Incidence and management of inadvertent puncture and sheath placement in the aorta during attempted transseptal puncture.

AIMS: Transseptal punctures (TSP) are routinely performed in cardiac interventions requiring access to the left heart. While pericardial effusion/tamponade are well-recognized complications, few data exist on accidental puncture of the aorta and its management and outcome. We therefore analysed our single centre database for this complication. METHODS AND RESULTS: We assessed frequency and outcome of inadvertent aortic puncture during TSP in consecutive patients undergoing ablation procedures between January 2005 and December 2014. During the 10-year period, two inadvertent aortic punctures occurred among 2936 consecutive patients undergoing 4305 TSP (0.07% of patients, 0.05% of TSP) and in one Mustard patient during attempted baffle puncture. The first two patients required left ventricular access for catheter ablation of ventricular tachycardia. In both cases, an 11.5F steerable sheath (inner diameter 8.5F) was accidentally placed in the ascending aorta just above the aortic valve. In the presence of surgical standby, the sheaths were pulled back with a wire left in the aorta. Under careful haemodynamic and echocardiographic observation, this wire was also pulled back 30 min later. None of the patients required a closing device or open heart surgery. None of the patients suffered complications from the accidental aortic puncture and sheath placement. CONCLUSION: Inadvertent aortic puncture and sheath placement are rare complications in patients undergoing TSP for interventional procedures. Leaving a guidewire in place during the observation period may allow introduction of sheaths or other tools in order to control haemodynamic deterioration.

Data on procedural handling and complications of pulmonary vein isolation using the pulmonary vein ablation catheter GOLD®.

AIMS: The second-generation multi-electrode-phased radiofrequency pulmonary vein ablation catheter (PVAC GOLD(®)) was redesigned with the intent to improve its safety and efficacy. METHODS AND RESULTS: Using a prospectively designed single-centre database, we retrospectively analysed 128 consecutive patients (102 paroxysmal and 43 female) who underwent their first pulmonary vein isolation with the PVAC GOLD(®). The analysis focused on procedural data as well as in-hospital complications. Baseline characteristics of the patient collective were as follows: mean age 57.9 years, mean CHA2DS2-VASC was 1.73 ± 1.30; structural heart disease was present in seven patients. The PVAC GOLD(®) exhibited procedure durations of 123.1 min ± 27.9, duration of energy delivery was 18.3 min ± 11.4, and fluoroscopy duration was 16.0 min ± 7.7. The redesigned catheter shows major complication [major bleeding, transitory ischaemic attack (TIA), and pericardial tamponade] rates of 2.3% (n = 3). The overall rate of adverse events was 5.4% (n = 7). Bleeding complications were observed in three patients (2.3%), in particular there were two cases (1.6%) of minor bleeding and one case (0.8%) of major bleeding. Two patients suffered pericardial effusion, but there was no need for pericardiocentesis. Besides one TIA, there was no other thrombo-embolic event. Furthermore, one case of post-procedural fever was observed. No deaths, stroke, or haemorrhagic shock occurred. Of the 510 pulmonary veins, 508 could be reached with the PVAC GOLD(®) device using a non-steerable long sheath. CONCLUSION: The PVAC GOLD(®) seems to have an acceptable safety profile. The handling is comparable with the previous generation PVAC(®).

Esophageal and Mediastinal Lesions Following Multielectrode Duty-Cycled Radiofrequency Pulmonary Vein Isolation: Simple Equals Safe?

