Different clinical courses and predictors of atrial fibrillation occurrence after transisthmic ablation in patients with preablation lone atrial flutter, coexistent atrial fibrillation, and drug induced atrial flutter

The aim of this prospective study was to compare the long-term follow-up after transisthmic ablation of patients with preablation lone atrial flutter, coexistent AF, and drug induced atrial flutter to determine if postablation AF followed a different clinical course and displayed different predictors in these groups. The study evaluated 357 patients who underwent transisthmic ablation for typical atrial flutter. These were divided into four groups according to their preablation history. Group A included patients with typical atrial flutter and without preablation AF (n=120, 33.6%). Group B included patients with preablation AF and spontaneous atrial flutter (n=132, 37.0%). Group C patients had preablation AF and atrial flutter induced by treatment with IC drugs (propafenone or flecainide) (n=63, 17.6%) Group D included patients with preablation AF and atrial flutter induced by treatment with amiodarone (n=42, 11.8%). During a mean follow-up of 15.2 double dagger 10.6 months (range 6-55 months) AF occurred more frequently in groups B (56.1%) and C (57.1%) patients than in groups A (20.8%, P <0.0001) and D (31.0%, P <0.0001) patients. The results of multivariate analysis revealed that different clinical and echocardiographical variables were correlated with postablation AF occurrence in the different groups. Patients with atrial flutter induced by amiodarone have a significantly lower risk of postablation AF than patients with spontaneous atrial flutter and AF, and those with atrial flutter induced by IC drugs. Different clinical and echocardiographical variables predict postablation AF occurrence in different subgroups of patients.     

Inhibition of bradycardia pacing and detection of ventricular fibrillation due to far-field atrial sensing in a triple chamber implantable cardioverter defibrillator

Oversensing of intracardiac signals or myopotentials may cause inappropriate ICD therapy. Reports on far-field sensing of atrial signals are rare, and inappropriate ICD therapy due to oversensing of atrial fibrillation has not yet been described. This report presents a patient with a triple chamber ICD and a history of His-bundle ablation who experienced asystolic ventricular pauses and inappropriate detection of ventricular fibrillation due to far-field oversensing of atrial fibrillation. Several factors contributed to the complication, which resolved after reduction of the ventricular sensitivity.     

Inappropriate detection and therapy from an implantable cardioverter defibrillator due to atrial undersensing

We present a case of inappropriate detection and therapy in a patient with an implantable cardioverter defibrillator. The device interpreted a supraventricular tachycardia as ventricular tachycardia due to unsensed P waves as a result of a relatively high level of atrial sensitivity setting. Subsequently, inappropriate therapy was delivered. The problem was resolved by decreasing the atrial sensitivity value.     

Quality of life and occurrence of atrial fibrillation in long-term follow-up of common type atrial flutter ablation:

Objectives The ablation of common type atrial flutter is mainly performed by two approved techniques, whose efficacy and outcome in terms of quality of life have not been evaluated so far in a long-term follow-up study over years. A high proportion of patients suffer from coexistent atrial fibrillation, which may worsen the ablation result. The question arises whether one technique is more effective than the other when immediate ablation results, the occurrence of atrial fibrillation and the quality of life are compared. Considering these facts, it is reasonable to think about new ablation strategies for common type atrial flutter in the era of new concepts in catheter ablation of atrial fibrillation. Methods In a retrospective study we evaluated a detailed questionnaire in 132 patients who underwent ablation of common type between 1999 and 2004. Radiofrequency ablation was performed irrespective of coexistent atrial fibrillation either with an irrigated tip or the 8 mm tip electrode. Acute and long-term ablation outcome, and the associated quality of life, pre-, under- and post-ablation was compared in the two different ablation groups. Recurrent tachycardia were re-evaluated by 12 lead ECG analysis and assessed for both ablation groups. Results 88 (67%) of the 132 patients contacted answered the questionnaire polling the perceived benefits of the procedure. Of the other 44 patients (33%); 4 (3%) had died, 7 (5.3%) had moved, 33 patients (25%) could not be included due to missing or incoherent answers. Independent of the ablation technique there was a high acute and long-term ablation success rate at about 95%. After a mean of 3 years of follow-up this benefit persists in spite of a high proportion of recurrent tachycardia, mainly atrial fibrillation (55/88 patients, 59.1%). Despite the occurrence of secondary tachycardia, there was a high significant long-term symptomatic benefit in the state of healthy and daily practice work, evaluated with a p-value of < 0.0005. The frequency of episodes and the symptom "tachycardia" were significantly reduced after effective ablation of common type atrial flutter, p-values of 0.003 and 0.002, respectively. Therefore the need for hospitalization was significant reduced (p = 0.001). Comparison of both approaches revealed that there was no significant difference related to the incidence and occurrence of atrial fibrillation. Conclusions The two mainly accepted and applied techniques for the ablation of common type atrial flutter show an excellent outcome under the aspect of ablation efficacy and quality of life in longterm follow-up. Three years after the ablation procedure the majority of patients consider the intervention beneficial. Despite the relatively high appearance of atrial fibrillation in the long-term follow-up this effect is still traceable.     

