[Influence of diastolic filling pattern on the efficacy of cardiac resynchronization therapy in patients with non-ischemic cardiomyopathy].

OBJECTIVE

To investigate the influence of diastolic filling pattern on the efficacy of cardiac resynchronization therapy (CRT) in patients with non-ischemic cardiomyopathy.

METHODS

Between January 2012 and September 2013, 100 patients with non-ischemic cardiomyopathy undergoing CRT were enrolled in the study, and all patients were grouped by the pre-CRT diastolic filling pattern as impaired relaxation, pseudonormalized and restrictive filling. After follow up for 12 months, the New York Heart Association (NYHA) Class and echocardiography were used to assess the efficacy of CRT.The endpoint was rehospitalization for heart failure or cardiac death. Kaplan-Meier survival curves were plotted to assess prognosis.

RESULTS

All patients had varying degrees of diastolic dysfunction.Logistic regression analysis indicated that diastolic filling pattern was the independent factor for the response of CRT.(1)The response rate (78.7%) of impaired relaxation group (n=61) was significantly higher than that of the other two groups (P<0.01); postoperative NYHA class, left ventricular ejection fraction (LVEF), fraction shortening (FS), left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV) were significantly improved (all P<0.01). (2)For pseudonormalized group (n=18), at the 3(rd) month, NYHA class decreased from 3.3±0.5 to 2.3±0.5, LVEF increased from 27%±7% to 31%±6% (both P<0.01), and FS improved significantly (P<0.05); no significant decrease of LVEDV and LVESV was found. At the 6(th) month, LVEF improved significantly (P<0.01); LVESV was reduced (P<0.05). (3)In restrictive filling group (n=21), CRT brought short-term improvement in NYHA class but did not induce any significant improvement in LVEF, FS, LVESV and LVEDV.At the 6(th) month, there were significant differences in efficacy among the three groups (P<0.05). At the end of follow-up, 5 patients died, and the cumulative endpoint incidence was significantly higher in restrictive filling group (81%) than the other two groups (P<0.05).

CONCLUSIONS

In patients with moderate-to-severe heart failure, left ventricular diastolic dysfunction affects the efficacy of CRT, patients with impaired relaxation benefit significantly, pseudonormalized patients take longer to benefit, but patients with restrictive filling do not benefit from CRT.