[National registry on cardiac electrophysiology (2010 and 2011)]. / Registo Nacional de Eletrofisiologia Cardíaca (2010 e 2011).

Based on a survey sent to Portuguese centers that perform diagnostic and interventional electrophysiology and/or implant cardioverter-defibrillators (ICDs), the authors analyze the number and type of procedures performed during 2010 and 2011 and compare these data with previous years. In 2011, a total of 2533 diagnostic electrophysiologic procedures were performed, which were followed by ablation in 2013 cases, a steady increase over previous years. The largest share of this increase compared to 2010 was in atrial fibrillation, which is now the second most frequent indication for ablation, after atrioventricular nodal reentrant tachycardia. The total number of ICDs implanted in 2011 was 1084, of which 339 were biventricular (BiV) cardiac resynchronization devices (BiV ICDs). This represents an increase in the total number relative to previous years, 2011 being the first year in which the rate of new ICD implantations in Portugal exceeded 100 per million population. However, compared to 2010, the number of BiV ICDs implanted decreased, despite the recent publication of updated European guidelines on device therapy in heart failure, which clarified and expanded the indications for implantation of these devices. Some comments are made on the current status of cardiac electrophysiology in Portugal and on factors that may influence its development in the coming years.

National Registry on Cardiac Electrophysiology 2009.

The authors analyze the number and type of electrophysiologic procedures (diagnostic and ablation, and implantation of defibrillators and biventricular pacemakers with defibrillator backup) that were performed during 2009 in all Portuguese electrophysiology centers. A total of 2669 diagnostic electrophysiologic procedures were performed during the year, of which 62% were followed by ablation, amounting to 1668 ablations. The authors describe the type of ablations performed by the various centers, and analyze the distribution and type of ablation procedures in the light of recent data from published international studies. A total of 1089 ICDs were implanted during 2009, and the authors also describe the type of devices employed and comment on these data bearing in mind recent published data.

Portuguese National Registry on Cardiac Electrophysiology, 2017 and 2018. / Registo Nacional de Eletrofisiologia Cardíaca 2017­2018.

INTRODUCTION: The authors present the results of the national cardiac electrophysiology registry of the Portuguese Association of Arrhythmology, Pacing and Electrophysiology (APAPE) and the Portuguese Institute of Cardiac Rhythm (IPRC) for 2017 and 2018. METHODS: The registry is annual, voluntary, and observational. Data are collected retrospectively. Developments over the years and their implications are analyzed and discussed. RESULTS: In the 22 electrophysiology centers, 3407 ablations were performed in 2017 and 3653 ablations in 2018. Atrial fibrillation (AF) ablation was the most frequently performed procedure: 1017 ablations in 2017 and 1222 procedures in 2018. Of the patients undergoing AF ablation, 63% were male, 60% were between 50 and 69 years old and 74% had paroxysmal AF. Clinically relevant complications were reported in 0.8% of the procedures. In 2017, 216 ventricular tachycardia (VT) ablation procedures were performed in 15 centers. In 2018, 19 centers performed 249 VT ablations. About 45% of VT ablations were performed in patients with structural heart disease. Complications were reported in 3.2% of the procedures, including one death (0.2%). CONCLUSIONS: The national electrophysiology registry showed a sustained increase in the number of catheter ablations. In addition, procedural complexity increased and AF ablation assumed a dominant position among the procedures performed.

Prevalence of atrial fibrillation in the Portuguese population aged 40 and over: the FAMA study.

