Long‐Term Outcome of Atrial Fibrillation Ablation: Impact and Predictors of Very Late Recurrence

Long‐Term Outcome of AF Ablation. Introduction: Ablation eliminates atrial fibrillation (AF) in studies with 1 year follow‐up, but very late recurrences may compromise long‐term efficacy. In a large cohort, we sought to describe the determinants of delayed recurrence after AF ablation. Methods and Results: Seven hundred and seventy‐four patients with AF (428 paroxysmal [PAF, 55%] and 346 persistent or longstanding persistent [PersAF, 45%]) underwent wide area circumferential ablation (WACA, 62%) or pulmonary vein isolation (38%). Over 3.0 ± 1.9 years, there were 135 recurrences in PAF patients and 142 in PersAF patients. AF elimination was achieved in 61% of patients with PersAF at 2 years after last ablation and in 71% of patients with PAF (P = 0.04). This finding was related to a higher initial rate of very late recurrence in PersAF. From 1.0 to 2.5 years, the recurrence increased by 20% (from 37% to 57%) in PersAF patients versus only 12% (from 27% to 39%) in PAF patients. Independent predictors of overall recurrence included diabetes (HR 1.9 [1.3–2.9], P = 0.002) and PersAF (HR 1.6 [1.2–2.0], P < 0.001). Independent predictors of very late recurrence included PersAF (HR 1.7 [1.1–2.7], P = 0.018) and WACA (HR 1.8 [1.1–2.7], P = 0.018), while diabetes came close to significance. In PAF patients, left atrial size >45 mm was identified as an AF‐type specific predictor (HR 2.4 [1.3–4.7], P = 0.009), whereas in PersAF patients, no unique predictors were identified. Conclusion: Late recurrences reduced the long‐term efficacy of AF ablation, particularly in patients with PersAF and underlying cardiovascular diseases. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1071‐1078)     

Pulmonary Vein Isolation Alone in Patients with Persistent Atrial Fibrillation: An Ablation Strategy Facilitated by Antiarrhythmic Drug Induced Reverse Remodeling

PVI Alone in Patients with Persistent AF . Introduction: Pulmonary vein isolation (PVI) alone has been thought to be insufficient in patients with persistent atrial fibrillation (PersAF). We hypothesized that preablation treatment of PersAF with a potent antiarrhythmic drug (AAD) would facilitate reverse atrial remodeling and result in high procedural efficacy after PVI alone. Methods and Results: Seventy‐one consecutive patients (59.4 ± 9.8 years) with PersAF and prior AAD failure were treated with oral dofetilide (768 ± 291 mcg/day) for a median of 85 days pre‐PVI. P‐wave duration (Pdur) on ECG was used to assess reverse atrial remodeling. Thirty‐five patients with paroxysmal (P) AF not treated with an AAD served as controls. All patients underwent PVI alone; dofetilide was discontinued 1–3 mos postablation. In the PersAF patients, the Pdur decreased from 136.3 ± 21.7 ms (assessed postcardioversion on dofetilide) to 118.6 ± 20.4 ms (assessed immediately prior to PVI) (P < 0.001). In contrast, no change in Pdur (122.6 ± 11.5 ms vs. 121.3 ± 13.7 ms, P = NS) was observed in PAF patients. The 6 and 12 mos AAD‐free response to ablation was 76% and 70%, respectively, in PersAF patients, similar to the 80% and 75%, response in PAF patients (P = NS). A decline in Pdur in response to dofetilide was the only predictor of long‐term clinical response to PVI in patients with PersAF. Conclusions: Pre‐treatment with AAD resulted in a decrease in Pdur suggesting reverse atrial electrical remodeling in PersAF patients. This may explain the excellent clinical outcomes using PVI alone, and may suggest an alternative ablation strategy for PersAF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 142‐148, February 2011)     

Randomized comparison between pulmonary vein antral isolation versus complex fractionated electrogram ablation for paroxysmal atrial fibrillation

