Heart rate turbulence assessed through ergometry after myocardial infarction: a feasibility study

Abstract

INTRODUCTIONCoronary artery disease is a condition characterized by increased atherosclerotic plaque in the epicardial arteries and is associated with high morbidity and mortality. Coronary artery disease accounts for nearly 360,000 events per year 1 in the United States, among which most occur in the hospital setting, and many events evolve to death before the patients are transported to the emergency room. 1 In the first six months of 2019, 137,713 hospitalizations due to coronary artery disease were recorded in Brazil, and 5.8% culminated in inhospital death. 2 Some clinical factors and complementary test markers help in the prognostic evaluation of coronary artery disease. Among these, the following can be highlighted: advanced age, male gender, systemic arterial hypertension, diabetes mellitus, dyslipidemia, smoking and myocardial dysfunction. 3,4 However, the impairment of cardiac vagal activity over the first year after a diagnosis of myocardial infarction has been made is also a good indicator for identifying the development of heart disease and sudden death over the short and medium term. [5][6][7] Analysis on the behavior of heart rate turbulence (HRT), obtained through 24-hour Holter monitoring, is one of the easiest and most efficient means for assessing cardiac autonomic dysfunction. 8 Sade et al. 8 found that HRT was similar to the ejection fraction in an assessment of the prognosis of 128 individuals post-infarction. On the other hand, the Innovative Stratification of Arrythmic Risk -Heart Rate Turbulence (ISAR-HRT) 9 study showed that altered HRT parameters increased the risk of death almost sixfold, in a prospective analysis on 1,500 survivors of myocardial infarction analyzed over a 22-month period. This risk exceeded the risks attributed to severe ventricular dysfunction, diabetes mellitus and age over 65 years.