PhD defence D.J.F. (Jie Fen) Chin

Below is a brief summary of the dissertation:

This thesis investigates the early detection, pathophysiology, and diagnostic challenges of obesity-related heart failure with preserved ejection fraction (HFpEF), a growing clinical problem driven by the global obesity epidemic. Since obesity is highly prevalent among patients with HFpEF, understanding obesity-specific cardiac remodeling is essential. However, diagnosis remains difficult because symptoms overlap with obesity itself and conventional diagnostic tools often perform suboptimal in this population.

The thesis first focuses on early left atrial dysfunction in obesity. Severe obesity was associated with left atrial enlargement, impaired atrial strain, and premature atrial contractions, suggesting that atrial cardiomyopathy develops before overt cardiovascular disease. In addition, conventional indexing of left atrial volume to body surface area underestimated atrial enlargement in obesity, whereas height-based indexing more accurately identified structural abnormalities.

A central theme of this thesis is the role of epicardial adipose tissue (EAT). Increased EAT was associated with impaired global longitudinal strain (GLS), a sensitive marker of subclinical cardiac dysfunction, while conventional echocardiographic parameters remained unchanged. Following bariatric surgery, reductions in EAT were independently associated with improvements in GLS. Circulating biomarkers linked to inflammation and fibrosis were also associated with both EAT and impaired GLS, supporting a mechanistic role for EAT in early obesity-related cardiac remodeling.

Finally, this thesis highlights obesity-specific limitations in HFpEF diagnosis and proposes tailored diagnostic approaches. It also presents the SCORhfE trial, which evaluates whether proactive heart failure screening in adults with obesity improves cardiac outcomes and enables earlier intervention.