Abstract 424: Impact of Ventricular Dyssynchrony on Post-Exercise Accommodation of Sytolic Myocardial Motion in Hypertensive Patients With Diastolic Failing Heart
Background. Whether dyssynchronous left ventricular (LV) contraction would affect post-exercise accommodation of myocardial motion in hypertensive patients (pts) with diastolic heart failure (DHF) was unclear.
Methods. We studied echocardiography (echo) with tissue-Doppler imaging in 100 hypertensive pts with LV ejection fraction > 50 %. Among them, 70 DHF pts with diastolic dysfunction [mitral annular early diastolic velocity (Ea) < 8 cm/s] and HF signs/symptoms were classified into systolic dyssynchrony [Dys: > 65 msec difference of electromechanical delay (EMD) between septum and lateral wall] (43 pts), and non-dyssynchrony (Ndys: 27pts) groups. The other 30 pts were as the control (Ctrl) group. All pts received a 6-minutes treadmill exercise by Bruce protocol, and the systolic myocardial velocity (Sm) of 6-basal LV segments was recorded.
Results. Pts in Dys and Ndys groups were older than Ctrl group (69±8 and 67±8 vs. 56±11 y/o, p<0.001, respectively), and the Dys group were mainly female [70 vs. 41 (Ndys) and 43 (Ctrl) %, p<0.05, respectively]. In echo study, the mean Sm of 6 LV segments was borderline (p = 0.05) lower in the Ndys group and significantly lower in the Dys group, when compared to the Ctrl group. (Table 1⇓) After exercise, the mean Sm of Ndys group became similar to Ctrl group while that of Dys group being the lowest due to similar % increase of septal Sm [31 (Dys) vs. 34 (Ndys) vs. 33 (Ctrl) %] among the 3 groups but a much higher % increase of lateral Sm after exercise in Ndys than the other 2 groups [49 (Ndys) vs. 29 (Dys) and 31 (Ctrl) %, p<0.05, respectively]. The difference of EMD between LV septum and lateral wall correlated negatively with post-exercise % increase of lateral Sm (r = −0.348, p = 0.004) in DHF pts.
Conclusions. In addition to depressed mean Sm at rest, the DHF pts with ventricular dyssynchrony had attenuation of post-exercise enhancement of lateral Sm over LV, which could exaggerate the effect of electromechanical uncoupling and HF symptoms.