Exercise-induced changes in E/E' ratio in patients with suspected coronary artery disease.

OBJECTIVES: Ischemia affects the left ventricular (LV) diastolic function earlier than the systolic function. The ratio of the early diastolic transmitral velocity to the early diastolic tissue velocity (E/E') measured by tissue Doppler echocardiography allows a reliable assessment of the diastolic function. We investigated whether exercise-induced changes in E/E' ratio may help in the detection of coronary artery disease (CAD).

METHODS: The study population consisted of 114 patients undergoing coronary angiography. Patients with impaired LV ejection fraction, earlier myocardial infarction, arterial hypertension greater than stage I, or LV hypertrophy were excluded. Patients underwent a treadmill exercise test combined with an echocardiogram at baseline and within the first minute after exercise.

RESULTS: Coronary angiography showed a stenosis more than 70% in 72 (63%) patients (CAD group), the remaining 42 formed the non-CAD group. The two groups did not differ regarding age, sex, LV dimensions, and function. At baseline, the E/E' lateral and septal ratios and their average did not differ between the two groups. The exercise-induced changes of the E/E' ratios were higher in the CAD group (change of E/E' average: 1.9+/-3.3 vs. -1.1+/-2.3, P<0.001). In the CAD group, 78% showed an exercise-induced increase of E/E' average compared with 24% in the non-CAD group (P<0.001). In multivariate analysis, the association between an increase of E/E' average and the presence of obstructive CAD was independent of traditional risk factors, exercise test result or exercise-induced wall motion abnormalities (odds ratio=8.1, P<0.001).

CONCLUSION: Exercise-induced changes in E/E' ratio may offer significant assistance in the detection of CAD.