Catheter Ablation of Paroxysmal AF. Introduction: Circumferential pulmonary vein antral isolation (PVAI) and atrial complex fractionated electrograms (CFEs) are both ablative techniques for the treatment of paroxysmal atrial fibrillation (PAF). However, data on the comparative value of these 2 ablation strategies are very limited. Methods and Results: We randomized 118 patients with drug‐refractory PAF to receive PVAI ablation (n = 60) or CFE ablation (n = 58). For CFE group, spontaneous/induced AF was mapped using validated, automated software to guide ablation until all CFE areas were eliminated. For PVAI group, all 4 pulmonary vein antra were electrically isolated as confirmed by circular mapping catheter. Patients with spontaneous/inducible AF after the initial ablation procedure were crossed over to the other arms. After initial ablation procedure, AF persisted/inducible in 24/59 patients (41%), and 34/58 patients (59%) assigned to PVAI and CFE ablation, respectively (P = 0.05). Then 58 patients underwent PVAI + CFE ablation. After 22.6 ± 6.4 months, PVAI ablation group was more likely than CFE ablation group to achieve control of any AF/atrial tachycardia (AT) off drugs (43/60, 72% vs 33/58, 57%, P = 0.075) and lower recurrence rate of AT (11.9% vs 34.5%, P = 0.004). Patients who received CFE ablation alone (38%) had significantly lower overall success rate to achieve control of AF/AT off drugs compared with patients who received PVAI ablation (77%, P = 0.002) alone or PVAI + CFE ablation (69%, P = 0.008) due to higher recurrence rate of AT (50% vs 6% vs 13%, P < 0.01). Conclusions: CFE ablation in PAF patients was associated with higher occurrence rate of postprocedure AT compared with PVAI ablation, whereby making it less likely to be a sole ablation strategy for PAF patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 973‐981, September 2011)     

Cryoballoon Versus Radiofrequency for Pulmonary Vein Re‐Isolation After a Failed Initial Ablation Procedure in Patients with Paroxysmal Atrial Fibrillation

Cryoballoon versus Radiofrequency Ablation . Aim: Catheter ablation of paroxysmal atrial fibrillation (PAF) is associated with an important risk of early and late recurrence, necessitating repeat ablation procedures. The aim of this prospective randomized patient‐blind study was to compare the efficacy and safety of cryoballoon (Cryo) versus radiofrequency (RF) ablation of PAF after failed initial RF ablation procedure. Methods: Patients with a history of symptomatic PAF after a previous failed first RF ablation procedure were eligible for this study. Patients were randomized to Cryo or RF redo ablation. The primary endpoint of the study was recurrence of atrial tachyarrhythmia, including AF and left atrial flutter/tachycardia, after a second ablation procedure at 1 year of follow‐up. All patients were implanted with a cardiac monitor (Reveal XT, Medtronic) to continuously track the cardiac rhythm. Patients with an AF burden (AF%) ≤ 0.5% were considered AF‐free (Responders), while those with an AF% > 0.5% were classified as patients with AF recurrences (non‐Responders). Results: Eighty patients with AF recurrences after a first RF pulmonary vein isolation (PVI) were randomized to Cryo (N = 40) or to RF (N = 40). Electrical potentials were recorded in 77 mapped PVs (1.9 ± 0.8 per patient) in Cryo Group and 72 PVs (1.7 ± 0.8 per patient) in RF Group (P = 0.62), all of which were targeted. In Cryo group, 68 (88%) of the 77 PVs were re‐isolated using only Cryo technique; the remaining 9 PVs were re‐isolated using RF. In RF group, all 72 PVs were successfully re‐isolated (P = 0.003 vs Cryo). By intention‐to‐treat, 23 (58%) RF patients were AF‐free vs 17 (43%) Cryo patients on no antiarrhythmic drugs at 1 year (P = 0.06). Three patients had temporary phrenic nerve paralysis in the Cryo group; the RF group had no complications. Of the 29 patients who had only Cryo PVI without any RF ablation, 11 (38%) were AF‐free vs 20 (59%) of the 34 patients who had RF only (P = 0.021). Conclusion: When patients require a redo pulmonary vein isolation ablation procedure for recurrent PAF, RF appears to be the preferred energy source relative to Cryo. (J Cardiovasc Electrophysiol, Vol. 24, pp. 274‐279, March 2013)     

What is the real atrial fibrillation burden after catheter ablation of atrial fibrillation? A prospective rhythm analysis in pacemaker patients with continuous atrial monitoring.

