Characteristics of Complex Fractionated Electrograms in Nonpulmonary Vein Ectopy Initiating Atrial Fibrillation/Atrial Tachycardia

Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non‐PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non‐PV ectopy initiating AF/AT. Methods: Twenty‐three patients (age 53 ± 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non‐PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real‐time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8‐second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds. Results: All patients (100%) with non‐PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non‐PV atrial ectopy or other atrial CFAEs (54.1 ± 5.6, 58.3 ± 11.3, 52.8 ± 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non‐PV ectopy in all patients (100%). During a follow‐up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non‐PV ectopy during the follow‐up. Conclusion: The sites of the origin of the non‐PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non‐PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated.     

Vagal Paroxysmal Atrial Fibrillation: Prevalence and Ablation Outcome in Patients Without Structural Heart Disease

Prevalence of Vagal Paroxysmal Atrial Fibrillation . Introduction: The prevalence of vagal and adrenergic atrial fibrillation (AF) and the success rate of pulmonary vein isolation (PVI) are not well defined. We investigated the prevalence of vagal and adrenergic AF and the ablation success rate of antral pulmonary vein isolation (APVI) in patients with these triggers compared with patients with random AF. Methods and Results: Two hundred and nine consecutive patients underwent APVI due to symptomatic drug refractory paroxysmal AF. Patients were diagnosed as vagal or adrenergic AF if >90% of AF episodes were related to vagal or adrenergic triggers; otherwise, a diagnosis of random AF was made. Clinical, electrocardiogram (ECG), and Holter follow‐up was every 3 months in the first year and every 6 months afterward and for symptoms. Of 209 patients, 57 (27%) had vagal AF, 14 (7%) adrenergic AF, and 138 (66%) random AF. Vagal triggers were sleep (96.4%), postprandial (96.4%), late post‐exercise (51%), cold stimulus (20%), coughing (7%), and swallowing (2%). At APVI, 94.3% of patients had isolation of all veins. Twenty‐five (12%) patients had a second APVI. At a follow‐up of 21 ± 15 months, the percentage of patients free of AF was 75% in the vagal group, 86% in the adrenergic group, and 82% for random AF (P = 0.51). Conclusion: In patients with PAF and no structural heart disease referred for APVI, vagal AF is present in approximately one quarter. APVI is equally effective in patients with vagal AF as in adrenergic and random AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 489‐493, May 2010)     

Mechanisms for atrial fibrillation in patients with Wolff-Parkinson-White syndrome

INTRODUCTION: Paroxysmal atrial fibrillation (PAF) frequently occurs in patients with Wolff-Parkinson-White (WPW) syndrome. To elucidate the mechanisms for PAF, we performed electrophysiologic studies (EPS) before and after ablation of accessory pathways (APs). METHODS AND RESULTS: We investigated 24 patients with WPW syndrome who had AV reciprocating tachycardia and prior PAF and had undergone successful ablation of APs. Patients in whom atrial fibrillation (AF) was induced by EPS at day 7 after ablation were considered the inducible AF group (n = 14), and patients in whom AF was not induced by EPS at day 7 after ablation were considered the noninducible AF group (n = 10). Fifteen patients with AV nodal reentrant tachycardia (AVNRT) but without PAF who underwent ablation of the slow AV nodal pathways served as the control group (AVNRT group). Maximal atrial conduction delay and conduction delay zone, which are indices of atrial vulnerability, were measured before and after ablation. Before ablation, maximal atrial conduction delay and conduction delay zone were significantly greater (P < 0.0001 and P < 0.0001, respectively) in the two WPW syndrome groups than in the AVNRT group, indicating increased atrial vulnerability in WPW syndrome with PAF. After ablation, these parameters did not change in the inducible AF group, whereas they were significantly (P < 0.0001) decreased in the noninducible AF group and were not different from those in the AVNRT group, indicating normalized atrial vulnerability in the noninducible AF group after ablation. The prospective study demonstrated that PAF recurred only in the inducible AF group during long-term follow-up (17+/-7 months). CONCLUSION: The findings of this study suggest that there are two mechanisms of PAF in patients with WPW syndrome: one mechanism is reversible and AP-dependent atrial vulnerability, and the other is intrinsic and AP-independent atrial vulnerability.     