BACKGROUND: The development of esophageal lesions following atrial fibrillation (AF) ablation has frequently been reported. Mediastinal tissue layers and the posterior wall of the left atrium are in close proximity to the site of ablation. Hence, mucosal lesions might solely represent the "tip of the iceberg." We therefore investigated patients undergoing multielectrode phased radiofrequency (RF) ablation (PVAC®, Medtronic Inc., Minneapolis, MN, USA) for symptomatic AF by radial endosonography (EUS) in conjunction with conventional endoscopy esophago-gastro-duodenoscopy (EGD) to visualize potential mediastinal injuries following pulmonary vein isolation (PVI). METHODS AND RESULTS: Eighteen patients (six women, mean age 52.8 ± 12.8 years, range 32-72 years) underwent PVI using multielectrode phased RF ablation and EGD and EUS following PVI within 48 hours. Postablation periesophageal lesions were detected by EUS in 10 out of 18 patients (56%). Four out of 10 lesions consisted of mild changes like small pericardial effusions, whereas six out of 10 patients had more severe lesions of the mediastinum, including one patient with changes of the esophageal mucosa. No atrio-esophageal fistula developed during follow-up (FU; mean FU 215 ± 105 days). CONCLUSIONS: Mediastinal and esophageal structural changes occurred in a substantial number of patients. These findings highlight the necessity of close FU and the awareness of the potential development of an atrio-esophageal fistula also after multielectrode catheter ablation.

Driver domains in persistent atrial fibrillation.

BACKGROUND: Specific noninvasive signal processing was applied to identify drivers in distinct categories of persistent atrial fibrillation (AF). METHODS AND RESULTS: In 103 consecutive patients with persistent AF, accurate biatrial geometry relative to an array of 252 body surface electrodes was obtained from a noncontrast computed tomography scan. The reconstructed unipolar AF electrograms acquired at bedside from multiple windows (duration, 9±1 s) were signal processed to identify the drivers (focal or reentrant activity) and their cumulative density map. The driver domains were catheter ablated by using AF termination as the procedural end point in comparison with the stepwise-ablation control group. The maps showed incessantly changing beat-to-beat wave fronts and varying spatiotemporal behavior of driver activities. Reentries were not sustained (median, 2.6 rotations lasting 449±89 ms), meandered substantially but recurred repetitively in the same region. In total, 4720 drivers were identified in 103 patients: 3802 (80.5%) reentries and 918 (19.5%) focal breakthroughs; most of them colocalized. Of these, 69% reentries and 71% foci were in the left atrium. Driver ablation alone terminated 75% and 15% of persistent and long-lasting AF, respectively. The number of targeted driver regions increased with the duration of continuous AF: 2 in patients presenting in sinus rhythm, 3 in AF lasting 1 to 3 months, 4 in AF lasting 4 to 6 months, and 6 in AF lasting longer. The termination rate sharply declined after 6 months. The mean radiofrequency delivery to AF termination was 28±17 minutes versus 65±33 minutes in the control group (P<0.0001). At 12 months, 85% patients with AF termination were free from AF, similar to the control population (87%,); P=not significant. CONCLUSIONS: Persistent AF in early months is maintained predominantly by drivers clustered in a few regions, most of them being unstable reentries.

Impact of Substrate-Based Ablation of Ventricular Tachycardia on Cardiac Mortality in Patients With Implantable Cardioverter-Defibrillators.

INTRODUCTION: This study sought to determine if the acute procedural outcome of ventricular tachycardia (VT) substrate ablation is associated with a mortality benefit in patients with implantable cardioverter-defibrillators (ICD). METHODS AND RESULTS: A total of 195 ICD recipients (65 ± 11years) with ischemic or nonischemic dilated cardiomyopathy underwent substrate-based ablation targeting elimination of local abnormal ventricular activities (LAVA). Acute procedural success, which was defined as elimination of all identified LAVA in addition to the lack of VT inducibility, was achieved in 95 (49%) patients. During a median follow-up of 23 months, patients with acute procedure success had a significantly lower incidence of ICD shocks compared to those with ablation failure (8% vs. 30%, P < 0.001). In multivariate analysis, acute procedural success was associated with a lower risk of VT recurrence (hazard ratio [HR] 0.30, 95% confidence interval [CI] 0.18-0.49, P < 0.001) and all-cause mortality (HR 0.32, 95% CI 0.17-0.60, P < 0.001). While the impact of ablation success on mortality was not statistically significant in patients with LVEF > 35% (HR 0.45, 95% CI 0.15-1.34, P = 0.15) and those with NYHA class I/II (HR 0.63, 95% CI 0.29-1.40, P = 0.26), it was marked in patients with LVEF ≤ 35% (HR 0.30, 95% CI 0.14-0.62, P = 0.001) and NYHA class III/IV (HR 0.17, 95% CI 0.05-0.57, P = 0.004). CONCLUSIONS: LAVA elimination in addition to VT noninducibility as a procedural outcome for substrate-based ablation is associated with reduced mortality and better VT-free survival during follow-up. This prognostic benefit may be most pronounced in patients with severe heart failure as indicated by severely depressed LV function and NYHA class III/IV symptoms.