INTRODUCTION: Atrial fibrillation (AF) is the most frequently encountered arrhythmia in clinical practice, and is an important cause of morbidity and an independent risk factor for overall mortality and sudden death. This study aims to assess the prevalence of AF in individuals aged 40 and over in order to characterize the situation in Portugal and improve the detection and management of this arrhythmia. METHODS: This was a cross-sectional study of a representative sample of the Portuguese population including subjects of both genders aged 40 and over, resident in Portugal. The sample was constructed using a random route method. The determination of AF prevalence was based on the results of ECGs, the rhythm being classified by a panel of cardiologists; a questionnaire was used to characterize the AF population by collecting demographic, socioeconomic, clinical, and therapeutic data. RESULTS: Of the 10,447 individuals included, 55% were female and the median age was 58 years (min=40; max=101). Two hundred and sixty-one cases of AF were identified, representing a prevalence of 2.5% (2.2-2.8%: 95% CI). No differences were found between genders, but AF prevalence increased with age, the prevalence being significantly higher in the group aged 70 and over (70-79: 6.6%; 80 and over: 10.4%). According to this study, the typical AF patient has a median age of 77, is overweight (mean BMI = 27.7 kg/m2), and does not exercise, smoke or consume alcohol. Logistic regression analysis identified male gender (OR: 1.689), age (OR: 1.094), BMI (OR: 1.056), hypertension (OR: 1.437), and lack of physical exercise (OR: 0.436) as risk factors. Only 1.6% of AF cases had known AF, usually diagnosed by a cardiologist (61%) based on an ECG (97.4%). Less than half of the patients were taking oral anticoagulants (38%). CONCLUSIONS: AF prevalence in the Portuguese population aged 40 and over is relatively high compared to studies carried out in other countries. As AF is a common arrhythmia and is a risk factor for stroke, it is essential to promote prevention strategies. It is important to control hypertension, reduce obesity, and establish screening programs in order to maximize the number of identified cases and optimize those patients' treatment, particularly in preventing the associated thromboembolic risk.

[Epidemiology of atrial fibrillation]. / Epidemiologia da fibrilhação auricular.

Atrial fibrillation (AF) is the most frequent maintained arrhythmia and constitutes a major morbidity cause, especially because of its associated risk of ischemic stoke. Additionally, it represents an independent risk factor for global mortality. The incidence of AF varies, according to different studies, between a minimum of 0.25 per 1000 person/year (women) and 0.9 per 1000 person/year (men) and a maximum of 8.9 per 1000 person/year (women) and 11.5 per 1000 person/year (men). Several cross sectional and prospective studies indicate that the prevalence of AF is inferior to 1% in individuals who are less than 55 years old. It is estimated that this arrhythmia's suffers a significant increase throughout the entire life span, and that its highest raise occurs between the ages of 65 and 80. A Portuguese study performe d between June and November 2003, in the scope of Rede Médicos-Sentinela, showed an AF prevalence of 0.53% in a population of 32,185 Health Centres patients. The mean age of patients suffering from this disease is situated within the interval of 70 to 80 years old. It is inferior for those who suffer from a concomitant cardiovascular disease, being significantly higher for women versus men. The risk factors and comorbidities which are most commonly associated to AF are age, several cardiovascular conditions, alcoholism, family history of AF and hyperthyroidism. Considering the high rate of stroke mortality in Portugal and assuming that AF is present in 15% ischemic stroke triggering and that it increases its risk 2 to 7 times, it can be concluded that knowledge regarding AF's incidence and prevalence in the different age groups will be important in order to improve its level of control, which is essential for preventing stroke and better management of this condition's treatment in the cardiovascular diseases' general context.

Portuguese National Registry of Cardiac Electrophysiology (2015/2016). / Português Registo Nacional de Eletrofisiologia Cardíaca (2015/2016).

INTRODUCTION: Knowledge of the activity performed in a country enables it to be positioned within the community of which it is part. OBJECTIVE: We present the results of the National Registry of Cardiac Electrophysiology of the Portuguese Association for Arrhythmology, Pacing and Electrophysiology (APAPE) for 2015 and 2016. METHODS: This is a voluntary, observational, annual registry collected retrospectively. RESULTS: The data on the electrophysiological studies and ablations performed in these two years are presented. CONCLUSION: Changes in these data over the years are analyzed and the relation of the Portuguese data in the European panorama and possible implications are discussed.

