Search

O aparecimento de um bloqueio atrioventricular (BAV) de esforço é um fenômeno bem conhecido1. A localizaçao do bloqueio é geralmente infra-hissiana. Descrevemos a seguir o caso de uma paciente que apresentava um BAV do segundo grau, de localizaçao intra-hissiano, provocado por esforço.

Aims: The Effectiveness and Cost of ICD follow-up Schedule with Telecardiology (ECOST) trial evaluated prospectively the economic impact of long-term remote monitoring (RM) of implantable cardioverter defibrillators (ICDs)., Methods and Results: The analysis included 310 patients randomly assigned to RM (active group) vs. ambulatory follow-ups (control group). Patients in the active group were seen once a year unless the system reported an event mandating an ambulatory visit, while patients in the control group were seen in the ambulatory department every 6 months. The costs of each follow-up strategy were compared, using the actual billing documents issued by the French health insurance system, including costs of (i) (a) ICD-related ambulatory visits and transportation, (b) other ambulatory visits, (c) cardiovascular treatments and procedures, and (ii) hospitalizations for the management of cardiovascular events. The ICD and RM system costs were calculated on the basis of the device remaining longevity at the end of the study. The characteristics of the study groups were similar. Over a follow-up of 27 months, the mean non-hospital costs per patient-year were €1695 ± 1131 in the active, vs. €1952 ± 1023 in the control group (P = 0.04), a €257 difference mainly due to device management. The hospitalization costs per patient-year were €2829 ± 6382 and €3549 ± 9714 in the active and control groups, respectively (P = 0.46). Adding the ICD to the non-hospital costs, the savings were €494 (P = 0.005) or, when the monitoring system was included, €315 (P = 0.05) per patient-year., Conclusion: From the French health insurance perspective, the remote management of ICD patients is cost saving., Clinical Trials Registration: NCT00989417, www.clinicaltrials.gov., (© The Author 2014. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: The ECOST trial examined prospectively the long-term safety and effectiveness of home monitoring (HM) of implantable cardioverter defibrillators (ICD)., Methods and Results: The trial's primary objective was to randomly compare the proportions of patients experiencing ≥ 1 major adverse event (MAE), including deaths from all causes, and cardiovascular, procedure-related, and device-related MAE associated with HM (active group) vs. ambulatory follow-ups (control group) in a sample of 433 patients. The 221 patients assigned to the active group were seen once a year, unless HM reported an ICD dysfunction or a clinical event requiring an ambulatory visit, while the 212 patients in the control group underwent ambulatory visits every 6 months. The characteristics of the study groups were similar. Over a follow-up of 24.2 months, 38.5% of patients in the active and 41.5% in the control group experienced ≥ 1 MAE (P < 0.05 for non-inferiority). The overall number of shocks delivered was significantly lower in the active (n = 193) than in the control (n = 657) group (P < 0.05) and the proportion of patients who received inappropriate shocks was 52% lower in the active (n = 11) than in the control (n = 22) group (P < 0.05). At the end of the follow-up, the battery longevity was longer in the active group because of a lower number of capacitor charges (499 vs. 2081)., Conclusion: Our observations indicate that long-term HM of ICD is at least as safe as standard ambulatory follow-ups with respect to a broad spectrum of MAE. It also lowered significantly the number of appropriate and inappropriate shocks delivered, and spared the device battery. Clinical trials registration NCT00989417.

Aims: Intracardiac electrograms (IEGMs) recorded by implantable cardioverter-defibrillators (ICDs) are essential for arrhythmia diagnosis and ICD therapy assessment. Short IEGM snapshots showing 3-10 s before arrhythmia detection were added to the Biotronik Home Monitoring system in 2005 as the first-generation IEGM Online. The RIONI study tested the primary hypothesis that experts' ratings regarding the appropriateness of ICD therapy based on IEGM Online and on standard 30 s IEGM differ in <10% of arrhythmia events., Methods and Results: A total of 619 ICD patients were enrolled and followed for 1 year. According to a predefined procedure, 210 events recorded by the ICDs were selected for evaluation. Three expert board members rated the appropriateness of ICD therapy and classified the underlying arrhythmia using coded IEGM Online and standard IEGM to avoid bias. The average duration of IEGM Online was 4.4±1.5 s. According to standard IEGM, the underlying arrhythmia was ventricular in 135 episodes (64.3%), supraventricular in 53 episodes (25.2%), oversensing in 17 episodes (8.1%), and uncertain in 5 episodes (2.4%). The expert board's rating diverged between determinable IEGM Online tracings and standard IEGM in 4.6% of episodes regarding the appropriateness of ICD therapy (95% CI up to 8.0%) and in 6.6% of episodes regarding arrhythmia classification (95% CI up to 10.5%)., Conclusion: By enabling accurate evaluation of the appropriateness of ICD therapy and the underlying arrhythmia, the first-generation IEGM Online provided a clinically effective basis for timely interventions and for optimized patient management schemes, which was comparable with current IEGM recordings.

Objectives: The purpose of this study was to assess whether additional ablation in the right atrium (RA) improves termination rate in long-lasting persistent atrial fibrillation (PsAF)., Background: Prolongation of atrial fibrillation (AF) cycle length (CL) measured from the left atrial appendage predicts favorable outcome during catheter ablation of PsAF. However, in some patients, despite prolongation of AF CL in the left atrium (LA) with ablation, AF persists. We hypothesized that this persistence is due to RA drivers, and that these patients may benefit from RA ablation., Methods: In all, 148 consecutive patients undergoing catheter ablation of PsAF (duration 25 +/- 32 months) were studied. AF CL was monitored in both atria during stepwise ablation commencing in the LA. Ablation was performed in the RA when all LA sources in AF had been ablated and an RA-LA gradient existed. The procedural end point was AF termination., Results: Two distinct patterns of AF CL change emerged during LA ablation. In 104 patients (70%), there was parallel increase of AF CL in LA and RA culminating in AF termination (baseline: LA 153 ms [range 140 to 170 ms], RA 155 ms [range 143 to 171 ms]; after ablation: LA 181 ms [range 170 to 200 ms], RA 186 ms [range 175 to 202 ms]). In 24 patients (19%), RA AF CL did not prolong, creating a right-to-left frequency gradient (baseline: LA 142 ms [range 143 to 153 ms], RA 145 ms [range 139 to 162 ms]; after ablation: LA 177 ms [range 165 to 185 ms], RA 152 ms [range 147 to 175 ms]). These patients had a longer AF history (23 months vs. 12 months, p = 0.001), and larger RA diameter (42 mm vs. 39 mm, p = 0.005), and RA ablation terminated AF in 55%. In the remaining 20 patients, biatrial ablation failed to terminate AF., Conclusions: A divergent pattern of AF CL prolongation after LA ablation resulted in a right-to-left gradient, demonstrating that the right atrium is driving AF in approximately 20% of PsAF., (Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: Catheter ablation of long-lasting persistent atrial fibrillation (AF) has been performed with varying results using a combination of different techniques. Whether arrhythmia termination during ablation is associated with an improved clinical outcome is controversial., Methods and Results: In this prospective study, 153 consecutive patients (56 +/- 10 years) underwent catheter ablation of persistent AF (25 +/- 33 months) using a stepwise approach with the desired procedural endpoint being AF termination. Repeat ablation was performed for patients with recurrent AF or atrial tachycardia (AT) after a 1 month blanking period. A minimum follow-up of 12 months with repeated Holter monitoring was performed. Atrial fibrillation was terminated in 130 patients (85%). There was a lower incidence of AF in those patients in whom AF was terminated during the index procedure compared with those who had not (5 vs. 39% P < 0.0001, mean follow-up 32 +/- 11 months). Seventy-nine patients underwent repeat procedures: 64/130 in the termination group (6 AF, 58 AT) and 15 in the non-termination group (9 AF, 7 AT). After repeat ablation, sinus rhythm was maintained in 95% in whom AF was terminated compared with 52% in those in whom AF could not be terminated., Conclusion: Procedural termination of long-lasting AF by catheter ablation alone is associated with an improved outcome.

