A novel finding to assess ischemia in pacing stress echocardiography (PASE)

Normalization of heart rate post-pacing stress echocardiography (PASE) could enable evaluation of effect of ischemia on diastolic function.

We examined the effect of pacing on left ventricular (LV) filling in 55 patients who underwent a transesophageal PASE. Pulse wave Doppler of mitral inflow was obtained at baseline and during transition from peak pacing to up to three beats immediate post pacing.

Thirty-four patients (62%; 62 +/- 12 years) had normal (NL) PASE, wall motion score index (WMSI) 1 +/- 0 at baseline and during PASE. Sixteen patients (29%; 64 +/- 12 years) had ischemic (ISCH) PASE, WMSI 1.07 +/- 0.08 at baseline and 1.40 +/- 0.21 during PASE. Five patients (9%; 81 +/- 5 years) had abnormal (ABN) PASE, WMSI 1.55 +/- 0.34 at baseline and 1.55 +/- 0.34 during PASE. The ABN group had the most pronounced decrease in deceleration time (DT) seen in all three post-PASE beats (221 +/- 29 ms at baseline vs. 145 +/- 46, 144 +/- 26 and 144 +/- 18 ms at beats 1, 2, and 3, P < 0.005 from baseline for all). The DT reduced significantly at post-PASE beat 1 from baseline (234 +/- 45 ms vs. 158 +/- 36 ms, P = 0.02) in the ISCH group, whereas no significant change in DT occurred in the NL group (239 +/- 74 ms vs. 222 +/- 58 ms, P = 0.14) at beat 1.

In ISCH and ABN ventricles the duration of early diastolic filling decreased post-pacing. This new finding of a shortened deceleration time (DT) may be a marker of an ischemic response in PASE reflecting abnormal LV compliance.