Benefits and risks of additional ablation of complex fractionated atrial electrograms for patients with atrial fibrillation: A systematic review and meta-analysis

Background

The benefits and risks of additional complex fractionated atrial electrograms (CFAE) ablation in patients with atrial fibrillation (AF) remain unclear.

Methods

Trials were identified in PubMed, Embase, Web of Science, and Cochrane Database, reviews, and reference lists of relevant papers. The primary end point was the recurrence of atrial arrhythmias after a single ablation.

Results

We meta-analyzed 11 studies (total, n = 983) using random-effects model to compare PVI (n = 478) with PVI plus CFAE ablation (PVI + CFAE) (n = 505). Additional CFAE ablation reduced recurrence of atrial tachyarrhythmia after a single procedure (pooled RR 0.73; 95% CI 0.61, 0.88; P = 0.0007) at ≥ 3-month follow-up. There was no evidence of heterogeneity among studies (I² = 33%). Subgroup analysis demonstrated that additional CFAE ablation reduced rates of recurrence in nonparoxysmal AF (RR 0.68; 95% CI 0.47, 0.99; P = 0.05), whereas had no effect on patients with paroxysmal AF (RR 0.79; 95% CI 0.59, 1.06; P = 0.12). Eight studies reported results of post-procedure ATs. The addition of CFAE ablation increased the rate of post-procedure ATs (RR 1.77; 95% CI 1.02, 3.07; P = 0.04). Additional CFAE ablation significantly increased mean procedural times (245.4 + 75.7 vs. 189.5 + 62.3 min, P < 0.001), mean fluoroscopy (72.1 + 25.6 vs. 59.5 + 19.3 min, P < 0.001), and mean RF energy application times (75.3 + 38.6 vs. 53.2 + 27.5 min, P < 0.001).

Conclusions

The adjunctive CFAE ablation could provide additional benefit in terms of reducing recurrence of atrial tachyarrhythmia for patients with nonparoxysmal AF but not for patients with paroxysmal AF after a single procedure with or without antiarrhythmic drugs (AADs). The main risk of adjunctive CFAE ablation is the increasing rate of untraceable postablation ATs.     

Maintenance of sinus rhythm after electrical cardioversion for recurrent atrial fibrillation following mitral valve surgery with or without associated radiofrequency ablation

Background

This study reports the outcomes of patients who underwent electrical cardioversion for atrial fibrillation recurrence following mitral valve surgery and associated radiofrequency ablation compared to those who did not undergo concomitant atrial fibrillation ablation.

Methods

The population consisted of 116 patients with persistent/long-standing persistent AF who underwent mitral valve surgery with (Group A, n = 54) or without (Group B, n = 62) associated radiofrequency ablation between January 2007 and January 2011 at three institutions and who subsequently underwent cardioversion for persistent atrial fibrillation within 12 months of their initial procedure.

Results

The mean follow-up duration was 30.7 ± 9.4 months. Of the 104 patients with acute restoration of SR 42 (40.3%) had AF recurrence. The average time to recurrence after cardioversion was 7.3 ± 4.2 days. Recurrence was significantly lower in patients undergoing ablation surgery (21.4%) than in those undergoing no ablation surgery (78.6%, p < 0.001). Non-performed ablation procedure (p < 0.001), time from surgery ≥ 88 days and left atrial dimensions ≥ 45.5 mm before cardioversion (both, p = 0.005) were multivariable predictors of atrial fibrillation recurrence. In Group B the use of amiodarone was inversely correlated with recurrence of AF (p < 0.001). This correlation was not significant (r = − 0.02, p = 0.85) in Group A.

Conclusions

Electrical cardioversion for recurrent AF showed better results and stable recovery of sinus rhythm in patients undergoing concomitant surgical ablation during mitral valve surgery. This might be attributable to substrate modification caused by surgical lesions. Amiodarone improved the ECV-success rate only in patients with no associate ablation. Further larger randomized studies are necessary to confirm our findings.     

Routine preprocedural transesophageal echocardiography might not be necessary for stroke prevention evaluation in AF patients on anticoagulation therapy

Background

Preprocedural transesophageal echocardiography (TEE) is used to reduce the stroke during atrial fibrillation (AF) ablation. This study evaluated whether routine preprocedural TEE in addition to multidetector computed tomography (MDCT) is necessary to prevent periprocedural stroke in AF ablation.