AIMS: Rhythm follow-up after catheter ablation of atrial fibrillation (AF ablation) is mainly based on Holter electrocardiogramm (ECG), tele-ECG or on patients symptoms. However, studies using 7-day Holter or tele-ECG follow-up revealed a significant number of asymptomatic recurrences. Thus, the aim of this study was to analyse continuous atrial recordings in pacemaker patients with an incorporated Holter function before and after AF ablation in order to determine all AF recurrences and thereby the 'real' success rates. METHODS AND RESULTS: The study comprised 37 patients (64.6 +/- 10 years) with prior pacemaker/implantable cardioverter defibrillator (ICD) implantation including an atrial Holter function referred for AF ablation. Holter data were obtained and correlated to patients' symptoms before and every 3-month after AF ablation. AF recurrence was defined as an atrial high frequency episode of less than 330 ms (180 b.p.m.) lasting longer than 30 s. The ablation procedure consisted of pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF, n = 20) and additional substrate modification aiming arrhythmia termination in patients with persistent or inducible AF after PVI as well as in patients with a history of long-lasting persistent AF (PersAF, n = 17). The mean atrial Holter monitoring period was 7.4 +/- 3.3 months before and 13.5 +/- 4.2 months after ablation with an overall AF burden of 33.7% prior to ablation. During follow-up, AF burden decreased from 17.3-0.65% (P = 0.001) in PAF patients and from 57.4 to 13.9% (P = 0.024) in patients with PersAF. Complete AF freedom was observed in 85% (17 patients) of PAF patients and 59% (10 patients) in patients with PersAF. The absence of symptoms correlated well with documented freedom of AF. CONCLUSION: In the present study we could show, that freedom from AF can be achieved by catheter ablation in a high percentage of patients even with PersAF. Continuous atrial monitoring reveals AF ablation success rates comparable with those assessed by clinical evaluation. Symptomatic freedom of AF correlated well with the actual freedom of AF at least in this highly symptomatic patient cohort.     

Results of Short‐Term and Long‐Term Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation Using Duty‐Cycled Bipolar and Unipolar Radiofrequency Energy

PV Isolation Using Bipolar/Unipolar RF Energy . Background: Electrical disconnection of the pulmonary veins (PV) plays an important role in the ablation of paroxysmal atrial fibrillation (AF). Antral ablation using a conventional steerable ablation catheter often is technically challenging and time consuming. Methods: Eighty‐eight patients (mean age 58 ± 11 years) with symptomatic paroxysmal AF underwent ablation with a circular mapping/ablation decapolar catheter (PVAC). Ablation was performed in the antral region of the PVs with a power‐modulated bipolar/unipolar radiofrequency (RF) generator using 8–10 W delivered simultaneously through 2–10 electrodes, as selected by the operator. Seven‐day Holter monitor recordings were performed off antiarrhythmic drugs at 3‐, 6‐, and 12‐month follow‐up, and patients were requested to visit the hospital in the event of ongoing palpitations. All follow‐up patients were divided into 2 groups: Group 1 with a follow‐up of less than 1 year and group 2 patients completing a 1‐year follow‐up. Results: Overall, 338 of 339 targeted PVs (99%) were isolated with the PVAC with a mean of 24 ± 9 RF applications per patient, a mean total procedure time of 125 ± 28 minutes, and a mean fluoroscopy time of 21 ± 13 minutes. Freedom from AF off antiarrhythmic drugs was found in 82 and 79% of group 1 and group 2 patients, respectively. No procedure‐related complications were observed. Conclusion: PV isolation by duty‐cycled unipolar/bipolar RF ablation can be effectively and safely performed with a circular, decapolar catheter. Twelve‐month follow‐up data compare favorably with early postablation results, indicating stable effects over time. (J Cardiovasc Electrophysiol, Vol. 21, pp. 399–405, April 2010)     

Initial results of efficacy of left linear ablation using a novel simultaneous multielectrode ablation catheter

LA Linear Ablation With Multielectrode Catheter. Introduction: Creating complete linear block with point‐by‐point ablation is challenging in the left atrium (LA). The purpose of this study was to evaluate the efficacy of LA linear ablation using a hexapolar linear multielectrode mapping/ablation catheter. Methods and Results: Seventeen patients (age 57 ± 10, 14 male, 6 paroxysmal AF (PAF)) were studied and underwent linear ablation at the mitral isthmus (MI) and LA roof. Ablation was performed with 90 second, 60 °C applications of duty‐cycled bipolar/unipolar radiofrequency in a 1:1 ratio simultaneously at all selected electrode pairs. The result could not be evaluated in 2 patients because AF persisted despite cardioversion. Roof line block was confirmed in 9 of 15 (60%) patients. The mean number of applications and the procedural time with and without block was 5.4 ± 2.4 and 4.5 ± 2.2 applications, and 15 ± 8 and 13 ± 7 minutes. MI block was confirmed in 4 of 15 (27%) patients. The mean number of RF applications with and without block was 5.3 ± 2.2 and 9.9 ± 4.4 applications, and the procedural time was 20 ± 9 and 27 ± 10 minutes, respectively. For patients with underlying persistent AF, power was lower than those with PAF but improved when ablation was performed in sinus rhythm. Char was observed in 2 cases; however, no procedure‐related complications were observed. Conclusions: In our initial experience, a linear multielectrode catheter using duty‐cycled bipolar and unipolar RF energy was inferior to conventional single point irrigated ablation in achieving LA linear block. However, successful linear block was obtained within a short period of time, when it was achieved . (J Cardiovasc Electrophysiol, Vol. 22, pp. 739‐745, July 2011)     

