低能量放电下标测无室性早搏的流出道室性心动过速

Objective This study reported initial experience of a new mapping method for ablation of syncope-caused ventricular tachycardia (VT) without combining frequent premature ventricular contraction (PVC). Methods All 11 recruited patients were female, mean age (39. 9 ± 13.7)years. They had experienced at least 1 syncope episode and were refractory to 2 or more antiarryhthmic agents in the past 1 to 3 years. Results ( 1 ) Clinical arrhythmia characteristics: In 5 patients, PVC or VT was induced by programmed stimuli without intravenous isoproterenol in right ventricular outflow tract(RVOT). In these patients, Holter monitoring recorded more PVCs ( mean 3678 beats/24 hours) with ventricular bigeminy or trigeminy, but less VT (mean 5. 8 episodes/24 hours). These patients suffered more transient amaurosis than syncope except one older woman combining hypertension. While in other 6 patients, VT could not be induced with programmed stimuli unless isoproterenol was administrated. These patients all suffered syncope in their medical history, their Holter monitoring recorded more VT (mean 15.5 episodes/24 hours)less PVC (mean 1208 beats/24 hours )with few ventricular bigeminy or trigeminy. (2) Electrophysiologic mapping and catheter ablation: Induced PVC or VT were frozen on monitor screen as reference, ablation catheter was posited on expected area of RVOT, pace mapping was performed firstly and Low Radio Frequency(LRF) energy( 15 ～20 W)was delivered at sites that paced VT morphology identical to reference VT in all 12 leads of ECG. Once the sites was found that VT morphology induced by LRF was identical to reference VT in all 12 leads of ECG,the radiofrequency energy would be increased to 35 ～50 W(50 ～55℃ )on same site until VT was eliminated. Then enlarge ablation area to about 1 cm2 around this site. All 11 patients were induced identical VT during low radiofrequency energy. ( 3 ) No VT/PVC was induced through program stimuli or intravenous isoproterenol repeatedly after ablation was considered as successful end point. Ten patients reached the end of ablation in the procedure ,9 targets located at sepal or posterior wall in RVOT, 1 did base of right coronary cusp. The only failure one also could be induced frequent matched VT by LRF, activating mapping found the earliest activated site located in inferior of left coronary cusp. However,PVC couldn't be eliminated,which suggested the target may locate at the pericardial layer.(4)No syncope or amaurosis was observed in 3 ～ 14 months of follow-up. Conclusions Low energy stimuli mapping can be used as a new mapping method as well as active mapping, pace mapping and spike potential mapping, especially to those patients suffer from repeat syncope or amaurosis induced by VT without combining frequent premature ventricular contraction.     

特发性右心室流出道室性心动过速/室性早搏的性别、年龄和临床特点

Objective The aim of this study was to clarify gender,age and clinical feature of idiopathic right ventricular outflow tract ventricular tachycardia/premature ventricular complexes(ROVT/PVC). Methods We studied 478 patients[mean age(39. 8 ± 13. 8)years]with idiopathic ROVT/PVC who were admitted to our center consecutively in past 15 years. All of them underwent catheter mapping and radiofrequency catheter ablation (RFCA), and the original sites of ventricular tachycardia/premature ventricular complexes were confirmed by catheter mapping and radiofrequency catheter ablation. Results Of 478 patients, 288 patients (60. 3% )were female, 190 patients(39. 7% )were male, female/male ratio was 1.52. The early onset of symptom was at (41.2 ± 12. 7 ) years for female, and ( 37.6 ± 15. 0) years for male ( P ＜ 0. 05 ). Almost all patients had palpitation in varying degrees. Sixty-seven of 478 patients( 14.2% ) had history of near-syncope,and 13 of 478 patients(2. 7% )had history of syncope. Two hundred and sixty-three patients( 55% )underwent unsuccessful treatment with antiarrhythmic drugs before the radiofrequency ablation. Of them, 110 patients (23%)had received one kind of antiarrhythmic drug, 104 patients (21.8%)had received two types of antiarrhythmic drugs,49 patients( 10. 3% )had received three types of antiarrhythmic drugs. Conclusion ROVT/VPC occur more in female than in male,the early onset of symptom is older for female than for male. Almost all patients have symptom in varying degrees, some of them have near-syncope or syncope.     

