Ablation of pulmonary vein foci for the treatment of atrial fibrillation; percutaneous electroanatomical guided approach.

AIMS: To evaluate the usefulness of three-dimensional (3D) electroanatomical mapping of the pulmonary veins (PV) for guiding radiofrequency (RF) ablation of focal atrial fibrillation (AF) in a single session and to correlate the electrophysiological results with the six month clinical outcome. METHODS AND RESULTS: Sixteen consecutive patients with idiopathic paroxysmal AF (more than 1 episode/month) were studied. A non-fluoroscopic mapping system was used to generate 3D electroanatomic maps of the left atrium and deliver RF energy. In patients with frequent ectopies, mapping was performed using the 'hot-cold' approach (looking for the earliest electrogram in the 3D reconstruction). In patients with infrequent/no ectopies, double/ multiple potentials recorded at the PV were tagged. Pacing at these sites to test for inducibility of ectopy or atrial fibrillation was used to define PV foci. The therapeutic endpoint was defined as suppression of premature beats, dissociation of PV potentials and inability to induce AF. Twenty-five foci were identified (multiple foci in 38%). In the 4 pts with frequent ectopies, Group A, these were suppressed by 4 +/- 4.7 applications. In the 12 pts with infrequent/no ectopies, Group B, an average 4.7 +/- 1.8 applications were delivered per focus; the endpoint was achieved in eight of the patients (13 of 21 foci). By 180 days follow-up, 11 patients were free of symptoms and in sinus rhythm, two had paroxysmal AF episodes and 3 have symptomatic ectopies and are receiving antiarrhythmic drugs. The overall success rate at six months was thus 69%, 100% for group A and 58% for group B. CONCLUSION: Electroanatomic guided RF ablation of paroxysmal AF was highly successful in patients with frequent ectopies. The use of electroanatomical mapping for precise anatomical localization of multiple potentials and for guiding the PV ostia isolation allowed successful RF ablation in 50% of pts with infrequent/no ectopies.

[Surgery of atrial fibrillation with intraoperative radiofrequency]. / Cirurgia da fibrilhação auricular utilizando radiofrequência intra-operatório.

Radiofrequency ablation is successful in most supraventricular tachyarrhythmias and the first results in percutaneous applications in atrial fibrillation have been published. At present, all the surgical techniques for the treatment of atrial fibrillation use extensive atrial incisions. A case report is presented of a 67 year old woman with chronic atrial fibrillation and rheumatic mitral and tricuspid valve disease. At surgery, pulmonary vein isolation was performed using a continuous linear ablation around the pulmonary veins, instead of using extensive atrial incisions. Concomitantly, a mitral valve replacement and tricuspid valve annuloplasty were performed. Five months after surgery the patient remains with a stable sinus rhythm surgery and in functional class I (NYHA).

Implantable cardioverter-defibrillator: beyond efficacy.

OBJECTIVES: The introduction of the implantable cardioverter-defibrillator was a very important advance in the treatment of malignant ventricular arrhythmias. However, its use is associated with some possible adverse events, which should be taken into consideration when a patient is proposed for implantation. These complications may occur early after implantation and be associated with the procedure itself, or they may be late complications, usually associated with the device or the arrhythmia. It was our objective to assess the incidence of these complications in our population of patients. POPULATION AND METHODS: We describe the complications found in 98 patients (55.9 +/- 13.9 years, 89% male) with an implantable cardioverter-defibrillator and compare our results with the incidence of complications described by other authors. RESULTS: We found complications associated with the presence of the implantable cardioverter-defibrillator in 32% of patients. The most frequent complication was inappropriate shocks in 13%. The presence of infection was detected in 4%, lead insulation faults in 5%, need for lead extraction in 2%, repositioning in 1% and re-establishment of the connection with the generator in 2%. In 5% of patients, there was inefficacy of the device, 3% due to non-detected ventricular tachycardias (slow tachycardias) and 2% due to electrical storms. There was syncope in 2% of patients. The total mortality in a 2.9 +/- 1.9 year follow-up was 13% (sudden death in 3%). CONCLUSIONS: Major complications associated with implantable cardioverter-defibrillators were in our experience relatively rare, our results agreeing with those of other centers.

Endocardial and epicardial radiofrequency ablation in the treatment of atrial fibrillation with a new intra-operative device.

