Differential change in left ventricular mass and regional wall thickness after cardiac resynchronization therapy for heart failure.
OBJECTIVE
LV reverse remodelling has been shown to be a favourable response after cardiac resynchronization therapy (CRT) in many clinical trials. This study investigated whether left ventricular (LV) reverse remodelling after CRT has any structural benefit, which include the improvement of LV mass or regional wall thickness.


RESULTS
Fifty patients (66 +/- 11 years) receiving CRT were followed up for at least 3 months. Echocardiography with tissue Doppler imaging was performed serially before and at day 1 and 3 months after CRT. Although LV end-systolic volume (LVESV) was decreased at day 1 after CRT (141 +/- 74 vs. 129 +/- 71 cm(3), P < 0.001), further LV reverse remodelling was observed at 3 months (110 +/- 67 cm(3), P < 0.001 vs. day 1). LV ejection fraction increased at day 1 (26.5 +/- 9.3 vs. 28.5 +/- 9.1%, P < 0.005) and was further improved at 3 months (34.2 +/- 10.5%, P < 0.001 vs. day 1). However, reduction of LV mass (231 +/- 67 vs. 213 +/- 59 g, P < 0.001) and regional wall thickness was only observed at 3 months, but not at day 1. The improvement of LV mass correlated with the change in LVESV (r = 0.66, P < 0.001) and the baseline systolic asynchrony index (Ts-SD) (r = -0.52, P < 0.001). LV mass was only decreased significantly in responders of LV reverse remodelling (245 +/- 66 vs. 207 +/- 61 g, P < 0.001), but increased in non-responders (209 +/- 64 vs. 223 +/- 56 g, P = 0.02). Responders had significant decrease in thickness of all the four walls for -6 to -11% (all P < or =0.02), whereas non-responders had increased thickness in septal and lateral walls for +11% (both P < 0.05).


CONCLUSIONS
The acute reduction in LV volume after CRT is mediated by haemodynamic and geometric benefits without actual changes in LV mass. However, at 3-month follow-up, reduction in LV mass and regional wall thickness was demonstrated, which represents structural reverse remodelling. Such benefit was only observed in volumetric responders but was worsened in non-responders.
Zhang
Qing
Q
Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, SH Ho Cardiovascular and Stroke Centre, Institute of Vascular Medicine, The Chinese University of Hong Kong, Shatin, NT.
Fung
Jeffrey Wing-Hong
JW
Auricchio
Angelo
A
Chan
Joseph Yat-Sun
JY
Kum
Leo C C
LC
Wu
Li Wen
LW
Yu
Cheuk-Man
CM