Background:
We studied whether dynamic changes in LV asynchrony may affect the functional improvement of LV in medically treated patients with non-ischemic cardiomyopathy (CMP).
Methods:
Supine bicycle exercise was performed in 41 patients (age 51±12 years, EF 33±8%). Using tissue Doppler imaging, the average of peak systolic velocities of 6 basal LV segments were obtained at rest (V
b
) and peak exercise (V
p
). ΔV was calculated by [V
p
-V
b
], reflecting the contractile reserve. Dyssynchrony index (SD
4
) was defined as the standard deviation of the time to peak systolic velocities at 4 basal & mid segments of septum and lateral wall on apical 4 chamber view. ΔSD
4
was calculated as [peak exercise SD
4
- resting SD
4
]. Follow-up echocardiography was done in 35 patients after medication for 11.2±4.2 months. Functional changes of LV was assessed by ΔEF
FU
and %change of ESV (ΔESV
FU
).
Results:
Baseline SD
4
was 24±17 ms. During exercise, SD
4
increased in 24 patients (ΔSD
4
=+14±12 ms), whereas decreased in 17 patients (ΔSD
4
=-17±14 ms). ΔSD
4
correlated with ΔV (r=-0.36, p=0.021) and exercise-induced increase in MR (ΔJet/LA area (%); r=0.31, p=0.05 and ΔPISA radius at 40cm/s of aliasing v; r=0.46, p=0.003). ΔV and ΔPISA were related to the follow-up change of LV function. Especially, ΔSD
4
independently correlated with ΔEF
FU
(β= -0.82, p<0.001) and also with ΔESV
FU
(β= 0.40, p=0.021)(Fig
). However, baseline SD
4
didn’t affect ΔEF
FU
. On ROC curve analysis, sensitivity and specificity of ΔSD
4
<4.0 ms were 82% and 78% for predicting ΔEF
FU
>+5% and 70% and 63% for predicting ΔESV
FU
<-15%.
Conclusion
: Exercise-induced changes in dyssynchrony (ΔSD
4
) can predict the functional improvement in non-ischemic CMP.
THE IMPACT OF AGE AND COMPLETION OF A MODERATE DISTANCE RUNNING RACE ON CARDIAC FUNCTION: RESULTS FROM P.E.A.C.H. (PROFILING THE EFFECTS OF AGING ON EXERCISE-INDUCED CHANGES IN CARDIAC MECHANICS)