OBJECTIVE: Atrial fibrillation has been a difficult problem to solve in many surgical patients, especially in those with mitral valve pathology. This study evaluates the results of endocardial and epicardial radiofrequency ablation with a new intra-operative device in the treatment of atrial fibrillation. METHODS: We operated on 65 patients with atrial fibrillation, 58 of which had concomitant mitral surgery. Atrial fibrillation was chronic (over 1 year) in 46 patients (group A) and paroxysmal or recent onset in 12 (group B). Group C had lone atrial fibrillation (two), concomitant coronary artery disease (four) or a sarcoma (one). Bilateral pulmonary vein isolation with a new intra-operative device was performed through multiple dry lesions in all patients. Groups A and B had endocardial applications at 70 degrees C during 60 s and group C had epicardial applications at 75 degrees C. Three group C patients had epicardial applications off pump. Atrial wall biopsies were performed in nine patients from groups A and B. RESULTS: There were no serious post-operative complications. At 1 month follow-up 54% of all patients were out of atrial fibrillation and 34% were in normal sinus rhythm with bilateral atrial contraction (Santa Crus Score 4). At 6 months follow-up, in spite of some crossover of patients among groups, similar results were obtained. The success of the procedure was 69% (Santa Crus scores 3 and 4) in mitral patients with a left atrial volume smaller than 200 cm(3). Preliminary data on the transmurality of the lesions is presented. The patients submitted to epicardial radiofrequency ablation (group C) have satisfactory results at 1 month (six out of seven were out of AF). CONCLUSIONS: Both endocardial and epicardial RF applications are simple and quick to perform and do not pose an additional risk for most patients. Furthermore we believe that it is possible to perform bilateral epicardial radiofrequency ablation of the pulmonary veins without cardiopulmonary bypass. Further refinements of the technique are needed to assure transmurality of all lesions and better results.

[Portuguese Association of Arrhythmology, Pacing and Electrophysiology (APAPE). National Registry of Interventional Electrophysiology for 1999]. / Associação Portuguesa de Arritmologia, Pacing e Electrofisiologia (APAPE). Registo Nacional de Electrofisiologia de Intervenção para 1999.

Based on data supplied by the centres that execute Interventional Electrophysiology in Portugal, the authors performed a survey of the electrophysiological studies, with or without associated catheter ablation. This report quantifies the experience of all centres, as well as with different classes of ablation techniques. Furthermore, the authors performed a survey of implanted cardiovertor defibrillators, distinguishing their distribution among the different centres. They conclude that the number of centres that practice Interventional Arrhythmias in Portugal is continuously increasing, as well as the number of catheter ablations performed, although these rates have somewhat stabilised in the last year. The number of implanted cardiovertor defibrillators has also grown yearly since 1992, with a 24% increase last year, but is not yet close to the European average of implants per million of inhabitants.

Microwave ablation of atrial flutter.

Radiofrequency (RF) ablation of the isthmus between the inferior vena cava and the tricuspid ring has proven to be a safe and successful method of treating atrial flutter (AF). However, RF ablation lesions are small in size requiring a considerable number of energy applications to ablate the AF circuit. The aim of this study was to evaluate the feasibility and efficacy of microwave energy for AF ablation. We report a case of sustained typical AF treated successfully and safely by 1 pulse of microwave (MW) energy. This showed it is possible to treat AF with a small number of pulse applications.

Electrosurgical treatment of atrial fibrillation with a new intraoperative radiofrequency ablation catheter.

BACKGROUND: To assess the efficacy of a new catheter for intraoperative radiofrequency ablation. METHODS: We operated 35 mitral patients with atrial fibrillation of which 27 had chronic atrial fibrillation with a mean duration of 8 +/- 6 years. Most patients were in functional class III or IV. All patients were operated under cardiopulmonary bypass using sternotomy in 29 patients, right thoracotomy in 5 and left thoracotomy in 1. RESULTS: Bilateral pulmonary vein isolation with radiofrequency catheter ablation was achieved in 7 +/- 4 minutes. There was no mortality or morbidity. Out of the 27 patients with one to three months follow-up 60% were out of atrial fibrillation and 48% had both atria contracting (scores 3 and 4). A longer time is required to assess the end result of these techniques, because the complete healing of the ablation lesions takes 3 to 6 months. CONCLUSIONS: We conclude that with appropriate tools and settings the use of intraoperative radiofrequency catheter ablation is fast, safe and effective. Its indications can be extended to other types of atrial fibrillation patients.

Surgery for atrial fibrillation using radiofrequency catheter ablation: assessment of results at one year.

