case_images: PMC3021246_01
case_images: 12-Lead surface electrocardiogram during normal ventricular conduction and during left bundle branch block. a Narrow QRS (90 ms), heart rate 67 bpm. b Wide QRS (160 ms) with complete LBBB, heart rate 73 bpm
case_images: 12471_2010_48_Fig1_HTML.jpg
case_images: PMC3021246_01_12471_2010_48_Fig1_HTML.jpg
case_images: Fig1
case_images: A 24-h electrocardiogram registration showed complete LBBB that disappeared at slower heart rates between 70 and 80 bpm (Fig. 1).
case_images: Acute haemodynamic response to cardiac resynchronisation therapy (CRT) during left bundle branch block (LBBB) and normal ventricular activation. a Absolute LV dP/dtmax values at baseline (no CRT) and during CRT with four different AV delays. b Relative increase in LV dP/dtmax during CRT compared with baseline without CRT. Mean +- standard error are shown. Squares narrow QRS, diamond LBBB, AVI intrinsic atrioventricular interval, AV delay atrioventricular delay
case_images: 12471_2010_48_Fig2_HTML.jpg
case_images: PMC3021246_01_12471_2010_48_Fig2_HTML.jpg
case_images: Fig2
case_images: LBBB (QRS 90 ms, interventricular delay 60 ms). LBBB caused a sudden decline in average baseline dP/dtmax from 820 +- 75 to 662 +- 52 mmHg/s (p < 0.001, paired t test; Fig. 2a). CRT during LBBB increased dP/dtmax by 19.9% (Fig. 2b). In the absence of LBBB, optimised CRT did not change dP/dtmax compared with baseline; CRT with short AV delay worsened dP/dtmax (Fig. 2b).