特发性右心室流出道室性心动过速/室性早搏的性别、年龄和临床特点

Objective The aim of this study was to clarify gender,age and clinical feature of idiopathic right ventricular outflow tract ventricular tachycardia/premature ventricular complexes(ROVT/PVC). Methods We studied 478 patients[mean age(39. 8 ± 13. 8)years]with idiopathic ROVT/PVC who were admitted to our center consecutively in past 15 years. All of them underwent catheter mapping and radiofrequency catheter ablation (RFCA), and the original sites of ventricular tachycardia/premature ventricular complexes were confirmed by catheter mapping and radiofrequency catheter ablation. Results Of 478 patients, 288 patients (60. 3% )were female, 190 patients(39. 7% )were male, female/male ratio was 1.52. The early onset of symptom was at (41.2 ± 12. 7 ) years for female, and ( 37.6 ± 15. 0) years for male ( P ＜ 0. 05 ). Almost all patients had palpitation in varying degrees. Sixty-seven of 478 patients( 14.2% ) had history of near-syncope,and 13 of 478 patients(2. 7% )had history of syncope. Two hundred and sixty-three patients( 55% )underwent unsuccessful treatment with antiarrhythmic drugs before the radiofrequency ablation. Of them, 110 patients (23%)had received one kind of antiarrhythmic drug, 104 patients (21.8%)had received two types of antiarrhythmic drugs,49 patients( 10. 3% )had received three types of antiarrhythmic drugs. Conclusion ROVT/VPC occur more in female than in male,the early onset of symptom is older for female than for male. Almost all patients have symptom in varying degrees, some of them have near-syncope or syncope.     

三维电解剖标测指导疑难右侧游离壁旁路的导管消融

Objective To demonstrate the electroanatomic substrates of right-sided free wall (RFW)accessory pathways (APs) which were refractory to conventional catheter ablation utilizing three-dimensional (3D) mapping. Methods Seventeen patients with RFW APs that failed initial conventional catheter ablation(s)by a mean of 1～3(1.8±0.6) attempts were enrolled in the study. Electroanatomic mapping of the right atrium was performed during right ventricular pacing in 14 patients and orthodromic reciprocating tachycardia in 3patients. Radiofrequency energy was delivered via irrigation catheter to the earliest atrial activation site. Results The earliest atrial activation site, which represented the atrial insertion of the APs, was separated from the tricuspid annulus by an average of 9 ～ 20 ( 13.6 ± 3.4 ) mm, and the local activation time was 18 ～ 80(31.5±16.3) ms earlier than that of the corresponding annular point. The target electrogram demonstrated AP potential in fourteen patients and ventriculoatrial fusion in the rest three. Accessory pathway was blocked in one case during moving the catheter and RF ablation delivery on the areas. One patient exhibited an AP with wide branching on the atrial side during mapping. RF ablation with an irrigated catheter successfully interrupted AP conduction in remaining 16 patients without complications. After a mean follow-up of 3 ～ 41 (18.6±12.7) months, there were no recurrences of ventricular preexcitation or episodes of tachycardia. Conclusion RFW APs refractory to conventional catheter ablation might be due to unique anatomic AP features such as more epicardial course at the annulus level with atrial insertion distance from the tricuspid annulus. Electroanatomic mapping is helpful to accurately localize the atrial insertion sites of these APs and facilitates catheter ablation.     

Radiofrequency catheter ablation of atrial tachycardias related to myocardial scar or incision

Objectives Intra-atrial re-entrant tachycardias(IARTs)are common late after heart surgery.Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops.In this study we aimed to evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia(AT)induced by myocardial scar or incision.Methods In 6 patients(three male and three female,aged 33.3±11.8 years)who had AT related to myocardial scar or incision, electrophysiological study and radiofrequency catheter ablation(RFCA)were performed.Earliest activation combined with entrain- ment mapping was adopted to determine a critical isthmus.Results Re-entry related to the lateral atriotomy scar was inducible in 5 of 6 patients.With entrainment mapping,the PPI(post-pacing interval)-TCL(tachycardia cycle length)difference was＜30 ms when pacing at the inferior margins of the right lateral atriotomy scar.Among them,3 patients had successful linear ablation between scar area to inferior vena cava,and 2 patients between scar area to tricuspid annulus.Re-entry involving an ASD patch was demonstrated in 1 of 6 patients.PPI-TCL differences＜30 ms were observed when entraining tachycardia at sites near the septal patch.But linear ablation failed in terminating AT.There was no complication during procedure.No recurrence of AT related to incision was observed during follow-up except for the failed patient.Conclusion Under conventional electrophysiological mapping,adopting linear ablation from scar area to anatomic barrier,successful ablation can be obtained in patients with IRATs related to myocardial scar or incision.     