Mechanism of spontaneous transition from typical atrial flutter to atrial fibrillation: role of ectopic atrial fibrillation foci

Paroxysmal AF has been known to be initiated by ectopic beats, especially in the pulmonary veins (PVs), and radiofrequency catheter ablation could cure it. We considered that the spontaneous transition from typical atrial flutter to AF also could be initiated by ectopic beats. Twenty patients (18 men, mean age 66 +/- 14 years) with episodes of spontaneous transition from typical atrial flutter to AF were included in this study. They underwent detailed mapping of both atria. All the patients had spontaneous AF initiated by ectopic beats, and all of them had typical atrial flutter and spontaneous transition from typical atrial flutter (12 patients with counterclockwise atrial flutter and 8 patients with clockwise atrial flutter) to AF. The transition was initiated by ectopic beats from the PVs (17 foci, 85%), crista terminalis (2 foci, 10%), and superior vena cava (1 focus, 5%). After successful ablation of AF foci, typical atrial flutter was induced again, but no spontaneous transition was found after at least 10 minutes of observation. We concluded that paroxysmal AF and spontaneous transition from typical atrial flutter to AF were initiated by ectopic beats, and successful catheter ablation of the ectopic foci can eliminate paroxysmal AF and spontaneous transition from typical atrial flutter to AF.     

T-wave oversensing by an implantable cardioverter defibrillator after successful ablation of idiopathic ventricular fibrillation

Focal ablation of trigger premature ventricular complexes (PVCs) from the Purkinje system helped to suppress idiopathic ventricular fibrillation (VF) in an athlete who had suffered from frequent appropriate shock therapies. However, only a few days after successful ablation T-wave oversensing occurred during exercise and resulted in repetitive distressing defibrillator shocks. Despite lack of any changes on the surface ECG, the endocardially recorded electrogram revealed an unfavorable ratio of R-to-T-wave amplitude predisposing to double counting with accelerated heart rates. This case illustrates that T-wave oversensing may complicate the clinical course after successful ablation of malignant Purkinje ectopy.     

Left atrial flutter after segmental ostial radiofrequency catheter ablation for pulmonary vein isolation

Segmental ostial ablation to electrically isolate pulmonary veins has been performed for atrial fibrillation. Left atrial flutter that utilized a critical isthmus adjacent to the ostium of the left superior pulmonary vein was diagnosed and successfully ablated in a patient 3 months after a successful pulmonary vein isolation procedure. Documenting the cause of symptoms after pulmonary vein isolation in patients with atrial fibrillation is critical in guiding therapy.     

Electroconvulsive therapy in patients with cardiac pacemakers and implantable cardioverter defibrillators

Electroconvulsive therapy (ECT) is used to treat major depressive illness, especially in elderly and medically frail patients. Not uncommonly, these patients have cardiac pacemakers or implantable cardioverter defibrillators (ICDs). Only a few case reports in the literature describe the use of ECT in such patients. Herein we review our ECT experience treating 26 pacemaker patients and 3 ICD patients. All patients obtained significant antidepressant benefits with ETC. Only one serious cardiac event occurred, a case of supraventricular tachycardia (SVT) requiring a stay on the cardiac intensive care unit. The SVT resolved and the patient went on to receive further uncomplicated ECT treatments. We conclude from this experience that with proper pre-ECT cardiac and pacemaker/defibrillator assessment, ECT can be safely and effectively administered to patients with an implanted cardiac device.     