Aims: The diagnosis of Brugada syndrome (BS) is typically made in a young and otherwise healthy population. In patients with a high risk of sudden cardiac death (SCD), the only currently recommended therapy is an implantable cardioverter defibrillator (ICD), but these are not without complications. We investigated whether remote ICD monitoring could simplify follow-up and detect potential complications in these patients., Methods and Results: Thirty-five consecutive patients (26 males, 44 +/- 11 years) implanted with an ICD for BS with a remote monitoring ['Home Monitoring' (HM), Biotronik, Germany] system were prospectively enrolled in this study. They were matched for age, sex, and follow-up duration with 35 BS patients implanted with an ICD without this capability. During a mean follow-up of 33 +/- 17 months, the number of cardiology consultations was significantly lower in the HM group (3 +/- 2 vs. 7 +/- 3; P < 0.001). Inappropriate shock(s) [IS(s)] occurred in three patients (8.5%) in the HM group vs. six (17%) in the control group (P = NS). Ten patients in the HM group had a median of four alerts ('ventricular tachycardia/ventricular fibrillation detection' in all patients, 'shock' in three, 'ineffective shock' in two patients with shock on noise, 'extreme ventricular pacing impedance' in one patient due to lead failure, and 'deactivated therapy' in two patients with lead failure before replacement). In 5 of these 10 patients, prompt reprogramming of the ICD may have prevented IS(s)., Conclusion: Remote ICD monitoring in patients with BS decreases outpatient consultations and may help prevent ISs.

Objectives: Our purpose was to evaluate the efficacy of antiarrhythmic drugs (AADs) in recurrent ventricular fibrillation (VF) associated with inferolateral early repolarization pattern on the electrocardiogram., Background: Although an implantable cardioverter-defibrillator is the treatment of choice, additional AADs may be necessary to prevent frequent episodes of VF and reduce implantable cardioverter-defibrillator shock burden or as a lifesaving therapy in electrical storms., Methods: From a multicenter cohort of 122 patients (90 male subjects, age 37 +/- 12 years) with idiopathic VF and early repolarization abnormality in the inferolateral leads, we selected all patients with more than 3 episodes of VF (multiple) including those with electrical storms (> or =3 VF in 24 h). The choice of AAD was decided by individual physicians. Follow-up data were obtained for all patients using monitoring with implantable defibrillator. Successful oral AAD was defined as elimination of all recurrences of VF with a minimal follow-up period of 12 months., Results: Multiple episodes of VF were observed in 33 (27%) patients. Electrical storms (34 +/- 47 episodes) occurred in 16 and were unresponsive to beta-blockers (11 of 11), lidocaine/mexiletine (9 of 9), and verapamil (3 of 3), while amiodarone was partially effective (3 of 10). In contrast, isoproterenol infusion immediately suppressed electrical storms in 7 of 7 patients. Over a follow-up of 69 +/- 58 months, oral AADs were poorly effective in preventing recurrent VF: beta-blockers (2 of 16), verapamil (0 of 4), mexiletine (0 of 4), amiodarone (1 of 7), and class 1C AADs (2 of 9). Quinidine was successful in 9 of 9 patients, decreasing recurrent VF from 33 +/- 35 episodes to nil for 25 +/- 18 months. In addition, quinidine restored a normal electrocardiogram., Conclusions: Multiple recurrences of VF occurred in 27% of patients with early repolarization abnormality and may be life threatening. Isoproterenol in acute cases and quinidine in chronic cases are effective AADs.

Background: The mainstay of treatment for atrial fibrillation (AF) remains pharmacological; however, catheter ablation has increasingly been used over the last decade. The relative merits of each strategy have not been extensively studied., Methods and Results: We conducted a randomized multicenter comparison of these 2 treatment strategies in patients with paroxysmal AF resistant to at least 1 antiarrhythmic drug. The primary end point was absence of recurrent AF between months 3 and 12, absence of recurrent AF after up to 3 ablation procedures, or changes in antiarrhythmic drugs during the first 3 months. Ablation consisted of pulmonary vein isolation in all cases, whereas additional extrapulmonary vein lesions were at the discretion of the physician. Crossover was permitted at 3 months in case of failure. Echocardiographic data, symptom score, exercise capacity, quality of life, and AF burden were evaluated at 3, 6, and 12 months by the supervising committee. Of 149 eligible patients, 112 (18 women [16%]; age, 51.1+/-11.1 years) were enrolled and randomized to ablation (n=53) or "new" antiarrhythmic drugs alone or in combination (n=59). Crossover from the antiarrhythmic drugs and ablation groups occurred in 37 (63%) and 5 patients (9%), respectively (P=0.0001). At the 1-year follow-up, 13 of 55 patients (23%) and 46 of 52 patients (89%) had no recurrence of AF in the antiarrhythmic drug and ablation groups, respectively (P<0.0001). Symptom score, exercise capacity, and quality of life were significantly higher in the ablation group., Conclusions: This randomized multicenter study demonstrates the superiority of catheter ablation over antiarrhythmic drugs in patients with AF with regard to maintenance of sinus rhythm and improvement in symptoms, exercise capacity, and quality of life.

Aims: The OEDIPE trial examined the safety and efficacy of an abbreviated hospitalization after implantation or replacement of dual-chamber pacemakers (PM) using a telecardiology-based ambulatory surveillance programme., Methods and Results: Patients were randomly assigned to (i) an active group, discharged from the hospital 24 h after a first PM implant or 4-6 h after replacement, and followed for 4 weeks with Home-Monitoring (HM), or (ii) a control group followed for 4 weeks according to usual medical practices. The primary objective was to confirm that the proportion of patients who experienced one or more major adverse events (MAE) was not higher in the active than in the control group. The study included 379 patients. At least one treatment-related MAE was observed in 9.2% of patients (n = 17) assigned to the active group vs. 13.3% of patients (n = 26) in the control group (P = 0.21), a 4.1% absolute risk reduction (95% CI -2.2 to 10.4; P = 0.98). By study design, the mean hospitalization duration was 34% shorter in the active than in the control group (P < 0.001), and HM facilitated the early detection of technical issues and detectable clinical anomalies., Conclusion: Early discharge with HM after PM implantation or replacement was safe and facilitated the monitoring of patients in the month following the procedure.

Catheter ablation is an effective treatment for symptomatic atrial fibrillation. A thorough understanding of the left atrium anatomy and its adjacent structures is critical for the success of the procedure and for avoiding complications. Pre-procedural imaging aims at determining left atrial size, anatomy, and function and is also used to rule out an atrial thrombus. During the procedure, while fluoroscopy remains the gold standard imaging modality for guiding transseptal catheterization and catheter ablation, numerous other imaging modalities have been developed to improve 3D navigation and ablation. Finally, post-operative imaging intends to monitor heart function and to search for potential complications like pulmonary vein stenosis or the rare but dramatic atrio-oesophageal fistula. This review discusses the relative merits of all imaging modalities available in the context of catheter ablation of atrial fibrillation.