Congestive heart failure after extensive catheter ablation for atrial fibrillation: prevalence, characterization, and outcome

Congestive Heart Failure After Catheter Ablation for AF. Introduction: This study sought to describe a new complication of catheter ablation for atrial fibrillation (AF): new onset congestive heart failure (CHF) after extensive ablation for AF. Methods and Results: Data from 12 patients developing CHF after ablation were prospectively collected. All patients underwent extensive ablation for AF including circumferential pulmonary venous ablation and complex fractionated atrial electrograms guided ablation. CHF was diagnosed using the following criteria: symptoms or signs of heart failure, elevated BNP, and echocardiographic evidence of left ventricular diastolic dysfunction. Twelve patients (5 persistent and 7 permanent AF) had CHF after extensive ablation out of 484 consecutive AF patients who underwent catheter ablation (prevalence 2.5%). None of these 12 patients had CHF prior to the procedure. The mean onset of the symptoms was 39 ± 14 hours after the index procedure. Dyspnea and pulmonary rales were the most observed symptoms or signs. White blood cell count, serum CRP, BNP, and echocardiographic parameters of left ventricular diastolic dysfunction (E/A, E/E′) were significantly increased after the onset of symptoms. All patients had complete recovery with supportive therapy within 3 days of the onset of symptoms. Conclusions: In this single‐center experience, CHF after extensive ablation for AF was a well‐recognized complication with a relatively high incidence of 2.5%. Measurement of BNP, CRP, and E/A, E/E′ is useful in managing these patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 632‐637, June 2011)     

Persistence of Pulmonary Vein Isolation After Robotic Remote‐Navigated Ablation for Atrial Fibrillation and its Relation to Clinical Outcome

Robotic Remote Ablation for AF . Aims: A robotic navigation system (RNS, Hansen?) has been developed as an alternative method of performing ablation for atrial fibrillation (AF). Despite the growing application of RNS‐guided pulmonary vein isolation (PVI), its consequences and mechanisms of subsequent AF recurrences are unknown. We investigated the acute procedural success and persistence of PVI over time after robotic PVI and its relation to clinical outcome. Methods and Results: Sixty‐four patients (60.7 ± 9.8 years, 53 male) with paroxysmal AF underwent robotic circumferential PVI with 3‐dimensional left atrial reconstruction (NavX?). A voluntary repeat invasive electrophysiological study was performed 3 months after ablation irrespective of clinical course. Robotic PVI was successful in all patients without complication (fluoroscopy time: 23.5 [12–34], procedure time: 180 [150–225] minutes). Fluoroscopy time demonstrated a gradual decline but was significantly reduced after the 30th patient following the introduction of additional navigation software (34 [29–45] vs 12 [9–17] minutes; P < 0.001). A repeat study at 3 months was performed in 63% of patients and revealed electrical conduction recovery in 43% of all PVs. Restudied patients without AF recurrence (n = 28) showed a significantly lower number of recovered PVs (1 (0–2) vs 2 (2–3); P = 0.006) and a longer LA‐PV conduction delay than patients with AF recurrences (n = 12). Persistent block of all PVs was associated with freedom from AF in all patients. At 3 months, 67% of patients were free of AF, while reablation of recovered PVs led to an overall freedom from AF in 81% of patients after 1 year. Conclusion: Robotic PVI for PAF is safe, effective, and requires limited fluoroscopy while yielding comparable success rates to conventional ablation approaches with PV reconduction as a common phenomenon associated with AF recurrences. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1079‐1084)     

Acute Termination of Human Atrial Fibrillation by Identification and Catheter Ablation of Localized Rotors and Sources: First Multicenter Experience of Focal Impulse and Rotor Modulation (FIRM) Ablation

FIRM Ablation of Human AF Rotors. Introduction: Catheter ablation of atrial fibrillation (AF) currently relies on eliminating triggers, and no reliable method exists to map the arrhythmia itself to identify ablation targets. The aim of this multicenter study was to define the use of Focal Impulse and Rotor Modulation (FIRM) for identifying ablation targets. Methods: We prospectively enrolled the first (n = 14, 11 males) consecutive patients undergoing FIRM‐guided ablation for persistent (n = 11) and paroxysmal AF at 5 centers. A 64‐pole basket catheter was used for panoramic right and left atrial mapping during AF. AF electrograms were analyzed using a novel system to identify sustained rotors (spiral waves), or focal beats (centrifugal activation to surrounding atrium). Ablation was performed first at identified sources. The primary endpoints were acute AF termination or organization (>10% cycle length prolongation). Conventional ablation was performed only after FIRM‐guided ablation. Results: Twelve out of 14 cases were mapped. AF sources were demonstrated in all patients (average of 1.9 ± 0.8 per patient). Sources were left atrial in 18 cases, and right atrial in 5 cases, and 21/23 were rotors. FIRM‐guided ablation achieved the acute endpoint in all patients, consisting of AF termination in n = 8 (4.9 ± 3.9 minutes at the primary source), and organization in n = 4. Total FIRM time for all patients was 12.3 ± 8.6 minutes. Conclusions: FIRM‐guided ablation revealed localized AF rotors/focal sources in patients with paroxysmal, persistent and longstanding persistent AF. Brief targeted FIRM‐guided ablation at a priori identified sites terminated or substantially organized AF in all cases prior to any other ablation. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1277‐1285, December 2012)     

