Timing of positive head-up tilt test for patients with suspected vasovagal syncope / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the time course of positive head-up tilt test (HUTT) for patients with suspected vasovagal syncope.</p><p><b>METHODS</b>Consecutive patients referred to the syncope unit of our center for recurrent unexplained syncope were included. The HUTT consisted of a 30 minute passive basic phase and a 20 minute sublingual nitroglycerin provocation phase if syncope did not develop during the passive phase.</p><p><b>RESULTS</b>Positive HUTT was observed in 427 out of 773 consecutive patients (55.2%) patients including 43 patients (10.1%) during the passive basic phase and 384 patients (89.9%) during the nitroglycerin provocation phase. During the basic phase, the positive Hutt developed at 7.5 minute (n = 2) and peaked at 22.5th minute (20.9%, n = 9) and then decreased gradually. Most positive reactions (93.0%, n = 40) occurred between the 10 and 25 minutes during the basic phase. During the nitroglycerin provocation phase, the percentage of positive reactions increased rapidly after sublingual nitroglycerin, peaked at the 10th minute (35.7%, n = 137) and decreased thereafter. Most positive reactions (96.1%, n = 369) occurred within the first 15 minutes of provocation phase.</p><p><b>CONCLUSION</b>The appropriate duration for HUTT test could be modified to a 25 minutes passive basic phase plus 15 minutes nitroglycerin provocation phase.</p>

Single dose of ibutilide for conversion of persistent atrial fibrillation after radiofrequency ablation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Patients with persistent or permanent atrial fibrillation (AF) often need direct current cardioversion after radiofrequency ablation. The aim of this study was to investigate the effectiveness and safety of ibutilide for cardioversion of persistent or permanent atrial fibrillation after radiofrequency ablation and the factors related to conversion.</p><p><b>METHODS</b>Patients with persistent or permanent atrial fibrillation were treated with combined ablation strategy including circumferential pulmonary vein isolation, linear ablation and CAFÉ potential ablation. If AF was not terminated after ablation, ibutilide was used for cardioversion (1 mg, intravenous injection in 10 minutes). These patients were divided into a conversion group and a non-conversion group according to whether AF was converted to sinus rhythm within 30 minutes after administration. ECG monitoring was performed during the injection of ibutilide. Atrial waves recorded by coronary sinus electrodes were measured for calculating average wavelength of AF waves in six seconds. The QT interval was measured immediately after conversion and 2 hours after injection of ibutilide.</p><p><b>RESULTS</b>Forty patients whose AF was not converted to sinus rhythm after radiofrequency ablation were given an intravenous injection of ibutilide. Of the 40 patients, 29 cases were converted to sinus rhythm, with a conversion rate of 72.5%. The average conversion time was (13.2 ± 5.5) minutes. Compared with the conversion group, patients in the non-conversion group had a longer history of AF (9.4 ± 5.3) years vs. (4.3 ± 2.8) years, P < 0.05), and a markedly enlarged left atrium (47.3 ± 2.9) mm vs. (42.1 ± 4.5) mm, P < 0.05). There were no significant differences in gender, age, body mass index and left ventricular function between the two groups. Ibutilide significantly prolonged the average wavelength of the AF wave (171.8 ± 29.5) ms vs. (242.0 ± 40.0) ms, P < 0.001). Two hours after ibutilide treatment, the QT interval was significantly shortened (421.0 ± 24.7) ms vs. (441.0 ± 37.4) ms, P < 0.05). No cases of serious arrhythmias or other adverse reactions were found.</p><p><b>CONCLUSIONS</b>A single dose of ibutilide for conversion of persistent or permanent AF after radiofrequency ablation is safe and effective.</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>

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>

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>

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>