Radiofrequency catheter ablation of the premature ventricular contractions originating from His bundle region / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the electrocardiogram and 3-dimensional electroanatomic mapping features and radiofrequency catheter ablation efficacy of patients with premature ventricular contractions (PVCs ) originating from His bundle region.</p><p><b>METHODS</b>Between February 2009 and February 2011, 10 consecutive patients ( 4 male, aged from 19 to 59 years) who underwent ablation for frequent PVCs originating close to His bundle region in our department were included. Electroanatomic mapping of RVOT and ASC, ablation was performed with the 7F 4-mm-tip ablation catheter.</p><p><b>RESULTS</b>Among these 10 patients with PVCs originating from His bundle region, 6 originated from the RVOT, 1 from NCC and 3 from RCC. Eight patients showed LBBB morphology,1 patient with PVCs originated from RCC and 1 patient with PVCs originated from NCC showed RBBB morphology. At the successful ablation sites, local ventricular activation v wave was detected 22-52 (32.6 ± 10.2) ms earlier than the QRS wave in the surface electrocardiogram. The distance between target and His bundle was 5.0-8.4(7.0 ± 1.1)mm. Ablation was successful in all 10 patients without complications (PVCs < 500 beats/24 h post ablation).</p><p><b>CONCLUSION</b>PVCs originating near the His bundle have similar electrocardiographic and electrophysiological characteristics for PVSc originated from the RVOT or ASC. Because of the close anatomical relationship between RVOT and ASC, it is necessary to mapping both RVOT and ASC to accurately identify the site of PVCs origin and to guild successful ablation.</p>

Value of identifying the slow conduction zone of idiopathic left ventricular tachycardia by electroanatomic mapping / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the value of identifying slow conduction zone(SCZ) of idiopathic left ventricular tachycardia(ILVT) by electroanatomic mapping.</p><p><b>METHODS</b>Twelve patients with ILVT were mapped by a 3-dimensional electroanatomic (EA) mapping system. Left posterior fascicular potential (PP) and the SCZ with diastolic potential (DP) in LV during sinus rhythm (SR) and ventricular tachycardia (VT) were mapped after a three-dimensional endocardial geometry of the left ventricular was established. Then we investigated the electrophysiological and anatomic characteristics of SCZ.</p><p><b>RESULTS</b>EA mapping was successfully performed in 9 patients during SR and VT, and in 3 patients during VT. The SCZ with DP was located at the inferoposterior septum, and the length of the SCZ was (25.1 ± 2.2) mm with a conduction velocity of (0.08 ± 0.01) m/s. There was no difference in these parameters between patients during SR and VT (P > 0.05). There was one area with PP located at the posterior septum. The areas with both DP and PP were found in 9 patients during SR and VT. In addition, this area was coincided with such area during VT during SR and radiofrequency ablation targeting the site within the area abolished VT in all patients.</p><p><b>CONCLUSIONS</b>The ILVT substrate within the junction area of the SCZ and the posterior fascicular can be identified by EA mapping and used to guide the ablation of ILVT.</p>

Preferential conduction to right ventricular outflow track leads to left bundle-branch block morphology in patient with premature ventricular contraction originating from the aortic sinus cusp / 中华心血管病杂志

<p><b>OBJECTIVE</b>The purpose of this study was to explore the relationship between originate and breakout and radiofrequency catheter ablation strategy in patients undergoing radiofrequency ablation for premature ventricular contractions originating from the aortic sinus cusp (ASC) using 3-dimensional electro anatomic mapping.</p><p><b>METHODS</b>This study included 21 consecutive patients (10 male) underwent ablation for frequent PVCs originating from ASC in our hospital between May 2009 and February 2012. Electro anatomic mapping and ablation of right ventricular outflow track (RVOT) and left ventricular outflow track (LVOT) were performed with the 7F 4-mm-tip ablation catheter from right femoral vein and artery. Activation mapping and pacing mapping were performed in all patients.</p><p><b>RESULTS</b>Ablation was successful in all 21 patients successful ablation target in left coronary sinus cusp (LCC, n = 17), in right coronary sinus cusp (RCC, n = 2) and in noncoronary sinus cusp (NCC, n = 2). Seven patients showed a RBBB morphology (group A) and 14 patients showed a LBBB morphology (group B). In group A, earliest ventricular activation (EVA) was recorded 22 - 34 (27.4 ± 4.6) ms earlier before QRS at the site of catheter ablation in ASC. In group B, EVA was later in RVOT than that in ASC in 5 patients and EVA at the site of catheter ablation in RVOT and ASC was 22 - 28 (25.2 ± 2.7) ms and 26 - 40 (32.8 ± 5.2) ms, respectively (t = -3.6, P = 0.024) while EVA was earlier in the remaining 9 patients and EVA recorded in RVOT and ASC was 22 - 38 (28.7 ± 5.9) ms and 18 - 28 (22.7 ± 3.6) ms, respectively (t = 3.8, P = 0.005).</p><p><b>CONCLUSION</b>Patients with premature ventricular contractions originating from the ASC often show preferential conduction to the RVOT, which may explain the LBBB morphology of ECG in these patients.</p>

