The additive prognostic value of restrictive pattern and dipyridamole-induced contractile reserve in idiopathic dilated cardiomyopathy

Background: Diastolic dysfunction and lack of contractile reserve are unfavorable prognostic predictors in patients with dilated cardiomyopathy (DCM). Aims: This study aims to assess whether diastolic dysfunction and lack of dipyridamole-induced contractile reserve were additive predictors of poor outcome in patients with DCM. Methods: A total of 116 patients with DCM and ejection fraction (EFb35%) were studied by dipyridamole echo (0.84 mg/kg over 10 min). At rest, a restrictive filling pattern was defined as: E/A ratio N2 and an E-wave deceleration time of b140 ms on transmitral flow velocity profile. Results: Rest wall motion score index (WMSI) was 2.2F0.3 and decreased to 1.9F0.41 after dipyridamole ( pb0.001). During follow-up (median 26.5 months), 22 cardiac deaths occurred. At multivariate analysis, dipyridamole-induced contractile reserve yielded significant incremental prognostic value (RR=0.275, pb0.006) over NYHA class (RR=1.971, pb0.03), angiotensin-converting enzyme inhibitor therapy (RR=0.173, pb0.001), and left ventricular end-diastolic diameter (RR=1.131, pb0.001). The worst prognostic combination was the presence of restrictive pattern at rest and the absence of contractile reserve (DWMSIb0.15). Conclusion: In patients with DCM, the ominous combination of restrictive transmitral flow pattern and lack of contractile reserve during dipyridamole stress predicts an unfavourable outcome.