Contact force distribution and the value of contact force catheter during pace-map in right ventricular outflow tract

Backgrounds Whether the contact force(CF)-sensing catheter could improve the efficiency of pace mapping(PM) in right ventricle outflow tract(RVOT) has not been fully studied.The present study was the first investigation of the CF distribution in the right ventricle(RV) by using a CF-sensing catheter and the relationship between CF and capture threshold in RVOT.Methods In total, 4543 mapping points with CF were recorded in 15 patients.Operators were blinded to CF data and data were analyzed according to 10 predefined RV segments.PM were performed at 6 different RVOT segments with 3 different intentional CF levels and 3 different pacing setup.The pacing threshold in RVOT and pacing capture level were recorded.The morphology matching score were recorded and analyzed.Results Median CF during RV mapping was 8(5-12) g and coefficient of variation was 71.64%.Median CF ranged from 9.5(5.8-16) g at the posterior-outflow tract freewall(OTFW) to 7(4-10) g at the apex.Distribution of CF ≥20 g in RV predefined segments mainly located in the OTFW.Distribution of CF ≤2 g in RV predefined segments mainly located in the inflow tract freewall(ITFW), anterior-OTFW, and apex.A total of 810 pacing were performed at RVOT with different CF and output.Stable capture rate could be significantly improved via increasing CF level under 2 mA output(46.7%/2-5 g vs.50%/6-9 g vs.91.1%/≥10 g), and no capture rate could be significantly declined simultaneously(16.7%/2-5 g vs.8.9%/6-9 g vs.2.2%/≥10 g).Conclusions A marked variability in CF was observed among the different predefined segments.CF mapping could improve the safety and efficacy of catheter ablation of premature ventricular contraction(PVC)/ventricular tachycardia(VT) in RV.CF was an essential factor in RVOT pace mapping process, especially under low-pacing output.[S Chin J Cardiol 2021;22(1):21-29]     

Fast Rate (≥ 250 bpm) Right Ventricular Burst Stimulation is Useful for Ventricular Tachycardia Induction in Arrhythmogenic Right Ventricular Cardiomyopathy

Background One of the major challenges in arrhythmogenic right ventricular cardiomyopathy (ARVC) ablation is ventricular tachycardia (VT) non-inducibility. The study aimed to assess whether fast rate (≥ 250 beats/min) right ventricular burst stimulation was useful for VT induction in patients with ARVC. Methods Ninety-one consecutive ARVC patients with clinical sustained VT that underwent electrophysiological study were enrolled. The stimulation protocol was implemented at both right ventricular apex and outflow tract as follows: Step A, up to double extra-stimuli; Step B, incremental stimulation with low rate (< 250 beats/min); Step C, burst stimulation with fast rate (≥ 250 beats/min); Step D, repeated all steps above with intravenous infusion of isoproterenol. Results A total of 76 patients had inducible VT (83.5%), among which 49 were induced by Step C, 15 were induced by Step B, 8 and 4 by Step A and D, respectively. Clinical VTs were induced in 60 patients (65.9%). Only two spontaneously ceased ventricular fibrillations were induced by Step C. Multivariate analysis showed that a narrower baseline QRS duration under sinus rhythm was independently associated with VT non-inducibility (OR: 1.1; 95% CI: 1.0–1.1; P = 0.019). Conclusion Fast rate (≥ 250 beats/min) right ventricular burst stimulation provides a useful supplemental method for VT induction in ARVC patients.     

递进式消融法治疗持续性心房颤动的初步体会

Objective To evaluate the effect of catheter ablation on persistent atrial fibrillation (AF) using step-wise approach. Methods Thirty-four patients [mean age (54.8 ± 11.4) years] with persistent AF [mean (36.5 ± 9.8) months] underwent catheter ablation were enrolled. Ablation was performed in following sequence. Circumferential ablation of pulmonary veins to achieve isolation, linear ablation of left atrium roof and mitral isthmus, ablation at sites possessing complex fractionated atrial electrograms. Using activation Carto mapping system, if AF converted to atrial flutter (AFL) or atrial tachycardia (AT), then catheter ablation was applied to terminate tachycardia. Results The step-wise ablation approach was successful in rhythm changes (AF converted to AFL/AT) in 88.2% of patients, 61.8% of patients conversion to sinus rhythm directly via ablation. At 12.6 ±6.2 months of follow-up, 82.4% of patients were maintained in sinus rhythm (42.9% of those patients taking oral amiedarone). Conclusion Catheter ablation using step-wise approach is effective in persistent AF treatment.     