Five years of catheter ablation procedures in South-Western Europe: meta-analysis of National Registries.

BACKGROUND: Radiofrequency catheter ablation is a well-established approach to treating several types of cardiac arrhythmias. The aim of our study was to provide data on the diffusion of catheter ablation procedures in clinical practice through a meta-analysis of National Registries of electrophysiological procedures performed over a 5-year period, from 2000 to 2005. METHODS: We found only two national registries of catheter ablation procedures published in the journals indexed in PubMed: The Spanish Catheter Ablation Registry and the Portuguese National Registry on Cardiac Electrophysiology. In addition, we included in our analysis the data from the Italian Registry of Electrophysiological Procedures. RESULTS AND CONCLUSIONS: This meta-analysis revealed a steady increase in the total number of catheter ablation procedures, particularly for the ablation of atrial flutter, of tachycardia due to double nodal pathways, and of the left atrial substrate in atrial fibrillation. However, the progress of catheter ablation and the impetus for additional research and development of new approaches and technologic advances requires further data on clinical indications, methodologic approach, complications, and long-term success rate in the real world.

National Registry on Cardiac Electrophysiology 2007 and 2008.

Clinical electrophysiology remains one of the most dynamic areas of cardiology, with continuing developments in equipping centers with more modern mapping and navigation systems. This has enabled an increase in the number and variety of interventions, resulting in significant improvements in results of therapeutic ablation of arrhythmias and prevention of sudden cardiac death. In this phase of transition towards implementation of a computerized national registry with nationwide data transmitted via the internet, publication of the registry in its previous form, although requiring more work, still seems justified, in order to appraise and disseminate qualitative and quantitative developments in this activity and enable comparisons with what is being done internationally, assess the centers' training capacity and inform national and European health authorities of the activities and real needs in this sector. The authors analyze the number and type of procedures performed during 2007 and 2008 based on a survey sent to centers performing diagnostic and interventional electrophysiology (16 centers in 2007 and 2008) and/or implanting cardioverter-defibrillators (ICDs) (19 centers in 2007 and 21 in 2008). Compared to 2006, one more center began interventional electrophysiology in 2007 and two centers began implanting ICDs in 2008. In the years under review, 2060 electrophysiological studies were performed in 2007 and 2007 were performed in 2008, of which 74 and 79.5% respectively were followed by therapeutic ablation, making totals of 1523 and 1596 ablations (increases of 10.7 and 4.6% from previous years). Atrioventricular nodal reentrant tachycardia was the main indication for ablation (28.4 and 28.7%), followed by accessory pathways (26.8 and 25.4%), atrial flutter (20.8 and 19.7%), atrial fibrillation (13.9 and 14.6%), ventricular tachycardia (4.7 and 5.1%), atrial tachycardia (2.8 and 2.6%) and atrioventricular junction ablation (2.7 and 3.9%). Regarding ICDs, a total of 890 devices were implanted in 2007 and 1040 devices in 2008, of which 63 and 75 respectively were battery replacements and 827 and 965 were first implantations, with the following distribution: single chamber--53.7% in 2007 and 61.4% in 2008; dual chamber--13.8 and 8.4% respectively in 2007 and 2008; resynchronization systems with ICD--32.5% in 2007 and 30.2% in 2008. The figures for first implantations show growth of 18.5% between 2006 and 2007 and 14.3% between 2007 and 2008. First implantations increased from 67.4 devices per million population in 2006 to 82.7 in 2007 and 96.5 in 2008.

Atrial fibrillation ablation: importance of cavotricuspid isthmus block.