Long- and Short-Term Temporal Stability of Complex Fractionated Atrial Electrograms in Human Left Atrium During Atrial Fibrillation

Background: Complex fractionated atrial electrograms (CFAEs) have been reported as targets for catheter ablation of atrial fibrillation (AF). However, the temporal stability of CFAE sites remains poorly defined.
Methods and Results: The study consisted of two phases. In the initial phase, two automated software algorithms, namely the interval confidence level (ICL) and the average interpotential interval (AIPI) were assessed for their diagnostic accuracy for automated CFAE detection. The AIPI was found to be superior to the ICL, and an AIPI of ≤100 ms was associated with a sensitivity and specificity of both 92% for detection of CFAEs. In the second phase of the study, 12 patients (2 females, mean age 54 ± 12 years) who underwent catheter ablation for persistent AF were studied to investigate the temporal stability of CFAEs. Two consecutive left atrial (LA) three-dimensional CFAE maps coded with AIPI readings were reconstructed during ongoing AF in each study patient, with a mean time difference of 34.3 ± 8.7 minutes between the two maps. Among a total of 149 CFAE sites and 238 non-CFAE sites on the first CFAE map that were precisely revisited during the repeat mapping process, 135 (90.6%) and 225 (94.5%) remained as CFAE sites and non-CFAE sites, respectively. RF ablation at the selected stable CFAE sites significantly prolonged AF cycle length (181 ± 26 ms to 199 ± 29 ms, P < 0.0001).
Conclusion: CFAEs recorded in the LA during AF display high temporal stability in patients with persistent AF. The clinical significance of our findings warrants further investigation.     

Complex electrograms within the coronary sinus: time- and frequency-domain characteristics, effects of antral pulmonary vein isolation, and relationship to clinical outcome in patients with paroxysmal and persistent atrial fibrillation

Background: The mechanistic and clinical significance of complex fractionated atrial electrograms (CFAE) in the coronary sinus (CS) has been unclear. Methods and Results: Antral pulmonary vein isolation (APVI) was performed in 77 patients with paroxysmal (32) or persistent AF (45). CS electrograms recorded for 60 seconds before and after APVI were analyzed in the time‐ and frequency‐domains. Dominant frequency (DF), complexity index (CI: change in polarity of depolarization), and fractionation index (FI: change in direction of depolarization slope) were determined. Before APVI, there was no difference in DF, CI, or FI between paroxysmal and persistent AF. APVI resulted in a significant decrease in DF, CI, and FI in all patients. Baseline CI (43 ± 13/s vs 54 ± 14/s, P = 0.03) and FI (64 ± 23/s vs 87 ± 30/s, P = 0.02) were lower in patients with paroxysmal AF who had AF terminated by ablation than who did not. At 10 ± 2 months, 69% of patients with paroxysmal AF and 49% of patients with persistent AF were free from AF after single ablation. Baseline CI was higher among patients with paroxysmal AF who had AF after APVI (56 ± 20/s vs 44 ± 10/s, P = 0.03). In patients with persistent AF, there was a larger decrease in DF after APVI among patients who remained free from AF (13 ± 11% vs 7 ± 9%, P < 0.05). Conclusions: Complexity of CS electrograms may reflect drivers of AF that perpetuate paroxysmal AF after APVI. In persistent AF, the extent to which APVI decreases DF in the CS correlates with efficacy, suggesting that DF identifies patients who may require additional ablation beyond APVI.     

Clinical Significance of Induced Atrial Tachycardia After Termination of Longstanding Persistent Atrial Fibrillation Using a Stepwise Approach