Atrial structure and function 5 years after successful ablation for persistent atrial fibrillation: an MRI study.

INTRODUCTION: The atrial outcome after extensive ablation is unknown. We sought to quantify atrial structure and function years after successful ablation for persistent atrial fibrillation (PsAF). METHODS AND RESULTS: We studied after 80 ± 15 months 26 patients (54 ± 8 years, 1 woman) with PsAF successfully treated by ablation (2.2 ± 0.7 stepwise approach procedures, cumulative RF duration 126 ± 37 minutes). At follow-up atrial scar burden and atrial outflows were quantified using delayed-enhanced and velocity-encoded MRI, respectively. Cine imaging was used to quantify atrial conduit function (CF), active emptying fraction (AEF), expansion index (EI), and the inter-appendage mechanical activation delay. Patients underwent exercise testing at baseline and follow-up. LA and RA scar extent were 29 ± 6 and 4.3 ± 2.8%, respectively. LA and RA AEF were 10.0 ± 5.3 and 30 ± 8%. Mean inter-appendage delay was 83 ± 47 ms [42-217]. Complete LAA isolation was found in 3 patients. A wave was absent in 9/26 patients. LA scar extent related to the number of procedures (R = 0.58, P = 0.002) and total RF duration (R = 0.56, P = 0.003). Among follow-up characteristics, LA scar extent related to LAAEF (R = -0.73, P < 0.0001), LAEI (R = -0.64, P = 0.0003), A-wave peak (R = -0.72, P < 0.0001), and inter-appendage mechanical delay (R = 0.47, P = 0.02). At multivariable analysis, LA scar extent was independently related to LAAEF and LAEI. LAAEF and LA scar extent correlated with exercise capacity at follow-up (R = 0.44, P = 0.02, and R = -0.40; P = 0.04). CONCLUSION: LA contractility and compliance are markedly impaired years after successful PsAF ablation. LA dysfunction is closely related to scar burden.

Modified phased radiofrequency ablation of atrial fibrillation reduces the number of cerebral microembolic signals.

AIMS: Phased radiofrequency (RF) ablation for atrial fibrillation is associated with an increased number of silent cerebral lesions on magnetic resonance imaging and cerebral microembolic signals (MESs) on transcranial Doppler ultrasound imaging compared with irrigated RF. The increased rate of embolic events may be due to a specific electrical interference of ablation electrodes attributed to the catheter design. The purpose of this study was to elucidate the effect of deactivating the culprit electrodes on cerebral MESs. METHODS AND RESULTS: Twenty-nine consecutive patients (60 ± 11 years, 10 female) underwent their first pulmonary vein isolation using phased RF energy. Electrode pairs 1 or 5 were deactivated to avoid electrical interference between electrodes 1 and 10 ('modified'). Detection of MESs by transcranial Doppler ultrasound was performed throughout the procedure to assess cerebral microembolism. Results were compared with the numbers of MESs in 31 patients ablated using all available electrodes ('conventional') and to 30 patients undergoing irrigated RF ablation of a previous randomized study. Ablation with 'modified' phased RF was associated with a marked decrease in MESs when compared with 'conventional' phased RF (566 ± 332 vs. 1530 ± 980; P < 0.001). This difference was mainly triggered by the reduction of MES during delivery of phased RF energy, resulting in MES numbers comparable to irrigated RF ablation (646 ± 449; P = 0.7). Total procedure duration as well as time of RF delivery was comparable between phased RF groups. Both times, however, were significantly shorter compared with the irrigated RF group (123 ± 28 vs. 195 ± 38; 15 ± 4 vs. 30 ± 9; P < 0.001, respectively). CONCLUSION: Pulmonary vein isolation with 'modified' phased RF is associated with a decreased number of cerebral microembolism especially during the delivery of ablation impulses, supporting the significance of electrical interference between ablation electrodes 1 and 10. Deactivation of electrode pairs 1 or 5 might increase the safety of this approach without an increase in procedure duration or RF delivery time.