INTRODUCTION AND OBJECTIVE: Maintenance of atrial fibrillation (AF) depends on the presence of multiple reentrant circuits in the atria. In AF ablation, after pulmonary vein (PV) isolation, substrate modification can be increased by performing linear lesions in the left atrium that reduce the fibrillatory surface. A cavotricuspid isthmus (CTI) block may be an easier and safer alternative to left atrial lines for this purpose. Non-inducibility after AF ablation is associated with a higher success rate. The aim of this study is to assess whether CTI ablation after PV isolation reduces inducibility of atrial arrhythmias, particularly AF. METHODS AND RESULTS: In 29 consecutive patients (23 male, mean age 54.6+/-11.4 years, 11 (38%) with hypertension and four (14%) with structural heart disease, mean left atrial dimension 43+/-6 mm) undergoing PV isolation for paroxysmal or persistent AF, atrial arrhythmia inducibility was tested before and after CTI ablation. The procedure was performed using a CARTO-Merge mapping system, one or two Lasso catheters, an irrigated ablation catheter and radiofrequency energy. Atrial arrhythmia inducibility was tested with burst pacing down to 150 ms or atrial refractoriness from the proximal coronary sinus. Atrial arrhythmias were considered inducible if they persisted for more than 60 seconds. Of the 29 patients, 26 (90%) had an inducible arrhythmia before CTI ablation--AF in 16, typical atrial flutter (AFL) in seven and atypical AFL in three. Three (10%) were non-inducible. After CTI ablation, only 11 patients (38%) maintained arrhythmia inducibility (p<0.001)--AF in nine and atypical AFL in two. There was a significant reduction of AF inducibility (16 vs. 9/29, p=0.016) and of combined AF and atypical AFL inducibility (19 vs. 11/29, p=0.021). After one year of follow-up, 23 patients (79%) had no recurrence of arrhythmia. Success rates were 83% in patients without and 73% in patients with inducible arrhythmias at the end of the procedure (p=NS). CONCLUSION: CTI ablation, in addition to PV isolation, significantly reduced the number of patients with inducible atrial arrhythmias and inducible AF.

Real-life data on heart failure before and after implantation of resynchronization and/or defibrillation devices - the Síncrone study. / Implantação de dispositivos de ressincronização e/ou desfibrilhação em doentes com insuficiência cardíaca: dados da vida real ­ o Estudo Síncrone.

INTRODUCTION: The aim of this study was to document clinical practice in Portugal regarding the use of electronic cardiac devices in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF). METHODS: The Síncrone study was an observational prospective multicenter registry conducted in 16 centers in Portugal between 2006 and 2014. It included adult patients with a diagnosis of HF, LVEF <35% and indication for implantable cardioverter-defibrillator (ICD) and/or cardiac resynchronization therapy (CRT) devices, according to the recommendations of the European Society of Cardiology at the beginning of the study. Patients were followed for one year according to the practice of each center. RESULTS: A total of 486 patients were included in the registry, half of whom received an ICD and the other half a CRT pacemaker (CRT-P) or CRT defibrillator (CRT-D). Mean age was 65±12 years and the most frequent causes of HF were ischemic (47%) and idiopathic dilated cardiomyopathy (28%). Overall mortality at one year was 3.6% and the hospitalization rate was 11%, significantly higher in patients with CRT-P/CRT-D than with ICD (17% vs. 5.6%, p<0.001). Patients who received CRT-P/CRT-D experienced significant reductions in QRS duration (160±21 vs. 141±24 ms, p<0.001) as well as improvement in New York Heart Association functional class. CONCLUSION: The Síncrone study shows that the use of implantable devices in HF with reduced LVEF in Portugal is in accordance with international recommendations and that patients presented functional improvement and reduced one-year mortality.

National Registry on Cardiac Electrophysiology--2006.

