Chronotropic incompetence and a higher frequency of myocardial ischemia in exercise echocardiography

Abstract

Background: Exercise echocardiography (EE) is an established method to diagnose coronary artery disease (CAD). Chronotropic incompetence (CI) during the EE may be a marker of myocardial ischemia. The purpose of this investigation was to evaluate the additive value of CI during EE in CAD diagnosis.

Parâmetros clínicos e ecocardiográficos associados a baixo índice cronotrópico em pacientes não idosos

“…For each increment of three units in the METs, the odds of incompetence is reduced by 66% (p <0.0001). Similar results were found by other studies that confirm the inverse relationship between the presence of incompetence and physical capacity 11,18,20,21,27,28 . In a comparative study among users of pacemaker with fixed ventricular rate and variable rate during exercise, it was observed that the first group, which behaves like HF patients, presented worse tolerance to exertion 29 .…”

“…Moreover, it is confirmed to present diagnostic accuracy superior to that of the ET, especially in patients with HF 11 .…”

“…Maddox et al 33 found ischemia on ECG in only 17% of incompetent patients, and Dresing al 27 , in 52% versus 65% of competent patients. Oliveira et al 11 described 30% of abnormalities in the incompetent group versus 43% in the competent group (p <0.0001). Thus, these data should not be interpreted as an attempt to study the association between myocardial ischemia and heart failure, but as a reflection of the interference of HF in the manifestation of the marker of myocardial ischemia on ST (ST segment depression).…”

“…However, the accuracy of ST in patients with HF has been questioned; the examination is often characterized as ineffective or not diagnostic 8,9 . Although there is an association between incompetence and myocardial ischemia 11 , the imbalance between oxygen supply-consumption in incompetent patients would not be so encouraged to the point of developing electrocardiographic abnormalities suggesting ischemia, as typically occurs in competent patients, which would decrease the sensitivity of ST in incompetent patients. In this study, the higher incidence of ST-segment depression was associated with lower odds of HF (OR = 0.58; p = 0.0003), similar to what was described by Cay et al 32 .…”

“…However, studies on SE are scarce. It has been demonstrated in an unselected population, including patients with prior CAD, that HF is associated with an increased frequency of myocardial ischemia on SE 11 . The same authors studied only the elderly and found that HF in this group is also associated with higher frequency of contractile alterations and adds to a positive predictive value to SE in identifying patients with obstructive CAD 17 .…”