Preliminary observations of prognostic value of left atrial functional reserve during dobutamine infusion in patients with dilated cardiomyopathy.
BACKGROUND
The importance of left atrial (LA) functional reserve in patients with depressed left ventricular function remains unclear. Thus, the aim of this study was to test the hypothesis that diminished augmentation of LA function during dobutamine stress might be associated with cardiovascular events in patients with dilated cardiomyopathy.


METHODS
Eighty-four patients with dilated cardiomyopathy with a mean ejection fraction of 34 ± 9% were retrospectively recruited, and LA strain was determined as the averaged global speckle-tracking longitudinal strain from apical four-chamber and two-chamber views during dobutamine stress (20 μg/kg/min). The systolic component of LA strain was considered to reflect reservoir function, whereas the passive and active emptying components were considered to reflect passive and active emptying function, respectively. Event-free survival was tracked for 17 months.


RESULTS
Multivariate Cox proportional-hazards analysis identified LA volume index (hazard ratio [HR], 1.060; P < .001) and β-blocker use (HR, 0.048; P < .05) as the independent variables associated with cardiovascular events among the baseline parameters and changes in systolic LA strain (HR, 0.971; P = .02), in passive emptying LA strain (HR, 0.942; P < .001), and in left ventricular early diastolic strain rate (HR, 0.986; P = .03) under dobutamine as the variables among the functional reserve parameters. In sequential Cox models, a model based on clinical variables (χ(2) = 9.3) was improved by conventional echocardiographic parameters (χ(2) = 19.2, P = .012) and LA strain parameters at rest (χ(2) = 40.1, P = .005) and further improved by the addition of changes in LA strain parameters under dobutamine (χ(2) = 61.6, P < .001).


CONCLUSIONS
The assessment of LA reservoir and passive emptying function during dobutamine stress provides important incremental prognostic value in patients with dilated cardiomyopathy.
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Kensuke
K
Matsumoto
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan. Electronic address: tanakah@med.kobe-u.ac.jp.
Hidekazu
H
Tanaka
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Junichi
J
Imanishi
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Kazuhiro
K
Tatsumi
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Yoshiki
Y
Motoji
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Tatsuya
T
Miyoshi
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Tetsuari
T
Onishi
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Hiroya
H
Kawai
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Ken-ichi
K
Hirata
D016275:Atrial Function / Q000187:drug effects*; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004280:Dobutamine / Q000008:administration & dosage; D004452:Echocardiography / Q000379:methods; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005080:Exercise Test; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014665:Vasodilator Agents / Q000008:administration & dosage
D014665:Vasodilator Agents; D004280:Dobutamine
Dobutamine stress echocardiography; Idiopathic dilated cardiomyopathy; Left atrial function; Left atrial reserve; Speckle-tracking strain