缓慢心室率心房扑动患者射频消融术后发生房室传导阻滞分析

目的探讨心房扑动射频消融术后出现房室传导阻滞的原因及对策。方法回顾性分析35例心房扑动患者,存在房室传导比率≥5:1,均采用消融下腔静脉至三尖瓣峡部,终点达到双向阻滞。29例于房扑下消融,6例是转窦性心律后消融,分析术后发生房室传导阻滞的原因。结果 9例患者术后发生I°至高度房室传导阻滞,其中4例患者恢复,5例患者未恢复。结论心房扑动行射频消融术有造成房室传导阻滞可能,但发生率低。缓慢心室率的心房扑动术前可能合并房室传导阻滞,转窦性心律后消融对增加手术安全性及是否存在并发症的判定有帮助。     

Mechanisms of ventricular fibrillation initiation in MADIT II patients with implantable cardioverter defibrillators

Background: The availability of stored intracardiac electrograms from implantable defibrillators (ICDs) has facilitated the study of the mechanisms of ventricular tachyarrhythmia onset. This study aimed to determine the patterns of initiation of ventricular fibrillation (VF) in Multicenter Automatic Defibrillator Implantation Trial (MADIT) II patients along with associated electrocardiogram (ECG) parameters and clinical characteristics.
Methods: Examination of stored electrograms enabled us to evaluate the rhythm preceding each episode of VF and to calculate (intracardiac) ECG parameters including QT, QT peak (QTp), coupling interval, and prematurity index.
Results: Sixty episodes of VF among 29 patients (mean age 64.4 ± 2.5 years) were identified. A single ventricular premature complex (VPC) initiated 46 (77%) episodes whereas a short-long-short (SLS) sequence accounted for 14 (23%) episodes. Of the 29 patients studied, 23 patients had VF episodes preceded by a VPC only, two patients with SLS only, and four patients with both VPC and SLS-initiated episodes. There were no significant differences between initiation patterns in regards to the measured ECG parameters; a faster heart rate with SLS initiation (mean RR prior to VF of 655 ± 104 ms for SLS and 744 ± 222 ms for VPC) approached significance (P = 0.06). The two patients with SLS only were not on β-blockers compared to 83% of the VPC patients.
Conclusion: Ventricular fibrillation is more commonly initiated by a VPC than by a SLS sequence among the MADIT II population. Current pacing modes designed to prevent bradycardia and pause-dependent arrhythmias are unlikely to decrease the incidence of VPC-initiated episodes of VF.     

Radiofrequency catheter ablation of "typical" atrial flutter in a patient with Kartagener's syndrome

Kartagener's syndrome and radiofrequency catheter ablation for the treatment of atrial flutter have been well described in separate reports. This case report includes both in describing a patient with Kartagener's syndrome who had medically refractory atrial flutter that was successfully treated with radiofrequency catheter ablation.     

Radiofrequency catheter ablation of atypical atrial flutter masquerading as atrial fibrillation

A patient with a surgically repaired double outlet right ventricle developed AF 6 months after successful RF catheter ablation of typical atrial flutter. Guided by a 64-electrode basket catheter, the patient's AF was found to be dependent on an atypical atrial flutter circuit rotating around the fossa ovalis. Successful RF catheter ablation was performed by creating a line of conduction block from the superior vena cava to the fossa ovalis.     

心房颤动导管消融的地位和进展

心房颤动(房颤)是临床常见的心律失常之一,最大风险是血栓栓塞,常见是脑卒中。随着人口的老龄化,房颤人数持续增加,治疗问题也逐渐成为人们关注重点。房颤导管消融是其重要治疗方法之一,可明显改善房颤患者预后。且随着技术发展,消融方法也日趋成熟,故导管消融术治疗房颤地位正在逐步提升。但消融方法尚无固定术式,发生机制尚未完全明确,尤其对于持续房颤。因此房颤消融术仍存在一些问题有待进一步探索。     

Percutaneous catheter ablation of atrial fibrillation

Atrial fibrillation is the most common arrhythmia and is associated with important morbidity and mortality. Antiarrhythmic therapy is recommended as initial therapy but is associated with modest efficacy and significant side effects. Over the past several years, catheter ablation has been demonstrated to provide effective and safe curative therapy for atrial fibrillation. Future investigations will assess advances in catheter ablation technology and will help to define the precise role of catheter ablation relative to alternative therapies, such as rate-control and antiarrhythmic therapy.     