Management of refractory ventricular tachycardia in patients with non-myxomas primary cardiac tumors / 中华心血管病杂志

<p><b>OBJECTIVE</b>To summarize the clinical characteristics and treatment experience of patients with non-myxomas primary cardiac tumors accompanied with refractory ventricular tachycardia (VT).</p><p><b>METHODS</b>Clinical and imaging data as well as therapy efficacy and outcome were analyzed in 10 patients with non-myxomas primary cardiac tumors accompanied with refractory VT.</p><p><b>RESULTS</b>There were 5 male and 5 female patients in this cohort [mean age (37.6±18.2) years]. Palpitation was presented in all 10 patients, 7 patients experienced syncope, and 2 patients suffered from amaurosis. The diagnosis was made by combined use of transthoracic echocardiograms, MRI, and CT scan. The time from symptom to diagnosis was (33.2±36.7) months. Symptom-related VT was documented by ECG or Holter monitoring. MRI suggested lipoma in 7 patients, lymphoma in 1 patient and fibroma in another patient. Seven tumors were located in the left ventricle, 1 in right atria, 1 at peri-aortic root and 1 near right ventricular outflow tract. Nine out of 10 patients received anti-arrhythmic drug therapy. The ventricular tachyarrhythmia disappeared after surgical tumor resection in 4 patients. All other patients who were treated with antiarrhythmic drugs, radiofrequency ablation or subtotal excision showed only suboptimal efficacy during (39.4±25.1) months follow-up.</p><p><b>CONCLUSION</b>Surgical tumor removal is the best treatment strategy for the treatment of refractory ventricular tachycardia in patients with primary cardiac benign tumors.</p>

Improvement of P-wave dispersion is associated with a lower incidence of atrial fibrillation after cardiac resynchronization therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>P-wave dispersion (PWD) is a useful predictor of paroxysmal atrial fibrillation (AF). The effect of cardiac resynchronization therapy (CRT) on PWD and the prognostic implications of the improvement in PWD remain undefined. The aim of the study was to explore the clinical significance of the improvement of PWD after CRT.</p><p><b>METHODS</b>Electrocardiographic studies were performed before and three months after CRT in 81 patients (57 men and 24 women; age (60.5 ± 11.2) years) with standard CRT indication but no history of AF. A significant improvement of PWD (PWD responder) was defined as a relative decrease ≥ 20% from baseline PWD. The primary endpoints were new-onset AF detected by electrocardiogram (ECG) or CRT.</p><p><b>RESULTS</b>After (30.6 ± 7.5) months of follow-up, PWD responders (n = 43) had a significantly lower incidence of AF than did PWD nonresponders, 12% vs. 29% (P < 0.001). In Cox proportional hazard analysis, PWD responders was the only predictor of lower risk of new-onset AF (HR 0.33, 95% confidence interval 0.12 - 0.96, P = 0.033).</p><p><b>CONCLUSION</b>Improvement of P-wave dispersion after CRT was associated with a lower incidence of AF, which may be related to the significant improvement in left ventricular systolic function and the reverse modeling of the left atrium.</p>

Right phrenic injury after radiofrequency catheter ablation of atrial tachycardia at crista terminalis / 中华医学杂志(英文版)

A 62-year-old woman with frequent occurrence of symptomatic atrial tachycardia with a foci located at the root of the upper crista terminalis was found to have right diaphragm paresis after receiving a total of 8 radiofrequency energy deliveries (40-60 W, 50-60ºC) and a total duration of 540 seconds of ablation therapy (7Fr 8 mm deflectable ablation catheter). The right diaphragm paresis remained resolved up to 14 months after the procedure as confirmed by repeated chest X-rays.

