Doppler mitral inflow variables time course after treadmill stress echo with and without ischemic response

Abstract

This study evaluated Doppler mitral inflow variables changes from rest to post-exercise among 104 subjects with and without echocardiographic evidence of ischemic response (IR) to exercise (63.9 ± 11 years, 54% male, 32% with IR) who underwent a clinically indicated treadmill stress echo (TSE) test. The time from exercise cessation to imaging (TIME) was recorded. The changes (after TSE minus baseline values) in the peak E-wave velocity (∆E) [34.2 vs. 24.2, p = 0.024] and E-wave deceleration rate (∆DR) [348.0 vs. 225.7, p = 0.010] were bigger in ischemic than in nonischemic subjects, while the changes in the peak A-wave velocity (∆A) did not differ [7.9 vs. 15.0, p = 0.082]. The correlations between Doppler variables and IR, TIME, and TIME × IR interaction were analyzed. We observed a significant interaction between TIME and IR regarding ∆E and ∆DR. The differences in the regression line slopes of time courses for ∆E and ∆DR based on IR were significant: ∆E (- 0.09 vs. - 8.17, p = 0.037) and ∆DR (11.23 vs. - 82.60, p = 0.022). Main findings: (1) Time courses after exercise of ∆E and ∆DR in subjects with and without IR were different. (2) ∆E and ∆DR did not differ between subjects with and without IR at exercise cessation (TIME = 0). (3) The simple main effect of ischemia on ∆E and ∆DR was significant at TIME of ≥ 3 min. Divergent time courses of ∆E and ∆DR after exercise might be promising for detecting diastolic dysfunction caused by ischemia. After the cessation of exercise, ΔE and ΔDR in nonischemic but not in ischemic subjects quickly tend to zero. The differences in ΔE and ΔDR between the two groups only became significant for TIME of ≥ 3 min. At the time of exercise cessation, the values of ΔE and ΔDR (taken from the regression lines) were not significantly different between the patients with and without IR. This divergent response is promising for detecting diastolic dysfunction caused by ischemia.

Keywords: Deceleration rate; Diastolic stress echocardiography; E-wave; Ischemia.