinations. RESULTS Similar values of skeletal muscle mass were found in both groups (CHF group: 3863 874 g; S group: 3743 540 g; p = 0.32). Significant correlations of oxygen consumption in the anaerobic threshold (CHF: r = 0.39; P= 0.02 and S: r = 0.14; P = 0.31) and of oxygen pulse also in the anaerobic threshold (CHF: r = 0.49; P = 0.01 and S: r =0.12; P = 0.36) were found only in the group of patients with chronic heart failure. CONCLUSION The results obtained indicate that skeletal muscle mass may influence the capacity of patients with CHF to withstand submaximal effort, due to limitations in their physical condition, even maintaining a value similar to that of healthy individuals. This suggests qualitative changes in the musculature.

Exercise stress testing in healthy subjects during cholinergic stimulation after a single dose of pyridostigmine

OBJECTIVE The evaluation, by exercise stress testing, of the cardiorespiratory effects of pyridostigmine (PYR), a reversible acetylcholinesterase inhibitor. METHODS A double-blind, randomized, cross-over, placebo-controlled comparison of hemodynamic and ventilation variables of 10 healthy subjects who underwent three exercise stress tests (the first for adaptation and determination of tolerance to exercise, the other two after administration of placebo or 45mg of PYR). RESULTS Heart rate at rest was: 68+/-3 vs 68+/-3bpm before and after placebo, respectively (P=0.38); 70+/-2 vs 59+/-2bpm, before and after pyridostigmine, respectively (P<0.01). During exercise, relative to placebo: a significantly lower heart rate after PYR at, respectively, 20% (P=0.02), 40% (P=0.03), 80% (P=0.05) and 100% (P=0.02) of peak effort was observed. No significant differences were observed in arterial blood pressure, oxygen consumption at submaximal and maximal effort, exercise duration, respiratory ratio, CO2 production, ventilation threshold, minute ventilation, and oxygen pulse. CONCLUSION Pyridostigmine, at a dose of 45mg, decreases heart rate at rest and during exercise, with minimal side effects and without interfering with exercise tolerance and ventilation variables.

Safety, feasibility, and results of exercise testing for stratifying patients with chest pain in the emergency room

OBJECTIVE To assess safety, feasibility, and the results of early exercise testing in patients with chest pain admitted to the emergency room of the chest pain unit, in whom acute myocardial infarction and high-risk unstable angina had been ruled out. METHODS A study including 1060 consecutive patients with chest pain admitted to the emergency room of the chest pain unit was carried out. Of them, 677 (64%) patients were eligible for exercise testing, but only 268 (40%) underwent the test. RESULTS The mean age of the patients studied was 51.7 12.1 years, and 188 (70%) were males. Twenty-eight (10%) patients had a previous history of coronary artery disease, 244 (91%) had a normal or unspecific electrocardiogram, and 150 (56%) underwent exercise testing within a 12-hour interval. The results of the exercise test in the latter group were as follows: 34 (13%) were positive, 191 (71%) were negative, and 43 (16%) were inconclusive. In the group of patients with a positive exercise test, 21 (62%) underwent coronary angiography, 11 underwent angioplasty, and 2 underwent myocardial revascularization. In a univariate analysis, type A/B chest pain (definitely/probably anginal) (p<0.0001), previous coronary artery disease (p<0.0001), and route 2 (patients at higher risk) correlated with a positive or inconclusive test (p<0.0001). CONCLUSION In patients with chest pain and in whom acute myocardial infarction and high-risk unstable angina had been ruled out, the exercise test proved to be feasible, safe, and well tolerated.