Pulmonary vein isolation using a circular, open irrigated mapping and ablation catheter (nMARQ): a report on feasibility and efficacy.

AIMS: Pulmonary vein isolation (PVI) is the mainstay of interventional treatment of paroxysmal atrial fibrillation (PAF). We report on the feasibility and efficacy of a novel, open-irrigated mapping and radiofrequency (RF) ablation catheter. METHODS AND RESULTS: Thirty-nine consecutive patients (pts; age 60 ± 10 years, 8 females) suffering from drug-refractory PAF referred for PVI were included in this prospective study. Pulmonary vein isolation was performed with the use of a novel 10-pole circular, open-irrigated mapping and ablation catheter (nMARQ, Biosense Webster). Outcome parameters were the acute success rate in establishing complete PVI and the rate of sustained sinus rhythm (SR) during follow-up (FU). Ten patients underwent a repeat procedure for recurrent AF. Ninety-eight percent of the PVs could be acutely isolated using solely the nMARQ catheter by applying a mean total of 10.0 ± 4.6 min of RF energy. The mean total procedure duration was 86 ± 29 min, and the mean fluoroscopy time was 22.2 ± 6.5 min, respectively. Transient reconnection provoked by adenosine was observed in 10 of 24 patients, most frequently in the right superior PV. Cardiac tamponade related to transseptal puncture occurred in one patient. Reconnected PVs could be identified as a source of recurrent AF in 9 of 10 patients undergoing a repeat procedure. Single and multiple procedure success rates during a mean FU of 140 ± 75 days were 66 and 77%, respectively. CONCLUSION: Irrigated multi-electrode RF ablation is fast and effective, providing a high rate of isolated PVs without the need of touch-up lesions. Success rates were comparable with other techniques with a low complication rate. Recurrences of AF were mainly due to recovered pulmonary vein/left atrium conduction.

Role of implantable cardioverter defibrillator therapy in patients with acquired long QT syndrome: a long-term follow-up.

AIMS: The use of implantable cardioverter defibrillators (ICD) in patients with torsade de pointes (TdP) and ventricular fibrillation in the presence of acquired long QT syndrome (aLQTS) is under debate, partly due to the fact that aLQTS is potentially reversible and currently no long-term follow-up data are available. We aimed to evaluate the long-term follow-up of patients with acquired long QT syndrome (aLQTS) who had received an implantable cardioverter defibrillator (ICD) for secondary prevention of sudden cardiac arrest (SCA). METHOD AND RESULTS: Over a 10 year period, 43 patients with an ICD after survived cardiac arrest (SCA) due to an aLQTS were included [female n= 27 (63%); mean age 61 ± 16 years]. There was no clinical evidence for congenital LQTS (Schwartz score 1.25 ± 0.8). Structural heart disease was present in 29 patients (47%; ischaemic n= 13; dilated cardiomyopathy n= 9; mean EF 41%± 12). The most common proarrhythmic trigger happened to be antiarrhythmic drugs (n= 34; 79%). Other triggers included contrast agent (n= 1), haloperidol (n= 2), severe hypokalaemia (n= 2), drug abuse/alcohol (n= 2), and mere severe bradycardia (n= 2). Under trigger QTc interval measured 536 ± 58 vs. 438 ± 33 ms without trigger (P< 0.001). During a mean follow-up of 84 ± 55 months, appropriate shocks occurred in 19 patients (44%); inappropriate shocks in 13 patients (30%; only inappropriate n= 3). Appropriate shocks were almost as common in patients without as in those with structural heart disease (35 vs. 48%; P= 0.32). None of the patients were re-exposed to the initial trigger during the follow-up period. Beta-blocker medication did not prevent ICD shocks (12 of 19 vs. 11 of 24 on medication). CONCLUSION: Appropriate ICD shocks are a common finding in patients with aLQTS and SCA irrespective of the underlying cause or structural heart disease. Thus, even in the presence of relevant acquired proarrhythmia ICD may be beneficial.