OBJECTIVE: The results obtained in 43 patients using direct intraoperative radiofrequency catheter ablation, as an alternative to surgical incisions, to perform atrial fibrillation surgery, are presented. METHODS: Forty-three patients with ages ranging from 43 to 74 years (x = 59), with chronic atrial fibrillation with an average duration 6+/-5 years were operated. Eleven patients suffered from clinically relevant tachyarrythmia and eight had previous thromboembolic events. All but one patient had concomitant mitral valve surgery. Direct intraoperative radiofrequency catheter ablation was used to perform endocardial bilateral isolation of the pulmonary veins from the left atrium. RESULTS: There were no local or general complications, namely bleeding or thromboembolic events. Of the 33 patients with more than 3 months of follow-up, 36% remained in atrial fibrillation (Santa Cruz score 0); 30% had Score 4; 18% had Score 3; 6% had Score 2; 9% had Score 1. CONCLUSIONS: We conclude that the use of intraoperative radiofrequency catheter ablation is fast and safe. Presently, this is our method of choice for surgical treatment of atrial fibrillation in mitral patients.

[The Brugada syndrome--a clinical case]. / Síndrome de Brugada--caso clínico.

A case report of a patient with syncope and family history of sudden death is presented. The precordial recordings in the standard 12-lead ECG showed a right bundle-branch block pattern with persistent ST elevation in V1 and V2-V3. After a thorough evaluation, we found no underlying organic cardiomyopathy. The diagnosis of symptomatic Brugada syndrome was made. A cardioverter-defibrillator was implanted.

[Role of auxiliary diagnostic tests in the clarification of the etiology of syncope: experience at an arrhythmia center]. / Papel dos exames auxiliares de diagnóstico no esclarecimento etiológico da síncope--experiência de uma consulta de arritmologia.

UNLABELLED: Syncope is a syndrome caused by a reversible reduction of blood to the brain. Three hemodynamic abnormalities can cause syncope: an acute decrease in cardiac output, an acute increase in cerebrovascular resistance and a fall in systemic blood pressure due to ineffective control of peripheral vascular resistance. We made a retrospective study of 121 patients with syncope history, 67 males, and 57 females, with mean age 48 +/- 14 years, and at least six months of clinical follow-up. Twelve patients had valvular disease, two patients had hypertrophic cardiomyopathy, eight patients had dilated cardiomyopathy, 14 patients had ischemic disease, three patients had congenital disease; 82 patients did not have cardiac disease. Syncope etiology was arrhythmic in 69 patients: 47 patients had tachyarrhythmia (supraventricular--in 27 patients and ventricular in 20 patients) and 15 patients had bradyarrhythmia (seven patients had sinus node disease and eight patients had atrioventricular block). Non arrhythmic etiology of syncope was identified in 29 patients (neurologic disease--ten patients, metabolic disease--one patient and iatrogenic--two patients; vasodepressor syncope--14 patients, and hypertrophic cardiomyopathy--two patients). It was not possible to determine the syncope etiology in 30 patients. The assessment of patients who present syncope depends on establishing the basis for the symptoms. The initial step is differentiating patients with normal cardiovascular systems from those with heart disease. In the former, tilt-table testing proved to be the most productive from a diagnostic perspective; in the latter group, electrophysiologic evaluation was the most elucidative from a diagnostic perspective. The ultimate goal is to obtain a sufficiently strong correlation between syncopal symptoms and detected abnormalities to permit an accurate assessment of prognosis and to develop an effective treatment plan. CONCLUSIONS: It is very important to establish the etiology of syncope for optimal management of patients and it is therefore possible to control the symptoms in the majority of them. The patients who present syncope require a complete history and a physical examination for an appropriate workup to be initiated. Tilt-table testing was the most accurate for the diagnosis of vasodepressor syncope while electrophysiologic testing provides an accurate method for assessing the etiology of tachyarrhythmic syncope.

[Syncope in a patient with Ebstein's anomaly and Wolff-Parkinson-White syndrome]. / Síncope em doente com anomalia de Ebstein e síndrome de Wolff-Parkinson-White.

We describe a clinical case of a patient with Ebstein's anomaly and syncope in Wolff-Parkinson-White's syndrome. After a radiofrequency ablation of an accessory atrioventricular pathway there was a different arrhythmia of ventricular origin. Although we have some doubts about their clinical relevance, we discuss the complex arrhythmic background, the medical management difficulties and the prognostic issues. There is an evaluation about ablation usefulness in this context regarding future attitudes in relation to other kinds of rhythm disorder.