Clinical Value of Noninducibility by High-Dose Isoproterenol Versus Rapid Atrial Pacing After Catheter Ablation of Paroxysmal Atrial Fibrillation

Noninducibility by High‐Dose Isoproterenol. Objective: To determine the relative clinical value of noninducibility of atrial fibrillation (AF) by isoproterenol (ISO) and by rapid atrial pacing (RAP) in patients with paroxysmal AF (PAF). Background: AF can be induced by RAP or ISO in >85% of patients with PAF. Methods: ISO was administered in escalating doses of 5, 10, 15, and 20 μg/min in 112 patients (age = 56 ± 13 years) with PAF before radiofrequency catheter ablation. AF was inducible in 97 of 112 patients (87%) at a mean dose of 15 ± 5 μg/min. RAP induced AF in the remaining 14 of 15 patients. Antral pulmonary vein (PV) isolation (APVI) was followed by ablation of complex fractionated atrial electrograms (CFAEs) as necessary to terminate AF and render AF noninducible in response to ISO. Results: AF terminated during APVI in 72 of 111 patients (65%) and after APVI plus ablation of CFAEs in 11 of 111 patients (10%). In the remaining 28 patients (25%), sinus rhythm was restored by transthoracic cardioversion. RAP was performed in the last 61 consecutive patients who were rendered noninducible by ISO. RAP initiated AF in 20 of 61 patients (33%) and atrial flutter in 6 patients (10%). No additional ablation was performed if AF was induced with RAP; however, atrial flutter was targeted. At 12 ± 5 months, 63/75 patients (84%) who were noninducible by ISO and 2 of 8 (25%) who still were reinducible by ISO were free from recurrent AF after a single ablation procedure without antiarrhythmic drugs (P = 0.001). AF recurred in 20 of 36 patients (56%) who required cardioversion for persistent AF after ablation (P < 0.001). Among the 61 patients who also underwent RAP, 12 of 20 (60%) who were, and 31 of 41 (76%) who were not inducible by RAP were free from recurrent AF (P = 0.21). The accuracy of noninducibility as a predictor of clinical outcome was 83% with ISO and 64% by RAP (P = 0.03). Conclusions: The response to isoproterenol after catheter ablation of PAF more accurately predicts clinical outcome than the response to RAP. (J Cardiovasc Electrophysiol, Vol. 21, pp. 13–20, January 2010)     

Role of Residual Potentials Inside Circumferential Pulmonary Veins Ablation Lines in the Recurrence of Paroxysmal Atrial Fibrillation

Residual Potentials After Pulmonary Vein Isolation. Background: Residual gaps due to incomplete ablation lines are known to be the most common cause of recurrent atrial fibrillation (AF) after catheter ablation. We hypothesized that any residual potentials at the junction of the left atrium and pulmonary vein (PV), inside the circumferential PV ablation (CPVA) lines, would contribute to the recurrence of AF or post‐AF ablation atrial flutter (AFL); therefore, the elimination of these potentials increases AF‐/AFL‐free survival rates. Methods and Results: One hundred and two patients with paroxysmal AF (PAF) were enrolled and prospectively randomized to a group with ablation of residual potentials as add‐on therapy to CPVA + PV electrical isolation (PVI) (group 1, n = 49), or a group without ablation of the residual potentials (group 2, n = 53). Post‐CPVA residual potentials, inside the ablation lines, were identified by contact bipolar electrode mapping catheter and a detailed 3‐dimensional voltage map. Twenty‐three patients in group 1 and 18 patients in group 2 had post‐CPVA residual potentials (46.9% vs 34.0%, P = 0.182). The AF‐/AFL‐free survival rate during follow‐up of 23.3 ± 7.9 months was not different in comparisons between the 2 groups (P = 0.818), and 79.6% and 81.1% of the patients in groups 1 and 2 maintained a sinus rhythm (P = 0.845), respectively. Conclusions: Residual potentials inside CPVA were commonly found in the patients with PAF after CPVA + PVI. Further ablation of residual potentials did not increase the efficacy of catheter ablation in patients with PAF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 959‐965, September 2010)     

