Impaired myocardial oxygen metabolism and energy efficiency in patients with dilated cardiomyopathy

Presenting Author(s)

• 

  Jie Zheng, PhD, FSCMR

  Professor
  Washington University in St. Louis
  Saint Louis, Missouri, United States

Primary Author(s)

• LD

  Liya Dai, MD

  associate chief physician
  The Fifth Affiliated Hospital of Wenzhou Medical University
  Lishui, China (People's Republic)

Co-Author(s)

• JQ

  Jinghan Qiao, MD

  physician
  the first affiliated hospital of zhengzhou university, China (People's Republic)
• KW

  Keyan Wang, MD

  physician
  the first affiliated hospital of zhengzhou university, China (People's Republic)
• RL

  Ran Li, MSc

  PhD student
  Washington University in St. Louis
  St. Louis, Missouri, United States
• YY

  Yang Yang, PhD

  professor
  University of California, San Francisco, United States
• CB

  Caleb Berberet, BSc

  research assistant
  Washington University in St. Louis
  St. Louis, Missouri, United States
• QH

  Qi Huang, PhD

  Postdoc
  Washington University in St. Louis, Missouri, United States
• CL

  Chenying Lu, MD, PhD

  chief physician
  The Fifth Affiliated Hospital of Wenzhou Medical University, China (People's Republic)
• jj

  jiansong ji, MD, PhD

  Chief physician
  The Fifth Affiliated Hospital of Wenzhou Medical University, China (People's Republic)
• SB

  Scott Bugenhagen, MD, PhD

  Cardiothoracic Radiologist
  Washington University School of Medicine
  St. Louis, Missouri, United States
• TS

  Thomas Schindler, MD

  Professor
  Washington University School of Medicine, United States
• LP

  Linda Peterson, MD

  Professor
  Washington University School of Medicine, United States
• PW

  Pamela Woodard, MD

  Professor
  Washington University School of Medicine, Missouri, United States

Background: Dilated cardiomyopathy (DCM) is a leading cause of heart failure, characterized by left ventricular (LV) dilatation and contractile dysfunction in the absence of abnormal loading conditions and significant coronary artery disease. Myocardial oxygen metabolism plays a central role in cardiac function, yet its status in DCM remains incompletely understood. In this study, we applied a novel cardiovascular magnetic resonance (CMR) technique to assess myocardial oxygenation, cardiac work, and energy efficiency in patients with DCM.

Methods: We prospectively enrolled 49 DCM patients and 10 healthy controls (HCs) and scanned them on a 3T Siemens MRI system. LV ejection fraction (LVEF) and strain indices (LVGLS, LVGRS, LVGCS) were derived from cine CMR images. Pre- and post-contrast T1 mapping was performed to quantify extracellular volume (ECV) maps, and first-pass perfusion imaging was acquired following gadolinium administration to assess myocardial blood flow (MBF). Additionally, a noncontrast CMR technique was applied to quantify myocardial oxygen extraction fraction (mOEF) and myocardial blood volume (MBV) maps. AHA segmented analysis was performed on all maps. Myocardial oxygen consumption (MVO₂), external work (EW), and myocardial external efficiency (MEE) were subsequently derived for statistical analysis.

Results: DCM patients exhibited significantly lower mOEF (50.2 ± 4.2% vs. 59.3 ± 2.5%), MBV (6.2 ± 0.5% vs. 7.5 ± 0.4%), EW (248.4 ± 97.9 vs. 337.1 ± 74.1), and MEE (22.9 ± 10.6% vs. 51.3 ± 13.1%), but a significantly higher total MVO₂ (8.0 ± 2.6 vs. 4.6 ± 1.3) compared to HCs (figure 1). No significant differences were observed in MBF (0.14 ± 0.02 vs. 0.13 ± 0.03, p = 0.26) and MVO₂ (0.07 ± 0.01 vs. 0.08 ± 0.01, p = 0.07) between the two groups. The MEE demonstrated moderately positive correlations with LVEF (r = 0.5) and LVGLS (r = 0.6). In contrast, mOEF showed no significant associations with LV functional parameters (all r < 0.1, p > 0.5). Notable sex differences were observed: females had lower total MVO₂ (5.80 ± 1.9 vs. 9.1 ± 2.2), higher LVEF (31.3 ± 10.2% vs. 22.5 ± 9.7%), LVGLS (-9.8 ± 3.6% vs. -7.2 ± 2.9%) and MEE (27.3 ± 11.9% vs. 20.7 ± 9.4%).

Conclusion: This is the first CMR-based study to noninvasively quantify myocardial oxygen metabolism and mechano-energetic coupling in DCM. Our findings demonstrate impaired myocardial energy metabolism and microvascular resistance, providing mechanistic insights into the pathophysiology of DCM.

Comparison of metabolic and mechanical parameters between DCM and HC groups. DCM patients exhibited lower mOEF, MBV, EW, and MEE, but a significantly higher total MVO₂ compared to HCs. DCM, dilated cardiomyopathy; HC, healthy control; mOEF, myocardial oxygen extraction fraction; MBV, myocardial blood volume; EW, external work; MEE, myocardial external efficiency; MVO2, myocardial oxygen consumption.