Aims: This study evaluates the clinical outcome and incidence of left atrial (LA) macro re-entrant atrial tachycardia (AT) in patients in whom persistent atrial fibrillation (AF) terminated during catheter ablation without the need of roof and mitral lines., Methods and Results: Persistent AF was terminated by ablation in 154 of 180 consecutive patients. AF history was 60 months including 11 months of continuous AF. Patients were divided into two groups: those who had not required both LA linear lesions to terminate AF (group A, 85 patients), and those who had (group B, 69 patients). There was no difference in clinical and echocardiographic characteristics between both groups except for a shorter duration of continuous AF in group A (9 vs.12 months, respectively) (P = 0.03). After 28 months of follow-up, the incidence of LA macro re-entrant AT necessitating linear ablation was higher in group A (76%) compared with group B (33%) (P = 0.002). When complete linear block could not be achieved during the index procedure, the incidence of subsequent roof (P = 0.008) or mitral isthmus (P = 0.010) dependent macro re-entrant AT was higher., Conclusion: Although persistent AF can be terminated by catheter ablation without linear lesions, the majority will require linear lesions for macro re-entrant AT.

Background: Transseptal puncture with a conventional mechanical technique can fail because of a resistant interatrial septum. We evaluated the efficacy and safety of a new method to cross-resistant septae by transmitting radiofrequency (RF) energy through the transseptal needle., Methods and Results: Among 269 consecutive transseptal punctures, 13 (5%) were unsuccessful in 12 different patients (11 men aged 52+/-12 years) using the conventional Brockenbrough technique. All 12 patients had previously undergone at least 1 transseptal catheterization. The needle position in relation to the fossa ovalis was assessed by fluoroscopy in orthogonal views and was confirmed with contrast injection and by visualizing the characteristic "tenting" of the fossa ovalis. Before using RF energy, there were a median of 6 unsuccessful attempts to perforate the septum conventionally, with 1 pericardial puncture (with a nonsignificant effusion). RF transseptal puncture was then performed by delivering unipolar RF with manual contact between the ablation catheter and the proximal extremity of the needle at the patient's groin. RF transseptal puncture was achieved at the first attempt in all patients within a median of 1 second (interquartile range, 1 to 4) and without any complication. The only parameter predictive of a septum resistant to conventional puncture was the total number of transseptal catheterizations (3.2+/-1 versus 1.8+/-1, P<0.001)., Conclusions: Transmission of RF energy from the ablation catheter up to the tip of the transseptal needle provides an easy and safe method for piercing the fossa ovalis when the conventional approach fails because of a resistant septum.

Aims: With the expanding indications for implantable cardioverter defibrillator (ICD) and reports of unexpected ICD failures, home monitoring (HM) was proposed to decrease follow-up workload and increase patient safety. Home monitoring implantable cardioverter defibrillators offer wireless, everyday transfer of ICD status and therapy data to a central HM Service Center, which notifies the attending physician of relevant HM events. We evaluated functionality and safety of HM ICDs., Methods and Results: A total of 260 patients with HM ICDs were monitored for a mean of 10 +/- 5 months. Time to HM events [medical (ventricular tachycardia/ventricular fibrillation) and technical (ICD system integrity)] since ICD implantation and since the latest in-clinic follow-up was analysed. Mean number of HM events per 100 patients per day was calculated, without and with a 2-day blanking period for re-notifying the same type of event. About 41.2% of the patients had HM events (38.1% medical, 0.8% technical, and 2.3% both types). Probability of any HM event after 1.5 years was 0.50 (95% confidence interval: 0.42-0.58). More than 60% of new HM event types occurred within the first month after follow-up. A mean of 0.86 event notifications was received per 100 patients per day or 0.45 with the 2-day blanking period., Conclusion: Home monitoring is feasible and associated with an early detection of medical and technical events.

Aims: Assess the impact of persistent/permanent atrial fibrillation (AF) ablation on endocrine and mechanical cardiac functions., Methods and Results: In all, 43 patients (40 males, 53 +/- 12 years) undergoing persistent/permanent AF ablation had atrial (ANP) and brain natriuretic peptide (BNP) measurements before day 1, 3, and 3 months after ablation. In the same period of time transthoracic echocardiography was performed. With a mean radiofrequency delivery of 98 +/- 29 min, sinus rhythm (SR) was restored in 30 patients (70%) without DC shock. ANP decreased significantly (P < 0.001) with restoration of SR and then increased until day 3 post ablation without reaching the level observed during AF. At 3 months, ANP was significantly lower than day 3 reaching normal value in 28 (65%) patients and being <7 pg/mL in 4 (9%). The BNP followed the same trend with normal BNP level in 23 (53%) patients at 3 months. Identifiable atrial filling waves on the pulsed Doppler transmitral recordings performed between day 2 and day 4 after the procedure were seen in 18 patients (42%). At 3 months, 39 (95%) of the patients with SR during echocardiography had a significant A wave., Conclusion: SR following persistent/permanent AF ablation is associated with a dramatic decrease in natriuretic peptides. At 3 months, despite relatively extensive atrial ablation, endocrine and mechanical cardiac functions are significantly improved.

Objectives: We compared the effects of triple-site versus dual-site biventricular stimulation in candidates for cardiac resynchronization therapy., Background: Conventional biventricular stimulation with a single right ventricular (RV) and a single left ventricular (LV) lead is associated with persistence of cardiac dyssynchrony in up to 30% of patients., Methods: This multicenter, single-blind, crossover study enrolled 40 patients (mean age 70 +/- 9 years) with moderate-to-severe heart failure despite optimal drug treatment, a mean LV ejection fraction of 26 +/- 11%, and permanent atrial fibrillation requiring cardiac pacing for slow ventricular rate. A cardiac resynchronization therapy device connected to 1 RV and 2 LV leads, inserted in 2 separate coronary sinus tributaries, was successfully implanted in 34 patients. After 3 months of biventricular stimulation, the patients were randomly assigned to stimulation for 3 months with either 1 RV and 2 LV leads (3-V) or to conventional stimulation with 1 RV and 1 LV lead (2-V), then crossed over for 3 months to the alternate configuration. The primary study end point was quality of ventricular resynchronization (Z ratio). Secondary end points included reverse LV remodeling, quality of life, distance covered during 6-min hall walk, and procedure-related morbidity and mortality. Data from the 6- and 9-month visits were combined to compare end points associated with 2-V versus 3-V., Results: Data eligible for protocol-defined analyses were available in 26 patients. No significant difference in Z ratio, quality of life, and 6-min hall walk was observed between 2-V and 3-V. However, a significantly higher LV ejection fraction (27 +/- 11% vs. 35 +/- 11%; p = 0.001) and smaller LV end-systolic volume (157 +/- 69 cm(3) vs. 134 +/- 75 cm(3); p = 0.02) and diameter (57 +/- 12 mm vs. 54 +/- 10 mm; p = 0.02) were observed with 3-V than with 2-V. There was a single minor procedure-related complication., Conclusions: Cardiac resynchronization therapy with 1 RV and 2 LV leads was safe and associated with significantly more LV reverse remodeling than conventional biventricular stimulation.

Objectives: This study sought to determine the characteristics of atrial electrograms predictive of slowing or termination of atrial fibrillation (AF) during ablation of chronic AF., Background: There is growing recognition of a role for electrogram-based ablation., Methods: Forty consecutive patients (34 male, 59 +/- 10 years) undergoing ablation for chronic AF persisting for a median of 12 months (range 1 to 84 months) were included. After pulmonary vein isolation and roof line ablation, electrogram-based ablation was performed in the left atrium and coronary sinus. Targeted electrograms were acquired in a 4-s window and characterized by: 1) percentage of continuous electrical activity; 2) bipolar voltage; 3) dominant frequency; 4) fractionation index; 5) mean absolute value of derivatives of electrograms; 6) local cycle length; and 7) presence of a temporal gradient of activation. Electrogram characteristics at favorable ablation regions, defined as those associated with slowing (a >or=6-ms increase in AF cycle length) or termination of AF were compared with those at unfavorable regions., Results: The AF was terminated by electrogram-based ablation in 29 patients (73%) after targeting a total of 171 regions. Ablation at 37 (22%) of these regions was followed by AF slowing, and at 29 (17%) by AF termination. The percentage of continuous electrical activity and the presence of a temporal gradient of activation were independent predictors of favorable ablation regions (p = 0.016 and p = 0.038, respectively). Other electrogram characteristics at favorable ablation regions were not significantly different from those at unfavorable ablation regions., Conclusions: Catheter ablation at sites displaying a greater percentage of continuous activity or a temporal activation gradient is associated with slowing or termination of chronic AF.