Association between abnormal electrocardiographic features and disease severity in patients with arrhythmogenic right ventricular cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze the relationship between electrocardiographic (ECG) features and disease severity in patients with the arrhythmogenic right ventricular cardiomyopathy (ARVC).</p><p><b>METHOD</b>The study group consisted of 61 subjects with a definite diagnosis of ARVC on the basis of published guideline criteria and patients were divided into 3 subgroups according to the extent of diseased myocardium defined by cardiac magnetic resonance imaging (MRI): Group A: local involvement (n = 19, 31%), Group B: diffuse involvement of whole right ventricle (n = 28, 46%) and Group C: involvement of both right and left ventricles (n = 14, 23%).</p><p><b>RESULTS</b>Normal electrocardiogram was shown in 1 patient in each group. Epsilon wave was detected in 24 (39%) patients, QRS duration was prolonged [≥ 110 ms (V(1)-V(3))] in 21 (34%) patients, S-wave upstroke was prolonged (≥ 55 ms) in 17 (28%) patients, complete right branch bundle block was evidenced in 10 (16%) patients and pathologic Q waves was found in 9 (15%) patients. The incidence of above abnormal ECG changes was increased in proportion to the degree of disease severity (group A < group B < group C). Incidence of Epsilon wave and prolonged QRS duration [ ≥ 110 ms (V(1)-V(3))] were significantly higher in Group C than in Group A. Incidence of prolonged S-wave upstroke (≥ 55 ms) was significantly higher in Group C than in Group A and Group B. T-wave inversion in V(1) leads was often found in Group A. T-wave inversion in inferior leads (V(1)-V(3) leads or beyond V(3)) was often presented in Group B and Group C.</p><p><b>CONCLUSIONS</b>Normal ECG does not exclude the possibility of diagnosis of ARVC. The extent of T-wave inversion in the precordial leads and incidence of Epsilon wave, prolonged QRS duration [ ≥ 110 ms (V(1)-V(3))] and prolonged S-wave upstroke (≥ 55 ms) were related to degree of disease severity in patients with ARVC.</p>

Association between electrocardiogram characteristics and long-term outcome in patients with idiopathic ventricular fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the association between clinical and ECG characteristics and prognoses in patients with idiopathic ventricular fibrillation (VF).</p><p><b>METHODS</b>We reviewed the data from 21 VF patients [male 47.6%, mean age (38.5 ± 19.0) years] with first event of VF, all patients were resuscitated after cardiac arrest and diagnosed as idiopathic VF. The prevalence of J wave was assessed and patients were divided into J wave positive (J+ group) and negative group (J- group). The end point was death or syncope from arrhythmia, and recorded VF recurrence during the follow-up.</p><p><b>RESULTS</b>J wave was frequent in subjects with idiopathic VF (71.4%). Among patients in the J+ group (15 cases), notch on the QRS wave was found in 7 subjects (46.7%), these patients were more likely to suffer from the sudden cardiac arrest during sleep at early morning than those with J wave but without notch on the QRS wave. Two patients dead suddenly in the J+ group and 1 dead from embolism in the J- group during follow-up [mean (42.4 ± 39.9) months]. The mean year-onset of VF or syncope was significantly higher in the J+ group than in the J-group [(1.3 ± 0.5) episodes/year vs. (0.4 ± 0.3) episodes/year, P < 0.01]. J wave positive was also associated with an increased risk of VF recurrence (RR 1.9, 95%CI 1.1 to 2.9, P = 0.03).</p><p><b>CONCLUSION</b>J wave prevalence is high in patients with history of idiopathic VF, and positive J wave is associated with high risk of recurrence of sudden cardiac death.</p>

