Teste cardiopulmonar de exercício na cardiomiopatia hipertrófica obstrutiva: segurança e valor adicional na estratificação do risco cardiovascular / Cardiopulmonary exercise testing in obstructive hypertrophic cardiomyopathy: safety and additional value in cardiovascular risk stratification

INTRODUÇÃO: A cardiomiopatia hipertrófica (CMHP) é uma doença cardíaca genética comum, com frequência aproximada de 1:500 na população geral e com expressões fenotípicas diversas. A forma obstrutiva caracteriza-se pela presença de gradiente pressórico intraventricular dinâmico, com manifestações mais graves e de difícil controle, sendo a realização de esforço físico contra indicada até recentemente, considerando-se a susceptilidade a arritmias ventriculares graves. Das variáveis do teste ergométrico a pressão arterial sistólica (PAS) é considerada fator determinante para morte súbita. OBJETIVO: avaliar a segurança do TCPE em pacientes com CMPH obstrutiva, bem como avaliar adicionalmente o comportamento de suas variáveis no auxílio à estratificação do risco cardiovascular. MÉTODOS: Foram incluídos pacientes com CMPH obstrutiva que realizaram TCPE entre o ano de 2013 e 2018. RESULTADOS: avaliados 18 pacientes com média de idade de 51 anos (DP 17.1) e 12 (67%) mulheres. Para caracterização anatômica foi empregada a ecodopplercardiografia que evidenciou: gradiente máximo da via de saída do ventrículo esquerdo: de 80 mmHg (DP 32.5); espessura septal (diástole) de 20 mm (DP 6.72); fração de ejeção do ventrículo esquerdo (FEVE) de 69.5 (DP 10.9). Todos em vigência de medicação específica, ressaltando-se os betabloqueadores em 16 pacientes (89%). Das variáveis obtidas durante o esforço, destacam-se as médias de tempo de exercício: 9,1 (DP 2.9) minutos ; frequência cardíaca pico = 111 (DP 19,4) bpm ou 65% do máxima; variação da PAS = 24.5 mmHg (DP 19.4), com curva deprimida em 75% dos pacientes; consumo de oxigênio pico de 18,25 ml.kg-1.min-1(DP 6.4), correspondendo a 62% do valor predito; VE / VCO2 slope = 30,2 (DP 7,60), Razão de trocas respiratórias ou RER = 1,02 (DP 0.13). Não houve arritmias ventriculares sustentadas, parada cardiorrespiratória, ou outra complicação que necessitasse de internação. CONCLUSÃO: Na amostra de pacientes avaliados o TCPE mostrou-se seguro durante sua realização em ambiente hospitalar, com variáveis hemodinâmicas e ventilatórias que podem auxiliar na caracterização prognóstica e no processo de decisão médica. (AU)

Exercise may cause myocardial ischemia at the anaerobic threshold in cardiac rehabilitation programs.

Myocardial ischemia may occur during an exercise session in cardiac rehabilitation programs. However, it has not been established whether it is elicited when exercise prescription is based on heart rate corresponding to the anaerobic threshold as measured by cardiopulmonary exercise testing. Our objective was to determine the incidence of myocardial ischemia in cardiac rehabilitation programs according to myocardial perfusion SPECT in exercise programs based on the anaerobic threshold. Thirty-nine patients (35 men and 4 women) diagnosed with coronary artery disease by coronary angiography and stress technetium-99m-sestamibi gated SPECT associated with a baseline cardiopulmonary exercise test were assessed. Ages ranged from 45 to 75 years. A second cardiopulmonary exercise test determined training intensity at the anaerobic threshold. Repeat gated-SPECT was obtained after a third cardiopulmonary exercise test at the prescribed workload and heart rate. Myocardial perfusion images were analyzed using a score system of 6.4 at rest, 13.9 at peak stress, and 10.7 during the prescribed exercise (P < 0.05). The presence of myocardial ischemia during exercise was defined as a difference > or = 2 between the summed stress score and summed rest score. Accordingly, 25 (64%) patients were classified as ischemic and 14 (36%) as nonischemic. MIBI-SPECT showed myocardial ischemia during exercise within the anaerobic threshold. The 64% prevalence of ischemia observed in the study should not be looked on as representative of the whole population of patients undergoing exercise programs. Changes in patient care and exercise programs were implemented as a result of our finding of ischemia during the prescribed exercise.

Exercise may cause myocardial ischemia at the anaerobic threshold in cardiac rehabilitation programs

Myocardial ischemia may occur during an exercise session in cardiac rehabilitation programs. However, it has not been established whether it is elicited when exercise prescription is based on heart rate corresponding to the anaerobic threshold as measured by cardiopulmonary exercise testing. Our objective was to determine the incidence of myocardial ischemia in cardiac rehabilitation programs according to myocardial perfusion SPECT in exercise programs based on the anaerobic threshold. Thirty-nine patients (35 men and 4 women) diagnosed with coronary artery disease by coronary angiography and stress technetium-99m-sestamibi gated SPECT associated with a baseline cardiopulmonary exercise test were assessed. Ages ranged from 45 to 75 years. A second cardiopulmonary exercise test determined training intensity at the anaerobic threshold. Repeat gated-SPECT was obtained after a third cardiopulmonary exercise test at the prescribed workload and heart rate. Myocardial perfusion images were analyzed using a score system of 6.4 at rest, 13.9 at peak stress, and 10.7 during the prescribed exercise (P < 0.05). The presence of myocardial ischemia during exercise was defined as a difference ≥2 between the summed stress score and summed rest score. Accordingly, 25 (64 percent) patients were classified as ischemic and 14 (36 percent) as nonischemic. MIBI-SPECT showed myocardial ischemia during exercise within the anaerobic threshold. The 64 percent prevalence of ischemia observed in the study should not be looked on as representative of the whole population of patients undergoing exercise programs. Changes in patient care and exercise programs were implemented as a result of our finding of ischemia during the prescribed exercise.