Importance of Sinus Rhythm as Endpoint of Persistent Atrial Fibrillation Ablation

Endpoint of Persistent AF Ablation . Background: The endpoint of persistent atrial fibrillation (AF) ablation is still a matter of debate. The purpose of this study was to evaluate if sinus rhythm (SR) as endpoint of persistent AF ablation has a better long‐term outcome compared to atrial tachycardia (AT) or AF at the end of the procedure. Methods and Results: Between 2008 and 2011, 191 consecutive patients undergoing de novo catheter ablation for symptomatic persistent and long‐standing persistent AF using a sequential ablation approach (including pulmonary vein isolation, ablation of complex fractionated electrograms and linear lesions) were included in the study. According to the result at the end of ablation procedure, patients were classified into 3 groups: patients with termination of AF into SR (Group 1, n = 62), patients with AT undergoing cardioversion (CV) (Group 2, n = 47), or patients with AF undergoing CV (Group 3, n = 82). The primary endpoint was freedom from any atrial tachyarrhythmia off antiarrhythmic drugs at 12 months. At 12 months, estimated proportions of patients free from any arrhythmia recurrence were 42% for Group 1, 13% for Group 2, and 25% for Group 3 (P = 0.002). In a Cox regression analysis only termination into SR was associated with a lower risk of arrhythmia recurrence (HR: 0.62; P = 0.04). Conclusion: If SR is achieved as endpoint of persistent and long‐standing persistent AF ablation using a sequential ablation approach it is associated with the highest long‐term single procedure success rate compared to AT or AF at the end of the procedure. (J Cardiovasc Electrophysiol, Vol. 24, pp. 388‐395, April 2013)     

Right Atrial Mapping and Linear Ablation for Paroxysmal Atrial Fibrillation

Objective: Catheter ablation techniques to cure atrial fibrillation (AF) are under investigation. This study evaluates a mapping-based, individualized approach to right atrial (RA) linear ablation in patients with paroxysmal AF. Methods: In this prospective observational study, 29 patients with recurrent symptomatic AF refractory to medical therapy, underwent linear ablation between May 1998 and December 1999. Inclusion criteria were symptomatic paroxysmal AF, failure of at least 2 antiarrhythmic medications, and informed consent. Radiofrequency ablation was performed in the RA using a 3.3 French multielectrode catheter, ablating through sequential electrodes to establish linear lesions. Lesions were delivered during sustained AF, guided by an empiric mapping scheme, targeting arrhythmogenic areas noted during electrophysiologic testing in sinus rhythm and areas of most disorganization during AF. Reinduction of AF was attempted at the end of successful ablation. Results: The mean age was 58 years. There were 15 male and 14 female patients. Sustained AF was inducible in all patients at electrophysiology study. Acute success was achieved in 24 patients (83%). Long term success (maintaining sinus rhythm off antiarrhythmic medications) was seen in 23 (79%) over a mean follow-up of 19.7 months. Ablation lines varied from patient to patient. There were no complications. Conclusions: Individualized linear ablation in the RA using a multielectrode catheter system can produce effective suppression of paroxysmal AF. Ablation during AF, and testing to reinduce AF at the end of the procedure, make this study unique.     

Ablation of Atrial Fibrillation at the Time of Cavotricuspid Isthmus Ablation in Patients With Atrial Flutter Without Documented Atrial Fibrillation Derives a Better Long‐Term Benefit

AF Ablation in Patients With Only Documentation of Atrial Flutter. Objectives: The aim of the study was to evaluate whether isolation of the pulmonary veins (PVs) at the time of cavotricuspid isthmus (CTI) ablation is beneficial in patients with lone atrial flutter (AFL). Background: A high proportion of patients with lone persistent AFL have recurrent episodes of atrial fibrillation (AF) after CTI ablation. However, the benefit of AF ablation in patients with only documentation of AFL has not been determined. Methods: Forty‐eight patients with typical lone persistent AFL (age 56 ± 6; 90% male) were randomized to CTI ablation (Group A; n = 25) or to CTI + PV isolation (PVI) (Group B; n = 23). In addition to PVI, some patients in group B underwent ablation of complex fractionated electrograms and/or creation of left atrial roof and mitral isthmus ablation line in a stepwise approach when AF was induced and sustained for more than 2 minutes. Mean follow‐up was 16 ± 4 months with a 48‐hour ambulatory monitor every 2 months. Results: There were no recurrences of AFL in either group. Six patients in group B (22%) underwent a stepwise ablation protocol. AF organized and terminated in 5 patients during ablation (83%). Complication rate was not significantly different among the groups. Twenty patients in group B (87%) and 11 patients in group A (44%) were free of arrhythmias on no medications at the end of follow‐up (P < 0.05). Conclusions: Ablation of AF at the time of CTI ablation results in a significantly better long‐term freedom from arrhythmias. (J Cardiovasc Electrophysiol, Vol. 22, pp. 34‐38, January 2011)     