Decrease of plasma N-terminal pro beta-type natriuretic peptide as a predictor of clinical improvement after cardiac resynchronization therapy for heart failure / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>N-terminal pro beta-type natriuretic peptide (NT pro BNP) has been shown to predict the prognosis and could guide the treatment of heart failure. We aimed to investigate the values of NT pro BNP in predicting the clinical response to cardiac resynchronization therapy (CRT).</p><p><b>METHODS</b>A total of 44 patients with chronic heart failure (34 male and 10 female, mean age of (58 +/- 13) years, New York Heart Association (NYHA) class 3.3 +/- 0.5, QRS duration (150 +/- 14) milliseconds) who underwent successful implantation of a CRT system were enrolled in this study. Pharmacotherapy remained stable during the first 3 months of follow-up. Plasma levels of NT pro BNP were evaluated before and 3 months after implantation. Clinical, echocardiographic and exercise parameters were monitored at each clinical visit after CRT implantation. Receiver operating characteristic analysis and a paired t test were performed to analyze the data.</p><p><b>RESULTS</b>After a mean of (16.3 +/- 5.5) months of follow-up, 11 nonresponders were identified. CRT resulted in a significant reduction in NT pro BNP ((1.70 +/- 1.28) vs (1.07 +/- 0.88) pmol/ml, P < 0.001) in responders. Percentage change in NT pro BNP level (DeltaBNP%) was a statistically significant predictor of long term clinical improvement at 3 months of follow-up.</p><p><b>CONCLUSIONS</b>DeltaBNP% from baseline to 3 months of follow-up is a predictor of long term response to CRT. NT pro BNP may be a simple method for monitoring the effects of CRT.</p>

Clinical study of 39 Chinese patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>There are few studies on the clinical profile of Chinese patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). The purpose of this study was to describe the clinical characteristics of ARVD/C patients from China, particularly to define the features of electrocardiograph and treatment outcomes.</p><p><b>METHODS</b>Thirty-nine patients hospitalized in Fu Wai Cardiovascular Hospital from 1998 to 2006 were included. The data were obtained from the medical archive and the follow-up records.</p><p><b>RESULTS</b>Of these patients 33 were male and 6 female (age at the first presentation was (34.9 +/- 9.8) years). The most common symptoms were palpitation (62%) and syncope (44%). Right precordial QRSd >or= 110 ms was detected in 69% of the patients, epsilon wave in 59%, and a ratio of QRSd in V(1) + V(2) + V(3)/V(4) + V(5) + V(6) >or= 1.2 in 82%. The most frequent features of electrocardiogram in patients without right bundle-branch block were T-wave inversions and S-wave upstroke in V(1)-V(3) >or= 55 ms (96% and 90% of 28 patients, respectively). Radiofrequency catheter ablation (RFCA) for ventricular tachycardia (VT) was successful in 15 (68%) of 22 patients. The recurrence rate of VT was 46% (7/15) during the follow-up of (16.7 +/- 11.2) months. Seven patients had cardioverter/defibrillator (ICD) implanted plus drug therapy and 17 patients took antiarrhythmic drugs alone. During the follow-up of (35.6 +/- 19.0) months, all patients with ICD implanted received at least one appropriate ICD shock. One patient died of ventricular fibrillation suddenly and one patient underwent heart transplantation for progressive biventricular heart failure during the drug therapy alone.</p><p><b>CONCLUSIONS</b>This study demonstrated the clinical and ECG features of the 39 ARVD/C Chinese patients. ICD provided life-saving protection by effectively terminating malignant arrhythmias, and the high recurrence of VT was the major problem of RFCA therapy.</p>

Radiofrequency catheter ablation of permanent atrial fibrillation under guidance of Carto merge technique / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effectiveness and advantages of the Carto merge technique in guiding radiofrequency catheter ablation (RFCA) of permanent atrial fibrillation (AF).</p><p><b>METHODS</b>A total of 15 patients with permanent AF underwent RFCA under guidance of the Carto merge technique. The virtual electroanatomical map of the left atrium (LA) and pulmonary veins (PVs) were reconstructed with Carto system during the procedure. Then the electroanatomical map was integrated with 3-D images of cardiac magnetic resonance angiography to form Carto merge map. Circumferential pulmonary vein ablation was performed first until complete PVs electric isolation confirmed by lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced. Finally direct current (DC) cardioversion were given if sinus rhythm did not return.</p><p><b>RESULTS</b>AF were terminated spontaneously during RFCA in 2 patients, and by DC cardioversion in the remaining 13 patients. Persistent AF recurred on 24 hours, first week, and 5th week, respectively in three patients. The remaining 12 patients were all free of AF during follow-up (1-10 months). The success rate was 80% in the study.</p><p><b>CONCLUSIONS</b>Carto merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping and enhance the success rate of RFCA of permanent AF.</p>

Clinical and ECG features of arrhythmogenic right ventricular cardiomyopathy: a retrospective analysis of 31 cases / 中华心血管病杂志

