P1237Left ventricular myocardial work characteristics and CRT response in patients with LBBB according to Strauss criteria and ESC 2013 definition

Abstract

Abstract Background The impact of left bundle branch block (LBBB) on left ventricular (LV) myocardial work may vary according to the specific definition of a LBBB. Quantification of the interplay between LV myocardial work and the underlying electrical dyssynchrony may improve our understanding of cardiac resynchronization therapy (CRT) response. Objective To evaluate the impact of LBBB, defined according to Strauss and ESC 2013 ECG criteria, as well as non-LBBB morphologies on different LV myocardial work indices and response to CRT. Methods LBBB was defined according to the Strauss criteria and ESC 2013 guidelines on heart failure. LV myocardial constructive and wasted work (CW and WW) were derived from pressure-strain loop analysis integrating valvular opening and closing times, speckle tracking strain echocardiography and noninvasive blood pressure measurement. LV myocardial work efficiency (WE) was calculated from the ratio of constructive work, divided by the sum of constructive and wasted work. CRT response was defined as a decrease in LV end-diastolic volume (EDV) ≥15% at 6 months' follow-up. Results Patients were divided into 3 groups: 1) LBBB according to Strauss criteria (group 1, n=109, age 64±10 years), 2) LBBB according to ESC 2013 criteria (group 2, n=22, age 64±10 years) and 3) non-LBBB (group 3, n=44, age 69±10 years). Patients from group 1 were 4.2 times more likely to respond to CRT than patients from group 3 (odds ratio [OR] 4.182; 95% confidence interval [CI], 1.999–8.750; p<0.001), whereas CRT response between groups 2 and 3 did not differ significantly (OR 1.100; 95% CI 0.387–3.124; p=0.859). Patients in group 1, were characterized by significantly lower WE, compared to groups 2 and 3 (67.6±9.9 mmHg% vs. 72.7±9.7 mmHg% and 75.4±9.6 mmHg%, respectively; p<0.001) as well as higher WW (313.2±144.9 mmHg% vs. 215.1±102.5 mmHg% and 229.0±113.5 mmHg%, respectively; p<0.001). There was no significant difference in CW between any of the groups (811.6±353.4 mmHg% vs. 798.6±440.6 mmHg% and 893.6±420.2 mmHg% respectively for groups 1, 2 and 3; p=0.447). Conclusion Patients with a LBBB according to Strauss criteria had a higher probability of response to CRT, compared to those with a LBBB defined by ESC 2013 guidelines criteria or with non-LBBB morphology. This is reflected in a greater amount of wasted work and more impaired LV myocardial work efficiency at baseline in patients with LBBB satisfying Strauss criteria, compared to the other two groups, representing the substrate for CRT. Acknowledgement/Funding Study was supported by ESC Research grant 2018