Utility of combined assessment of baseline dyssynchrony and its acute improvement to predict long-term outcomes after cardiac resynchronization therapy.

Although left ventricular (LV) mechanical dyssynchrony can predict the response to cardiac resynchronization therapy (CRT), the presence of baseline LV dyssynchrony might not be the only determinant of the response to CRT. The objectives of the present study were to test the hypothesis that a combined assessment of baseline LV dyssynchrony and its acute improvement can produce a more accurate prediction of the long-term outcomes after CRT. We studied 121 patients with heart failure undergoing CRT. LV dyssynchrony was determined by measuring the anteroseptal-to-posterior wall time delay using the speckle-tracking radial strain (≥130 ms was predefined as significant) and was assessed at baseline and 7 ± 3 days after CRT. Long-term unfavorable outcome events were tracked for 5 years. Acute improvement in LV dyssynchrony of ≥33% was predictive of the long-term outcome with an area under the curve of 0.67 (p = 0.0024). Using this cutoff value, the Kaplan-Meier curve showed that patients with acute improvement in LV dyssynchrony experienced fewer cardiovascular events than those without (log-rank p = 0.0002). The event-free survival of patients whose baseline LV dyssynchrony was ≥130 ms and whose acute improvement in LV dyssynchrony was ≥33% was greater than that of the patients with baseline LV dyssynchrony of ≥130 ms but with acute improvement in LV dyssynchrony of <33% (88% vs 65%, p = 0.012). In conclusion, the combined assessment of baseline LV dyssynchrony and its acute improvement after CRT produced a more accurate prediction of long-term outcomes after CRT.