Methods

Each patient underwent MDCT and TEE (group 1, n = 247) or MDCT alone (group 2, n = 103) for the initial evaluation before AF ablation. In group 2, TEE was performed only in patients who had left atrial (LA) thrombus or blood stasis in MDCT.

Results

There was no difference in sex, CHADS₂ score, or LA dimension between the two groups. In group 1, a thrombus was detected in 12 (5%) and 6 (2%) patients by the MDCT and TEE, respectively. All (100%) patients, who were revealed to have thrombus in TEE, also had a thrombus in MDCT. In group 2, 3 (3%) patients exhibited LA thrombus in MDCT, among whom thrombus was observed in only one patient (1%) in TEE. AF ablation was not performed in patients with thrombus. While one patient had a periprocedural stroke in group 1, no patient had in group 2 (P = 0.52).

Conclusion

The overall periprocedural stroke rate was low (0.3%) in AF patients on anticoagulation therapy. The preprocedural MDCT detected all patients with the LA thrombus. In AF patients with low CHADS2 score, optimal anticoagulation and relatively preserved left ventricular ejection fraction, routine preprocedural TEE in addition to the MDCT might not be necessary to decrease the periprocedural stroke rate.     

Incidence and prognostic significance of silent atrial fibrillation in acute myocardial infarction

Background

Silent atrial fibrillation (AF) has been suggested to be frequent after acute myocardial infarction (MI). Continuous ECG monitoring (CEM) has been shown to improve AF screening in patients at risk of stroke.

Objectives

We aimed to assess the incidence and prognosis of silent AF in patients with acute MI.

Methods

All the consecutive patients with acute MI were prospectively analyzed by CEM ≥ 48 h after admission. Silent AF was defined as asymptomatic episodes lasting at least 30 s. The population was divided into three groups: no-AF, silent AF and symptomatic AF.

Results

Among the 849 patients, 135 (16%) developed silent AF and 45 (5%) symptomatic AF. Compared with the no-AF group, patients with silent AF were markedly older (80 vs. 62 y, p < 0.001), more frequently women (43% vs. 30%, p = 0.006) and less likely to be smokers (20% vs. 36%, p < 0.001). They had impaired left ventricular ejection fraction (LVEF) and left atrial (LA) enlargement. By multivariate analysis, age, history of AF, indexed LA area and LVEF were identified as independent predictors of silent AF. In-hospital heart failure and death rates were markedly higher in silent AF group when compared with no-AF patients (41.8% vs 21.0% and 10.4% vs. 1.3%, respectively).

Conclusion

Our large prospective study showed for the first time that silent AF is more frequent than symptomatic AF after MI. Our work suggests that indexed LA area could help to predict the risk of developing silent AF. Moreover, the onset of silent AF is associated with worse hospital prognosis.     

Comparison of catheter ablation and surgical ablation in patients with long-standing persistent atrial fibrillation and rheumatic heart disease: A four-year follow-up study

Background

In our previous prospective and randomized study, we have demonstrated that the concomitant surgical ablation using saline-irrigated cooled tip radiofrequency ablation (SICTRA) system is more effective than subsequent circumferential pulmonary vein isolation (CPVI) combined with substrate modification in treating patients with long-standing persistent atrial fibrillation (LS-AF) and rheumatic heart disease (RHD) undergoing cardiac surgery during middle-term follow-up. Whether this strategy also decreases longer-term arrhythmia recurrence is unknown. This study describes the 4-year efficacy of SICTRA for these patients. Furthermore, we seek to compare the electrophysiological characteristics for recurrent atrial tachyarrhythmia (ATa) at the session of catheter ablation between two groups.

Methods

Long-term follow-up was performed in 95 patients who underwent the catheter ablation strategy (n = 47, Group A) or SICTRA (n = 48, Group B) combined with valvular surgery for symptomatic LS-AF patients with RHD.

Results

After one procedure, Group B had a significantly higher freedom from ATa compared with Group A (29/48 vs 15/47, P = 0.005) after a mean follow-up of 54 months (range 48 to 63 months). Catheter-based mapping and ablation of recurrent ATa showed larger amounts of macro-reentrant atrial tachycardias (ATs) in Group B and higher incidence of pulmonary vein (PV) recovery in Group A. After multiple catheter ablations for recurrent ATa, sinus rhythm (SR) could be maintained equally between two groups.