Induced Atrial Tachyarrhythmia During Atrial Fibrillation Ablation. Introduction: The utility of inducibility test of atrial tachycardia (AT) in patients with longstanding persistent atrial fibrillation (AF; LPAF) is unclear. This study aimed to evaluate the significance of induced AT and the impact of their ablation on the clinical outcome. Methods: In 194 patients with LPAF (>1 year) who underwent catheter ablation (pulmonary vein isolation with substrate ablation), an inducibility test was performed after AF termination. Results: AT was induced in 108 (56%) patients (induced AT group); neither AT nor AF was inducible in 37 (19%, noninduction group). During 39 ± 21 months, AT recurred in 30 patients (28%), AF in 19 (17%), and no arrhythmia in 56 (52%) among induced AT group, although there was a recurrence of AT in 9 (24%, P = 0.68), AF in 6 (16%, P = 0.85), and no arrhythmia in 22 (60%, P = 0.42) among noninduction group (P = NS). Note that 10 patients with repeated ablation in induced AT group revealed 8 different and 2 similar recurrent ATs compared to the induced ATs at first session. The mean cycle length of induced AT that terminated by ablation (271 ± 64 ms) was longer than that without (249 ± 58 ms, P < 0.05). In induced AT group, AT recurrence rate in patients who achieved AT termination by ablation was lower than those without termination (5% vs 36%, P < 0.05). Conclusions: ATs that are inducible after LPAF termination do not necessarily become clinical AT. However, patients who achieved noninducibility of AT by ablating slower cycle length of AT had better outcomes. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1171–1178, November 2012)     

Time- and frequency-domain characteristics of atrial electrograms during sinus rhythm and atrial fibrillation

Ablation and Spectral Characteristics of Fibrillation. Background: Complex fractionated atrial electrograms (CFAE) have been considered to be helpful during catheter ablation of atrial fibrillation (AF). The purpose of this study was to analyze the characteristics of CFAEs recorded during sinus rhythm (SR) and AF, and to determine their relationship to perpetuation of AF and clinical outcome. Methods and Results: Antral pulmonary vein isolation (APVI) was performed in 34 consecutive patients (age = 59 ± 10 years) with paroxysmal AF who presented in SR. Time‐ and frequency‐domain characteristics of electrograms recorded from the same sites in the coronary sinus (CS) were analyzed during SR and AF, before and during isoproterenol infusion. There was a modest correlation in fractionation index (FI: change in the direction of depolarization, r = 0.40, P = 0.001) and complexity index (CI: change in the polarity of depolarization, r = 0.41, P = 0.001), but not in the dominant frequency (DF) between SR and AF. There was no relationship between the DF and CI or FI during AF. Isoproterenol was associated with an increase in DF during AF (6.6 ± 0.9 vs 5.1 ± 0.6 Hz, P < 0.001) but had no effect on CI or FI (P = 0.6). A higher CI (58.3 ± 21.0/s vs 38.0 ± 21.0/s, P < 0.01), and FI (123.5 ± 44.8/s vs 75.6 ± 44.6/s, P < 0.01) during AF were associated with a lower likelihood of termination of AF during APVI and a higher probability of recurrent AF after ablation. Ratio of FI during AF to SR was also higher when AF persisted than terminated after APVI (29.7 ± 12.4 vs 19.1 ± 9.7, P = 0.002). However, time‐ or frequency‐domain parameters during SR were not predictive of termination or clinical outcome. Conclusions: Structural and functional properties of the atrial myocardium during AF contribute to electrogram complexity, which may indicate the presence of extra‐PV mechanisms of AF that are not eliminated by APVI. Mapping of complex electrograms in SR is not likely to be sufficient to identify drivers of AF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 851‐857, August 2011)     

Electrophysiologic Characteristics of Complex Fractionated Atrial Electrograms in Patients with Atrial Fibrillation

Introduction: The underlying mechanisms of complex fractionated atrial electrogram (CFAE) during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) have not yet been clearly elucidated. We explored the relationships between CFAE and left atrial (LA) voltage, or conduction velocity (CV).
Methods and Results: In 50 patients with AF (23 paroxysmal AF [PAF], 41 males, mean age 55.76 ± 10.16 years), the CFAE (average index of fractionation of electrograms during AF by interval-analysis algorithm, cycle length [CL]≤ 120 ms) areas, voltage, and CV were measured at eight different quadrants in each patient's LA by analyzing a NavX-guided, color-coded CFAE CL map, a voltage map, and an isochronal map (500 ms pacing) generated by contact bipolar electrograms (70–100 points in the LA). The results were: (1) CFAE areas were predominantly located in the septum, roof, and LA appendage; (2) CFAE area had lower voltage than those in non-CFAE area and was surrounded by the areas of high voltage (P < 0.0001); (3) The CFAE areas had low CVs compared with non-CFAE areas (P < 0.001); and (4) The percentage of CFAE area was lower in patients with persistent atrial fibrillation (PeAF) compared with those with PAF (P < 0.05).
Conclusions: The CFAE area, which is primarily located at the septum, has a low voltage with a lower CV, and is surrounded by high-voltage areas. Underlying electroanatomical complexity is associated with clustering of CFAEs.     

