| Part?Non-contact mapping and ablation of idiopathic ventricular arrhythmia originating in the right ventricular outflow tractObjective: The aim of this study is to discuss the electrophysiologic characteristics, non-contact mapping methods, and catheter ablation strategy of premature ventricular contractions or tachycardias (PVCs/VT) originating in right ventricular outflow tract (RVOT).Methods: 33 consecutive patients (17 men and 16 women; mean age, 40.7±13.2 years) were included in the study. The target site was identified by non-contact mapping and confirmed by successful ablation. Non-contact mapping were used in 33 cases, and identified the earliest activation (EA), the exit (EX) point and preferential conduction. Routine activation mapping and pace mapping were also used in these cases. Dynamic substrate mapping (DSM) identified low-voltage zone in RVOT, and revealed the relationship between EA/EX and low-voltage zone. Radiofrequency energy was delivered through temperature controlled ablation catheter in patients.Results: Catheter ablation was successful in 33 patients. The target sites were located in the superior area in eight patients, the inferior area in 25 patients, the anterior area in 21 patients, the posterior area in 12 patients, the free wall in 12 patients and the septum in 21 patients. 17 target sites were located on EA, and 16 target sites on EX. The low-voltage zone were mostly located in the superior area of RVOT. There is a close relation between EA and low-voltage zone.Conclusion: Non-contact mapping can reveal the electrophysiologic characteristics of right ventricular outflow tract idiopathic ventricular arrhythmia, and guide the successful catheter ablation.Part?Non-contact mapping and ablation of idiopathic ventricular arrhythmia originating in the main stem of the pulmonary arteryObjective: The aim of this study is to discuss the electrophysiologic characteristics, electrocardiogram features, non-contact mapping methods and catheter ablation strategy of premature ventricular contractions or tachycardias (PVCs/VT) originating in the main stem of the pulmonary artery (MSPA).Methods: fourty-six consecutive patients with ECG documentation of idiopathic ventricular arrhythmia with the feature of right ventricular outflow tract origin were referred for catheter ablation, 13 ( 23 men and 23 women; mean age, 40.1±14.3 years ) of which (28%) were found to be main stem of the pulmonary artery origin by pulmonary artery or right ventricular angiogram. Non-contact mapping were used in 46 cases, and identified the earliest activation (EA), the exit (EX) point and preferential conduction. Routine activation mapping and pace mapping were also used in these cases. ECG data obtained from 46 patient with RVOT-PVCs/VT were analyzed, and compared between RVOT group and MSPA group. Radiofrequency energy was delivered through temperature controlled ablation catheter in patients.Results: All the patients originating from main stem of the pulmonary artery did not have any sign to suggest structural heart disease. All 13 patients had the symptom of palpitation during idiopathic ventricular arrhythmia, but only one had syncope. There were not distinctive differential in ECG characteristics between RVOT group and MSPA group. Non-contact mapping suggested the earliest activation (EA) point was far from the above of the center of EnSite Array with a longer distance between the EA point and the exit (EX) point. Endocardial recording of the target site showed a mean of (20.84±7.88) ms proceding the onset of QRS complex, with atrial and ventricular electrogram in 8 patients, and a fusion of spike or fractionated potential and the ventricular elctrogram in 8 patients. Perfect pace mapping could be done with higher output in 5 patients. Catheter ablation was successful in 11 patients, and failed in 2 patient.Conclusion: idiopathic ventricular arrhythmia originating from main stem of the pulmonary artery is not uncommon. Its diagnosis can be rapidly made by non-contact mapping but need to be confirmed by pulmonary artery or right ventricular angiogram. Detailed activation mapping and routine pace mapping should be done above the pulmonary valve to guide the successful catheter ablation.Part?Three Dimensional Distribution of the Target Sites and The Electrocardiographic Characteristics of idiopathic ventricular arrhythmia Originating from Right Ventricular Outflow TractObjective: The purpose of the study was to explore the relationship between electrocardiogram (ECG) patterns of right ventricular outflow tract idiopathic ventricular arrhythmia and three dimensional distribution of the target sites which were identified by non-contact mapping.Methods: 33 consecutive patients (17 men and 16 women; mean age,40.7±13.2 years) were included in the study. The target site was identified by non-contact mapping and confirmed by successful ablation. The distribution of the target site in three dimentional geometry of RVOT was classified into 4 subdivisions: anterior area (A)–posterior area (P), free wall (F)–septum (Se); each subdivision was further divided into two areas: superior (Su)–inferior (I). The ECG characteristics were analyzed according to their ablation sites with the following characteristics: the QRS duration, amplitude, the r wave pattern in the inferior leads, and the initial r wave width in lead V1; the QS-wave amplitude in aVR and aVL; and the initial r wave amplitude in lead V1 and V2.Results: The target sites were located in the superior area in eight patients, the inferior area in 25 patients, the anterior area in 21 patients, the posterior area in 12 patients, the free wall in 12 patients and the septum in 21 patients. On the 12-lead ECG, the following indexes were helpful to identify the position of the target site: (1) the QRS duration (?150 ms, F; <150 ms, Se; diagnostic accuracy: 70%) (p<0.05) and the r wave pattern in the inferior leads (RR'or Rr', F; R, Se; diagnostic accuracy: 73%) (p<0.05), the R wave amplitude in the inferior leads (high, Se; low, F) (1.54±0.46 vs 1.21±0.38mv; p<0.05), the initial r wave width in lead V1 (wide, F; narrow, Se) (39.17±25.51 vs 19.19±23.92ms; p<0.05), (2) the QS-wave amplitude in aVR and aVL (aVR<aVL, A; aVR?aVL, P; diagnostic accuracy: 70%) (p<0.05), and (3) the initial r wave amplitude in lead V1 and V2 (V1?0.15mv and V2?0.3mv, Su; V1<0.15mv or V2 <0.3mv, I; diagnostic accuracy: 81%) (p<0.05).Conclusion: The ECG characteristics of RVOT-PVCs/VT had distinctive relationship with the target sites localized with the use of non-contact mapping. |
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