Left atrial rather than left ventricular impaired mechanics are associated with the pro-fibrotic ST2 marker and outcomes in heart failure with preserved ejection fraction.

AIMS: Left ventricular (LV) mechanics have been extensively investigated in heart failure with preserved ejection fraction (HFpEF) overshadowing for a long time the potential role of left atrium (LA) in that setting. Soluble suppression of tumorigenicity-2 receptor (ST2) is a novel biomarker of pro-fibrotic burden in HF. We hypothesized that due to the thinner LA wall, the fibrotic myocardial changes in HFpEF as indicated by elevated ST2 levels might more readily be reflected by impairments in the LA rather than the LV performance. METHODS AND RESULTS: In 86 patients with HFpEF, enrolled in the Karolinska Rennes (KaRen) biomarker prospective substudy, global LA strain (GL-LS) along with other echocardiographic as well as haemodynamic parameters and ST2 levels were measured. ST2 levels were inversely associated with LA-GS (r = -0.30, P = 0.009), but not with LA size, LV geometry, systolic or diastolic LV function (P > 0.05 for all). Furthermore, symptom severity correlated with ST2 and LA-GS, but not with LV structural or functional indices. Finally, during a median 18-month follow-up, LA-GS independently predicted the composite endpoint of HF hospitalization and all-cause mortality, even after adjustment for potential clinical and cardiac mechanical confounders, including LV global longitudinal strain and filling pressures (odds ratio: 4.15; confidence interval: 1.2-14, P = 0.023). CONCLUSIONS: Reduced LA-GS but not LV functional systolic and diastolic parameters were associated with the pro-fibrotic ST2 marker, HF symptoms and outcome in HFpEF.

Left ventricular untwisting in athlete's heart: key role in early diastolic filling?

Untwisting contributes to left ventricular filling through suction generation. We sought to investigate diastolic function and untwisting dynamics in different forms of left ventricular hypertrophy: in athlete's heart and hypertrophic cardiomyopathy. Elite athletes in kayaking, canoeing and rowing (n=28), patients with hypertrophic cardiomyopathy (HCM, n=15) and healthy sedentary volunteers (n=13) were compared. Left ventricular volumes, wall thickness-to-volume ratio were assessed by cardiac MRI. Following conventional and tissue Doppler measurements, untwist and untwist rate were determined by speckle tracking echocardiography. Wall thickness-to-volume ratio describing remodelling was significantly higher in HCM, but similar in athletes and controls (athlete vs. HCM vs. control: 0.107±0.019 vs. 0.271±0.091 vs. 0.104±0.012 mm×m²/ml, mean±SD, p<0.001). Mitral lateral annulus e' velocity referred to diastolic dysfunction in HCM (15.3±3.6 vs. 7.9±3.3 vs. 15.0±3.0 cm/s, p<0.01). At time point of mitral valve opening, untwist and untwist rate were significantly different: the highest values were measured in athletes, while the lowest were found in HCM (untwist: 51.3±19.1 vs. 11.6±10.4 vs. 35.9±16.3%; untwist rate: -32.5±13.0 vs. -10.6±10.8 vs. -23.0±7.7°/s, p<0.05). Untwisting correlated with E/A, e' and E/e'. Athlete's heart is characterized by increased untwist and untwist rate, which can aid diastolic function. Evaluation of untwisting dynamics may help to distinguish pathological hypertrophy.