Aims: To evaluate the contribution of the posterior left atrium (LA) to chronic atrial fibrillation (AF)., Methods and Results: Twenty-seven patients with chronic-AF were studied. After pulmonary vein (PV) isolation, the posterior-LA was isolated by ablation joining the right- and left-PVs using an irrigated-tip catheter. Isolation was demonstrated by absent/dissociated posterior-LA activity and the inability to pace the region. Ablation impact was determined by the effect on cycle length (CL) and AF termination. Posterior-LA isolation was achieved using 35 +/- 12 min of radiofrequency with total fluoroscopic and procedural durations of 64 +/- 16 and 199 +/- 46 min, resulting in abolition of electrograms (n = 21) or autonomous activity (n = 6; CL 820 +/- 343 ms). AFCL increased from 156 +/- 28 ms to 162 +/- 27 ms with PV-isolation and to 175 +/- 32 ms by posterior-LA exclusion (P < 0.0001). AF persisted in all after PV-isolation and terminated in 5 (19%) during posterior-LA-isolation. After 10 +/- 6 months, 12 patients developed atrial tachycardia (four) or AF (eight); four underwent repeat posterior-LA-isolation, while the others required additional ablation/antiarrhythmics. After 21 +/- 5 months, 17 (63%) were in sinus rhythm following posterior-LA-isolation., Conclusion: This study demonstrates the feasibility of complete posterior-LA exclusion by catheter ablation. This strategy results in maintenance of sinus rhythm in 63% at 2 years follow-up.

Background: Cardiovascular diseases leading to pacemaker implantations are suspected of being associated with a high rate of undiagnosed sleep apnea syndrome (SAS). We sought to determine the prevalence and consequences of SAS in pacemaker patients according to pacing indications: heart failure, symptomatic diurnal bradycardia, and atrioventricular block., Methods and Results: Ninety-eight consecutive patients (mean age, 64+/-8 years) not known to have sleep apnea were included; 29 patients were paced for dilated cardiomyopathy (29%), 33 for high-degree atrioventricular block (34%), and 36 for sinus node disease (37%). All underwent Epworth Sleepiness Scale assessment and polysomnography with the pacemaker programmed to right ventricular DDI pacing mode (lower pacing rate, 50 pulses per minute). SAS was defined as an apnea-hypopnea index > or = 10/h. Mean Epworth Sleepiness Scale was in the normal range (7+/-4), although 13 patients (25%) had an abnormal score > 11/h. Fifty-seven patients (59%) had SAS; of these, 21 (21.4%) had a severe SAS (apnea-hypopnea index > 30/h). In patients with heart failure, 50% presented with SAS (mean apnea-hypopnea index, 11+/-7) compared with 68% of patients with atrioventricular block (mean apnea-hypopnea index, 24+/-29) and 58% with sinus node disease (mean apnea-hypopnea index, 19+/-23)., Conclusions: In paced patients, there is an excessively high prevalence of undiagnosed SAS (59%). Whether treating SAS would have changed the need for pacing is unknown. Treatment effects should be further evaluated particularly because these patients are less symptomatic than typical SAS patients. In any case, SAS should be systematically searched for in paced patients owing to potential detrimental effects on their cardiovascular evolution.

Objectives: This study sought to evaluate the effects of stepwise catheter ablation of chronic atrial fibrillation (AF) on atrial electrical and mechanical properties., Background: Although stepwise catheter ablation of chronic AF is associated with acute arrhythmia termination and a favorable clinical outcome, atrial tissue damage following the procedure has not been evaluated., Methods: Forty patients who had previously undergone catheter ablation of chronic AF were studied. In the index procedure, termination of AF was achieved by catheter ablation alone in 36 of 40 patients (90%). Electroanatomical mapping was performed in sinus rhythm > or =1 month after the index procedure, during which the surface area of scar (bipolar voltage of <0.05 mV), low-voltage tissue (<0.5 mV), and atrial propagation were evaluated. Left atrial (LA) mechanical function was assessed by transthoracic echocardiography., Results: Electroanatomical mapping showed areas of scar and low-voltage accounting for 31% +/- 12% and 32% +/- 17% of the total LA surface area respectively, with the ablated pulmonary vein region accounting for 20% +/- 4% of the LA surface area. The area of scar outside the pulmonary vein region represented 14% +/- 12% of the LA surface area using the initial randomized ablation strategy, and 6% +/- 8% (p = 0.02) using a specific ablation strategy. Atrial conduction was diversely affected by ablation with a wide range of LA conduction times observed (range 100 to 360 ms). The LA contraction was shown in all patients by the presence of late diastolic mitral flow (37 +/- 15 cm/s) and a mean LA active emptying fraction of 18 +/- 11%. At 9 +/- 5 months of follow-up, 39 patients (98%) were in sinus rhythm., Conclusions: Stepwise ablation achieving sinus rhythm in patients with chronic AF has a significant impact on LA electrical activity but is associated with recovery of LA function.

Background: Brugada syndrome is an arrhythmogenic disease characterized by an increased risk of sudden cardiac death (SCD) by ventricular fibrillation. At present, an implantable cardioverter-defibrillator (ICD) is the recommended therapy in high-risk patients. This multicenter study reports the outcome of a large series of patients implanted with an ICD for Brugada syndrome., Methods and Results: All patients (n=220, 46+/-12 years, 183 male) with a type 1 Brugada ECG pattern implanted with an ICD in 14 centers between 1993 and 2005 were investigated. ICD indication was based on resuscitated SCD (18 patients, 8%), syncope (88 patients, 40%), or positive electrophysiological study in asymptomatic patients (99 patients, 45%). The remaining 15 patients received an ICD because of a family history of SCD or nonsustained ventricular arrhythmia. During a mean follow-up of 38+/-27 months, no patient died and 18 patients (8%) had appropriate device therapy (10+/-15 shocks/patient, 26+/-33 months after implantation). The complication rate was 28%, including inappropriate shocks, which occurred in 45 patients (20%, 4+/-3 shocks/patient, 21+/-20 months after implantation). The reasons for inappropriate therapy were lead failure (19 patients), T-wave oversensing (10 patients), sinus tachycardia (10 patients), and supraventricular tachycardia (9 patients). Among implantation parameters, high defibrillation threshold, high pacing threshold, and low R-wave amplitude occurred, respectively, in 12%, 27%, and 15% of cases., Conclusions: In this large Brugada syndrome population, a low incidence of arrhythmic events was found, with an annual event rate of 2.6% during a follow-up of >3 years, in addition to a significant risk of device-related complications (8.9%/year). Inappropriate shocks were 2.5 times more frequent than appropriate ones.

