射频导管消融起源于主肺动脉干的室性早搏和/或室性心动过速

Radiofrequency catheter ablation of premature ventricular contractions/ventricular tachycardia originating from the main stem of pulmonary artery

目的探讨起源于主肺动脉干(MSPA)的室性早搏/室性心动过速(室早/室速)的电生理特征、标测方法和导管消融。方法 27例疑似右心室流出道室早/室速的患者中4例(15%)起源于MSPA,其中男性3例,平均年龄(25±10)岁。3例使用非接触式标测系统结合常规标测,1例采用常规标测。2例使用温控导管消融,2例采用冷盐水灌注导管消融。结果1例(N_4)超声心动图提示致心律失常性右心室心肌病,余3例未发现器质性心脏病。1例患者为室早/室速伴有晕厥,另3例仅有室早。室早/室速体表心电图表现为下壁导联 R 波振幅高、心电轴右偏和 Q_(aVL)/Q_(aVR)比值较大。非接触式标测显示最早激动点位于球囊上方较远距离,激动面积大,最早激动点至爆发点距离远。成功靶点处激动较体表 QRS 波起始提前(28±6)ms,2例记录到等大的 A 波和 V 波,3例记录到融合的尖峰或碎裂电位,局部高能量可以获得较满意的起搏标测图形。4例患者均消融成功,随访(6.5±3.0)个月,1例复发后再次消融成功。结论起源于 MSPA 的室早/室速并非少见,非接触式标测的特殊表现可快速揭示诊断,详细的激动标测和起搏标测指导的消融具有较好的临床效果。

Objective The aim of this study is to discuss the electrophysiologic characteristics, body surface electrocardiogram features, mapping methods and catheter ablation strategy of premature ventricular contractions or tachycardias （PVCs/VT）originating from the main stem of pulmonary artery（MSPA）. Methods Twenty-seven consecutive patients with ECG documentation of PVCs/VT with the feature of right ventricular outflow tract origin were referred for catheter ablation, 4 [ 3 male, mean age （25 ± 10 ）years old ] of which （ 15% ）were found to be MSPA origin by pulmonary artery angiogram. Noncontact mapping were used in 3 cases and rountine activation mapping and pace mapping in one case. Radiofrequency energy was delivered through temperature controlled ablation catheter in 2 patients and irrigation catheter in other 2 cases. Results All the patients did not have any sign to suggest structural heart disease except one （ N4 ） with suspect of arrhythmogenic right ventricular cardiomyopathy. All 4 patients had the symptom of palpitation during PVC/VT attack, but only one had syncope. Surface ECG of PVC/VT showed a great QRS amplitude in the in- ferior leads, right QRS axis deviation and big QavL/QavR ratio. Noncontact mapping suggested the earliest activation （EA） point was far from the above of the center of EnSite Array with a longer distance between EA point and the breakout point. Endocardial recording of the target site showed a mean of （ 28 ± 6） ms proceding the onset of QRS complex, with equal atrial and ventricular electrogram in 2 patients, a fusion of spike or fractiona- ted potential and the ventricular elctrogram in 3 patients. Perfect pace map could he done with higher output in all patients. Catheter ablation was all successful. After a mean follow-up of （6. 5 ± 3.0） months, I patient had PVC recurrence and need a second successful ablation above the pulmonary valve. Conclusion PVCs/VT originating from MSPA is not uncommon. Its diagnosis can be rapidly made by noncontact mapping but needs to be confirmed by pulmonary artery angiogram. Detailed activation mapping and pace mapping should be done above the pulmonary valve to guide the successful catheter ablation.