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


METHODS
Between 2000 and 2006, 4042 patients (1900 men with a mean age of 56 +/- 11 years) were evaluated by EE. Based on the heart rate (HR) reached during the exercise test, the subjects were divided into two groups: G1 group - 490 patients who failed to achieve 85% of the maximal age-predicted HR, and G2 group - 3552 patients who were able to achieve 85% of the maximal age-predicted HR. Clinical characteristics, left ventricular wall motion abnormalities - wall motion score index (WMSI) - and coronary angiography (CA) were the parameters compared between the two groups.


RESULTS
The left ventricular wall motion abnormalities were more frequent in G1 group than in G2 group (54% versus 26%; P < 0.00001). WMSI was higher in G1 group than in G2 group, both at rest (1.06 +/- 0.17 versus 1.02 +/- 0.09; P < 0.0001) and after exercise (1.12 +/- 0.23 versus 1.04 +/- 0.21; P < 0.0001). In G1 group, 82% of the patients with positive EE for myocardial ischemia presented obstructive coronary, compared to 71% (P = 0.03) in G2 group.


CONCLUSIONS
CI is associated with a higher frequency of myocardial ischemia during EE, reinforcing the concept that CI is a marker of the severity of myocardial ischemia.
Oliveira
Joselina L M
JL
Department of Internal Medicine, Cardiology Division, Federal University of Sergipe, Aracaju, Sergipe, Brazil. joselinasergipe@ig.com.br
Góes
Thiago J S
TJ
Santana
Thaiana A
TA
Travassos
Thiago F
TF
Teles
Lívia D
LD
Anjos-Andrade
Fernando D
FD
Nascimento-Júnior
Adão C
AC
Alves
Erica O
EO
Barreto
Martha A
MA
Barreto-Filho
José A
JA
D'Oliveira
Argemiro
A
Sousa
Antônio C S
AC
D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D001938:Brazil / Q000453:epidemiology; D015897:Comorbidity; D004452:Echocardiography / Q000706:statistics & numerical data*; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006339:Heart Rate; D006801:Humans; D015994:Incidence; D008297:Male; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity