Impairment of Left Atrial Mechanics Is an Early Sign of Myocardial Involvement in Systemic Sclerosis

Background: Left ventricular (LV) diastolic dysfunction is common in systemic sclerosis (SSc). Less is known, however, about left atrial (LA) mechanics in this context. The aim of this study was to investigate the correlation between LV diastolic function and LA mechanics in SSc patients with the use of volumetric and 2-dimensional speckle tracking-derived strain techniques and to compare the results with those obtained in healthy subjects.

Methods and results: Seventy-two SSc patients and 30 healthy volunteers (H) were investigated. LV diastolic function was classified as normal (I), impaired relaxation (II), and pseudonormal pattern (III). LA reservoir (H: 51.8 ± 7.4%; I: 45.1 ± 8.1%; II: 42.2 ± 6.6%; III: 36.6 ± 7.3%; analysis of variance: P < .001) and contractile strain (H: 24.8 ± 4.9%; I: 18.2 ± 4.4%; II: 21.5 ± 2.8%; III: 16.8 ± 3.6%; P < .001) already showed significant worsening in SSc patients with preserved LV diastolic function compared with healthy subjects. LA conduit strain (H: 27.1 ± 4.6%; I: 26.9 ± 5.7%; II: 20.6 ± 6.1%; III: 19.5 ± 5.3%; P < .001) was preserved in this early phase. Further deterioration of reservoir strain was pronounced in the pseudonormal group only. LA contractile strain increased significantly in the impaired relaxation group and then decreased with the further worsening of the LV diastolic function. Regarding phasic volume indices, the differences between groups were not always statistically significant.

Conclusion: LA mechanics strongly reflects the changes in LV diastolic function in SSc. On the other hand, strain parameters of the LA reservoir and contractile function already show significant worsening in SSc patients with preserved LV diastolic function, suggesting that impairment of the LA mechanics is an early sign of myocardial involvement in SSc.