Prophylactic proton pump inhibition after atrial fibrillation ablation: is there any evidence?

The development of an atrio-oesophageal fistula following catheter ablation for atrial fibrillation is a well known, but rare complication with a high mortality, partially due to the late fistula formation weeks after the initial procedure. Technical measurements are undertaken to avoid oesophageal damage during catheter ablation of atrial fibrillation, yet, oesophageal and mediastinal lesions occur in a substantial number of patients following pulmonary vein isolation. This has led to prophylactic use of proton pump inhibitors in many centres. Current guidelines and consensus reports list no objectives on this issue. The aim of the paper is therefore to review current clinical and experimental evidence for this treatment.

Successful treatment of catecholaminergic polymorphic ventricular tachycardia with flecainide: a case report and review of the current literature.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disease that can cause sudden cardiac death due to ventricular fibrillation (VF). While pharmacological therapy with beta-blockers and/or Ca(2)(+) antagonists is often unreliable, a recent study has demonstrated that flecainide can effectively suppress arrhythmia in a murine model of CPVT as well as clinically in two human subjects suffering from CPVT. We here present the case of an 11-year-old boy suffering from CPVT-1 as well as a review of the current relevant literature. After resuscitation due to VF at age 9, an automated implantable cardioverter-defibrillator (ICD) was implanted in 2007. Under beta-blocker therapy, repeated shocks were delivered due to either fast ventricular tachycardia (VT) or VF. This persisted under additional therapy with verapamil. Implantable cardioverter-defibrillator routine interrogations showed frequent non-sustained VT with an average of 8.8 per day. Additionally, the patient suffered from impaired physical performance due to decreased chronotropic competence. In July 2009, flecainide was added to the beta-blocker/verapamil regimen, resulting in a plasma level of 0.20 mg/L. No ICD shock or sustained VT occurred until December 2010. Genetic testing revealed an RyR2 receptor mutation. The case demonstrates the challenge of diagnosis and management of CPVT. It furthermore supports recent experimental evidence that the class 1 antiarrhythmic drug flecainide can suppress CPVT. The presented case supports a novel strategy in treating CPVT with the class I antiarrhythmic agent flecainide.

Pulmonary vein variants predispose to atrial fibrillation: a case-control study using multislice contrast-enhanced computed tomography.

AIMS: Pulmonary veins (PV) play a pivotal role in atrial fibrillation (AF). Anatomical variants of PV have been described and related to a higher arrhythmogenic potential. The aim of this study was to compare the prevalence of PV variants and diameters of PV ostia in AF patients and controls. METHODS AND RESULTS: Variants of PV were defined as right or left common ostia (RCO, LCO), a right middle or right top PV . A long common trunk (LCT) was defined as an LCO with a distance to the first branching ≥ 10 mm. Multislice contrast-enhanced thoracic computed tomography was performed prior to AF ablation in 166 consecutive patients, 47.6% with paroxysmal, 52.4% with persistent AF, as well as in a sex- and age-matched control group without AF, for non-cardiological indications. Images were evaluated by two independent observers. The mean age was 59 ± 10 years, 108 were men (65.1%). A higher prevalence of LCO was found in the AF group: 33.7 vs. 19.9% (P= 0.004), odds ratio (OR) 2.1; 15.4% in patients vs. 10.2% in controls had an LCT (P= 0.14). No differences in other PV variants were found. The ostial diameters were greater in AF-patients (P< 0.001). CONCLUSIONS: To the best of our knowledge, the present study shows for the first time a higher prevalence of an LCO in patients with AF as compared with controls, with an OR of 2.1. This suggests a pre-disposing role of LCO in the development of AF.

