Background Recently, substrate mapping （SM） has been described to facilitate catheter ablation of stable and unstable ventricular tachycardia （VT） after myocardial infarction. However, SM is time consuming with po...Background Recently, substrate mapping （SM） has been described to facilitate catheter ablation of stable and unstable ventricular tachycardia （VT） after myocardial infarction. However, SM is time consuming with potential disadvantages of multiple ablation lines such as impairment of ventricular function or proarrhythmia. The aim of the present study was to delineate a stepwise approach to SM to shorten procedure time and limit the possibility of complications. Methods SM was performed in 14 infarct survivors referred for VT ablation using an electroanatomical mapping system （CARTO） to define infarct regions. A new stepwise approach for SM was designed as follows. The initial ablation site was identified by pace- and entrainment mapping in case of stable VT and by pace mapping only in case of unstable VT. Based on the CARTO voltage mapping, linear ablation was done from this site to the center of the scar and perpendicular to the boundary of the scar or to the mitral annulus. Additional lines were performed only when VT remained inducible. A maximum of 3 ablation lines were created during one procedure. Results A total of 57 VTs （21 stable, 36 unstable） were induced during the procedures. VT was no longer inducible after the first linear ablation in 2 patients, after the second linear ablation in 6 patients and after the third linear ablation in 3 patients. Either VT or ventricular fibrillation was still inducible at the end of the procedure in 3 patients. Procedure time averaged （291 ±85） minutes, fluoroscopy time （10±7） minutes. VT recurred in 3 patients. Following a second procedure in 2 patients, there were no further VT recurrences. Overall, there was a significant reduction in VT episodes 3 months after [median： 0, interquartile ranges （IQR）： 0-1] compared with 3 months before ablation （median： 25, IQR： 16-105, P〈0.01）. Conclusions This stepwise approach to SM is effective in facilitating ablation of stable and unstable VT. It reduces procedure and fluoroscopy time, and may help to improve the risk-benefit ratio of VT ablation.展开更多
Background Substrate modification guided by CARTO system has been introduced to facilitate linear ablation of ventricular tachycardia （VT） after myocardial infarction （MI）. However, there is no commonly accepted s...Background Substrate modification guided by CARTO system has been introduced to facilitate linear ablation of ventricular tachycardia （VT） after myocardial infarction （MI）. However, there is no commonly accepted standard approach available for drawing these ablation lines. Therefore, the aim of the present study was to practically refine this time consuming procedure.Methods Substrate modification was performed in 23 consecutive patients with frequent VTs after MI using the CARTO system. The initial target site （ITS） for ablation was identified by pace mapping （PM） during sinus rhythm and/or entrainment pacing （EM） during VT. According to the initial target site, two approaches were used. The initial target site in approach one has a similar QRS morphology as VT and an interval from the stimulus to the onset of QRS cmplex （S-QRS） of ≥50 ms during PM in sinus rhythm or a difference of the post pacing interval and VT cycle length ≤30 ms during concealed entrainment pacing of VT; The initial target site in approach two has an similar QRS morphology as VT and an S-QRS of 〈50 ms during PM in sinus rhythm.Results Overall, 50 lines were performed with a length of （35±11） mm. Procedure time averaged （232±56） minutes, fluoroscopy time （10±8） minutes. Sixteen patients were initially involved into approach one. After completion of 3±1 ablation lines, no further VT was inducible in 13 patients. The remaining 3 patients were switched to use the alternative approach. However, in none of them the alternative approaches were successful. Approach two was initially used in 7 patients. After completion of 3±1 ablation lines, no further VT was inducible in only 2 patients. The remaining 5 patients were switched to approach one, which resulted in noninducibility of VT in 4 of them. The initial successful rate was significantly higher in the group of approach one compared to that in the group of approach two （13/16 patients vs 2/7 patients, P=-0.026）.Conclusions The approach for substrate modification of VT after MI can be optimized by identifying the appropriate initial target site with specific characteristics within the zone of slow conduction. The refined approach may facilitate linear ablation of VT, and further reduce the procedure and fluoroscopy time.展开更多