<p><b>OBJECTIVE</b>To retrospectively analyze the clinical and electrocardiographic features of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).</p><p><b>METHODS</b>The clinical, electrocardiographic features and the efficacy of various therapies were analyzed in 31 patients (27 males) diagnosed as ARVC according to the criteria established by European Society of Cardiology.</p><p><b>RESULTS</b>The averaged age when the ARVC was first diagnosed was (34.7 +/- 9.4) years (19 - 58 years), palpitation was present in 28 patients (90.3%) and syncope in 13 patients (41.9%), a family history of sudden death was present in 1 patient. Dilatated right ventricle was documented in 29 patients by echocardiography and (or) magnetic resonance imaging (MRI), 2 of them with dilated left ventricles. ECG changes included: T wave inversion, mostly seen in precordial leads (100%); epsilon (epsilon) wave (54.8%); QRS duration >or= 110 ms in V(1) to V(3) (83.9%); reduced extremity amplitude (41.9%); the first degree of AV block (22.6%); sustained VT (100%) including 15 monomorphic VT (48.4%) and 16 polymorphic VT (51.6%). The mean values of QRS duration in leads of V(1 - 3) [(120.8 +/- 13.7) ms] was significantly longer than that in V(4 - 6) [(99.4 +/- 13.7) ms, P < 0.05]. Fourteen patients underwent radiofrequency catheter ablation (RFCA) with an immediate success rate of 78.6% (11/14). During follow up (18.3 +/- 10.2) months, VT reoccurred in 6 patients (54.5%). The remaining 17 patients were treated with conventional medications, 7 of them were medicated under implanted cardioverter defibrillator (ICD). During the follow-up (35.6 +/- 19.0) months, VT reoccurred in 11 patients (64.7%) and one patient died suddenly.</p><p><b>CONCLUSIONS</b>ARVC patients developed symptoms at mid-30s with significant ECG changes including appearance of an epsilon wave, T wave inversion and QRS duration >or= 110 ms in leads of V(1 - 3). The long term therapy efficacy was not satisfactory both for RFCA and conventional medications and ICD implantation should be recommended to patients with ARVC.</p>

Radiofrequency catheter ablation of permanent atrial fibrillation under guidance of carto-merge technique / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the feasibility and effectiveness of radiofrequency catheter ablation (RFCA) to treat per-manent atrial fibrillation (AF) under the guidance of Carto-Merge technique.</p><p><b>METHODS</b>Fifteen male patients with permanent AF underwent RFCA under the guidance of Carto-Merge technique. The mean age was 54.00 +/- 10.44 years, and duration of AF was 23.66 +/- 14.93 months. Cardiac magnetic resonance angiography (MRA) was performed to obtain pre-procedural three-dimensional (3D) images on the anatomy of left atrium (LA) and pulmonary veins (PVs) before RFCA procedure. Then the electroanatomical map was integrated with 3D images of MRA to form Carto-Merge map that guided step-by-step ablation strategy of permanent AF. Circumferential PV ablation was performed first until complete PVs electric isolation confirmed by Lasso catheter. If AF was not terminated, lesion lines on roof of LA, mitral isthmus, and tricuspid isthmus were produced.</p><p><b>RESULTS</b>The episodes of AF were terminated during RFCA in 2 patients, by direct current cardioversion in the remaining 13 patients. Transient AF occurred in 2 patients after ablation on 1st day and 1st week respectively, AF terminated spontaneously not long after taking metoprolol. One patient developed persistent atrial flutter (AFL) in 2 months after procedure and AFL was eliminated by the second ablation. Persistent AF recurred on 1st day, 1st and 5th week respectively in 3 patients, and did not terminate after 3 months even though amiodarone was given. The remaining 12 patients were all free of AF during 2-11 months of follow-up. The recent success rate for RFCA of permanent AF was 80%.</p><p><b>CONCLUSIONS</b>Carto-Merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping, it can simplify the mapping, lower expenses, and enhance the success rate of RFCA of permanent AF.</p>

