Impaired left ventricular (LV) functional reserve has been shown to contribute to exercise intolerance in heart failure. Little is known about the role of left atrial (LA) functional response to exertion in this context. LA strain has recently emerged as a valuable diagnostic marker reflecting both LA and LV performance. Aim To investigate the association between LA strain response to exercise and exercise capacity across different stages of heart failure with preserved ejection fraction (HFpEF). Methods Transthoracic echocardiography (including peak atrial longitudinal strain (PALS) and LV global longitudinal strain (GLS) assessment) was performed at rest and immediately post exercise test in 55 patients with stage A, 62 patients with stage B and 54 patients with stage C HFpEF. Results There was a progressive worsening of peak oxygen uptake from stage A through stage B to stage C, which was accompanied by a gradual impairment of changes from rest to exercise in PALS, GLS, tissue early diastolic velocity e', LA ejection fraction and E/e' ratio (Table 1). In multivariable analysis including LV and LA components of cardiac functional reserve, changes from rest to exercise in PALS (beta 0.34, SE 0.07, p<0.001), e' (beta 0.29, SE 0.07, p<0.001) and GLS (beta 0.17, SE 0.07, p=0.014) were among the independent correlates of exercise capacity. However, after adjustment for age, sex and beta-blocker treatment, only the former two remained statistically significant. Conclusions LA strain response to exercise progressively deteriorates from stage A through stage B to stage C HFpEF, and is independently associated with exercise capacity. Accordingly, it might be considered in the risk stratification of the transition from the asymptomatic phase to overt HFpEF. Funding Acknowledgement Type of funding sources: None.

Funding Acknowledgements Type of funding sources: None. Background The identification of mechanisms in hypertensive heart disease (HHD) that favor the development of symptomatic heart failure (HF) is essential. Little is known about the role of left atrial (LA) mechanical response to exertion in this context. Objectives We sought to investigate the association of LA strain parameters response to exercise with functional capacity and symptomatic HF in a representative group with HHD. Methods Echocardiography (including LA strain and strain-derived LA stiffness index assessment) was performed at rest and immediately post exercise test in 61 patients with stage A, 67 patients with stage B and 73 patients with stage C HF. Results There was a progressive worsening of exercise capacity from stage A through stage B to stage C, which was accompanied by a gradual impairment of changes from rest to exercise in LA reservoir and contractile strain, whereas LA stiffness reserve remained unchanged until the HF stage C (Table). In multivariable analysis including LA and left ventricular reserve and clinical variables, changes from rest to exercise in LA reservoir strain and mitral annular e’ (both beta 0.16, SE 0.07, p = 0.02) were the only cardiac function parameters independently correlating with exercise capacity. However, LA stiffness reserve and E/e’ were the strongest associations of symptomatic HF stage C (Akaike information criterion 111.6 and 101.1, respectively). Conclusions LA reservoir strain and LA stiffness exercise reserves are among the mediators of reduced functional capacity in HHD, however the trajectories of changes of these parameters are not parallel. While LA strain reserve progressively deteriorates across HF stages, a marked impairment in LA stiffness reserve can only be seen in patients with HF symptoms. This suggests a potential role for these parameters in stratifying the risk of progression to overt HF in HHD.

Funding Acknowledgements Type of funding sources: None. Background Impaired cardiovascular functional reserve is believed to contribute to adverse outcomes in heart failure with preserved ejection fraction (HFpEF). However, overweight and mild to moderate obesity is associated with substantially improved survival compared to normal weight patients, a phenomenon known as the "obesity paradox". Aim We sought to investigate the association between LA and LV strain response to exercise and BMI in patient with heart failure with HFpEF. Methods A group of 140 subjects (54 ± 12 yrs) with symptomatic HFpEF underwent clinical evaluation and resting and exercise stress echocardiography (including peak atrial longitudinal strain [PALS], peak atrial contractile strain [PACS] and LV global longitudinal strain [GLS] assessment). Results Patients were divided into 3 groups according to BMI ( group A: BMI < 25 kg/m2, group B: BMI 25–30 kg/m2, group C: BMI ≥ 30 kg/m2). The subset with normal weight demonstrated greater changes from rest to exercise in GLS compared to overweight and obese patients (Table). No significant differences were shown for other components of cardiac reserve. Significant correlations were found between BMI and GLS and PACS exercise reserve (r=0.15; p<0.05, and r=0.19; p<0.02, respectively). Conclusions In patients with HFpEF, among LV and LA functional reserve parameters, GLS is most predisposed to the detrimental effect of weight excess. The profiles of changes in cardiac reserve parameters across the BMI strata do not indicate that better cardiac reserve should be considered as an explanation for the obesity paradox.