特发性右室流出道室性早搏触发多形性室性心动过速或心室颤动四例的临床特点

Clinical characteristics of 4 cases of polymorphic ventricular tachycardia/ventricular fibrillation initiated by idiopathic premature ventricualr contraction originating from right ventricular outflow tract

目的报道4例特发性右室流出道(RVOT)室性早搏(PVC)触发多形性室性心动过速/心室颤动(PVT/VF)的临床特点。方法 76例起源于RVOT的VT患者,其中4例为PVC触发PVT/VF,总结4例的临床资料并与另72例有关资料相比较。结果所有4例触发PVT/VF时的PVC与孤立PVC的形态一致,但2种PVC的联律间期发生了明显改变,其改变幅度均≥70 ms,其中2例缩短,2例延长。1例孤立PVC时的联律间期亦不恒定。72例PVC触发的单形VT患者每天PVC次数为15 427±1 109,QT间期为404±15 ms,孤立PVC联律间期为419±22ms。4例PVC触发PVT/VF患者中3例1天的PVC次数与72例PVC触发的单形VT患者平均PVC次数相当。4例患者的QT间期及孤立PVC联律间期与另72例患者相当。而4例PVT/VF的周长均小于280 ms,明显短于72例VT的平均周长(324±59 ms)。72例单形VT患者发生晕厥比率4.1%;4例PVT/VF患者中发生晕厥者2例。采用激动标测和起搏标测证实4例患者PVC均起源于RVOT间隔侧,经射频导管消融PVC取得成功。结论起源于RVOT的PVC触发PVT/VF具有PVC联律间期不恒定及PVT/VF的周长短的临床特征,射频导管消融治疗有效。

Objective To report clinical characteristics of 4 cases of polymorphic ventricular tachycardia / ventricular fibrillation（PVT/VF） initiated by idiopathic premature ventricualr contraction（PVC） originating from right ventricular outflow tract（RVOT）.Methods Among 76 patients with ventricular tachycadia（VT） arising from RVOT,the clinical characteristics of 4 patients with PVT/VF triggered by PVC originating from RVOT were investigated and compared with the clinical characteristics of the other 72 patients.Results The same PVC morphology was shown in triggering PVCs which initiated PVT/VF and in isolated PVCs.The coupling intervals of the above two kinds of PVCs were markdly different.The coupling intervals of triggering PVCs were shortened in 2 cases and prolonged in the remain 2 cases while compared with those of isolated PVCs,and the variation magnitude of the coupling interval in every case was more than 70 ms.The coupling intervals of isolated PVCs were not fixed in 1 case.The number of PVCs per day,the coupling interval of isolated PVC and the baseline QT interval were 15 427±1 109,419±22 ms and 404±15ms respectively in 72 monomorphic VT patients.The numbers of PVCs per day in 3 of the 4 PVT/VF patients were equivalent to those of 72 VT patients,and the same equivalence was found in the coupling intervals of isolated PVC and the baseline QT intervals of the 4 patients.The cycle lengths of PVT/VF were all less than 280 ms which was shorter than that of monomorphic VT（324±59 ms） obviously.Among 4 patients,episodes of syncope were documented in 2 patients,and the syncope rate of 72 VT patients was 4.1%.Activating mapping and pacing mapping confirmed that the PVCs of these 4 patients all originated from septal of RVOT,and were successfully eliminated by radiofrequency catheter ablation.Conclusions PVCs which trigger PVT/VF and originated from tract RVOT have the characteristics of unstable coupling intervals and short circle lenth of PVT/VF.Radiofrequency catheter ablation is effective as a treatment option for these patients.