Clinical electrophysiology is one of the areas of cardiology that has seen most growth in Portugal, particularly in interventional cardiology, which includes ablation of arrhythmias and prevention of sudden cardiac death. The annual publication of a national registry enables us to assess qualitative and quantitative progress, compare our results with international data, assess the centers' training capabilities and inform health authorities of the activities and needs of the sector. The authors analyze the number and type of procedures performed during 2006 based on a survey sent to 19 national centers (15 public and 4 private) that performed diagnostic and interventional electrophysiology (15 centers) and/or implanted cardioverter-defibrillators (ICDs) (19 centers) in that year. The number of electrophysiology centers remained unchanged from 2005, but four new centers began implanting ICDs in 2006. In the year under review, 1805 electrophysiological studies were performed, 75.3% of which were followed by ablation therapy, a total of 1360 ablation procedures (a 22.3% increase over the previous year). Accessory pathways were the main indication for ablation (32%), followed by atrial flutter (25%), atrioventricular nodal reentrant tachycardia (23%), atrial fibrillation (10%), ventricular tachycardia (5%), atrial tachycardia (3%) and atrioventricular junction ablation (2%). In 2006, a total of 738 ICD devices were implanted, of which 64 were battery replacements and 674 were first implantations, with the following distribution: 346 single chamber (51.3%), 98 dual chamber (14.5%) and 230 integrated in ventricular resynchronization systems (34.1%). These figures reflect a lower growth rate than that of 2005, even though in 2006 first implantations rose from 54.7 to 67.4 devices per million population. The ICD implantation rate in Portugal is still far below the European average, which means there is a continuing need to raise awareness of this therapeutic option among the Portuguese medical community. With regard to the training capabilities currently available in Portugal, only 5 centers (all public) had a sufficient level of activity to fulfill the requirements stipulated for the subspecialty of cardiac electrophysiology. As for implantation of ICDs, 12 centers implanted more than 10 units, the minimum annual curricular limit for this subspecialty.

Portuguese National Registry on Cardiac Electrophysiology, 2013 and 2014. / Registo nacional de eletrofisiologia cardíaca (2013/2014).

The authors present the results of the national registry of electrophysiology of the Portuguese Association for Arrhythmology, Pacing and Electrophysiology (APAPE) for 2013 and 2014. The registry is annual and voluntary, and data are collected retrospectively. Data for electrophysiological studies, ablations and cardioverter-defibrillator implantations for 2013 and 2014 are presented. Developments over the years and their implications are analyzed and discussed.

Ventricular tachycardia ablation in patients with coronary heart disease: beyond the reentry circuit.

INTRODUCTION: Patients with coronary heart disease and left ventricular dysfunction are at increased risk for the development of ventricular tachycardia (VT) related to areas of myocardial fibrosis. Although the mechanism and the circuit of this arrhythmia are well understood, little is known about the triggers that precipitate VT episodes. Purkinje fiber potentials may be responsible for idiopathic VT, and recent studies have related them to polymorphic VT and ventricular fibrillation. METHODS: Between January 2002 and December 2003, we performed ablation in 10 patients with coronary heart disease, left ventricular systolic dysfunction and VT refractory to pharmacological therapy. All patients had implantable cardioverter-defibrillators. Electroanatomical activation and voltage mapping (CARTO) and electrophysiological criteria (premature activation during VT, pace mapping, and presence of diastolic potentials) were used to define scar regions, slow conduction areas and the reentry circuit isthmuses. RESULTS: Spike potentials were recorded in the scars of three patients. These potentials were almost fused with the ventricular electrogram during sinus rhythm, and were more premature during VT, probably reflecting local activation of Purkinje fibers. During ablation, we were able to dissociate the spike from the ventricular electrogram, thus terminating the VT. In the cases with conduction recovery, ventricular; ectopic beats recurred, preceded by a spike and degenerating into short runs of VT. The ablation strategy was not modified since persistence of the VT required the isthmus. CONCLUSION: The results suggest that residual Purkinje fibers may be present in scar regions and that the activity of these fibers may trigger VT in pre-established circuits.

Evaluation of bilateral pulmonary vein isolation for the treatment of atrial fibrillation: value of postoperative electrophysiological study.