[Atrial fibrillation surgery using intraoperative radiofrequency]. / Cirurgia da fibrilhação auricular utilizando radiofrequência intra-operatória.

Radiofrequency ablation is successful in most supraventricular tachyarrhythmias and the first results in percutaneous applications in atrial fibrillation have been published. At present, all the surgical techniques for the treatment of atrial fibrillation use extensive atrial incisions. A case report is presented of a 67 year old woman with chronic atrial fibrillation and rheumatic mitral and tricuspid valve disease. At surgery, pulmonary vein isolation was performed using a continuous linear ablation around the pulmonary veins, instead of using extensive atrial incisions. Concommitantly, a mitral valve replacement and tricuspid valve annuloplasty were performed. Five months after surgery, the patient remains with a stable sinus rhythm surgery and in functional class I (NYHA).

Clinical implications of the "Multicenter Automatic Defibrillator Implantation Trial" (MADIT)

Efficacious therapy for chronic coronary patients, known to be at high risk of sudden arrhythmic death, has been a long-lasting challenge for cardiologists. The "Multicenter Automatic Defibrillator Implantation Trial" (MADIT) has demonstrated in a prospective, randomized trial that such patients achieve 54% better survival (p < or = 0.009) when treated with implantable defibrillators (ICDs) compared to conventional pharmaceutical therapy-primarily amiodarone. The identification of these patients is well-defined, and patients with previous myocardial infarction fitting the appropriate risk profile as defined by MADIT (ejection.fraction < or = 0.35), non-sustained ventricular tachycardia should seriously be considered for prophylactic ICD implantation.

[The implantable cardioverter-defibrillator: the Portuguese experience]. / Cardioversor-desfibrilhador implantável: experiência portuguesa.

OBJECTIVE: The aim of this study was to review the Portuguese experience with implantable cardioverter-defibrillator therapy (ICD), in order to evaluate the increase in the number of ICD implanted, the main indications for this kind of therapy, the technical evolution of the procedure and the results of the follow-up of these patients during the last five years. PATIENT SELECTION: The study group consists of 58 patients, 53 male and 5 female, mean age 54 +/- 14 years with ICD implanted in our country since 1992. The ICDs were implanted in 4 Hospitals, namely, Santa Cruz Hospital with 36 patients, Santa Maria Hospital with 11, Santa Marta Hospital with 8 and Coimbra University Hospital with 3 patients. Twenty six patients were resuscitated from cardiac arrest and the other 32 had ventricular tachycardia (VT) not tolerated haemodynamically and refractory to therapy. The diagnosis was coronary artery disease in 31 patients, dilated cardiomyopathy in 8, valvular disease in 4, congenital cardiopathy in 3, right ventricular dysplasia in 2, congenital long QT syndrome in 1, hypertrophic cardiomyopathy in one. Seven patients had idiopathic ventricular fibrillation without structural heart disease and one patient had isolated right ventricular dilatation. METHODS: All patients underwent electrophysiological study before ICD implantation. In 2 patients epicardial leads were used and in the remaining 56 patients a transvenous approach was used. The device was implanted in an abdominal position in 36 patients and in a pectoral position in 22. Defibrillation and pacing thresholds were measured during the implantation procedure and whenever necessary. Patients were followed up on an outpatient basis with evaluation of the number of arrhythmic episodes, therapy efficacy with reprogramming of the device when required. RESULTS: The number of implantations has increased, from 4 devices implanted in 1992, to 32 in 1996. The implantation was successful and without mortality or complications in all patients. Defibrillation threshold was 16 +/- 3 J, with an electrode impedance of 48 +/- 9 Ohms. During a mean follow-up time of 18 +/- 15 months (1 to 56) 5 patients died, one of sudden death and 4 of non cardiac deaths, 15 patients were re-admitted to hospital and in 8 patients the device was replaced due to exhaustion. In this period, 37 patients (64%) had arrhythmic episodes detected by the device, 32 patients (55%) had shocks and 9 (16%) were treated with anti-tachycardia pacing. Inappropriate shocks were observed in 10 patients (17%). The ICD were reprogrammed in 11 patients. CONCLUSIONS: Portuguese experience with IC implantation is increasing and has shown to be a safe procedure with no operative mortality or morbidity. The incidence of appropriate shocks was high with a good efficacy in sudden death reduction.