Atrial Arrhythmias in long-QT syndrome under daily life conditions: a nested case control study.

BACKGROUND: The long-QT syndromes (LQTS) are inherited electrical cardiomyopathies characterized by prolonged ventricular repolarization and ventricular arrhythmias. Several genetic reports have associated defects in LQTS-causing genes with atrial fibrillation (AF). We therefore studied whether atrial arrhythmias occur in patients with LQTS under daily-life conditions. METHODS: We systematically assessed atrial arrhythmias in LQTS patients and matched controls using implanted defibrillators or pacemakers as monitors of atrial rhythm in a nested case-control study. Twenty-one LQTS patients (3 male; 39 +/- 18 years old; 18 on beta blocker, ICD therapy duration 6.3 +/- 2.7 years; 4 LQT1, 6 LQT2, 2 LQT3) were matched to 21 control subjects (13 male; 50 +/- 19 years old; 3 on beta blocker; pacemaker therapy duration 8.5 +/- 5.5 years; 19 higher-degree AV block, 2 others). LQTS patients were identified by a systematic search of the LQTS patient databases in Münster and Munich. RESULTS: One-third (7 of 21) of the LQTS patients developed self-terminating atrial arrhythmias (atrial cycle lengths <250 ms). Only one control patient developed a single episode of postoperative AF (P < 0.05 vs LQTS). CONCLUSIONS: LQTS patients at high risk for ventricular arrhythmias may develop short-lasting atrial arrhythmias under daily-life conditions, suggesting that prolonged atrial repolarization may contribute to the initiation of AF.

Diastolic isthmus length and 'vertical' isthmus angulation identify patients with difficult catheter ablation of typical atrial flutter: a pre-procedural MRI study.

AIMS: Catheter ablation of isthmus-dependent atrial flutter is technically demanding in some patients and extremely simple in others. The intervention targets a defined anatomical structure, the so-called cavotricuspid isthmus (CTI). We sought to characterize CTI anatomy in vivo in patients with difficult and simple catheter ablation of atrial flutter. METHODS AND RESULTS: Twenty-six patients were studied. Seven patients with difficult (n = 6) or extremely simple (n = 1) CTI ablation procedures were retrospectively selected from our catheter ablation database. Thereafter, we prospectively studied 19 patients undergoing CTI ablation in our department. We visualized CTI anatomy by ECG- and respiration-gated free precession 1.5 T cardiac magnetic resonance imaging (MRI). Magnetic resonance imaging was analysed for systolic and diastolic CTI length, the angle between the vena cava inferior and CTI, and pouch-like recesses. These parameters were compared between patients with difficult and simple procedures, split by the median number of energy applications. Patients with difficult procedures had a longer diastolic CTI length (diastolic isthmus length 20.3 +/- 1.8 mm) than those with simple procedures (diastolic isthmus length 16.6 +/- 1.7 mm, all data as mean +/- SEM, P < 0.05). Cavotricuspid isthmus angulation with respect to inferior vena cava was closer to 90 degrees in patients with difficult procedures (deviation from 90 degrees: 15 +/- 2 degrees) than those with simple procedures (deviation 23 +/- 4 degrees, P < 0.05). Systolic CTI length was not different between groups (32 +/- 2 mm in both groups, P > 0.2). CONCLUSION: Longer diastolic, but not systolic, CTI length and a rectangular angle between CTI and inferior vena cava render CTI catheter ablation difficult. Visualization of isthmus anatomy may help to guide difficult CTI ablation procedures.

