Left atrial strain in acute heart failure: clinical and prognostic insights.

AIMS: In acute heart failure (AHF), the consequences of impaired left atrial (LA) mechanics are not well understood. We aimed to define the clinical trajectory of LA mechanics by left atrial strain (LAS) analysis. METHODS AND RESULTS: Eighty-five consecutive AHF patients with reduced, mildly reduced, and preserved left ventricular ejection fraction (LVEF) were enrolled in the LAS-AHF trial and underwent LA mechanics analysis by speckle tracking echocardiography. Seventy-seven patients were followed-up (FU) at 6 and 12 months. At hospital admission, discharge, 6 and 12 months post-discharge, LA reservoir function (LAS), LA pump strain, LAVi, LA stiffness, indicators of right ventricular (RV) and left ventricular (LV) function, congestion indexes (B lines, inferior vena cava, X-ray congestion score index), and biomarkers (NT-pro-BNP) were measured. The primary outcome was time to first event of re-hospitalization, worsening HF, or cardiovascular death. From admission to discharge, RV function significantly improved after decongestion, whereas no significant differences were observed in LA dynamics and LV function. In sinus rhythm patients with mild or no mitral regurgitation, decongestion was associated with a significant improvement of LAS and LA pump strain rate during hospitalization. At 12 months, 24 CV events occurred and lack of LAS improvement at 12 months FU emerged as the most powerful predictor followed by NT-pro-BNP. Kaplan-Meier curves showed a better survival for LAS >16%, improvement of LAS > 5%, and an LAS/LAVi ratio >0.25%/mL/m2 compared with lower cut-off values [log-rank: heart rate (HR) 3.5, 95% confidence interval (CI) 1.8-7.3, P = 0.004; log-rank: HR 3.6, 95% CI 2-7.9, P < 0.01; log-rank: HR 3.27, 95% CI 1.4-7.7, P = 0.007]. CONCLUSION: In AHF of any LVEF, LA dynamics is highly predictive of re-hospitalization and cardiovascular outcome and allows to ease risk-stratification, potentially becoming an early reference target for improving long-term outcome.

Left Atrial Dynamics During Exercise in Mitral Regurgitation of Primary and Secondary Origin: Pathophysiological Insights by Exercise Echocardiography Combined With Gas Exchange Analysis.

OBJECTIVES: The aim of this study was to identify the pattern of exercise left atrial (LA) dynamics, its gas exchange correlates, and prognosis in mitral regurgitation (MR) of primary and secondary origin. BACKGROUND: The adaptive response and clinical significance of LA function during exercise in MR is undefined. METHODS: A total of 196 patients with MR (81 with primary MR, 115 with secondary MR) and 54 control subjects underwent exercise stress echocardiography and cardiopulmonary exercise testing with LA function assessment. Patients with MR were divided into 4 groups according to etiology and severity using a cutoff of 3+. RESULTS: LA dynamics was studied using speckle-tracking echocardiography. Compared with control subjects, patients with MR had a lower LA strain and strain rate at rest. Exercise LA strain and LA strain rate progressively worsened from primary MR <3+ through secondary MR ≥3+. In primary MR, some reserve in exercise LA strain and LA strain rate was observed, but not in secondary MR. In secondary MR, LA strain at rest and during exercise (18.1 ± 5.7 s-1, 18.3 ± 6.9 s-1, 18.6 ± 5.5 s-1, 13.9 ± 3.8 s-1) and peak oxygen consumption (11.7 ± 3 ml/min/kg) were decreased compared with the other groups. In secondary MR ≥3+, the slope of ventilation versus carbon dioxide was higher compared with the other groups: 35.1 (interquartile range [IQR]: 29.0 to 44.2) compared with control subjects: 26.5 (IQR: 24.4 to 29.0); patients with primary MR <3+ (26.9; IQR: 24.0 to 31.9); those with primary MR >3+ (25.5; IQR: 23.4 to 29.0); and those with secondary MR <3+ (29.5; IQR: 26.5 to 33.7) (p < 0.05 for all). A progressive impairment in exercise LA mechanics combined with limited cardiac output increase and right ventricular-to-pulmonary circulation uncoupling was observed from primary to secondary MR. LAS during exercise was predictive of all-cause mortality and hospitalization for heart failure. CONCLUSIONS: In MR of any origin, exercise LA reservoir and pump function are impaired. For similar MR extent, secondary MR exhibits worse atrial function, resulting in the lowest exercise performance, limited cardiac output increase, impaired right ventricular-to-pulmonary circulation coupling, and the highest event rate.