Relationship of septal flash with electromechanical dyssynchrony and super-response to cardiac resynchronization therapy

Objectives  – to identify a relationship of septal flash (SF) with a super-response to cardiac resynchronization therapy (CRT), apical rocking (AR) and signs of left bundle brunch block (LBBB) in patients with congestive heart failure (CHF). Material and methods.  The study included 38 patients (92.1% men; mean age 54.3±9.4 years) with II-IV NYHA functional class CHF. Left bundle brunch block (LBBB) was diagnosed according to 3 criteria: American Heart Association (AHA) 2009, European Society of Cardiology (ESC) 2013, Strauss. Septal flash (SF, mechanical anomaly of interventricular septum (IVS) movement) is determined according to speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI). The patients were divided into two groups: with SF (I group, n=8) and without SF (II group, n=30). Mean follow-up was 34.5 [13.8;55.3]. Results.  At baseline the groups did not differ in main clinical characteristics including QRS. The left ventricular (LV) ejection fraction (EF) was higher in group I (33.1%±1.7 and 30.0%±4.0; p=0.044). Basal segment of IVS longitudinal strain (LS) delay by STE (258.0 [144.0;294.0] ms vs 323.5 [273.3;385.0] ms; р=0.024) and LS delay by TDI (176.0 [146.8;287.3] ms vs 415.5 [315.8;493.5] ms; р<0.001) were significantly lower in group with SF. There was significant relationship between SF signs and Apical rocking (AR) (r=0.791; p=0.034). According to electrocardiogram (ECG) it was found that the q wave in the I and V5, V6 was absent in all patients with SF. Monophasic R wave was in 62.5% in group I and in 16.7% in group II (p=0.019). All patients in group I had a super-response to CRT (ESV LV decrease ≥30%); 53.1% of patients in group II were super responders (р<0.034). Conclusion.  SF is associated with AR, super-response to CRT, and the change of the direction of interventricular septum depolarization vector.