Relationship of Myocardial Tissue Characterization and Intraventricular Conduction Disease in Patients with Cardiomyopathy and Left Ventricular Dysfunction (RF_FR_372)

Friday, January 31, 2025

2:20 PM – 2:30 PM East Coast USA Time

Location: Blue Room PreFunction

Presenting Author(s)

AN

Amal Nehmeh, MD DRCPSC

Cardiac Imaging Fellow
University of Ottawa Heart Institute, Canada

Primary Author(s)

AN

Amal Nehmeh, MD DRCPSC

Cardiac Imaging Fellow
University of Ottawa Heart Institute, Canada

Co-Author(s)

AN

Amal Nehmeh, MD DRCPSC

Cardiac Imaging Fellow
University of Ottawa Heart Institute, Canada
DP

David Ian Paterson, MD, FSCMR

Director of Cardiac Imaging
University of Ottawa Heart Institute, Canada

Background: A cause-effect relationship has been widely recognized between left ventricular dysfunction (LVD) and intraventricular conduction delay (IVCD) on electrocardiogram. However, it is unclear whether there are IVCD-specific tissue characterization features in cardiac magnetic resonance (CMR) imaging. We aimed to investigate this relationship in patients with significant LVD.

Methods: We conducted a retrospective review of patients undergoing a clinical contrast enhanced CMR at 1.5 T (Magnetom Aera, Siemens) at our center between 2018 and 2023. Inclusion criteria were left ventricular ejection fraction < 40% on CMR and 12-lead ECG within 6 months of the scan. Patients with acute myocardial injury, infiltrative cardiomyopathy, hypertrophic cardiomyopathy and severe valvular disorders were excluded. Intraventricular conduction delay was defined as QRS duration > 120 ms and patients were grouped according to the QRS pattern on 12-lead ECG: no IVCD, left bundle branch block (LBBB), and non-LBBB IVCD. Biventricular function, myocardial late gadolinium enhancement (LGE), and pre- and post-contrast T1 mapping were assessed by a blinded reader using commercially available software (CVI42, Circle Inc). The demographic and CMR features of patient groups were compared using ANOVA and Kruskar-Wallis tests for continuous variables depending on the distribution of normality. Chi-square test was used for comparison of categorical variables. Correlation between continuous variables were sought with Pearson’s test.

Results:

94 patients (mean age 65.2 years, 39.4% male) were included; 42 with non-ischemic cardiomyopathy, 27 with ischemic cardiomyopathy and 25 with mixed etiology on CMR. 12-lead ECG identified 37 patients with no IVCD, 32 with LBBB, and 25 with non-LBBB IVCD. Patients with no IVCD had more comorbidities and lower LV mass and volumes compared to those with LBBB or non-LBBB IVCD (Tables 1 and 2). The distribution of cardiomyopathy type was similar between QRS groups.

Patients with LBBB had lower global and regional LGE burden and lower global ECV values compared to other groups (Figure 1). However, basal septal myocardial T1 relaxation time was increased in patients with LBBB and a modest correlation with QRS duration (r: 0.40, p=0.025) was observed. A moderate correlation between QRS duration and LV end-diastolic (r: 0.42, p< 0.001) and end-systolic volume indices (r: 0.41, p< 0.001) was also found in the entire p</span>opulation.

Conclusion: Patients with significant left ventricular function on CMR and LBBB has lower scan burden compared to those with no IVCD or non-LBBB IVCD. Basal septal myocardial T1 correlated to QRS duration but only in patients with LBBB. Future work will evaluate the impact of these findings on clinical outcomes including response to cardiac resynchronization therapy.