Conclusions

Single procedure success seems to be higher with SICTRA but repeated catheter ablation potentially results in comparable outcomes in treating patients with LS-AF and RHD during long-term follow-up. More macro-reentrant ATs and more PV recoveries are identified to be responsible for ATa in SICTRA and catheter ablation group, respectively.     

Does the amount of atrial mass reduction improve clinical outcomes after radiofrequency catheter ablation for long-standing persistent atrial fibrillation? Comparison between linear ablation and defragmentation

Background

Although a large isolated surface area of the left atrium (LA) may improve the success rate of catheter ablation (CA) for paroxysmal atrial fibrillation (AF), little is known about the relation between clinical outcomes and the amount of atrial mass reduction (AMR: ratio of total isolated and ablated areas to LA surface area) in different ablation strategies for patients with long-standing persistent AF (L-PeAF).

Methods

We randomly assigned 119 consecutive L-PeAF patients to adjunctive linear ablation (n = 60) or complex fractionated atrial electrogram (CFAE)-guided ablation (n = 59) after circumferential antral pulmonary vein isolation (PVI). Linear lesions included roof and anterior lines with conduction block. LA defragmentation was performed with an automated CFAE-detection algorithm. Cavotricuspid isthmus block was performed in all patients. Creatine kinase-MB (CK-MB) and troponin-T levels were measured 1 day post-CA.

Results

CK-MB and troponin-T levels were higher, ablation time was longer, and AMR was greater in the CFAE-guided ablation group than in the linear ablation group. AF termination during CA was more frequently observed in the linear ablation group than in the CFAE-guided ablation group (P = 0.031). Twelve months after a single procedure, recurrence occurred in 16 (26.7%) patients with linear ablation and 27 (45.8%) patients with CFAE-guided ablation (P = 0.023). On multivariate analysis, LA volume and ablation method were the only independent risk factors for arrhythmia recurrence.

Conclusion

Conduction block through linear lines + PVI was an efficient ablation strategy for L-PeAF, whereas the AMR amount did not influence clinical outcomes.     

Long duration of radiofrequency energy delivery is an independent predictor of clinical recurrence after catheter ablation of atrial fibrillation: Over 500 cases experience

Background

Although radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) is an effective rhythm control strategy, there is a substantial amount of recurrence. We explored the predictors of AF recurrence after RFCA with consistent ablation strategy.

Methods and results

This study included 575 patients (77% male, 56 ± 11 years old) with AF (65.7% paroxysmal AF [PAF], 34.3% persistent AF [PeAF]) who underwent RFCA. We evaluated the clinical, serological, and electrophysiological parameters thereof. Results: 1. During 15 ± 7 months of follow-up, patients who experienced AF recurrence (21.8%) were older (58 ± 10 vs. 55 ± 11 years old, p = 0.019) and more likely to have PeAF (50.4% vs. 29.4%, p < 0.001) and greater LA volume (137.3 ± 49.1 vs. 116.6 ± 37.9 mL, p < 0.001). 2. In patients with clinical recurrence after RFCA, both ablation time (110.1 ± 43.8 vs. 92.3 ± 30.1 min, p < 0.001) and procedure time (222.7 ± 79.6 vs. 205.8 ± 58.8 min, p < 0.001) were prolonged, and the early recurrence rate within 3 months of the procedure was higher (63.0% vs. 26.4%, p < 0.001) than those without clinical recurrence. 3. In logistic regression analysis, LA volume (OR 1.008, CI 1.001–1.014), ablation time (per quartile, OR 1.380, CI 1.031–1.847), and early recurrence (OR 3.858, CI 2.420–6.150) were independent risk factors for recurrence of AF after RFCA.

Conclusion

In this single center consistent study of over 500 cases of AF ablation, patients with AF recurrence had a larger atrium, longer ablation time, and a higher chance of early recurrence than those remained in sinus rhythm. Inadvertent, long duration of ablation was an independent predictor of worse clinical outcomes after catheter ablation of AF.     