OBJECTIVE: To evaluate electrophysiological changes after bilateral pulmonary vein isolation in patients undergoing mitral valve surgery and to relate the clinical outcome at 1-year follow-up with the results of the postoperative electrophysiological study. METHODS: Prospective study of patients with atrial fibrillation undergoing bilateral pulmonary vein isolation using radiofrequency energy and concomitant mitral valve surgery. Pulmonary vein isolation was performed with a heptapolar catheter. Each set of up to 7 simultaneous applications aimed at a maximal duration of one minute and a maximal preset temperature of 70 degrees C. Energy delivery (< 150 watts) was controlled by thermosensors located on each electrode. Before hospital discharge, all patients presenting sinus rhythm underwent an electrophysiological study, using epicardial pacing wires placed during surgery. Isolated areas were compared to the non-isolated left atrium with respect to electrogram amplitudes and atrial capture thresholds. At one-year follow up, cardiac rhythm was assessed in all patients and correlated with the results of the postoperative electrophysioloical study. RESULTS: The study population consisted of 20 patients with mitral valve disease (mean age 59 +/- 11 years), chronic atrial fibrillation present for 0.5 to 18 years and dilated left atria (55 +/- 11 mm assessed by M-mode echocardiography). The radiofrequency procedure added, on average, 7 minutes (3 to 17) to the duration of the mitral valve surgery. No patient died or suffered surgical complications. Eleven patients presented sinus rhythm before hospital discharge. The electrogram amplitude inside the isolated zones was less than 25% of that in nonisolated areas (0.3 +/- 0.2 mV versus 2.1 +/- 1.7 mV, p = 0.002). Atrial capture thresholds were significantly higher for the isolated areas (13.5 +/- 9.3 mA versus 8.5 +/- 4.0 mA; p < 0.05). At one-year follow-up, nine patients maintained atrial fibrillation, nine remained in sinus rhythm and two lost sinus rhythm to atrial fibrillation. In both these patients, the reduction in electrogram amplitude inside the isolated zones was similar to that of the remaining patients discharged in sinus rhythm. However, postoperative electrophysiological studies in these patients showed that atrial capture thresholds for isolated areas had not increased significantly (8 mA and 6 mA, respectively). CONCLUSION: Rhythm at discharge after bilateral pulmonary vein isolation tends to remain at one-year follow up. Radiofrequency-induced modifications in electrogram amplitudes may be less important than increases in pacing thresholds of isolated zones with respect to maintenance of sinus rhythm.

Ablation of atrial fibrillation in mitral valve disease patients: five year follow-up after percutaneous pulmonary vein isolation and mitral balloon valvuloplasty.

BACKGROUND: The association between atrial fibrillation (AF) and mitral valve disease is frequent. Isolation of the pulmonary veins by radiofrequency energy applications performed intraoperatively has been proposed for patients with AF in whom mitral valve surgery has been indicated. Balloon mitral valvuloplasty is currently the preferred procedure for patients with mitral stenosis and a favorable valve anatomy. AIM: To evaluate the short- and long-term results of percutaneous pulmonary vein isolation for the treatment of AF in patients with mitral stenosis undergoing balloon mitral valvuloplasty. METHODS: Five patients (four male and one female, age 43 +/- 4 years) underwent balloon mitral valvuloplasty concomitant with pulmonary vein isolation between August 1996 and February 1997. These patients had permanent AF, diagnosed 31 +/- 12 months previously; their mitral valve area was 1.0 +/- 0.25 cm2 and their left atria measured 54 +/- 5 mm. Balloon mitral valvuloplasty was performed via a transseptal approach, and then four ablation lines were created in the left atrial posterior wall to encircle all four pulmonary veins. Radiofrequency applications lasted 45 seconds each, and aimed at a maximum preset temperature of 65 degrees C. Electrical cardioversion was performed at the end of the procedure. RESULTS: Mitral valve area increased 1.0 +/- 0.3 cm2 after valvuloplasty. The number of radiofrequency applications per patient was 37 +/- 3, and the average duration of the entire treatment was 131 +/- 28 minutes. Fluoroscopy time averaged 32 +/- 12 minutes. All patients were discharged in sinus rhythm, and mitral flow Doppler evaluation at one month showed a biphasic pattern in all cases, with the A wave measuring 70 +/- 15 cm/sec. Three patients maintained sinus rhythm at five-year follow-up. Of these patients, one had developed a left atrial flutter at four-year follow-up and underwent ablation. The remaining two patients presented AF at five year follow-up. CONCLUSIONS: Percutaneous isolation of the pulmonary veins concomitant with balloon mitral valvuloplasty had suppressed AF in 60% of patients by five-year follow-up.