Objectives: The purpose of this study was to characterize the occurrence of phrenic nerve injury (PNI) and its outcome after radiofrequency (RF) ablation of atrial fibrillation (AF)., Background: It is recognized that extra-myocardial damage may develop owing to penetration of ablative energy., Methods: Between 1997 and 2004, 3,755 consecutive patients underwent AF ablation at five centers. Among them, 18 patients (0.48%; 9 male, 54 +/- 10 years) had PNI (16 right, 2 left). The procedure consisted of pulmonary vein (PV) isolation in 15 patients and anatomic circumferential ablation in 3 patients, with additional left atrial lesions (n = 11) and/or superior vena cava (SVC) disconnection (n = 4)., Results: Right PNI occurred during ablation of right superior PV (n = 12) or SVC disconnection (n = 3). Left PNI occurred during ablation at the left atrial appendage. Immediate features were dyspnea, cough, hiccup, and/or sudden diaphragmatic elevation in 9, and in the remaining the diagnosis was made after ablation owing to dyspnea (n = 7) or on routine radiographic evaluation (n = 2). Four patients (22%) were asymptomatic. Complete recovery occurred in 12 patients (66%). Recovery occurred within 24 h in the two patients with left PNI and in one patient with right PNI occurring with SVC disconnection. In the other nine patients, right PNI recovery occurred after 4 +/- 5 months (1 to 12 months) with respiratory rehabilitation. After a mean follow-up of 36 +/- 33 months, six patients have persistent PNI (three with partial and three with no recovery)., Conclusions: In this multicenter experience, PNI was a rare complication (0.48%) of AF ablation. Ablation of the right superior PV, SVC, and left atrial appendage were associated with PNI. Complete (66%) or partial (17%) recovery was observed in the majority.

Objectives: The aim of the present study was to assess the feasibility of identifying sites of focal atrial activity by localized high-density endocardial mapping during atrial fibrillation (AF)., Background: Sites of focal activity in the left atrium have been demonstrated by epicardial mapping during AF., Methods: Twenty-four patients (15 with paroxysmal, 3 with persistent, and 6 with permanent AF) underwent endocardial mapping during AF. A 20-pole catheter with five radiating spines was used to map both atria for 30 s in each of 10 pre-determined segments. A focal activity was defined as > or =3 atrial cycles with activation spreading from center to periphery of the mapping catheter. Catheter ablation was performed independent of the mapping results., Results: Spontaneous focal activities were observed in 13 sites in the left atrium (9%; anterior 1, roof 2, posterior 6, inferior 4) in 12 patients (9 paroxysmal, 3 persistent). Focal activity was observed continuously (two sites) or intermittently (11 sites, median 5 episodes), and associated with shortening of the cycle length (from 183 +/- 33 ms to 172 +/- 29 ms; p < 0.05). The mean duration of an intermittent episode was 1.5 s (range 0.4 to 7.1 s). Atrial fibrillation terminated without ablation at the foci in all of 12 patients, but in 2 of them, re-initiated arrhythmia was successfully ablated at these foci. Nine of these 12 patients (75%) were arrhythmia-free without antiarrhythmic drugs during a follow-up period of 7.0 +/- 3.1 months., Conclusions: Termination of AF without ablation at the sites of atrial focal activity suggests that this activity may be triggered by impulses originating from other regions, such as the pulmonary veins.

Much of our understanding of the mechanisms of macro re-entrant atrial tachycardia comes from study of cavotricuspid isthmus (CTI) dependent atrial flutter. In the majority of cases, the diagnosis can be made from simple analysis of the surface ECG. Endocardial mapping during tachycardia allows confirmation of the macro re-entrant circuit within the right atrium while, at the same time, permitting curative catheter ablation targeting the critical isthmus of tissue located between the tricuspid annulus and the inferior vena cava. The procedure is short, safe and by demonstration of an electrophysiological endpoint - bidirectional conduction block across the CTI - is associated with an excellent outcome following ablation. It is now fair to say that catheter ablation should be considered as a first line therapy for patients with documented CTI-dependent atrial flutter.

Objectives: The goal of the present prospective study is to evaluate the impact of vagal excitation on ongoing atrial fibrillation (AF) during pulmonary vein (PV) isolation., Background: The role of vagal tone in maintenance of AF is controversial in humans., Methods: Twenty-five patients (18 with paroxysmal AF, 7 with chronic AF) were selected by occurrence of vagal excitation during AF (atrioventricular [AV] block: R-R interval >3 s) produced by PV isolation. Fibrillatory cycle length (CL) in the targeted PV and coronary sinus (CS) were determined before, during, and after vagal excitation. The CL was available at PV ostium during vagal excitation in 11 patients., Results: Forty-eight episodes of vagal excitation were observed. During vagal excitation, CL abruptly decreased both in CS and PV (CS, 164 +/- 20 ms to 155 +/- 23 ms, p < 0.0001; PV, 160 +/- 22 ms to 143 +/- 28 ms, p < 0.0001), and both returned to the baseline value with resumption of AV conduction. The decrease in PVCL occurred earlier (2.5 +/- 1.5 s vs. 4.0 +/- 2.6 s, p < 0.01) and was of greater magnitude than that in CSCL (16 +/- 16 ms vs. 8 +/- 9 ms, p < 0.01). A sequential gradient of CL was observed from PV to PV ostium and CS during vagal excitation (138 +/- 29 ms, 149 +/- 24 ms, and 159 +/- 26 ms, respectively). The decrease in CL was significantly greater in paroxysmal than in chronic AF (CS, 11 +/- 9 ms vs. 5 +/- 7 ms, p < 0.05; PV, 23 +/- 25 ms vs. 8 +/- 14 ms, p < 0.05)., Conclusions: Vagal excitation is associated with shortening of fibrillatory CL. This occurs earlier in PV with a sequential gradient to PV ostium and CS, suggesting that vagal excitation enhances a driving role of PV.

Background: Endocardial mapping of localized sources driving atrial fibrillation (AF) in humans has not been reported., Methods and Results: Fifty patients with AF organized by prior pulmonary vein and linear ablation were studied. AF was considered organized if mapping during AF showed irregular but discrete atrial complexes exhibiting consistent activation sequences for >75% of the time using a 20-pole catheter with 5 radiating spines covering 3.5-cm diameter or sequential conventional mapping. A site or region centrifugally activating the remaining atrial tissue defined a source. During AF with a cycle length of 211+/-32 ms, activation mapping identified 1 to 3 sources at the origin of atrial wavefronts in 38 patients (76%) predominantly in the left atrium, including the coronary sinus region. Electrograms at the earliest area varied from discrete centrifugal activation to an activity spanning 75% to 100% of the cycle length in 42% of cases, the latter indicating complex local conduction or a reentrant circuit. A gradient of cycle length (>20 ms) to the surrounding atrium was observed in 28%. Local radiofrequency ablation prolonged AF cycle length by 28+/-22 ms and either terminated AF or changed activation sequence to another organized rhythm. In 4 patients, the driving source was isolated, surrounded by the atrium in sinus rhythm, and still firing at high frequency (228+/-31 ms) either permanently or in bursts., Conclusions: AF associated with consistent atrial activation sequences after prior ablation emanates mostly from localized sources that can be mapped and ablated. Some sources harbor electrograms suggesting the presence of localized reentry.