Diagnostic accuracy of a new software for complex fractionated electrograms identification in patients with persistent and permanent atrial fibrillation

Introduction: The elimination of complex fractionated atrial electrograms (CFAEs) has been proposed as a potential target for guiding successful AF substrate ablation. The possibility to efficiently map the atria and rapidly identify CFAEs sites is necessary, before the CFAEs ablation becomes a routine approach. The aims of this study, conducted in patients with persistent and permanent atrial fibrillation (AF), were to analyze by CARTO mapping in the right (RA) and in the left atrium (LA) during AF: (1) the diagnostic accuracy of a new software for CFAEs analysis, (2) the spatial distribution of CFAEs, (3) the regional beat to beat AF intervals (FF). Methods and Results: Twenty‐five consecutive patients (four women, 58.8 ± 11.4 years) undergoing radiofrequency catheter ablation for persistent and permanent AF were enrolled in the study. The CFAE software showed a high sensitivity (90%) and specificity (91%) in the identification of CFAEs, using a specific setting of parameters. The LA had a significantly higher prevalence of CFAEs as compared with the RA (30.5% vs 20.3%, P = 0.016). The CFAEs were mostly present in the septum and in the area of coronary sinus ostium (CS os). The FF intervals were significantly shorter in the LA than in the RA (P < 0.01). Conclusion: CARTO system has a high diagnostic accuracy in the identification of CFAEs. Atrial electrical activity (CFAEs, mean FF intervals) during AF showed a significant spatial inhomogeneity.     

Catheter Ablation of Long‐Standing Persistent Atrial Fibrillation: A Lesson from Circumferential Pulmonary Vein Isolation

Catheter Ablation of Long‐Standing Persistent AF. Introduction: Circumferential pulmonary vein isolation (CPVI) is associated with a high success rate in patients with paroxysmal and persistent atrial fibrillation (AF). However, in patients with long‐standing persistent AF, the ideal ablation strategy still remains a matter of debate. Methods and Results: Two‐hundred and five patients underwent catheter ablation for long‐standing persistent AF defined as continuous AF of more than 1‐year duration. In a first step, all patients underwent CPVI. If direct‐current cardioversion failed following CPVI, ablation of complex fractionated atrial electrograms (CFAEs) was performed. The goal was conversion into sinus rhythm (SR) or, alternatively, atrial tachycardia (AT) with subsequent ablation. A total of 340 procedures were performed. CPVI alone was performed during 165 procedures in 124 of 205 (60.5%) patients. In the remaining 81 patients, additional CFAE ablation was performed in 45, left linear lesions for recurrent ATs in 44 and SVC isolation in 15 patients, respectively, resulting in inadvertent left atrial appendage isolation in 9 (4.4%) patients. After the initial ablation procedure, 67 of 199 patients remained in SR during a mean follow‐up of 19 ± 11 months. Six patients were lost to follow‐up. After a mean of 1.7 ± 0.8 procedures, 135 of 199 patients (67.8%) remained in SR. Eighty‐six patients (43.2%) remained in SR following CPVI performed as the sole ablative strategy. Conclusions: CPVI alone is sufficient to restore SR in 43.2% of patients with long‐standing persistent AF. Multiple procedures and additional ablation strategies with a significant risk of inadvertent left atrial appendage isolation are often required to maintain stable SR. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1085‐1093)     

The Optimal Automatic Algorithm for the Mapping of Complex Fractionated Atrial Electrograms in Patients With Atrial Fibrillation