Left posterior fascicular block: a new endpoint of ablation for verapamil-sensitive idiopathic ventricular tachycardia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Verapamil-sensitive, idiopathic left ventricular tachycardia (ILVT) with right bundle branch block configuration and left-axis deviation is known to be due to re-entry mechanism but the exact nature of reentrant circuit in ILVT is not fully elucidated. Radiofrequency (RF) ablation was applied during ventricular tachycardia (VT) and termination of the VT or abolishing the inducibility of the tachycardia was used as an endpoint for successful RF. In this study, the left posterior fascicular block in surface electrocardiogram (ECG) was used as a new endpoint of ablation to cure ILVT.</p><p><b>METHODS</b>Electrophysiological studies and radiofrequency ablation were performed in 39 consecutive patients [30 men, 9 women; age ranging from 10 to 64 years, mean (29 +/- 16) years] with verapamil-sensitive ILVT and structurally normal hearts. VT could be terminated by the intravenous administration of verapamil in all patients. The target site was the midseptum of LV where the earliest Purkinje potentials were recorded during VT. RF current was applied to the target site with or without late diastolic potential (LDP) during sinus rhythm in 37 patients and during VT in 2 patients to meet the ablation endpoint: the left posterior fascicular block in the surface ECG.</p><p><b>RESULTS</b>Thirty-seven patients with ILVT had been treated by RF ablation during sinus rhythm and two had been treated during VT. All of them met the endpoint of the left posterior fascicular block. Thirty-eight cases were symptom-free without medications during the follow-up period (range from 3 to 95 months, median 17 months). One patient developed a clinical recurrence and the left posterior fascicular block in surface ECG disappeared. The patient received another treatment. The endpoint was met and the procedure was successful.</p><p><b>CONCLUSIONS</b>The left posterior fascicular block in surface ECG used as an endpoint of RF ablation to treat ILVT is effective. It is important especially in those patients whose VT can not be induced or the inducible condition is unstable. The effective endpoint implied that the left posterior fascicle might be a critical part of the re-entrant circuit.</p>

Radiofrequency catheter ablation at the left coronary cusp in treatment of repetitive monomorphic tachycardia of the left ventricular outflow tract / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The aim of this study was to clarify the electrocardiographic characteristics of repetitive monomorphic ventricular tachycardia (RMVT) originating from the left ventricular outflow tract, and to describe the results of treatment with radiofrequency catheter ablation (RFCA).</p><p><b>METHODS</b>Routine 12-lead surface electrocardiography and electrophysiological studies were performed on 11 RMVT patients with no organic heart disease, who were subsequently treated with RFCA directed at targets identified by pace mapping.</p><p><b>RESULTS</b>The surface electrocardiogram QRS characteristics of RMVT included an atypical left bundle branch block and right axis deviation, with a low amplitude "rs" or "rS" pattern in lead I, an "rS" or "RS" pattern in V1, and a precordial R wave transition zone in V2 or V3. In 1 patient, a small S wave was observed in V5. Using pace mapping techniques, we selected the left coronary cusp as the ablation target. RMVT was eliminated in all 11 patients immediately after radiofrequency energy delivered. During a follow-up of 13 +/- 7 months, RMVT recurred in only 1 patient.</p><p><b>CONCLUSION</b>RMVT originating from the left ventricular outflow tract has specific electrocardiographic characteristics, and can be successfully and safely cured using RFCA directed at the left coronary cusp.</p>

The automaticity of Mahaim fibre and its response to effective ablation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Typical accessory pathways (APs) of Wolf-Parkinson-White syndrome have been widely discussed in recent decades. However, the characteristics of the special AP, Mahaim fibre, are not so clear. It is known that these fibres have antegrade conduction only, long conduction time, decremental node-like conduction and automaticity properties. This study was to elucidate the automaticity of Mahaim fibre and its response to effective ablation.</p><p><b>METHODS</b>Thirteen patients with Mahaim fibre (ten atrioventricular and three atriofascicular accessory pathways) were subjected to electrophysiological study and radiofrequency ablation via catheter. The incidence and characteristics of anautomatic rhythm originating from Mahaim fibre were observed during the whole procedure, especially during radiofrequency current delivery.</p><p><b>RESULTS</b>Repetitive and short-run automatic rhythm (rate: 65-72 beats per minute), with a QRS morphology similar to that of clinical pre-excited atrioventricular re-entrant tachycardia (AVRT), occurred in two patients during sinus rhythm. Conduction via Mahaim fibre was successfully eliminated by radiofrequency current. Fourteen applications of RF were associated with irregularly accelerated automatic tachycardia of Mahaim fibre (with a sensitivity of 78%), lasting for 1.2-14 seconds. However, such automatic tachycardia of Mahaim fibre did not occur during 54 failed applications of radiofrequency current.</p><p><b>CONCLUSIONS</b>Mahaim fibre has the function of automaticity. The accelerated automatic tachycardia of Mahaim fibre occur red during radiofrequency catheter ablation can be used as a predictor for successful procedure.</p>