Are SPECT MPI measures of dyssynchrony dyssynchronous?

Prognostic value of left ventricular mechanical dyssynchrony in hypertrophic cardiomyopathy patients with low risk of sudden cardiac death

PURPOSES

This study aims to explore the prognostic value of left ventricular mechanical dyssynchrony (LVMD) in hypertrophic cardiomyopathy (HCM) patients with low risk of sudden cardiac death (SCD).

METHODS

This retrospective study was performed in 50 patients with HCM who underwent Tc-99m sestamibi GSPECT-MPI. All patients were at low risk of SCD, defined as HCM risk-SCD scores <6%. Phase SD (PSD) and phase histogram bandwidth (PBW) were measured for assessment of LVMD. The primary endpoint was the composite major adverse cardiovascular events (MACE), including all-cause mortality, rehospitalization of heart failure symptoms, new-onset stroke, and new-onset syncope. Variables with significant difference between MACE group and non-MACE group were further assessed by Cox regression analysis.

RESULTS

During follow-up, MACE occurred in 20 patients. Systolic-PSD, systolic-PBW, diastolic-PSD, and diastolic-PBW were all significantly greater in the MACE group. Multivariate analysis revealed that history of syncope, history of atrial fibrillation, and all the four LVMD parameters were independent predictors of MACE. All LVMD parameters showed similar accuracy to predict MACE. Sequential models indicated that both systolic and diastolic LVMD parameters added incremental value beyond atrial fibrillation and syncope.

CONCLUSION

LVMD parameters are independent predictors of MACE, which add incremental prognostic information in patients with HCM risk-SCD scores <6%.