Abstract
OBJECTIVES: Impaired cardiac function has been confirmed in patients with chronic fatigue syndrome (CFS). Magnetic resonance cardiac tagging is a novel technique that assesses myocardial wall function in vivo. We hypothesized that patients with CFS may have impaired development and release of myocardial torsion and strain. METHODS: Cardiac morphology and function were assessed using magnetic resonance imaging and cardiac tagging methodology in 12 CFS patients (Fukuda) and 10 matched controls. RESULTS: Compared to controls, the CFS group had substantially reduced left ventricular mass (reduced by 23%), end-diastolic volume (30%), stroke volume (29%) and cardiac output (25%). Residual torsion at 150% of the end-systolic time was found to be significantly higher in the patients with CFS (5.3 ± 1.6°) compared to the control group (1.7 ± 0.7°, P = 0.0001). End-diastolic volume index correlated negatively with both torsion-to-endocardial-strain ratio (TSR) (r = -0.65, P = 0.02) and the residual torsion at 150% end-systolic time (r = -0.76, P = 0.004), so decreased end-diastolic volume is associated with raised TSR and torsion persisting longer into diastole. Reduced end-diastolic volume index also correlated significantly with increased radial thickening (r = -0.65, P = 0.03) and impaired diastolic function represented by the ratio of early to late ventricular filling velocity (E/A ratio, r = 0.71, P = 0.009) and early filling percentage (r = 0.73, P = 0.008). CONCLUSION: Patients with CFS have markedly reduced cardiac mass and blood pool volumes, particularly end-diastolic volume: this results in significant impairments in stroke volume and cardiac output compared to controls. The CFS group appeared to have a delay in the release of torsion.