递进式消融法治疗持续性心房颤动的初步体会

Objective To evaluate the effect of catheter ablation on persistent atrial fibrillation (AF) using step-wise approach. Methods Thirty-four patients [mean age (54.8 ± 11.4) years] with persistent AF [mean (36.5 ± 9.8) months] underwent catheter ablation were enrolled. Ablation was performed in following sequence. Circumferential ablation of pulmonary veins to achieve isolation, linear ablation of left atrium roof and mitral isthmus, ablation at sites possessing complex fractionated atrial electrograms. Using activation Carto mapping system, if AF converted to atrial flutter (AFL) or atrial tachycardia (AT), then catheter ablation was applied to terminate tachycardia. Results The step-wise ablation approach was successful in rhythm changes (AF converted to AFL/AT) in 88.2% of patients, 61.8% of patients conversion to sinus rhythm directly via ablation. At 12.6 ±6.2 months of follow-up, 82.4% of patients were maintained in sinus rhythm (42.9% of those patients taking oral amiedarone). Conclusion Catheter ablation using step-wise approach is effective in persistent AF treatment.     

递进式消融法治疗持续性心房颤动的初步体会

Objective To evaluate the effect of catheter ablation on persistent atrial fibrillation (AF) using step-wise approach. Methods Thirty-four patients [mean age (54.8 ± 11.4) years] with persistent AF [mean (36.5 ± 9.8) months] underwent catheter ablation were enrolled. Ablation was performed in following sequence. Circumferential ablation of pulmonary veins to achieve isolation, linear ablation of left atrium roof and mitral isthmus, ablation at sites possessing complex fractionated atrial electrograms. Using activation Carto mapping system, if AF converted to atrial flutter (AFL) or atrial tachycardia (AT), then catheter ablation was applied to terminate tachycardia. Results The step-wise ablation approach was successful in rhythm changes (AF converted to AFL/AT) in 88.2% of patients, 61.8% of patients conversion to sinus rhythm directly via ablation. At 12.6 ±6.2 months of follow-up, 82.4% of patients were maintained in sinus rhythm (42.9% of those patients taking oral amiedarone). Conclusion Catheter ablation using step-wise approach is effective in persistent AF treatment.     

Idiopathic verapamil-sensitive left ventricular tachycardia complicated by right ventricular outflow tract ventricular tachycardia and ventricular fibrillation.

Idiopathic ventricular tachycardias (VTs) are generally divided into those arising from the right ventricle and those arising from the left ventricle. There has been few reports of two morphologically distinct VT occurring in patients with no apparent structural heart disease. We report a patient with verapamil-sensitive left VT with a right bundle branch block pattern that spontaneously changed to VT with a left bundle branch block pattern. Ventricular fibrillation was induced by the application of programmed stimulation. Although it is unclear if our patient with pleomorphic VT has ventricular vulnerability, it is necessary to investigate further and follow him carefully.     

Isolated left ventricular noncompaction mimicking ventricular mass

Isolated left ventricular noncompaction is an inherited cardiomyopathy characterized by multiple prominent trabeculations with deep intertrabecular recesses. The diagnosis is often missed because echocardiography poses inherent problems of poor echo window in assessment of the LV apex, which is most commonly involved in noncompaction. We report a case in which conventional 2D echocardiography failed to demonstrate multiple prominent trabeculations. Contrast echocardiography confirmed the presence of multiple trabeculations with deep intertrabecular recesses. This report emphasizes the importance of contrast echocardiography in the diagnosis of ventricular noncompaction.     

Congenital ventricular diverticulum associated with ventricular tachycardia

Congenital ventricular diverticula are rare. Clinically, they may be asymptomatic or cause systemic embolization, heart failure, valvular regurgitation, ventricular rupture, ventricular arrhythmia, or sudden death. We report the case of a 56-year-old woman with sustained ventricular tachycardia, who, during investigation, was diagnosed with a diverticulum in the inferobasal portion of the left ventricle. The clinical characteristics and treatment of this rare disease are discussed.