Beyond the left ventricle: three-dimensional echocardiographic analysis of biventricular synchronization after
Hisashi Okada1, Shohei Kikuchi2, Yomei Sakurai2
1Department of Cardiology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-Cho, Mizuho-Ku, Nagoya, 4678601, Japan. h-okada@med.nagoya-cu.ac.jp.
Background:
Cardiac resynchronization therapy (CRT) aims to improve intraventricular dyssynchrony, but the impact on interventricular dyssynchrony remains unclear. This study investigates biventricular mechanical synchronization under different CRT pacing configurations using three-dimensional speckle-tracking echocardiography (3D-STE).
Methods:
We analyzed 22 heart failure patients with CRT implantation using 3D-STE under four pacing modes: Own/right ventricular pacing (Own/RV pacing), simultaneous biventricular pacing (LVRV pacing), biventricular pacing with 30 ms left ventricular (LV) lead preactivation (LV30RV pacing), and LV only pacing (LV pacing). Activation imaging (AI) quantified mechanical propagation, comparing mean AI differences between both ventricles (LV-RV difference), and the standard deviation of AI (AI-SD) for each region to assess the interventricular dyssynchrony and dispersion of mechanical propagation.
Results:
LV-RV difference was greater in Own/RV pacing than in LVRV pacing, LV30RV pacing and LV pacing (p = 0.12, 0.016, 0.009, respectively), indicating the prominent interventricular dyssynchrony. (LV-RV difference: Own/RV pacing: 41.1 ± 32.3 ms, LVRV pacing: 22.6 ± 29.2 ms, LV30RV pacing: 2.4 ± 38.5 ms, LV pacing: 17.8 ± 37.7 ms). In LVRV and LV30RV pacing, the AI-SD for both ventricles was significantly reduced compared to Own/RV pacing and LV pacing (p = 0.002, 0.005, 0.015, 0.002, respectively), indicating that biventricular pacing improved dyssynchrony in both ventricles (Own/RV pacing AI-SD: 57.1 ± 17.3, LVRV pacing AI-SD: 44.7 ± 12.7, LV30RV pacing AI-SD 47.0 ± 16.1, LV pacing AI-SD: 58.0 ± 17.0).
Conclusions:
3D-STE provides a comprehensive assessment of biventricular mechanical propagation, revealing that LVRV and LV30RV pacing improve both intraventricular and interventricular synchrony. Incorporating RV mechanics into CRT optimization may enhance patient selection and treatment outcomes.
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