| Background:Ventricular tachycardia(VT)often occurs in the setting of structural heart disease,but it can also occur in patients without structural heart disease.Idiopathic ventricular tachycardia is found in no evidence of structural heart disease,electrolyte abnormalities and ion channel dysfunction,and so on.The incidence of idiopathic ventricular tachycardia is about 10%of ventricular tachycardia,mostly in young adults.Stability hemodynamic and high success rate of radiofrequency ablation,better prognosis are demonstrated for the majority of patients with idiopathic ventricular tachycardia because of the absence of underlying heart disease.Patients with organic ventricular tachycardia always have higher sudden death risk,poor effect of drug and radiofrequency ablation because of the persistent existence of the underlying heart disease.Implantable cardioverter defibrillator(ICD)is a class I indication for patients with structural heart disease who have sustained ventricular tachycardia and ventricular fibrillation/flutter.Little is known about the mechanism of idiopathic ventricular tachycardia,especially about the difference of electrocardiogram ventricular repolarization parameters for idiopathic and organic ventricular tachycardia.Objective:This study aimed to analyze electrocardiogram ventricular repolarization parameters in healthy population,in patients with idiopathic ventricular tachycardia and organic ventricular tachycardia,so as to verify some useful repolarization parameters to predict ventricular arrhythmia.Method:55 patients with idiopathic ventricular tachycardia,41 patients with organic ventricular tachycardia and 110 healthy people with matched age and gender as comtrol group are selected in the First Affiliated Hospital of Dalian Medical University.We firstly require electrocardiogram in sinus rhythm.Then analyze ventricular repolarization parameters on electrocardiogram:QTc,QRS-T angle,TpTe,QTd,tax and morphological parameters of T wave(PCA,MCS-score,VAngT_F,VAngT_S,VAngT_T,VMaxT_F,VMaxT_S,VMaxT_T,to_V5,td_V5,bmTar_V5).Finally,the differences of all indexs between the three groups were compared.Results:1.The comparison between three groups of ventricular repolarization parameters:comparison between healthy group with idiopathic ventricular tachycardia group,there are statistic significant differences between QTc,QRS-T angle,and TpTe(P<0.01,P?0.04,P=0.02),while there is no statistic significant differences between QTd and tax(P=0.24,P=0.32)?Comparison between healthy group with the group of ventricular tachycardia having structural heart disease,there are statistic significant differences between QTc,QRS-T angle,TpTe,QTd,and tax(P<0.01,P<0.01_P=0.01,P<0.01,P<0.01)?Comparison between idiopathic ventricular tachycardia group with the group of ventricular tachycardia having structural heart disease,there are statistic significant differences between QTc,QRS-T angle,and tax(P<0.01,P<0.01,P<0.01),while there is no statistic significant differences between TpTe,QTd(P?0.59,P=0.10)?2.Predictive value of ventricular repolarization parameters for organic ventricular tachycardia and ROC curve:The area under the QRS-T angle curve is 0.916,it is best predictive index for ventricular tachycardia with structural heart disease(P<0.01);The areas under the QTc,tax curve are 0.736?0.752 respectively,which are better for ventricular tachycardia with structural heart disease(P<0.01,P<0.01).3.T wave morphology:comparison between healthy group with idiopathic ventricular tachycardia group,there are statistic significant differences between PCA,MCS-score,VAngT_S,VMaxT_F,VMaxT_T,ta_V5,and bmTar_V5(P<0.01,P=0.04,P=0.02,P?0.02,P?0.03,P=0.01,P=0.01)while there is no statistic significant differences between VAngT_F,VAngT_T,VMaxT_S,and td_V5(P=0.97_P=0.54,P=0.30,P?0.84)Comparison between healthy group with the group of ventricular tachycardia having structral heart disease,there are statistic significant differences between PCA,MCS-score,VAngT_F,VAngT_S,VAngT_T,VMaxT_F,ta_V5,td_V5,and bmTar_V5(P<0.01,<0.01,<0.01,P?0.02,P<0.01,P<0.01,P<0.01,P<0.01,P<0.01),while there is no statistic significant differences between VMaxT_S,and VMaxT_T T(P=0.87,P=0.23).Comparison between idiopathic ventricular tachycardia group with the group of ventricular tachycardia having structural heart disease,while there are some statistic significant differences between PCA,MCS-score,VAngT_F,VAngT_S,VAngT_T,ta_V5,td_V5,and bmTar_V5(P<0.01,P<0.01,P<0.04,P<0.01,P<0.01,P<0.0,P<0.01,P<0.01),there is no statistic significant differences between VMaxT F,VMaxT_S,and VMaxT_T(P?0.06,P?0.33,P?0.47).4.Predictive value of T wave morphology for organic ventricular tachycardia and ROC curve:The areas under the PCA,VAngT_S,VAngT_T,ta_V5,bmTar_V5,and Tax curve are 0.725,0.755,0.752,0.803,0.812,0.752respectively,which are better for ventricular tachycardia with structral heart disease;the areas under the MCS-score,VAngT_F,VMaxT_F,and td_V5 curve are 0.629,0.634,0.656,0.615 respectively,which are fair for judging ventricular tachycardia with structural heart disease.Conclusion:1.Ventricular repolarization parameters in patients with ventricular tachycardia are different from health people.Among them,the changes of ventricular repolarization parameters in organic heart disease are significnat.The changes of ventricular repolarization parameters in idiopathic ventricular tachycardia group,it indicates that the idiopathic ventricular tachycardia patients may have electrophysiological substrates for ventricular tachycardia.2.Idiopathic ventricular tachycardia and organic ventricular tachycardia have differences in ventricular repolarization parameters.These results suggest that there could be differences between two kinds of matrix or there could be difference in electrophysiological mechanisms.3.The greatest differences between the three groups are QRS-T angle,tax and part of T wave morphological parameters,they are better repolarization parameters for ventricular arrhythmia risk stratification. |
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