Objective To investigate the role of QT interval dynamicity in predicting sudden death in patients with idiopathic dilated cardiomyopathy (DCM).
Methods 55 patients with DCM (DCM group) and 27 health people (Control group, Con) were enrolled according to certain criteria. Investigations included history collection, clinical examination, echocardiography, ECG and 24 h ambulatory ECG. Following indexes were determined, left ventricle end diastolic dimension (LVEDD), left ventricle ejection fraction (LVEF), QT dispersion (QTd), SDNN, the slope of QT/RR plots of the linear regression, ventricular premature beats (VPB) and non-sustained ventricular tachycardia (NSVT). Patients with DCM were followed-up until all cause death.
Results Comparing with Con group, the LVEDD, QTd, VPB/24 h, NSVT/24 h, QTe/RR slope and QTp/RR slope were higher in DCM group, while LVEF and SDNN were lower in DCM group (p<0.05). The LVEDD, LVEF, QTd, SDNN, QTe/RR slope and QTp/RR slope were significant different among DCM sudden death group, DCM non sudden death group and Con group (p<0.05). Comparing between DCM sudden death and non sudden death group, LVEF, SDNN, QTp/RR slope and QTp/RR slope shown significant difference (p<0.05). Comparing between DCM with NSVT and without NSVT group, LVEF, QTd, VPB/24 h, QTp/RR slope and QTp/RR slope shown significant difference (p<0.05). The sudden death rate of DCM patients with QTe/RR slope≥0.210 was higher than those <0.210 (54.5% vs 21.1%, p<0.05). Sudden death rate of QTp/RR slope≥0.190 was higher than those <0.190 (52.2% vs 21.9%, p<0.05). The sudden death rate of DCM patients with both LVEF 35% and NSVT+ was 62.5%. Combining QTe/RR≥0.210 with NSVT+ or LVEF 35%, the sudden death rates were 62.5% or 66.7%. Combining QTp/RR≥0.190 with NSVT+ or LVEF 35%, the sudden death rates were 66.7% or 61.5%. Combining QTe/RR≥0.210 or QTp/RR≥0.190 with NVST+ and LVEF 35%, the sudden death rates were 77.8% or 70.0%.
Conclusions QT/RR slope of DCM sudden death group was higher than DCM non sudden death and Con group significantly. QT/RR slope show high predicting value for sudden death in DCM patients independently or combined with NSVT or LVEF.
- QT Interval
- idiopathic dilated cardiomyopathy
- sudden death
- risk predicting
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