应用三维电解剖标测系统与常规方法指导射频消融治疗心房扑动的对比研究

目的快速三维心内膜电解剖标测（Carto）系统可较好的显示心脏解剖的三维结构。本研究通过Carto系统与常规方法指导下标测和射频消融心房扑动（房扑）的比较,评价Carto系统的临床应用价值。方法30例房扑患者,常规组16例,行常规方法和X线透视下标测和消融;Carto组14例,在房扑持续发作时,应用Carto系统在相关心房标测,实时重建心腔三维电解剖图,设计消融路标放电消融,然后验证消融效果。比较两组的手术即时成功率、手术时间、曝光时间及并发症和随访结果。结果常规组16例中,14例典型房扑,2例非典型房扑;15例即时消融成功。Carto组14例中,11例典型房扑,3例非典型房扑,均即时消融成功。两组间比较,Carto组较常规组曝光时间显著缩短,（36．1±8．7）min vs（48．5±19．1）min（P〈0．01）。手术时间延长,（224．6±45．3）minVS（181．4±61．6）min（P〈0．05）。两组均无严重并发症。随访4～8个月,常规组中1例2周后复发,第2次消融采用常规方法消融成功。结论本研究显示,应用Carto系统标测和消融房扑安全有效,较常规方法定位准确可靠、明显缩短曝光时间,且有定位记忆功能,尤其是在复杂的房扑,有助于准确定位靶点和判断线性损伤的连续性。     

Circadian variations in the occurrence of ventricular tachyarrhythmias in patients with implantable cardioverter defibrillators

A circadian distribution has been demonstrated in episodes of sudden cardiac death, acute myocardial infarction, ventricular premature complexes, heart rate variability, and ventricular tachyarrhythmias. The aim of this study was to evaluate the circadian distribution of ventricular tachyarrhythmia episodes in a population of ICD patients. Data were gathered from 72 patients (55 men, 17 women; mean age 62.7 +/- 12.2 years, mean LVEF 0.0037 +/- 0.0011) with ICDs implanted for standard indications. Patients were followed every 3 months over a mean period of 21 +/- 12.8 months. At each examination, symptoms at arrhythmia onset and perception of ICD therapy were recorded, and the ICD memory was interrogated. During follow-up, 1,023 episodes' of malignant ventricular arrhythmias were detected and effectively terminated, 506 of which were fully analyzed. A morning peak in ventricular tachyarrhythmias was demonstrated between 7:00 and 11:00 AM, and an afternoon peak between 6:00 and 7:00 PM. A significantly lower occurrence of VT was observed at 1:00 AM and between 4:00 and 6:00 AM. A circadian distribution in the occurrence of ventricular tachycardias was found. The three striking features of the data are: the early morning peak (about three hours after waking up), relatively stable incidence throughout waking hours, and decline in incidence in the previous period.     

Incidence of antitachycardia therapy suspension due to magnet reversion in implantable cardioverter defibrillators

Electromagnetic interference may result in transient or persistent suspension of antitachycardia therapies in ICDs. The incidence of such events has not been assessed so far. Patient charts were retrospectively analyzed for the occurrence of temporary suspension of antitachycardia therapies as it is stored in the Holter of St. Jude Medical or Ventritex ICDs. Follow-up data of 46 patients and 83.7-patient years were analyzed. Overall, 43 episodes of transient ICD inactivation occurred. Twenty-two of these episodes were related to intentional ICD inactivation in the emergency room or during surgery and 12 episodes were related to ICD follow-up. In nine episodes an environmental source of electromagnetic interference is presumed. None of the interactions resulted in persistent ICD inactivation or reprogramming of the devices. The risk for temporary suspension of ICD therapies unrelated to surgery, intentional magnet application in the emergency room, or routine follow-up is 11% per patient and year. Evaluation of its potential sources and the prevalence of ICD inhibition is warranted.     

Early recurrence of atrial tachyarrhythmias following radiofrequency catheter ablation of atrial fibrillation

The use of blanking periods, the immediate period postablation during which transient tachyarrhythmia episodes are not considered recurrences, has been predicated on the assumption that not all early recurrences of atrial tachyarrhythmias (ERAT) will lead to later recurrences and, as such, does not necessarily represent treatment failure. While ERAT can be expected to occur in approximately 38% of patients within the first 3 months of atrial fibrillation (AF) ablation, only half of these patients will manifest later recurrences. Clinical features related to the patient's history of AF, the index ablation procedure, and particularities of the ERAT can help identify patients at higher risk of later recurrence in whom aggressive attempts to control rhythm, including early cardioversion and reintervention, may be justified.