Electrical disconnection versus anatomical isolation of the pulmonary veins: two sides of the same treatment for atrial fibrillation?

OBJECTIVE: There are currently two techniques for percutaneous electrical isolation of the pulmonary veins (PV): anatomical isolation and electrical disconnection. The aim of the present study was to assess the continuity and circumferential extension of the radiofrequency applications necessary for PV electrical disconnection in order to evaluate the differences between this technique and anatomical isolation. METHODS: We studied 9 patients with paroxysmal atrial fibrillation who underwent PV electrical disconnection. The electrophysiologic study was performed with a decapolar circular catheter (Lasso) introduced in the PV ostia and a mapping and ablation catheter (CARTO). Ablation was performed following the activation sequence of PV potentials. Using the CARTO system we evaluated the number of applications, their distribution in quadrants, and the maximum distance between contiguous and opposite RF applications. We assessed the number of veins with circumferential applications. The number of applications and maximum distance between contiguous applications were compared to the maximum distance between opposite applications. RESULT: A total of 26 PV were isolated, including 9 right superior, 5 right inferior, 6 left superior and 6 left inferior. On average more than 10 applications were necessary, with a heterogeneous distribution. In 80.8% of the PVs the maximum distance between contiguous application was less than 1 cm and maximum distance between opposite application were highest in the right superior PV and lowest in the right inferior PV. The applications were circumferential in 80.8% of the disconnections. The number of RF applications was significantly higher in PVs with greater distances between opposite applications (correlation coefficient 0.51; p=0.008). No relation was found between maximum distances in contiguous and opposite applications (correlation coefficient r=0.13; p=NS). CONCLUSION: Electrical disconnection was achieved in the great majority of cases with circumferential applications, similarly to anatomical isolation. However, the heterogeneous distribution of the applications implies the existence of areas that need a greater number of applications and that can only be identified during electrophysiologic study. Therefore, rather than two aspects of the same treatment for atrial fibrillation, electrical disconnection and anatomical isolation complement each other in the achievement of effective PV isolation.

Epicardial electroanatomical mapping for intraoperative evaluation of bilateral pulmonary vein isolation.

UNLABELLED: Eight patients (pts; 2 female, 58 +/- 12 yrs) with paroxysmal atrial fibrillation (AF) (duration 39 +/- 20 months) underwent AF surgery, with concomitant myocardial revascularization in 2 pts and myomectomy in 1 (HOCM). AF was idiopathic in the remaining 5 pts. AF surgery consisted of bilateral isolation of the pulmonary veins (PV) using radiofrequency (RF) energy applied epicardially by a heptapolar catheter (Thermaline) in 5 pts and by a new system (Atricure) in 3 pts. For the former, each set of 7 simultaneous applications aimed at a maximum duration of 2 + 2 min., preset temperature 80 degrees C and output 150 watts. With the new system, bipolar applications were carried out; energy delivery was controlled by impedance monitoring and applications were ended after abrupt, sustained elevation of impedance. Epicardial bipolar voltage mapping (CARTO) was performed before and after each RF procedure. Using the navigator catheter, points were recorded at the insertion of each PV and at the non-isolated left atrial posterior wall. The amplitude of the local electrograms (LE) was measured before and after RF applications. If the LE amplitude inside the isolated zone was not 0.1 mV and not reduced by > 80%, a second application was performed. A maximum of 2 epicardial applications were carried out in each pt and if the final result was unsatisfactory, further endocardial applications were performed. RESULTS: Baseline LE amplitudes were > 1 mV in all cases. Successful isolation of right PVs was achieved in 7 pts, after one set of applications in 5 and a second set in 2. Left PV isolation required 2 sets of epicardial applications in all pts, being successful in only 2; 4 pts (one with associated myomectomy and 3 with idiopathic AF) received endocardial applications. Overall, bilateral PV isolation was achieved in 5 pts. CONCLUSIONS: CARTO bipolar voltage mapping is a fast, simple means for evaluation of epicardial PV isolation.

