P782 Septal flash is a prevalent and early dyssynchrony marker in transcatheter aortic valve replacement-induced left bundle branch block

Abstract

Abstract BACKGROUND New-onset left bundle branch block (LBBB) is a frequent complication after transcutaneous aortic valve replacement (TAVR). LBBB is associated with echocardiographic dyssynchrony in heart failure patients, but this has not been thoroughly investigated in acute LBBB following TAVR. PURPOSE This study aims to assess the timing and incidence of echocardiographic dyssynchrony in acute TAVR-induced LBBB patients. METHODS The study enrolled all TAVR-induced LBBB patients at our Hospital between January 2013 and May 2019. Presence of LBBB was scored within 72 hours following TAVR. Dyssynchrony was assessed by: 1/ presence of septal flash (SF), 2/ interventricular mechanical delay (IVMD, the difference between left and right ventricular pre-ejection interval using pulsed wave Doppler; cut-off ≥40 ms) and 3/ presence of ‘classical dyssynchronous strain pattern’ assessed with speckle tracking (Figure 1). As a control, these three LBBB-related dyssynchrony markers were assessed and compared to LBBB patients without TAVR (non-TAVR patients) in normal ànd reduced EF, but all having SF. RESULTS Out of 134 consecutive TAVR procedures, 30 (22%) were complicated by acute LBBB. SF was present in 72% of TAVR-induced LBBB patients, with a median time from TAVR to SF diagnosis of 24 hours. However, only 1 (5%) of these TAVR patients exhibited a classical dyssynchronous contraction strain pattern (Figure 1), despite presence of SF. Finally, the IVMD values in these TAVR-LBBB patients did not meet the ‘dyssynchrony’ cut-off. As a control, we compared these dyssynchrony parameters in patients with non-TAVR related LBBB with normal and reduced EF, all exhibiting SF. A classical strain pattern was present in 33% of non-TAVR LBBB patients with preserved left ventricular ejection fraction (LV EF) (p = 0.17), and in 80% of non-TAVR LBBB patients with reduced LV EF ≤30% (p < 0.001). The IVMD in non-TAVR LBBB patients with SF and preserved LV EF was 52 ms (p = 0.002) and 57 ms in non-TAVR LBBB patients with SF and LV EF ≤30% (p = 0.009). CONCLUSION SF as dyssynchrony marker develops early after TAVR-induced LBBB and is much more prevalent than the classical strain-based dyssynchrony pattern and IVMD. Our findings from the control population suggest that progressive LBBB-induced LV remodeling (septal thinning and relative lateral thickening) may be required for a ‘classical dyssynchrony strain pattern’ or significant IVMD to occur in TAVR-LBBB patients, but longitudinal follow-up studies in TAVR-LBBB patients are required as proof-of-concept. Abstract P782 Figure 1