Left Atrial Passive Emptying Function During Dobutamine Stress MR Imaging Is a Predictor of Cardiac Events in Patients With Suspected Myocardial Ischemia

Abstract

OBJECTIVES The aim of this study was to determine the prognostic value of assessing left atrial function during dobutamine stress testing. BACKGROUND Left ventricular diastolic dysfunction precedes systolic wall motion abnormalities in the ischemic cascade. Severity of left ventricular diastolic function during cardiac stress is not characterized well by current clinical imaging protocols but may be an important prognostic factor. We hypothesized that abnormal early left atrial emptying measured during dobutamine stress cardiac magnetic resonance will reflect these diastolic changes and may be associated with cardiovascular outcomes. METHODS We enrolled 122 consecutive patients referred for dobutamine stress cardiac magnetic resonance for suspected myocardial ischemia. Left atrial volumes were retrospectively measured by the biplane area-length method at left ventricular end-systole (VOLmax) and before atrial contraction (VOLbac). Left atrial passive emptying fraction defined by (VOLmax – VOLbac) × 100%/VOLmax and the absolute percent increase in left atrial passive emptying fraction during dobutamine stress (ΔLAPEF) were quantified. RESULTS Twenty-nine major adverse cardiac events (MACE) occurred during follow-up (median 23 months). By Kaplan-Meier analysis, patients with ΔLAPEF <10.8 (median) experienced higher incidence of MACE than did patients with a ΔLAPEF >10.8 (p = 0.004). By univariable analysis, ΔLAPEF was strongly associated with MACE (unadjusted hazard ratio for every 10% decrease = 1.56, p < 0.005). By multivariable analysis, every 10% decrease in ΔLAPEF carried a 57% increase in MACE, after adjustment to presence of myocardial ischemia and infarction. CONCLUSIONS Reduced augmentation of left atrial passive emptying fraction during dobutamine stress demonstrated strong association with MACE. We speculate that reduced left atrial passive emptying reserve during inotropic stress may represent underlying diastolic dysfunction and warrants further investigation.

Implications of Early Aortic Stiffening in Patients With Transposition of the Great Arteries After Arterial Switch Operation

“…Both LA volumes and LAEF Passive have been used as markers of LV diastolic dysfunction. 12,13 Therefore, our data suggest that impaired aortic distensibility is likely to contribute to LV diastolic dysfunction in TGA patients.…”

“…Therefore, the purpose of this study was to evaluate the bioelastic properties of the thoracic aorta in TGA patients after ASO with respect to age, aortic dimensions, LV systolic function and left atrial (LA) volumes, and LA passive emptying function (LAEF Passive ), as markers of LV diastolic function, 12,13 using cardiovascular MRI (CMR).…”

“…12,13 Furthermore, the angulation of the aortic arch angle was measured. The scan parameters for the cine sequences were as follows: field of view, 280×224 mm; voxel size, 1.88×1.94×6 mm; repetition time/time to echo=4.4/2.5 ms; 25 cardiac phases; nonbreath-hold; number of repetitions, 2; total scan duration, 3 to 6 minutes.…”

“…LA volumes were used to calculate LAEF Passive according to the following formula: (LAVol max −LAVol ac )× 100%/LAVol max . 13 In 37 patients the aortic arch angle was measured from oblique sagittal gradient echo cine images between the intersection of 2 lines (A, B). The lines started at the midpoint of the ascending (line A) or descending aorta (line B) at the level of the pulmonary artery bifurcation and were connected with the highest point of the aortic arch as shown in Figure 4.…”

The Year in Cardiac Imaging

“…Inducible wall motion abnormalities and inducible perfusion defects were both associated with adverse outcomes on univariate and multivariate analysis (p Ͻ 0.001 for both). Farzaneh-Far et al (42) performed dobutamine stress MRI and evaluated inducible wall motion abnormalities, presence of delayed enhancement, and stress-induced change in left atrial EF in 122 patients. They followed the patients for 23 months (range 6 to 54 months) for a combined endpoint of all-cause mortality, acute MI, unstable angina, or heart failure.…”