CFAEs and the Voltage.   Introduction: Catheter ablation of atrial fibrillation (AF) can be guided by the identification of complex fractionated atrial electrograms (CFAEs). We aimed to study the prediction of the CFAEs defined by an automatic algorithm in different atrial substrates (high voltage areas vs low voltage areas).
Methods and Results: This study included 13 patients (age = 56 ± 12 years, paroxysmal AF = 8 and persistent AF = 5), who underwent mapping and catheter ablation of AF with a NavX system. High-density voltage mapping of the left atrium (LA) was performed during sinus rhythm (SR) (248 ± 75 sites per patient) followed by that during AF (88 ± 24 sites per patient). The CFAE maps were based on the automatic-detection algorithm. "Operator-determined CFAEs" were defined according to Nademannee's criteria. A low-voltage zone (LVZ) was defined as a bipolar voltage of less than 0.5 mV during SR. Among a total of 1150 mapping sites, 459 (40%) were categorized as "operator-determined CFAE sites," whereas 691 (60%) were categorized as "operator-determined non-CFAE sites." The sensitivity and negative predictive value increased as the fractionated interval (FI) value of the automatic algorithm increased, but the specificity and positive predictive value decreased. The automatic CFAE algorithm exhibited the highest combined sensitivity and specificity with an FI of <60 ms for the sites inside the LVZ and FI < 70 ms for the sites outside the LVZ, when compared with a single threshold for both the high- and low-voltage groups combined (i.e., no regard for voltage) (ROC: 0.89 vs 0.86).
Conclusions: The clinical relevance of the CFAE map would be improved if the calculated index values were accordingly scaled by the electrogram peak-to-peak amplitude. (J Cardiovasc Electrophysiol, Vol. 21, pp. 21–26, 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)     

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)     

The Novel Electrophysiology of Complex Fractionated Atrial Electrograms: Insight from Noncontact Unipolar Electrograms

Unipolar Characteristics of CFAEs. Background: The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping. Objective: We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF). Methods: Twenty patients (age 55 ± 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32–300 Hz) and NCM virtual unipolar electrograms (0.5–300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 ± 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of ≤ 120 ms with an intervening isoelectric interval of more than 50 ms (Group 1A, n = 63, rapid repetitive CFAEs) or continuous fractionated activity (Group 1B, n = 59, continuous fractionated CFAEs), measured over a 7.2‐second duration. Group 2 consisted of those with a bipolar cycle length of more than 120 ms (n = 101). Results: The Group 1A CFAE sites exhibited a shorter unipolar electrogram cycle length (129 ± 11 vs 164 ± 20 ms, P < 0.001), and higher percentage of an S‐wave predominant pattern (QS or rS wave, 63 ± 13% vs 35 ± 13%, P < 0.001) than the Group 2 non‐CFAE sites. There was a linear correlation between the bipolar and unipolar cycle lengths (P < 0.001, R = 0.87). Most of the Group 1A CFAEs were located over arrhythmogenic pulmonary vein ostia or nonpulmonary vein ectopy with repetitive activations from those ectopies (62%) or the pivot points of the turning wavefronts (21%), whereas the Group 1B CFAEs exhibited a passive activation (44%) or slow conduction (31%). Conclusions: The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 640‐648, June 2010)     

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)     

Complex fractionated electrograms in the right atrial free wall and the superior/posterior wall of the left atrium are affected by activity of the autonomic nervous system

CFAEs and Autonomic Nervous System . Background: Complex fractionated atrial electrograms (CFAEs) are supposed to be related to structural and electrical remodeling. Animal studies suggest a role of the autonomic nervous system (ANS). However, this has never been studied in humans. Objective: The goal of this study was to investigate the influence of ANS on CFAEs in patients with idiopathic atrial fibrillation (AF). Methods: Thirty‐six patients (28 men, 55 ± 9 years) were included before undergoing catheter ablation. In the 24 hours preceding the procedure, 20 patients were in AF (group 1) and 16 were in sinus rhythm (SR, group 2). With 2 decapolar catheters, 1 in the right atrium (RA) and 1 in the left atrium (LA), 20 unipolar electrograms were simultaneously recorded during a 100‐second AF‐period (in group 2 after induction of AF). After atropine and metoprolol administration, a second 100‐second AF‐period was recorded 30 minutes later. Five patients of group 2 served as controls and did not receive atropine and metoprolol prior to the second recording. CFAEs were assessed and the prevalence of CFAEs was expressed as percentage of the recording time. Results: The prevalence of CFAEs was greater in group 1 than in group 2 in both RA and LA (P = 0.026, P < 0.001, respectively). Atropine and metoprolol significantly reduced CFAEs in group 1 (P < 0.001) and prevented the time‐dependent increase of CFAEs in group 2. Conclusion: The prevalence of CFAEs is greater in long‐lasting AF episodes. Atropine and metoprolol administration reduces CFAEs in both atria. Thus, CFAEs are at least partly influenced by the ANS. (J Cardiovasc Electrophysiol, Vol. 23, pp. 26‐33, January 2012)     

