Myocardial blood flow quantification in patients with heart failure with and without left bundle branch block (RF_TH_266)

Thursday, January 30, 2025

5:40 PM – 5:50 PM East Coast USA Time

Location: Blue Room PreFunction

Presenting Author(s)

RT

Raluca Tomoaia, MD, PhD

Clinical Research Fellow
Leeds Institute of Cardiovascular and Metabolic Medicine, United Kingdom

Primary Author(s)

RT

Raluca Tomoaia, MD, PhD

Clinical Research Fellow
Leeds Institute of Cardiovascular and Metabolic Medicine, United Kingdom

Co-Author(s)

WJ

Wasim Javed, MBChB, MRes, PhD

Specialist Registrar and Research Fellow
University of Leeds, United Kingdom
CS

Chin Soo, MB

CRF
LICAMM, United Kingdom
ML

May T. Lwin, MB

Clinical Research Fellow
University of Leeds, United Kingdom
TA

Thomas Anderton, MBChB

Clinical research fellow
University of Leeds, Multidisciplinary Cardiovascular Research Centre and Biomedical Imaging Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, LS2 9JT, United Kingdom, United Kingdom
CK

Christel h. Kamani, MD

Cardiovascular Imaging Fellow
Leeds Institute of Cardiovascular and Metabolic Medicine, United Kingdom
PH

Peter L M Harrison, MD

Dr
LICAMM, United Kingdom
AW

Ali Wahab, MD

Postgraduate Research Fellow
University of Leeds, United Kingdom
PT

Patrick Thompson

Cardiac Imaging Fellow
Leeds Institute of Cardiovascular and Metabolic Medicine, United Kingdom
PK

Peter Kellman, PhD

Director of the Medical Signal and Image Processing Program
National Heart, Lung, and Blood Institute, National Institutes of Health
Peter P. Swoboda, PhD

Consultant Cardiologist
Leeds Institute of Cardiovascular and Metabolic Medicine, United Kingdom
Sven Plein, MD PhD

Professor of Cardiovascular Imaging
University of Leeds, United Kingdom

Background: Septal perfusion abnormalities have been separately reported in patients with heart failure (HF) with and without left bundle branch block (LBBB). It remains uncertain if LBBB leads to abnormal septal perfusion. In this study we aimed to 1) measure regional myocardial blood flow (MBF) at rest and during vasodilator stress and myocardial perfusion reserve (MPR) in a large cohort of HF patients with and without LBBB, 2) compare these values to a cohort of healthy volunteers, and 3) identify potential factors associated with impaired regional myocardial perfusion in each HF phenotype.

Methods: Patients recently diagnosed with HF with reduced left ventricular ejection fraction (LVEF ≤ 50%) on echocardiography who were referred for CMR examination were enrolled in this study. Patients with coronary artery disease, known structural heart disease and congenital heart disease were excluded. Quantitative myocardial perfusion CMR during adenosine stress and at rest was acquired using a dual sequence perfusion method with inline quantification of pixelwise MBF for three short axis slices. Rest and stress MBF and MPR were calculated for the entire myocardium and separately for the septum and the lateral segments in all three short-axis slices.

Results: A total of 389 HF patients were included in the study, out of which 125 (32.1%) had LBBB. HF patients showed significantly more reduced septal and lateral stress MBF and MPR compared to healthy volunteers, irrespective of the presence or absence of LBBB. Both HF groups had higher lateral rest MBF than healthy volunteers, while showing similar septal rest MBF. In both HF groups, there was a significantly higher lateral to septal perfusion ratio both at stress and in terms of MPR (LBBB stress MBF 1.48 [1.19 - 1.84] vs 1.74 [1.42 - 2.10] mL/g/min, p < 0.0001, LBBB MPR 2.34 [1.96 - 3.00] vs 2.52 [2.12 - 3.22], p < 0.0001; non-LBBB stress MBF 1.58 [1.22 - 1.98] vs 1.77 [1.38 - 2.22] mL/g/min, p < 0.0001; non-LBBB MPR 2.55 [1.97 - 3.13] vs 2.82 [2.10 - 3.49], p < 0.0001). Only lateral rest MBF was higher in patients with LBBB than in those without (0.67 [0.57 - 0.81] vs 0.63 [0.51 - 0.74] mL/g/min, p = 0.01). LV mass index and QRS duration were associated with septal rest MBF in the LBBB group only. The presence of ischaemic fibrosis was not associated with stress or rest MBF in either group.

Conclusion: All HF patients have significantly higher lateral to septal perfusion ratio both at stress and in terms of MPR, regardless of the presence or absence of LBBB. HF patients with LBBB have higher lateral rest perfusion than those without. The association between perfusion and distinct factors in patients without LBBB suggests different mechanisms of LV dysfunction. These findings emphasize the need for tailored therapeutic strategies that address the specific pathophysiological profiles of HF.