Discordant vs. concordant left bundle branch block: A potential clinical significance

• Left bundle branch block can be further classified into discordant and concordant. These subtypes carry clinical significance.
• Discordant pattern in patients with LBBB is associated with lower LVEF, wider QRS, larger LA size, moderate to severe mitral and tricuspid regurgitation, CKD, CAD, and had more frequently underwent CABG.
• Discordant pattern in patients with LBBB shows more prominent bi-ventricular dyssynchrony which raises the hypothesis of it being used to better predict response to CRT.

AimLBBB in heart failure patients has prognostic significance. Subtypes of LBBB (concordant and discordant) have not been considered when considering management. The aim of this study is to explore the clinical difference between the two subtypes.Methods216 patients with LBBB were included and categorized into concordant (LBBBC) and discordant (LBBBD) groups.ResultsOf the 216 patients (age 69.13 ± 11.7; 56% male 44% female), 133 (61.5%) were LBBBD and 83 (38.5%) were LBBBC. LBBBD patients presented with lower LVEF (mean 36% vs 51%; P < 0.001), wider QRS (mean 160 ms vs 151 ms; P < 0.001), larger LA (mean 45 cm2 vs 40 cm2; P < 0.001), moderate to severe mitral and tricuspid regurgitation (17% vs 3%; P < 0.05, 10% vs 1%; P < 0.05 respectively), CKD (41% vs 18%; P < 0.001), COPD (4.6% vs 0%; P < 0.01), CAD (67% vs 36%; P < 0.001), and CABG (39% vs 16%; P < 0.001).ConclusionLBBBD is significantly associated with worse cardiac function and clinical characteristics.