Posicionamento Oficial da Sociedade Brasileira de Medicina do Esporte sobre: esporte Competitivo em Indivíduos acima de 35 anos

o fato de que o idoso nao tolera bem os extremos de tem-peratura e umidade, devendo ser evitados exercicios inten-sos sob tais condicoes climaticas, devido a possibilidadede hipertermia ou hipotermia.Documentos institucionais previamente publicados tra-caram recomendacoes quanto a pratica de exercicios com-petitivos em portadores de doencas cardiovasculares; quan-to aos criterios de afastamento e elegibilidade para compe-ticao desportiva; e quanto aos criterios para deteccao dedoencas cardiovasculares em uma populacao aparentementesaudavel. Entretanto, esses documentos se concentraram,principalmente, em atletas jovens ou individuos idosos pra-ticantes de atividade fisica de carater nao-competitivo.As competicoes para veteranos, organizadas pelas con-federacoes nacionais, federacoes regionais ou por associa-coes de atletas apresentam com frequencia bom nivel tec-nico. Alguns atletas com idades para serem consideradosveteranos ( master) ainda mantem carreiras competitivas emalgumas modalidades, participando de campeonatos mun-diais absolutos ou mesmo dos Jogos Olimpicos, com bonsresultados.O objetivo deste Posicionamento Oficial da SociedadeBrasileira de Medicina do Esporte (

Cardiopulmonary Exercise Test: Background, Applicability and Interpretation

Cardiopulmonary exercise test (CPET) has been gaining importance as a method of functional assessment in Brazil and worldwide. In its most frequent applications, CPET consists in applying a gradually increasing intensity exercise until exhaustion or until the appearance of limiting symptoms and/or signs. The following parameters are measured: ventilation; oxygen consumption (VO2); carbon dioxide production (VCO2); and the other variables of conventional exercise testing. In addition, in specific situations, pulse oximetry and flow-volume loops during and after exertion are measured. The CPET provides joint data analysis that allows complete assessment of the cardiovascular, respiratory, muscular and metabolic systems during exertion, being considered gold standard for cardiorespiratory functional assessment.1-6 The CPET allows defining mechanisms related to low functional capacity that can cause symptoms, such as dyspnea, and correlate them with changes in the cardiovascular, pulmonary and skeletal muscle systems. Furthermore, it can be used to provide the prognostic assessment of patients with heart or lung diseases, and in the preoperative period, in addition to aiding in a more careful exercise prescription to healthy subjects, athletes and patients with heart or lung diseases. Similarly to CPET clinical use, its research also increases, with the publication of several scientific contributions from Brazilian researchers in high-impact journals. Therefore, this study aimed at providing a comprehensive review on the applicability of CPET to different clinical situations, in addition to serving as a practical guide for the interpretation of that test.

Avaliação clínica e funcional tardia de arritmias em crianças operadas de Tetralogia de Fallot