Age- and training-dependent development of arrhythmogenic right ventricular cardiomyopathy in heterozygous plakoglobin-deficient mice.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disorder that causes sudden death and right ventricular heart failure in the young. Clinical data suggest that competitive sports may provoke ARVC in susceptible persons. Genetically, loss-of-function mutations in desmosomal proteins (plakophilin, desmoplakin, or plakoglobin) have been associated with ARVC. To test the hypothesis that reduced desmosomal protein expression causes ARVC, we studied the cardiac effects of heterozygous plakoglobin deficiency in mice. METHODS AND RESULTS: Ten-month-old heterozygous plakoglobin-deficient mice (plakoglobin+/-) had increased right ventricular volume, reduced right ventricular function, and spontaneous ventricular ectopy (all P<0.05). Left ventricular size and function were not altered. Isolated, perfused plakoglobin+/- hearts had spontaneous ventricular tachycardia of right ventricular origin and prolonged right ventricular conduction times compared with wild-type hearts. Endurance training accelerated the development of right ventricular dysfunction and arrhythmias in plakoglobin+/- mice. Histology and electron microscopy did not identify right ventricular abnormalities in affected animals. CONCLUSIONS: Heterozygous plakoglobin deficiency provokes ARVC. Manifestation of the phenotype is accelerated by endurance training. This suggests a functional role for plakoglobin and training in the development of ARVC.

Slow pathway modification in patients presenting with only two consecutive AV nodal echo beats.

BACKGROUND: Slow pathway modification (SPM) is the therapy of choice for AV-nodal reentry tachycardia (AVNRT). When AVNRT is not inducible, empirical ablation can be considered, however, the outcome in patients with two AV nodal echo beats (AVNEBs) is unknown. METHODS: Out of a population of 3003 patients who underwent slow pathway modification at our institution between 1993 and 2013, we retrospectively included 32 patients with a history of symptomatic tachycardia, lack of paroxysmal supraventricular tachycardia (pSVT) inducibility but occurrence of two AVNEBs. RESULTS: pSVT documentation by electrocardiography (ECG) was present in 20 patients. The procedural endpoint was inducibility of less than two AVNEBs. This was reached in 31 (97%) patients. Long-term success was assessed by a telephone questionnaire (follow-up time 63±9 months). A total 94% of the patients benefited from the procedure (59% freedom from symptoms; 34% improvement in symptoms). Among those patients in whom ECG documentation was not present, 100% benefited (58% freedom from symptoms, 42% improvement). CONCLUSION: This is the first collective analysis of a group of patients presenting with symptoms of pSVT and inducibility of only two AVNEBs. Procedural success and clinical long-term follow-up were in the range of the reported success rates of slow pathway modification of inducible AVNRT, independent of whether ECG documentation was present. Thus, SPM is a safe and effective therapy in patients with two AVNEBs.

Complexity and Distribution of Drivers in Relation to Duration of Persistent Atrial Fibrillation.

BACKGROUND: The underlying mechanisms sustaining human persistent atrial fibrillation (PsAF) is poorly understood. OBJECTIVES: This study sought to investigate the complexity and distribution of AF drivers in PsAF of varying durations. METHODS: Of 135 consecutive patients with PsAF, 105 patients referred for de novo ablation of PsAF were prospectively recruited. Patients were divided into 3 groups according to AF duration: PsAF presenting in sinus rhythm (AF induced), PsAF <12 months, and PsAF >12 months. Patients wore a 252-electrode vest for body surface mapping. Localized drivers (re-entrant or focal) were identified using phase-mapping algorithms. RESULTS: In this patient cohort, the most prominent re-entrant driver regions included the pulmonary vein (PV) regions and inferoposterior left atrial wall. Focal drivers were observed in 1 or both PV regions in 75% of patients. Comparing between the 3 groups, with longer AF duration AF complexity increased, reflected by increased number of re-entrant rotations (p < 0.05), number of re-entrant rotations and focal events (p < 0.05), and number of regions harboring re-entrant (p < 0.01) and focal (p < 0.05) drivers. With increased AF duration, a higher proportion of patients had multiple extra-PV driver regions, specifically in the inferoposterior left atrium (p < 0.01), superior right atrium (p < 0.05), and inferior right atrium (p < 0.05). Procedural AF termination was achieved in 70% of patients, but decreased with longer AF duration. CONCLUSIONS: The complexity of AF drivers increases with prolonged AF duration. Re-entrant and focal drivers are predominantly located in the PV antral and adjacent regions. However, with longer AF duration, multiple drivers are distributed at extra-PV sites. AF termination rate declines as patients progress to longstanding PsAF, underscoring the importance of early intervention.