[Catheter ablation with radiofrequency energy in 100 patients with Wolff-Parkinson-White syndrome]. / Ablação por cateter com energia de radiofrequência de 100 doentes com síndrome de Wolff-Parkinson-White.

OBJECTIVE: The aim of this paper was to evaluate our results of radiofrequency catheter ablation (RFCA) of accessory pathways in patients with WPW syndrome. STUDY PATIENTS: We studied 100 consecutive patients with WPW syndrome, 52 men and 48 women, mean age 37 +/- 15 years who underwent RFCA. All patients were symptomatic, with documented episodes of supraventricular tachycardia and 9% of patients had underlying cardiac disease. METHODS: The RFCA was performed without antiarrhythmic drugs in the same session of the electrophysiologic diagnosis. The location of the accessory pathway site was obtained by catheter mapping, based on the premature and/or the presence of Kent potentials. According to the location of the accessory pathway, the ablation catheter was introduced either by the femoral vein or artery with mapping of the tricuspid or mitral ring. In the first cases performed energy application was manually controlled and thereafter was temperature guided with an upper temperature limit of 70 degrees C. We considered primary success criteria the disappearance of the delta wave in the surface ECG and the absence of ventricular preexcitation under atrial pacing and after adenosine injection. Clinical success was defined as the absence of clinical recurrence of tachycardia during the follow-up period. RESULTS: The primary success rate achieved was 88%; 91% in the left free wall pathways, 100% in the right free wall and 85% in the septal pathways (antero-septal-83%; right postero-septal-76.5%; left postero-septal-92%). A second ablation procedure was performed in seven of the twelve patients with primary unsuccess obtaining a final success rate of 93% (left free wall-94.5%; septal pathways-91.6%). After a mean follow-up period of 8 +/- 7 months clinical recurrence occurred in 9% (eight patients), five of which are under anti-arrhythmic therapy (62.5%). Clinical success rate at the end of the follow-up period was 88%. CONCLUSIONS: In our experience RFCA has shown to be safe and with a high success rate in patients with symptomatic pre-excitation. In this group of patients it was an effective therapy.

Operative risks of the maze procedure associated with mitral valve surgery.

Twelve patients were operated on for mitral valve disease with concomitant chronic atrial fibrillation. Valve repair was performed in five patients and replacement in seven. Maze I and maze III procedures were applied in eight and four patients, respectively, and are compared. There was a regular rhythm in all maze I patients with a constant junctional rhythm in three and an alternating sinus and junctional rhythm in the remainder. In one case, part of the left atrium was in atrial fibrillation with the remaining atria in sinus rhythm. In the maze III group, one patient was always on a regular rhythm, two had episodes of atrial fibrillation and one was in atrial fibrillation with controlled ventricular rate. Echocardiography showed atrial contraction in two maze I patients, but systolic atrial flow across both atrioventricular valves could only be demonstrated in two patients in the maze III group.

[The prognostic significance of late potentials in patients with chronic coronary disease]. / Significado prognóstico dos potenciais tardios em doentes com doença coronária crónica.

OBJECTIVE: The prognostic value of late potentials (LP) in the subacute phase of myocardial infarction (MI) is well known, but its prognostic value in long-standing coronary disease (LSCD) has not yet been established. In a population with LSCD we searched for a relation between the presence of LP in signal-averaged ECG (SAECG) performed before cardiac catheterization, and the incidence of cardiac events. METHODS: Based on our department's casuistics, we selected 50 consecutive patients with coronary disease confirmed by an angiogram and LP, and a control group without LP, in SAECG. We selected 91 men and nine women with an average age of 59 +/- 8 years. None of the patients had had ischemic events or revascularization procedures, in the 3 month period before catheterization. The follow-up was made between the time of the SAECG and the last medical visit. The events recorded were: ventricular arrhythmia, cardiac death, coronary angioplasty, coronary artery by-pass graft, MI or unstable angina. RESULTS: During a follow-up period of 20.1 +/- 8 months, we found no statistically significant difference between the two groups, regarding the incidence of such events. However, there was a higher incidence of ventricular arrhythmic events in the group with LP (four patients with ventricular tachycardia against none in the control group). All patients with ventricular tachycardia had had a previous MI. CONCLUSIONS: In this study, the presence of LP in SAECG did not have the same prognostic value found in the subacute phase of MI, but a higher incidence of arrhythmic events was observed in the group with LP and a previous MI.