BACKGROUND Cardiac arrhythmias are the major cause of late sudden death in patients undergoing repair of Tetralogy of Fallot (TF). OBJECTIVE To evaluate the occurrence of cardiac arrhythmias in children and adolescents undergoing repair of TF, and to associate them with clinical aspects and laboratory tests. METHODS Cross-sectional study of 37 patients undergoing repair of TF at Instituto Estadual de Cardiologia Aloysio de Castro (Rio de Janeiro). After review of the medical records and clinical assessment, the patients underwent electrocardiography (ECG), echocardiography (Echo), 24-h Holter monitoring and exercise test (ET), whose results were subjected to statistical analysis. RESULTS A total of 37 patients of whom 54% were males with a mean age of 9.7 ± 3.5 years and mean follow-up period of 4.7 ± 1.9 years were studied. The abnormalities most frequently found were: on ECG: right bundle branch block (89%); Echo: severe pulmonary regurgitation (43%), mild pulmonary stenosis (73%), moderate right ventricular hypertrophy (RVH, 57%); on ET: low exercise capacity (90%), impaired chronotropic response (40%), arrhythmias (20%); on Holter monitoring: arrhythmias (59%, of which 44% were ventricular, 38% supraventricular, and 24% both ventricular and supraventricular, with predominance of infrequent and benign ventricular premature beats). Five patients (15%) presented with multiform ventricular premature beats. There was an association of ventricular arrhythmia with moderate and severe RVH (p=0.026), as well as with right ventricle-to-pulmonary artery gradient (RV/PA) > 45 mmHg (p=0.004). The logistic regression analysis showed that increased RV/PA gradient was an independent predictor of ventricular arrhythmia (p=0.017). CONCLUSION Cardiac arrhythmia was a common finding in a large proportion of children and adolescents after surgical repair of TF; however, it was infrequent and benign in most of the cases. The RV/PA gradient was considered a strong predictor of ventricular arrhythmia.FUNDAMENTO: Arritmias cardiacas sao a maior causa de morte subita tardia em pacientes operados de Tetralogia de Fallot (TF). OBJETIVO: Avaliar a ocorrencia de arritmias cardiacas em criancas e adolescentes operados de TF, associando-as aos aspectos clinicos e de exames complementares. METODOS: Estudo transversal em 37 pacientes submetidos a cirurgia de TF no Instituto Estadual de Cardiologia Aloysio de Castro (RJ). Apos revisao de prontuarios e avaliacao clinica, os pacientes foram submetidos a eletrocardiograma (ECG), ecocardiograma (Eco), Holter 24h (Holter) e teste ergometrico (TE), sendo os resultados submetidos a analise estatistica. RESULTADOS: Estudados 37 pacientes, 54% masculinos, idade 9,7 ± 3,5 anos, seguimento medio de 4,7 ± 1,9 anos. Alteracoes mais prevalentes: ECG: bloqueio de ramo direito (89%); Eco: insuficiencia pulmonar grave (43%), estenose pulmonar leve (73%), hipertrofia ventricular direita (HVD) moderada (57%). No TE, baixa capacidade de exercicio (90%), deficit cronotropico (40%), arritmias (20%). Ao Holter, 59% apresentaram arritmias: ventriculares 44%, supraventriculares 38% e ambas 24%, com predominio de extrassistoles pouco frequentes e benignas. Cinco pacientes (15%) apresentaram extrassistoles polimorficas. Houve associacao entre arritmia ventricular e HVD moderada e grave (p=0,026) e tambem com gradiente ventriculo direito-arteria pulmonar (VD/AP) > 45 mmHg (p=0,004). Atraves da Regressao Logistica, o aumento do gradiente VD/AP foi fator preditivo independente para arritmia ventricular (p=0,017). CONCLUSAO: Arritmias cardiacas foram um achado comum em grande parte de criancas e adolescentes apos reparo cirurgico de TF, porem pouco frequentes e benignas, na maioria dos casos. O gradiente pressorico VD-AP foi considerado forte preditor para arritmia ventricular.

Cardiopulmonary Exercise Test: Fundamentals, Applicability and Interpretation

Cardiopulmonary exercise test (CPET) has been gaining importance as a method of functional assessment in Brazil and worldwide. In its most frequent applications, CPET consists in applying a gradually increasing intensity exercise until exhaustion or until the appearance of limiting symptoms and/or signs. The following parameters are measured: ventilation; oxygen consumption (VO2); carbon dioxide production (VCO2); and the other variables of conventional exercise testing. In addition, in specific situations, pulse oximetry and flow-volume loops during and after exertion are measured. The CPET provides joint data analysis that allows complete assessment of the cardiovascular, respiratory, muscular and metabolic systems during exertion, being considered gold standard for cardiorespiratory functional assessment.1-6 The CPET allows defining mechanisms related to low functional capacity that can cause symptoms, such as dyspnea, and correlate them with changes in the cardiovascular, pulmonary and skeletal muscle systems. Furthermore, it can be used to provide the prognostic assessment of patients with heart or lung diseases, and in the preoperative period, in addition to aiding in a more careful exercise prescription to healthy subjects, athletes and patients with heart or lung diseases. Similarly to CPET clinical use, its research also increases, with the publication of several scientific contributions from Brazilian researchers in high-impact journals. Therefore, this study aimed at providing a comprehensive review on the applicability of CPET to different clinical situations, in addition to serving as a practical guide for the interpretation of that test.

Chagas' cardiomyopathy prognosis assessment through cardiopulmonary exercise testing

variable found an area of 0.91 (95% CI 0.78-1.00; p=0.006) with a cutoff value ≤1280 mmHg.mL.kg -1 .min -1 in the CG and an area of 0.75 (95% CI 0.64-0.86; p<0.0001) with a cutoff value of ≤1245 mmHg.mL.kg -1 .min -1 in the NCG. Conclusion: Circulatory power was the variable associated with death in both groups and should be more widely used as an indicator of prognosis in heart failure.