Background: There are no reports describing the technique, electrophysiological evaluation, and clinical consequences of complete linear block at roofline joining the superior pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (AF)., Methods and Results: Ninety patients with drug-refractory paroxysmal AF undergoing radiofrequency ablation were prospectively randomized into 2 ablation strategies: (1) PV isolation (n=45) or (2) PV isolation in combination with linear ablation joining the 2 superior PVs (roofline; n=45). In both groups, the cavotricuspid isthmus, fragmented peri-PV-ostial electrograms, and spontaneous non-PV foci were ablated. Roofline ablation was performed at the most cranial part of the left atrium (LA) with complete conduction block demonstrated during LA appendage pacing by the online mapping of continuous double potential and an activation detour propagating around the PVs to activate caudocranially the posterior wall of the LA. The effect of ablation at the LA roof was evaluated by the change in fibrillatory cycle length, termination and noninducibility of AF, and clinical outcome. PV isolation was achieved in all patients with no significant differences in the radiofrequency duration, fluoroscopy, or procedural time between the groups. Roofline ablation required 12+/-6 (median 11, range 3 to 25) minutes of radiofrequency energy delivery with a fluoroscopic duration of 7+/-2 minutes and was performed in 19+/-7 minutes. Complete block was confirmed in 43 patients (96%) and resulted in an activation delay that was shorter circumventing the left than the right PVs during LA appendage pacing (138+/-15 versus 146+/-25 ms, respectively; P=0.01). Roofline ablation resulted in a significant increase in the fibrillatory cycle length (198+/-38 to 217+/-44 ms; P=0.0005), termination of arrhythmia in 47% (8/17), and subsequent noninducibility of AF in 59% (10/17) of the patients inducible after PV isolation. However, LA flutter, predominantly perimitral, could be induced in 10 patients (22%) after roofline ablation. At 15+/-4 months, 87% of the roofline group and 69% with PV isolation alone are arrhythmia free without antiarrhythmics (P=0.04)., Conclusions: This prospective randomized study demonstrates the feasibility of achieving complete linear block at the LA roof. Such ablation resulted in the prolongation of the fibrillatory cycle, termination of AF, and subsequent noninducibility and is associated with an improved clinical outcome compared with PV isolation alone.

Objectives: The goal of this study was to characterize the origin of focal atrial tachycardias (AT)., Background: Focal ATs originate from a small area and spread centrifugally; however, activation at the AT origin has not been characterized., Methods: Twenty patients with AT having failed prior ablation or occurring after atrial fibrillation ablation were studied. After excluding macro-re-entry, AT was mapped using a 20-pole catheter (five radiating spines; diameter 3.5 cm), performing vector mapping to identify the earliest activity followed by high-density mapping at the AT origin. Localized re-entry was considered if >85% of the tachycardia cycle length (CL) was observed within the mapping field and was confirmed by entrainment., Results: A total of 27 ATs were mapped to the pulmonary vein ostia (n = 5), and left (n = 16) and right atria (n = 6). A localized focus was evidenced at the site of origin in 19 ATs (70%), whereas in 8 (30%), localized re-entry was evidenced by 95.2 +/- 4.5% of the tachycardia CL recorded within the mapping field and entrainment showed a post-pacing interval <20 ms longer than tachycardia CL (6 of 6 tested). Localized re-entry had a shorter CL (p = 0.009), slowed conduction at its origin (fractionated potential 115 +/- 19 ms vs. 64 +/- 22 ms, representing 49 +/- 10% and 20 +/- 10% of tachycardia CL, respectively; p < 0.0001), and were more often contiguous with regions of electrical silence or conduction abnormalities (88% vs. 32%; p = 0.01). In addition, mapping documented varying degrees of intra-atrial conduction block, preferential conduction (n = 5), and rapid bursts of myocardial activity (n = 1). At 11 +/- 7 months, none have had recurrence of AT., Conclusions: High-density multielectrode mapping can be used to perform vector mapping to localize complex AT. It provides novel insight into the mechanisms of focal AT, distinguishing focal AT from localized re-entry.

Aims: Anatomical and wide atrial encircling of the pulmonary veins (PVs) has been proposed as a cure of atrial fibrillation (AF). We evaluated the acute achievement of electrical PV isolation using this approach. In addition, the consequences of wide encircling of the PVs with isolation were assessed., Methods and Results: Twenty patients with paroxysmal AF were studied. Anatomically guided ablation was performed utilizing the CARTO system to deliver coalescent lesions circumferentially around each PV to produce a voltage reduction to <0.1 mV, with the operator blinded to recordings of circumferential PV mapping. After achieving the anatomical endpoint, the incidence of residual conduction and the amplitude and conduction delay of residual PV potentials were determined. Electrical isolation of the PV was then performed and the residual far-field potentials evaluated. Individual PV ablation was performed in all PVs. Anatomically guided PV ablation was performed for 47.3+/-11 min, after which 44 (55%) PVs were electrically isolated. In the remaining 45%, despite abolition of the local potential at the ablation site, PV potentials [amplitude 0.2 mV (range 0.09-0.75) and delay of 50.3+/-12.6 ms] were identified by circumferential mapping. After electrical isolation (12.2+/-11.7 min ablation), 55 (69%) PVs demonstrated far-field potentials; with a greater incidence (P=0.015) and amplitude (P=0.021) on the left compared with the right PVs. At 13.2+/-8.3 months follow-up, 13 patients (65%) remained arrhythmia-free without anti-arrhythmics. In four patients (20%), spontaneous sustained left atrial macrore-entry required re-mapping and ablation. Macrore-entry was observed to utilize regions around or bordering the previous ablation as its substrate., Conclusion: Anatomically guided circumferential PV ablation results in apparently coalescent but electrically incomplete lesions with residual conduction in 45% of PVs. Wide encircling of the PVs was associated with left atrial macrore-entry in 20% of patients.

Background: This prospective clinical study evaluates the feasibility and efficacy of combined linear mitral isthmus ablation and pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (AF)., Methods and Results: One hundred consecutive patients (13 women; age 55+/-10 years) with drug-refractory, symptomatic paroxysmal AF underwent PV isolation and linear ablation of the cavotricuspid isthmus and the mitral isthmus (lateral mitral annulus to the left inferior PV). They were compared with 100 consecutive patients (14 women; age, 52+/-10 years) undergoing PV isolation and cavotricuspid ablation without mitral isthmus ablation. Bidirectional mitral isthmus block was confirmed by demonstrating (1) a parallel corridor of double potentials during coronary sinus (CS) pacing, (2) an activation detour by pacing either side of the line, and (3) differential pacing techniques. Isolation of all PVs and cavotricuspid isthmus ablation were performed successfully in all. Mitral isthmus block was achieved in 92 patients after 20+/-10 minutes of endocardial radiofrequency application and an additional 5+/-4 minutes of epicardial radiofrequency application from within the CS in 68, resulting in a conduction delay of 151+/-26 ms during CS pacing. Thirty-two patients with mitral isthmus ablation compared with 49 without had recurrent atrial arrhythmia (P=0.02) requiring further ablation. At 1 year after the last procedure, 87 patients with mitral isthmus ablation and 69 without (P=0.002) were arrhythmia free without antiarrhythmic drugs, mitral isthmus ablation being the only factor associated with long-term success (RR for AF recurrence, 0.2; CI, 0.1 to 0.4; P<0.001)., Conclusions: Catheter ablation of the mitral isthmus results consistently in demonstrable conduction block and is associated with a high cure rate for paroxysmal AF.

Background: The modification of atrial fibrillation cycle length (AFCL) during catheter ablation in humans has not been evaluated., Methods and Results: Seventy patients undergoing ablation of prolonged episodes of AF were randomized to pulmonary vein (PV) isolation or additional ablation of the mitral isthmus. Mean AFCL was determined at a distance from the ablated area (coronary sinus) at the following intervals: before ablation, after 2- and 4-PV isolations, and after linear ablation. Inducibility of sustained AF (> or =10 minutes) was determined before and after ablation. Spontaneous sustained AF (715+/-845 minutes) was present in 30 patients and induced in 26 (AFCL, 186+/-19 ms). PV isolation terminated AF in 75%, with the number of PVs requiring isolation before termination increasing with AF duration (P=0.018). PV isolation resulted in progressive or abrupt AFCL prolongation to various extents, depending on the PV: to 214+/-24 ms (P<0.0001) when AF terminated and to 194+/-19 ms (P=0.002) when AF persisted. The increase in AFCL (30+/-17 versus 14+/-11 ms; P=0.005) and the decrease in fragmentation (30.0+/-26.8% to 10.3+/-14.5%; P<0.0001) were significantly greater in patients with AF termination. Linear ablation prolonged AFCL, with a greater prolongation in patients with AF termination (44+/-13 versus 22+/-23 ms; P=0.08). Sustained AF was noninducible in 57% after PV isolation and in 77% after linear ablation. At 7+/-3 months, 74% with PV isolation and 83% with linear ablation were arrhythmia free without antiarrhythmics, which was significantly associated with noninducibility (P=0.03) with a recurrence rate of 38% and 13% in patients with and without inducibility, respectively., Conclusions: AF ablation results in a decline in AF frequency, with a magnitude correlating with termination of AF and prevention of inducibility that is predictive of subsequent clinical outcome.