Atrial flutter ablation: correlation between isthmic activation times and flutter cycle.

BACKGROUND: Ablation of typical atrial flutter relies on the suppression of electrical conduction along the cavo-tricuspid isthmus. Bidirectional isthmus block is a criterion of successful ablation and is associated with the presence of different activation times on each side of the ablation line. OBJECTIVE: The aim of this study was to determine whether the difference in isthmic activation times correlates with the length of the atrial flutter cycle. POPULATION AND METHODS: We studied 31 patients with typical atrial flutter (93.6% male, mean age 66 +/- 9 years) who underwent successful ablation during tachycardia. CARTO electroanatomic mapping was used to confirm diagnosis of isthmus-dependent atrial flutter, guide the ablation line creation and assess its efficacy. At the end of the procedure, a three-dimensional activation map of the right atrium was constructed, under pacing from the coronary sinus ostium (with a 500 ms cycle). Activation times on the lateral (right) and septal (left) sides of the ablation line were measured. The difference between these two activation times was termed the difference in isthmic activation times (delta IAT), and was compared to the flutter cycle length. RESULTS: Mean activation times were 173.7 +/- 34.3 ms on the lateral border of the ablation line and 19.1 +/- 12.5 ms on the septal border. Mean delta IAT was 154.6 +/- 27.8 ms and mean atrial flutter cycle length was 257.5 +/- 30.6 ms. delta IAT and flutter cycle length were significantly correlated (r = 0.503, p = 0.0039). The linear regression equation that best described this result was: delta IAT = 37 + (0.46 x flutter cycle). CONCLUSION: After atrial flutter ablation, a difference in isthmic activation times of more than half the flutter cycle length was associated with isthmus conduction block.

Identification of pulmonary vein foci by non-contact mapping in patients with paroxysmal atrial fibrillation.

AIMS: Ectopies from the pulmonary veins may cause paroxysmal atrial fibrillation and their discrete ablation may be curative. In the absence of focal activity during the procedure, identification of target sites with conventional techniques is difficult. We investigated the feasibility of non-contact mapping (EnSite) for identification and successful ablation of pulmonary vein foci in such cases. METHODS AND RESULTS: We studied 7 patients with idiopathic paroxysmal atrial fibrillation referred for percutaneous ablation and not presenting spontaneous or inducible atrial premature beats during the procedure. An EnSite balloon catheter and an ablation catheter (NaviStar) were placed inside the left atrium. The ablation catheter was also used for electroanatomic mapping (CARTO) of specific sites. Multiphasic pulmonary vein potentials were detected on virtual electrograms and tagged on the non-contact map and confirmed with conventional mapping. The procedural endpoint was elimination or dissociation of the multiphasic potential. Non-contact mapping identified 13 foci of multiphasic potentials in the seven patients (5 foci were initially identified by EnSite), and discrete ablation suppressed 9 of them (69%). Six months later, 4 of the 5 patients in whom all foci were suppressed remain asymptomatic, in sinus rhythm, under no medication. CONCLUSION: In patients with paroxysmal atrial fibrillation and no ectopic activity during electrophysiological study virtual electrograms may complement conventional techniques in detecting hidden pulmonary vein foci and may be used to evaluate ablation efficacy.