Abstract 9565: Left Atrial “Reservoir” and “Passive Emptying” Reserve During Dobutamine Stress Have Prognostic Relevance for Patients With Dilated Cardiomyopathy
Background: Left atrial (LA) structural and functional remodeling has been proposed as a predictor of cardiovascular outcomes. However, the importance of LA functional reserve for patients with depressed left ventricular (LV) function remains unclear. The objective of this study was thus to test the hypothesis that diminished augmentation of LA function during dobutamine stress may be associated with adverse cardiovascular events in patients with dilated cardiomyopathy (DCM).
Methods: Sixty-seven DCM patients with ejection fractions of 35±9% were recruited, and LA strain was determined as the averaged global speckle-tracking longitudinal strain from apical 4- and 2-chamber views during dobutamine stress (20μg/kg/min). The systolic component of LA strain (S-LAs) was considered to reflect reservoir function, whereas the passive (S-LApass) and active emptying components (S-LAa) were considered to reflect conduit and booster-pump function, respectively. Event-free survival was tracked over a 17-month period.
Results: Both relative increases in the LA reservoir (cut-off ≤10.9%; 71% sensitivity and 89% specificity, p<0.001) and in passive emptying function(cut-off ≤12.3%; 93% sensitivity and 85% specificity, p<0.001) during dobutamine stress were significantly predictive of adverse cardiovascular events. The patients with good LA “reservoir reserve” (ΔS-LAs >24.7% [median]) and “passive emptying reserve” (ΔS-LApass >32.5% [median]) had a significantly better prognosis than those with poor functional reserve (log rank p<0.001, respectively). Of particular importance was that the absence of “reservoir reserve” and “passive emptying reserve” was associated with the worst outcome (event rate: 90.0%), whereas the reverse condition was associated with the lowest adverse event rate (2.4%; p<0.001).
Conclusions: Diminished augmentation of LA reservoir and passive emptying function is closely associated with adverse cardiovascular event.
- © 2013 by American Heart Association, Inc.