Lower rate of left atrial tachycardia after pulmonary vein isolation with PVAC versus irrigated-tip circumferential antral ablation.

BACKGROUND: Left atrial tachycardias (LAT) occur in about 5% of patients after irrigated-tip circumferential antral (CA) pulmonary vein isolation (PVI). They may cause debilitating symptoms in the patient and may be very difficult to treat. OBJECTIVE: To assess the incidence of LAT after PVI with the multielectrode phased-radiofrequency pulmonary vein ablation catheter (PVAC) compared to circumferential antral PVI with an irrigated-tip catheter. METHODS: We analyzed data from our ablation database. A total of 150 patients who underwent their first PVI with the PVAC system and 300 patients who underwent their first PVI with irrigated-tip circumferential antral (CA) radiofrequency ablation were matched by age and sex, as well as by type of atrial fibrillation. RESULTS: Of 150 PVAC patients, only 1 patient (0.7%) developed LAT during mean follow-up of 21 ± 14 months. The mechanism was macroreentry and the patient underwent successful ablation at our institution. Eleven of 300 irrigated-tip CA PVI patients (3.7%) developed LAT during mean follow-up of 22 ± 14 months and subsequently underwent ablation (P = .05). CONCLUSION: LAT occurs more frequently after irrigated-tip CA PVI compared to single-shot-device ablation with PVAC. Apart from being less technically demanding, lower incidence of LAT may influence choice of ablation technology.

Persistent Atrial Fibrillation From the Onset: A Specific Subgroup of Patients With Biatrial Substrate Involvement and Poorer Clinical Outcome.

OBJECTIVES: This study sought to characterize the clinical characteristics, atrial substrate, and prognosis in a subgroup of patients with persistent atrial fibrillation (AF) from the onset (PsAFonset). BACKGROUND: Patients with AF frequently progress from trigger-driven paroxysmal arrhythmias to substrate-dependent persistent arrhythmias. METHODS: Patients referred for persistent AF (PsAF) ablation were enrolled from 3 centers. Consecutive patients with PsAFonset (n = 129) were compared with patients with PsAF that progressed from paroxysmal AF (n = 231). In addition, 90 patients (30 patients with PsAFonset and 60 control subjects) were studied with noninvasive mapping to characterize the AF drivers. The degree of fractionation and endocardial voltages were assessed invasively. RESULTS: Patients with PsAFonset were younger (p = 0.047) and more obese (p < 0.001); there were more men (p = 0.034), more patients with hypertension (p = 0.044), and these patients had larger left (p < 0.05) and right atria (p < 0.05). Baseline AF cycle length was shorter in the PsAFonset group (p < 0.01); the degree of fractionation was higher (p < 0.001 for both atria), and the endocardial voltage was lower (p < 0.05 for both atria). Patients with PsAFonset had higher a number of re-entrant driver regions (p < 0.001) and extrapulmonary vein regions that had re-entrant drivers (p < 0.05), whereas control subjects displayed more focal driver regions (p = 0.029). The acute AF termination rate was lower in the PsAFonset group (42% vs. 81%; p < 0.001). During a mean follow-up of 17 ± 11 months from the last procedure, patients with PsAFonset had significantly higher AF, atrial tachycardia (AT), and AF/AT recurrence rates (p < 0.01). CONCLUSIONS: Patients with PsAFonset represent a distinct subgroup defined by specific demographics, underlying diffuse biatrial substrate disease, and worse clinical outcome. The findings highlight the importance of defining criteria for early detection of atrial substrate disease.