Background: The left superior vena cava (LSVC) is the embryological precursor of the ligament of Marshall, which has been implicated in the initiation and maintenance of atrial fibrillation (AF). Rarely, the LSVC may persist and has been associated with some organized arrhythmias, though not with AF. We report 5 patients in whom the LSVC was a source of ectopy, initiating AF., Methods and Results: In 5 patients (4 men; age, 46+/-11 years) with symptomatic drug-refractory AF, ectopy from the LSVC resulting in AF was observed after pulmonary vein isolation. The ectopics were spontaneous in 2 and induced by isoproterenol in the others and preceded P-wave onset by 67+/-13 ms. During multielectrode or electroanatomic mapping, venous potentials were recorded circumferentially at the proximal LSVC near its junction with the coronary sinus (CS), but at the mid-LSVC level, they were recorded only on part of the circumference. The LSVC was electrically connected to the lateral left atrium (LA) and through the CS to the right atrium, with 4.1+/-2.3 CS-LSVC and 1.6+/-0.5 LA-LSVC connections per patient. Catheter ablation in the LSVC targeting these connections resulted in electrical isolation in 4 of the 5 patients without complications. After 15+/-10 months, the 4 patients with successful isolation, including 1 who had successful reablation for LA flutter, remained in sinus rhythm without drugs., Conclusions: The LSVC can be the arrhythmogenic source of AF with connections to the CS and LA. Ablation of these connections resulted in electrical isolation.

We describe three cases of patients with Alzheimer's disease who presented with cardiac syncope soon after initiation of a cholinesterase inhibitor therapy (donepezil). Bradyarrhythmia was documented in two patients, considered probable in one, and was presumed related to the cholinergic therapy. Pacemaker implantation seemed justified rather than donepezil cessation. More over, it permitted an increase in donepezil dosage.

Background: Symptomatic prolonged sinus pauses on termination of atrial fibrillation (AF) are an indication for pacemaker implantation. We evaluated sinus node function and clinical outcome in patients with prolonged sinus pauses on termination of arrhythmia who underwent ablation of paroxysmal AF., Methods and Results: Twenty patients with paroxysmal AF and prolonged sinus pauses (> or =3 seconds) on termination of AF underwent ablation between May 1995 and November 2002. Patients with sinus pauses independent of episodes of AF were excluded from the analysis. The procedure included pulmonary vein and linear atrial ablation. After ablation, sinus node function was assessed during the first week and at 1, 3, and 6 months, by 24-hour ambulatory monitoring to determine the mean heart rate and heart rate range, and by exercise testing to determine the maximal heart rate. Corrected sinus node recovery time was determined at the completion of ablation and at 24.0+/-11.3 months at 600 and 400 ms. After AF ablation, there was a significant improvement of sinus node function, with an increase in the mean heart rate (P=0.001), maximal heart rate (P<0.0001), and heart rate range (P<0.0001). The corrected sinus node recovery time decreased in all patients evaluated at 600 ms (P=0.016) and 400 ms (P=0.019). At 26.0+/-17.6 months, 18 patients (85%) had no recurrence of AF (in the absence of medication), with no symptoms attributable to bradycardia or sinus pauses on ambulatory monitoring. Two patients had infrequent episodes of AF, 1 requiring pacemaker implantation., Conclusions: Prolonged sinus pauses after paroxysms of AF may result from depression of sinus node function that can be eliminated by curative ablation of AF. This is accompanied by improvement in parameters of sinus node function, suggesting reverse remodeling of the sinus node.

Background: The long-QT and Brugada syndromes are important substrates of malignant ventricular arrhythmia. The feasibility of mapping and ablation of ventricular arrhythmias in these conditions has not been reported., Methods and Results: Seven patients (4 men; age, 38+/-7 years; 4 with long-QT and 3 with Brugada syndrome) with episodes of ventricular fibrillation or polymorphic ventricular tachycardia and frequent isolated or repetitive premature beats were studied. These premature beats were observed to trigger ventricular arrhythmias and were localized by mapping the earliest endocardial activity. In 4 patients, premature beats originated from the peripheral right (1 Brugada) or left (3 long-QT) Purkinje conducting system and were associated with variable Purkinje-to-muscle conduction times (30 to 110 ms). In the remaining 3 patients, premature beats originated from the right ventricular outflow tract, being 25 to 40 ms ahead of the QRS. The accuracy of mapping was confirmed by acute elimination of premature beats after 12+/-6 minutes of radiofrequency applications. During a follow-up of 17+/-17 months using ambulatory monitoring and defibrillator memory interrogation, no patients had recurrence of symptomatic ventricular arrhythmia but 1 had persistent premature beats., Conclusions: Triggers from the Purkinje arborization or the right ventricular outflow tract have a crucial role in initiating ventricular fibrillation associated with the long-QT and Brugada syndromes. These can be eliminated by focal radiofrequency ablation.

Background: Atrial fibrillation (AF) is frequently initiated from pulmonary veins (PVs), but little is known of the electrophysiological properties of PVs., Methods and Results: Two groups were studied: 28 patients (49+/-13 years old) with paroxysmal AF and 20 control patients (49+/-14 years old) without AF. Effective and functional refractory period and conduction time from PV to left atrium (LA) were compared in the 2 groups by use of programmed stimulation with a single extrastimulus in the PVs and LA. In the AF group, the venous effective refractory periods (ERPs) were shorter than that of the LA: 185+/-71 versus 253+/-21 ms, P<0.001, whereas in the control group, they were longer (282+/-45 versus 253+/-41 ms, P=0.009). The venous ERPs and functional refractory periods in patients with AF were also shorter than that observed in control subjects (185+/-71 versus 282+/-45 ms and 210+/-77 versus 315+/-43 ms, respectively, P<0.001), whereas LA ERPs were not significantly different. Decremental conduction in PVs was more frequent (93% versus 56%, P=0.01) and had a greater increment (102+/-65 versus 42+/-40 ms, P<0.001) in patients with AF. Finally, AF was more frequently induced when pacing was performed in PVs (22 of 90) versus LA (1 of 81) in patients with AF (P<0.001)., Conclusions: The PVs of patients with AF exhibited distinctive electrophysiological properties, which were strikingly different from those of patients devoid of AF, potentially explaining their arrhythmogenicity.

Background: Ventricular fibrillation is the main mechanism of sudden cardiac death. The feasibility of eliminating recurrent episodes by catheter ablation has not been reported., Methods and Results: Twenty-seven patients without known heart disease (13 men, 14 women, 41+/-14 years of age) were studied after being resuscitated from recurrent (10+/-12) episodes of primary idiopathic ventricular fibrillation; 23 had received a defibrillator. The first initiating beat of ventricular fibrillation had an identical electrocardiographic morphology and coupling interval (297+/-41 ms) to preceding isolated premature beats typically noted in the aftermath of resuscitation. These triggers were localized by mapping the earliest electrical activity and ablated by local radiofrequency delivery. Outcome was assessed by Holter and defibrillator memory interrogation. Premature beats were elicited from the Purkinje conducting system in 23 patients: from the left ventricular septum in 10, from the anterior right ventricle in 9, and from both in 4. The interval from the Purkinje potential to the following myocardial activation varied from 10 to 150 ms during premature beat but was 11+/-5 ms during sinus rhythm, indicating location at peripheral Purkinje arborization. The premature beats originated from the right ventricular outflow tract muscle in 4 patients. The accuracy of mapping was confirmed by acute elimination of premature beats during local radiofrequency delivery. During a follow-up of 24+/-28 months, 24 patients (89%) had no recurrence of ventricular fibrillation without drug., Conclusions: Primary idiopathic ventricular fibrillation is a syndrome characterized by dominant triggers from the distal Purkinje system. These sources can be eliminated by focal energy delivery.