Outcomes of Ablation of Paroxysmal Atrial Fibrillation in Patients on Chronic Hemodialysis

AF Ablation in HD Patients . Introduction: It is not common for patients on chronic hemodialysis (HD) to undergo catheter ablation of atrial fibrillation (AF). We aimed to show the outcomes of AF ablation in the HD patients. Methods and Results: Thirty HD patients who underwent pulmonary vein (PV) isolation for drug refractory paroxysmal AF were retrospectively studied, and their AF recurrence free rate and frequency of periprocedural complications were compared to 60 age‐ and gender‐matched control patients not requiring HD. A nonirrigated ablation catheter was used in both patient groups. During a mean follow‐up period of 821 ± 218 days, 16 (54%) of the HD patients remained free from AF recurrence without any antiarrhythmic agents versus 47 (78%) of the control patients with an initial ablation (P = 0.013). A second ablation procedure was performed in 12 patients with an AF recurrence, and consequently 20 (67%) of the HD patients were in sinus rhythm compared to 53 (88%) of the controls during a follow‐up duration of 747 ± 221 after the last ablation (P = 0.012). Bleeding from the venipuncture site requiring a prolonged hospital stay was identified in 2 HD patients and 1 control subject, while no life‐threatening complications were observed in either patient group. Conclusion: Although the success rate of the PV isolation in HD patients was far from satisfactory, it may be considered as one of the therapeutic options for them. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1289‐1294, December 2012)     

A Prospective Study Evaluating the Role of Obesity and Obstructive Sleep Apnea for Outcomes After Catheter Ablation of Atrial Fibrillation

Effect of Obesity and OSA on Outcomes Post AF Ablation . Background: Obesity and obstructive sleep apnea (OSA) have a strong association with atrial fibrillation (AF). The purpose of this study was to prospectively determine the effects of obesity, assessed by the body mass index (BMI) and OSA on the efficacy of catheter ablation of AF. Methods: The patient population consisted of 109 patients (mean age: 60 ± 10 years, 79% male, 67% paroxysmal, mean BMI 28 ± 5 kg/m²) who underwent catheter ablation of AF. Based on BMI, patients were classified as normal (<25 kg/m²), overweight (≥25 and <30 kg/m²), or obese (≥30 kg/m²). OSA was assessed by the Berlin questionnaire. Clinical success was defined as at least 90% reduction in AF burden after 3‐month blanking period. Mean duration of follow‐up was 11 ± 4 months. Results: Of the 75 patients with clinical success, 25 (33%) had normal BMI, 29 (39%) were overweight, and 21 (28%) were obese. Among the 34 patients with failed outcome, 5 (15%) had normal BMI, 14 (41%) were overweight, and 15 (44%) were obese (P = 0.04). Twenty‐eight of the 48 patients with OSA (58%) had clinical success as opposed to 47 of the 61 patients (77%) without OSA (P = 0.036). On multivariate analysis, only BMI emerged as an independent predictor of procedural failure ((OR 1.11, CI: 1.00–1.21, P = 0.03). Conclusions: The results of this prospective study show that obesity, a modifiable risk factor, is an independent predictor of procedural failure after catheter ablation of AF. Whether treating obesity may improve the results of catheter ablation of AF warrants further investigation. (J Cardiovasc Electrophysiol, Vol. 21, pp. 521‐525, May 2010)     