文摘Background Recently, substrate mapping （SM） has been described to facilitate catheter ablation of stable and unstable ventricular tachycardia （VT） after myocardial infarction. However, SM is time consuming with potential disadvantages of multiple ablation lines such as impairment of ventricular function or proarrhythmia. The aim of the present study was to delineate a stepwise approach to SM to shorten procedure time and limit the possibility of complications. Methods SM was performed in 14 infarct survivors referred for VT ablation using an electroanatomical mapping system （CARTO） to define infarct regions. A new stepwise approach for SM was designed as follows. The initial ablation site was identified by pace- and entrainment mapping in case of stable VT and by pace mapping only in case of unstable VT. Based on the CARTO voltage mapping, linear ablation was done from this site to the center of the scar and perpendicular to the boundary of the scar or to the mitral annulus. Additional lines were performed only when VT remained inducible. A maximum of 3 ablation lines were created during one procedure. Results A total of 57 VTs （21 stable, 36 unstable） were induced during the procedures. VT was no longer inducible after the first linear ablation in 2 patients, after the second linear ablation in 6 patients and after the third linear ablation in 3 patients. Either VT or ventricular fibrillation was still inducible at the end of the procedure in 3 patients. Procedure time averaged （291 ±85） minutes, fluoroscopy time （10±7） minutes. VT recurred in 3 patients. Following a second procedure in 2 patients, there were no further VT recurrences. Overall, there was a significant reduction in VT episodes 3 months after [median： 0, interquartile ranges （IQR）： 0-1] compared with 3 months before ablation （median： 25, IQR： 16-105, P〈0.01）. Conclusions This stepwise approach to SM is effective in facilitating ablation of stable and unstable VT. It reduces procedure and fluoroscopy time, and may help to improve the risk-benefit ratio of VT ablation.
基金This study was supported by grants from the National Natural Science Foundation of China （No, 30670831）, and Shanghai Pujiang Program （No. 05PJ14063）.
文摘Background Substrate modification guided by CARTO system has been introduced to facilitate linear ablation of ventricular tachycardia （VT） after myocardial infarction （MI）. However, there is no commonly accepted standard approach available for drawing these ablation lines. Therefore, the aim of the present study was to practically refine this time consuming procedure.Methods Substrate modification was performed in 23 consecutive patients with frequent VTs after MI using the CARTO system. The initial target site （ITS） for ablation was identified by pace mapping （PM） during sinus rhythm and/or entrainment pacing （EM） during VT. According to the initial target site, two approaches were used. The initial target site in approach one has a similar QRS morphology as VT and an interval from the stimulus to the onset of QRS cmplex （S-QRS） of ≥50 ms during PM in sinus rhythm or a difference of the post pacing interval and VT cycle length ≤30 ms during concealed entrainment pacing of VT; The initial target site in approach two has an similar QRS morphology as VT and an S-QRS of 〈50 ms during PM in sinus rhythm.Results Overall, 50 lines were performed with a length of （35±11） mm. Procedure time averaged （232±56） minutes, fluoroscopy time （10±8） minutes. Sixteen patients were initially involved into approach one. After completion of 3±1 ablation lines, no further VT was inducible in 13 patients. The remaining 3 patients were switched to use the alternative approach. However, in none of them the alternative approaches were successful. Approach two was initially used in 7 patients. After completion of 3±1 ablation lines, no further VT was inducible in only 2 patients. The remaining 5 patients were switched to approach one, which resulted in noninducibility of VT in 4 of them. The initial successful rate was significantly higher in the group of approach one compared to that in the group of approach two （13/16 patients vs 2/7 patients, P=-0.026）.Conclusions The approach for substrate modification of VT after MI can be optimized by identifying the appropriate initial target site with specific characteristics within the zone of slow conduction. The refined approach may facilitate linear ablation of VT, and further reduce the procedure and fluoroscopy time.
