Prediction of cardiac events in patients with reduced left ventricular ejection fraction with dobutamine cardiovascular magnetic resonance assessment of wall motion score index.

OBJECTIVES: The purpose of this study was to assess the utility of dobutamine cardiovascular magnetic resonance (DCMR) results for predicting cardiac events in individuals with reduced left ventricular ejection fraction (LVEF).
BACKGROUND: It is unknown whether DCMR results identify a poor cardiac prognosis when the resting LVEF is moderately to severely reduced.
METHODS: Two hundred consecutive patients ages 30 to 88 (average 64) years with an LVEF <or=55% that were poorly suited for stress echocardiography underwent DCMR in which left ventricular wall motion score index (WMSI), defined as the average wall motion of the number of segments scored, was assessed at rest, during low-dose, and after peak intravenous infusion of dobutamine/atropine. All participants were followed for an average of 5 years after DCMR to ascertain the post-testing occurrence of cardiac death, myocardial infarction (MI), and unstable angina or congestive heart failure warranting hospital stay.
RESULTS: After accounting for risk factors associated with coronary arteriosclerosis and MI, a stress-induced increase in WMSI during DCMR was associated with future cardiac events (p < 0.001). A DCMR stress-induced change in WMSI added significantly to predicting future cardiac events (p = 0.003), after accounting for resting LVEF, but this predictive value was confined primarily to those with an LVEF >40%.
CONCLUSIONS: In individuals with mild to moderate reductions in LVEF (40% to 55%), dobutamine-induced increases in WMSI forecast MI and cardiac death to a greater extent than an assessment of resting LVEF. In those with an LVEF <40%, a dobutamine-induced increase in WMSI does not predict MI and cardiac death beyond the assessment of resting LVEF.