The use of dabigatran immediately after atrial fibrillation ablation

Dabigatran After AF Ablation. Introduction: Atrial fibrillation (AF) ablation requires postprocedural anticoagulation to prevent thromboembolic events because of the ablation procedure itself or due to recurrent AF postprocedure. Dabigatran is a new anticoagulant and may be useful after AF ablation to prevent thromboembolic events. Methods and Results: We evaluated 123 consecutive patients who were started on dabigatran after AF ablation. Patients were given enoxaparin 0.5 mg/kg at the end of the procedure, which was repeated 12 hours later and then discontinued. Dabigatran was started 22 hours postablation with drug dose based on renal function. Primary outcomes were thromboembolic events, bleeding complications, and side effects over a 30‐day follow‐up period. The preablation anticoagulant was warfarin in 56 (45.5%) patients, dabigatran in 34 (27.6%), and aspirin in 26 (21.1%). Seven (5.7%) patients were on no anticoagulant before ablation. The patients on dabigatran before ablation with normal renal function had the drug stopped 36 hours preablation. There were no preprocedural or intraprocedural thromboembolic episodes or bleeding. Three patients received dabigatran 75 mg bid and the rest 150 mg bid. There were no postablation strokes, transient ischemic attacks, or systemic thromboemboli in any patient. Three patients discontinued dabigatran and were changed to warfarin, 2 because of gastrointestinal side effects and 1 because of a diffuse rash. Conclusions: Dabigatran is safe and well tolerated after AF ablation. It did not cause bleeding complications and there were no thromboembolic events. Dabigatran appears to be an alternative to warfarin after AF ablation . (J Cardiovasc Electrophysiol, Vol. 23 p. 264‐268, March 2012.)     

Baseline B-type natriuretic peptide: a gender-specific predictor of procedure-outcome in atrial fibrillation patients undergoing catheter ablation

Baseline BNP Predicts Ablation Outcome in Male AF Patients. Background: Close association between atrial fibrillation (AF) and brain natriuretic peptide (BNP) has been demonstrated by several studies. Important gender differences exist in AF patients including a higher plasma BNP level in women. Therefore, it is imperative to evaluate the relationship between AF and BNP separately in men and women. Objective: This study examined possible gender‐specific role of BNP in predicting procedure outcome in AF patients undergoing catheter ablation. Method: The study population included 568 consecutive patients (age 62 ± 10, male 73%, paroxysmal 25%, persistent 38%, and long‐standing persistent AF 37%) undergoing AF ablation, who had structurally normal heart and left ventricular ejection fraction ≥45%. Baseline BNP was measured in all. Patients were grouped into “normal” and “high” BNP based on gender‐specific cut‐off values (<50 and ≥50 pg/mL in males, <100 and ≥ 100 pg/mL in females). Result: Baseline BNP was significantly higher among women than men (126 ± 112 versus 87 ± 99, P = 0.009). At 12 ± 6 month follow‐up, 304 of 414 (73%) males and 98 of 154 (64%) females were AF/atrial tachycardia‐free off antiarrhythmic drugs (log‐rank P = 0.018). In multivariable analysis, BNP remained an independent predictor of AF recurrence (BNP ≥ 50: hazard ratio [HR] 2.54, P = 0.006) in males. No such association was observed among females (BNP ≥ 100: HR 0.79, 95% CI 0.43–1.42; P = 0.426). Conclusion: Baseline BNP was found to be an independent predictor of AF recurrence in male patients undergoing ablation. This correlation between BNP and AF recurrence was not observed in females. Thus, BNP plays a gender‐specific prognostic role in AF . (J Cardiovasc Electrophysiol, Vol. 22, pp. 858‐865, August 2011)     

Pulmonary Vein Contraction Before and After Radiofrequency Ablation for Atrial Fibrillation

Pulmonary Vein Contraction After Ablation. Introduction: Cardiovascular magnetic resonance imaging (cMRI) may provide a noninvasive method to test for pulmonary vein (PV) isolation after ablation for atrial fibrillation (AF) by detecting changes in PV contraction. Methods: PV contraction (the maximal percentage change in PV cross‐sectional area [CSA] during the cardiac cycle) measured 1 month before and 2 months after PV isolation was compared in 63 PVs from 16 patients with medically refractory AF. Repeat cMRI imaging and invasive catheter mapping was performed prior to repeat PV ablation in 50 PVs from 14 additional patients with recurrent AF. Contraction in PVs with sustained isolation after the initial ablation was compared to contraction in PVs with electrical reconnection to adjacent atrium. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff PV contraction value for prediction of PV‐atrial reconnection after ablation. The cutoff value was then prospectively tested in 40 PVs from 12 additional patients. Results: PV contraction decreased after AF ablation (22.4 ± 10% variation in CSA before ablation vs 10.1 ± 8% variation in CSA after ablation, P < 0.00001). PVs with sustained isolation on invasive mapping contracted less than PVs with electrical reconnection to adjacent atrium (13.7 ± 10.6% vs 21.4 ± 9.3%, P = 0.021). PV contraction produced a c‐index of 0.74 for prediction of PV‐atrial reconnection after ablation and >17% variation in PV CSA predicted reconnection with a sensitivity of 84.6% and specificity of 66.7%. Conclusion: PV contraction is reduced by ablation. PV contraction measurement may provide a noninvasive method to test for PV isolation after ablation procedures. (J Cardiovasc Electrophysiol, Vol. 22, pp. 169‐174, February 2011)