Electrophysiological characteristics of left atrial diverticulum in patients with atrial fibrillation: Electrograms,impedance and clinical implications

Background

Left atrial diverticulum (LAD) is not rare in patients with atrial fibrillation (AF). Recent reports focused on its morphology however data on its electrophysiological characteristics are lacking. Our study aims to investigate the electrogram and impedance features of LAD.

Methods

This study included 24 patients (mean age, 58.5 ± 10.7 years) with LAD undergoing catheter ablation for AF and 24 gender-and-age-matched individuals without LAD as controls. A bipolar LAD electroanatomic map was acquired in sinus rhythm from all study participants. Points were acquired for diverticulum in the LAD group and for corresponding areas in the control group. Electrogram deflections were counted, bipolar voltage and impedance were measured for each point, and average ?impedance and highest ?impedance were calculated.

Results

A total of 234 points were collected in the two groups. In the LAD vs. control group, median (Q1, Q3) of electrogram deflections was 6 (5, 7) and 4 (4, 5) (P < 0.0001), respectively, voltage was not significantly different (1.58 ± 0.68 mV vs. 1.28 ± 0.65 mV, P = 0.10), and average ?impedance was significantly higher in the LAD group (19.5 ± 9.0 Ω vs 3.9 ± 1.7 Ω, P < 0.0001). A cut-off value of 9.5 Ω for ?impedance predicted LAD with sensitivity, specificity, and positive and negative predictive values of 83.5%, 92.8%, 92.1% and 84.9%, respectively.

Conclusions

Electrogram was more fractionated and impedance was higher at LAD than in corresponding areas without LAD, which might help to differentiate LAD during catheter ablation for AF.     

Importance of pericardial fat in the formation of complex fractionated atrial electrogram region in atrial fibrillation

Background/Objectives

Pericardial fat (PF) and complex fractionated atrial electrogram (CFAE) are both associated with atrial fibrillation (AF). Therefore, we examined the relation between PF and CFAE area in AF.

Methods

The study population included 120 control patients without AF and 120 patients with AF (80 paroxysmal AF and 40 persistent AF) who underwent catheter ablation. Total cardiac PF volume, representing all adipose tissue within the pericardial sac, was measured by contrast-enhanced computed tomography. The location and distribution of CFAE region were identified by left atrial endocardial mapping using a three-dimensional mapping system. We analyzed the significance of total cardiac PF volume and total area of CFAE region on AF, persistence of AF from paroxysmal to persistent form, and the relation between total cardiac PF volume and total CFAE area. We also evaluated the regional distribution of PF volume and CFAE area in five areas of the left atrium (LA).

Results

Total cardiac PF volume correlated with AF (odds ratio [OR]: 1.024, p < 0.001). Total cardiac PF volume and total CFAE area were both independently associated with persistence of AF (OR: 1.018, p = 0.018, OR: 1.144, p = 0.002, respectively). Multivariate linear regression analysis identified total cardiac PF volume as a significant and independent determinant of total CFAE area (r = 0.488, p < 0.001). Furthermore, regional PF volume correlated with local CFAE area in an each LA area.

Conclusions

PF volume correlated significantly with CFAE area in patients with AF. This finding suggests that PF is directly related to the progression of CFAE area and promotes the pathogenic process of AF.     

Post-shock sinus node recovery time is an independent predictor of recurrence after catheter ablation of longstanding persistent atrial fibrillation

Background

Electro-anatomical remodeling of the atria has been reported to be associated with sinus node dysfunction in patients with atrial fibrillation (AF). We hypothesized that post-shock sinus node recovery time (PS-SNRT: the time from cardioversion to the earliest sinus node activation) is related to the degree of left atrial (LA) remodeling and the clinical outcome of radiofrequency catheter ablation (RFCA) in patients with longstanding persistent AF (L-PeAF).