Atrial fibrillation, the most common arrhythmia, is frequently disabling and drug resistant. Non-pharmacological approaches including surgery and catheter-based ablation have been developed for the most symptomatic patients. These new treatment strategies have dramatically increased our knowledge of the pathophysiology of this arrhythmia but most importantly demonstrated that atrial fibrillation is curable. These approaches are far from being perfect but good enough to be offered in routine practice to selected patients in experienced centers. The importance of pulmonary veins in the initiation of AF has clearly been demonstrated and their role in maintaining AF is likely. Most of the curative approaches are therefore based on their isolation. Future technical improvements based on presently applied concepts are likely to widen the indications for ablation therapy of AF.

Objectives: We assessed the anatomical distribution and electrogram characteristics of breakthrough from the left atrium (LA) to the pulmonary veins (PVs)., Background: Localization of LA-PV breakthrough is an important technique for PV ablation in patients with atrial fibrillation (AF)., Methods: A total of 157 patients with paroxysmal AF underwent PV disconnection guided by mapping with a circumferential 10-electrode catheter. Radiofrequency (RF) current was delivered ostially at the site(s) of earliest activation (113 patients) or electrogram polarity reversal defined by opposite polarity across adjacent bipoles (44 patients). Breakthrough sites were proved by changes in pulmonary vein potential activation sequence occurring as a result of localized RF delivery and were classified into four segments around the ostium (top, bottom, anterior, posterior). Results of mapping and ablation were compared between the two groups., Results: A total of 99% of 411 targeted PVs were successfully disconnected in both groups. Breakthroughs were most frequent at the bottom of superior PVs (85% prevalence) and the top of inferior PVs (75% prevalence). A wide activation front (>5 synchronous bipoles) indicating broad breakthrough was observed in 18% of PVs. Polarity reversal occurred with 88% sensitivity and 91% specificity at breakthrough sites. Polarity reversal was restricted to fewer bipoles (2.0 +/- 0.4 bipoles vs. 3.4 +/- 2.0 bipoles, p < 0.01) compared with earliest activation. Shorter RF application time was required to disconnect PVs with wide synchronous activation using polarity reversal compared with using conventional earliest activity (10.3 +/- 3.0 min vs. 12.3 +/- 3.4 min, p < 0.05)., Conclusions: Bipolar electrogram polarity reversal allows more precise localization of breakthrough compared with the earliest activation, particularly in cases of wide synchronous PV activation.

We report the case of a 20-year-old female patient with Beckwith-Wiedemann syndrome presenting with high blood pressure and bilateral adrenal pheochromocytoma successfully removed with laparoscopy in the same time. To our knowledge, the present case is the first observation of a bilateral pheochromocytoma occurring in the Beckwith-Wiedemann syndrome. It provides further support for a genetic anomaly in this condition. Our case also indicates the interest of laparoscopy for the surgical treatment of adrenal pheochromocytoma, even in bilateral tumors.

Objectives: We sought to assess the value of 12-lead electrocardiogram (ECG) P-wave morphology to recognize the paced pulmonary vein (PV)., Background: Prediction of arrhythmogenic PVs producing ectopy or initiating atrial fibrillation (AF) using 12-lead ECG may facilitate curative ablation., Methods: In 30 patients P-wave configurations were studied during sinus rhythm and during pacing at six sites from the four PVs: top and bottom of each superior PV and both inferior PVs. The P-wave amplitude, duration and morphology were assessed, and predictive accuracies were calculated for the most significant parameters. An algorithm predicting the paced PV was developed and prospectively evaluated in a different population of 20 patients. RESULTS; Three criteria were used to distinguish right from left PV: 1) a positive P-wave in lead aVL and the amplitude of P-wave in lead I > or =50 microV indicated right PV origin (specificity 100% and 97%, respectively); 2) a notched P-wave in lead II was a predictor of left PV origin (specificity 95%); and 3) the amplitude ratio of lead III/II and the duration of positivity in lead V(1) were also helpful in distinguishing left versus right PV origin. In addition, superior PVs could be distinguished from inferior according to the amplitude in lead II (> or =100 microV). In prospective evaluation, an algorithm based on the above four criteria identified 93% of left versus right PV and totally 79% of the specific PVs paced., Conclusions: Pacing from the different PVs produced a P-wave with distinctive characteristics that could be used as criteria in an algorithm to identify the PV of origin with an accuracy of 79%.

Aims: Preliminary studies have shown that peak endocardial acceleration (PEA), measured by a micro-accelerometer at the right ventricular apex, is highly correlated with left ventricular contractility (dp/dt max). Furthermore, changes in PEA are closely correlated with sinus node rate changes during exercise and during pharmacological interventions. Peak endocardial acceleration has, therefore, been used to drive a rate-responsive DDD pacemaker. This study compared the chronotropic performance of such devices implanted in 14 patients suffering from chronotropic incompetence with that observed in 18 control subjects in normal sinus rhythm., Methods and Results: Five standardized daily life activities (hall walk, climbing up and down stairs, squatting and hyperventilation) and two types of exercise (Bruce treadmill protocol and bicycle ergometry) were performed in a random order after individual programming of each pacemaker. For each test, a correlation coefficient was calculated between changes in PEA and variations in paced rate, between instantaneous variations in heart rate monitored by telemetry and continuous measurement of heart rate by the pacemaker, and between sensor-driven rate in patients and normal sinus rhythm in controls. The variations in paced heart rate were closely correlated with those observed in subjects with normal sinus rhythm, and proved to be sensitive, specific, rapid and independent of the type of exercise. After optimal programming of the sensor, PEA modulates the heart rate as expected during normal sinus rhythm., Conclusions: In this study, a single PEA sensor successfully restored chronotropic response in a population of paced patients with severe chronotropic incompetence. Peak endocardial acceleration can be monitored on a beat-to-beat basis, in parallel with heart rate, and the pacemaker can be accurately programmed with a single exercise test.

Background: Radiofrequency catheter ablation of accessory pathways (APs) is very effective in all but a minority of patients. We examined the usefulness and safety of irrigated-tip catheters in treating patients with APs resistant to conventional catheter ablation., Methods and Results: Among 314 APs in 301 consecutive patients, conventional ablation failed to eliminate AP conduction in 18 APs in 18 patients (5.7%), 6 of which were located in the left free wall, 5 in the middle/posterior-septal space, and 7 inside the coronary sinus (CS) or its tributaries. Irrigated-tip catheter ablation was subsequently performed with temperature control mode (target temperature, 50 degrees C), a moderate saline flow rate (17 mL/min), and a power limit of 50 W (outside CS) or 20 to 30 W (inside CS) at previously resistant sites. Seventeen of the 18 resistant APs (94%) were successfully ablated with a median of 3 applications using irrigated-tip catheters. A significant increase in power delivery was achieved (20.3+/-11.5 versus 36.5+/-8.2 W; P:<0.01) with irrigated-tip catheters, irrespective of the AP location, particularly inside the CS or its tributaries. No serious complications occurred., Conclusions: Irrigated-tip catheter ablation is safe and effective in eliminating AP conduction resistant to conventional catheters, irrespective of the location.