单纯碎裂电位指导心房颤动消融的初步临床观察

目的探讨碎裂电位指导心房颤动（房颤）射频导管消融的可行性。方法22例药物治疗无效有症状的房颤患者（阵发性16例,持续性6例）,在自发或诱发房颤时,用Carto构建左心房或左、右心房的三维模型并标测、消融碎裂电位,终点是消除标测到所有碎裂电位或转复窦性心律。结果碎裂电位消融后,13例（59％）转复为窦性心律（直接转复7例,先转为房性心动过速（房速）／心房扑动（房扑）然后转复6例）,9例消融未转复窦性心律患者行电复律或药物复律成功。6例复发（5例房速／房扑,1例阵发性房颤）再次消融,5例成功,随访3—18（10．9±4．8）个月,共有16例（73％）无快速房性心律失常事件,碎裂电位主要分布于左侧房间隔、肺静脉周围、左心房顶部。碎裂电位消融后房颤终止前房颤周期与碎裂电位消融前相比明显延长[（157±18）ms vs （211±32）ms,P〈0．05]。除一例发生心脏压塞且心包穿刺成功引流外,无消融术相关的并发症和后遗症。结论碎裂电位指导房颤导管射频消融安全有效可行。     

Catheter Ablation of Inducible Atrial Flutter, in Combination with Atrial Pacing and Antiarrhythmic Drugs (“Hybrid Therapy”) Improves Rhythm Control in Patients with Refractory Atrial Fibrillation

Atrial flutter or tachycardia may coexist with atrial fibrillation [AF] and can be treated with ablation techniques in attempt to reduce the total AF burden. The role of ablation of latent atrial tachyarrhythmias elicited at electrophysiologic study in conjunction with atrial pacing and antiarrhythmic drugs in patients with refractory AF has not been evaluated. We evaluated the efficacy of catheter ablation of electrically induced atrial flutter or atrial tachycardia in improving rhythm control in patients with refractory AF. Methods: Consecutive patients with refractory AF, and spontaneous atrial flutter (Group 1) or without spontaneous atrial flutter (Group 2) underwent programmed stimulation in a baseline drug-free state. All patients had electrically induced atrial flutter or tachycardia. Radiofrequency ablation of the arrhythmia substrate was performed in all patients. Primary endpoints evaluated for patient outcome in both groups included maintenance of rhythm control and freedom from recurrent atrial tachyarrhythmias. Results: Forty-three patients, with a mean age of 66±13 years were studied. Group 1 consisted of 22 patients while Group 2 had 21 patients. Ablation of the tricuspid valve-inferior venacaval isthmus was performed in 41 patients who had common atrial flutter induced at electrophysiologic study. Ablation of other atrial sites was performed in 8 patients with induced atypical flutter and 4 patients with induced atrial tachycardia. Ten of these patients had ablation of more than one arrhythmia. 17 patients (40%) had atrial pacing instituted and 28 patients remained on a class 1/3 antiarrhythmic drug. During a mean follow-up of 26±14 months, 33 patients (82.5%) remained in rhythm control. Actuarial analysis showed 96% of patients in rhythm control at 6 months, 94% at 12 months, and 90% at 24 months. Freedom from symptomatic AF recurrence was 64% at 6 months, 58% at 12 months, and 42% at 24 months. The outcome for both of these endpoints was similar for Group 1 and Group 2 (p = NS). The AF free interval increased significantly from 7±9 days to 172±121 days (p < 0.01) after ablation. This increase was again similar in both the groups. In the 14 patients were who did not receive atrial pacing and who remained on the same class 1/3 antiarrhythmic drug, the AF free interval increased from 18±17 days to 212±102 days (p < 0.01). Conclusions: We conclude that electrophysiologic studies can elicit latent atrial flutter or tachycardia in patients with refractory AF without spontaneous monomorphic atrial tachyarrhythmias. Catheter ablation of electrically induced atrial flutter or tachycardia either alone, or with atrial pacing and with antiarrhythmic drug may improve rhythm control and reduce AF recurrences. This is similar in patients with and without spontaneous atrial flutter and refractory AF.     

Time to Cardioversion of Recurrent Atrial Arrhythmias After Catheter Ablation of Atrial Fibrillation and Long‐Term Clinical Outcome

Introduction: It is unclear whether early restoration of sinus rhythm in patients with persistent atrial arrhythmias after catheter ablation of atrial fibrillation (AF) facilitates reverse atrial remodeling and promotes long‐term maintenance of sinus rhythm. The purpose of this study was to determine the relationship between the time to restoration of sinus rhythm after a recurrence of an atrial arrhythmia and long‐term maintenance of sinus rhythm after radiofrequency catheter ablation of AF. Methods and Results: Radiofrequency catheter ablation was performed in 384 consecutive patients (age 60 ± 9 years) for paroxysmal (215 patients) or persistent AF (169 patients). Transthoracic cardioversion was performed in all 93 patients (24%) who presented with a persistent atrial arrhythmia: AF (n = 74) or atrial flutter (n = 19) at a mean of 51 ± 53 days from the recurrence of atrial arrhythmia and 88 ± 72 days from the ablation procedure. At a mean of 16 ± 10 months after the ablation procedure, 25 of 93 patients (27%) who underwent cardioversion were in sinus rhythm without antiarrhythmic therapy. Among the 46 patients who underwent cardioversion at ≤30 days after the recurrence, 23 (50%) were in sinus rhythm without antiarrhythmic therapy. On multivariate analysis of clinical variables, time to cardioversion within 30 days after the onset of atrial arrhythmia was the only independent predictor of maintenance of sinus rhythm in the absence of antiarrhythmic drug therapy after a single ablation procedure (OR 22.5; 95% CI 4.87–103.88, P < 0.001). Conclusion: Freedom from AF/flutter is achieved in approximately 50% of patients who undergo cardioversion within 30 days of a persistent atrial arrhythmia after catheter ablation of AF.     

Clinical Significance of Early Recurrences of Atrial Tachycardia After Atrial Fibrillation Ablation

Early Recurrence After AF Ablation. Background: Atrial tachycardia (AT) commonly recurs within 3 months after radiofrequency catheter ablation for atrial fibrillation (AF). However, it remains unclear whether early recurrence of atrial tachycardia (ERAT) predicts late recurrence of AF or AT. Methods: Of 352 consecutive patients who underwent circumferential pulmonary vein isolation with or without linear ablation(s) for AF, 56 patients (15.9%) with ERAT were identified by retrospective analysis. ERAT was defined as early relapse of AT within a 3‐month blanking period after ablation. Results: During 21.7 ± 12.5 months, the rate of late recurrence was higher in patients with ERAT (41.1%) compared with those without ERAT (11.8%, P < 0.001). In a multivariable model, positive inducibility of AF or AT immediately after ablation (65.2% vs 36.4%, P = 0.046; odd ratio, 3.9; 95% confidence interval, 1.0–14.6) and the number of patients who underwent cavotricuspid isthmus (CTI) ablation (73.9% vs 42.4%, P = 0.042; odd ratio, 4.5; 95% confidence interval, 1.1–19.5) were significantly related to late recurrence in the ERAT group. The duration of ablation (174.3 ± 62.3 vs 114.7 ± 39.5 minutes, P = 0.046) and the procedure time (329.3 ± 83.4 vs 279.2 ± 79.7 minutes, P = 0.027) were significantly longer in patients with late recurrence than in those without late recurrence following ERAT. Conclusions: The late recurrence rate is higher in the patients with ERAT compared with those without ERAT following AF ablation, and is more often noted in the patients who underwent CTI ablation and had a prolonged procedure time. Furthermore, inducibility of AF or AT immediately after ablation independently predicts late recurrence in patients with ERAT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1331‐1337, December 2010)