Methods and results

We included 117 patients with L-PeAF (82.0% males, 55.4 ± 10.7 years old) who underwent RFCA. PS-SNRTs were measured after internal cardioversion (serial shocks 2, 3, 5, 7, 10, and 15 J) before RFCA. All patients underwent the same ablation design, and we compared regional LA volume (3D-CT imaging) and LA voltage (NavX). Results: 1. During the 13.5 ± 5.8-month follow-up period, it was noted that the patients with recurrent AF 3 months after RFCA (n = 31) had longer PS-SNRTs (1622.90 ± 1196.92 ms vs. 1112.53 ± 690.68 ms, p = 0.005) and greater anterior LA volume (p = 0.032) than those who remained in sinus rhythm. 2. The patients with PS-SNRT ≥ 1100 ms showed lower AF-free rates (58.3%) compared to those with PS-SNRT < 1100 ms (89.5%, p < 0.001). However, shock energy, number of cardioversion, and LA volume were not different between two groups. 3. Multivariate Cox regression analysis demonstrated PS-SNRT ≥ 1100 ms was a significant predictor of clinical recurrence of AF (HR 5.426, 95% CI 2.099–14.028, p < 0.001).

Conclusion

In patients with L-PeAF, prolonged PS-SNRT is an independent predictor of clinical recurrence of AF after RFCA, but not closely associated with electro-anatomical remodeling of LA.     

Effects of ganglionated plexi ablation on ventricular electrophysiological properties in normal hearts and after acute myocardial ischemia

Background

Ganglionated plexi (GP) ablation has been shown to play an important role in atrial fibrillation (AF) initiation and maintenance. Also, GP ablation increases chances for prevention of AF recurrence. This study investigated the effects of GP ablation on ventricular electrophysiological properties in normal dog hearts and after acute myocardial ischemia (AMI).

Methods

Fifty anesthetized dogs were assigned into normal heart group (n = 16) and AMI heart group (n = 34). Ventricular dynamic restitution, effective refractory period (ERP), electrical alternans and ventricular fibrillation threshold (VFT) were measured before and after GP ablation in the normal heart group. In the AMI heart group, the incidence of ventricular arrhythmias and VFT were determined.

Results

In the normal heart group, GP ablation significantly prolonged ERP, facilitated electrical alternans but did not increase ERP dispersion, the slope of restitution curves and its spatial dispersion. Also, GP ablation did not cause significant change of VFT. In the AMI heart group, the incidence of ventricular arrhythmias after GP ablation was significantly higher than that in the control group or the GP plus stellate ganglion (SG) ablation group (P < 0.05). Spontaneous VF occurred in 8/12, 1/10 and 2/12 dogs in the GP ablation group, the GP plus SG ablation group and the control group, respectively (P < 0.05). VFT in the GP ablation group showed a decreased trend though a significant difference was not achieved compared with the control or the GP plus SG ablation group.

Conclusions

GP ablation increases the risk of ventricular arrhythmias in the AMI heart compared to the normal heart.     

Does linear ablation and defragmentation really improve the success rate of persistent AF? Follow-up results and electrophysiological findings from 169 consecutive patients

Background

Catheter ablation of persistent atrial fibrillation (AF) has been performed with varying results using a combination of different techniques. We sought to evaluate the efficacy of additional linear lesion and defragmentation of left atrium (LA).

Methods

A cohort of 169 patients with persistent AF was studied. Ablation was performed following a sequential strategy consisted of circumferential pulmonary vein isolation (CPVI), LA roof linear ablation, posterior mitral area, coronary sinus and cavotricuspid isthmus, and complex fractionated electrograms ablation.

Results

During a mean follow-up of 15 ± 8 months after a single procedure, 84 (50%) patients were in sinus rhythm, 34 (20%) had an AF recurrence and 51(30%) developed atrial tachycardias (ATs). Repeat procedures were performed in 24 recurrent AF and 46 AT patients. A total of 81 different ATs were mapped and ablated in 46 AT patients, characterized as focal for 45 and macroreentry for 36 ATs. Most of the ATs were likely to be attributed to the previous lesions by an analysis of substrate and activation mapping in the redo procedure and a review of the lesions placed in the initial procedure. Overall, 75 (93%) ATs were ablated successfully. Procedural complications occurred in 11 of the 239 procedures. After a mean follow-up of 20 ± 9 months, 128 (76%) patients were free of arrhythmias after the final procedure.

Conclusions

CPVI supplemented by linear ablation and defragmentation does not seem to improve the overall success rate of persistent AF. The efficacy of linear ablation and defragmentation might be diluted by their proarrhythmic effects.     

Analysis of oxidative stress expressed by urinary level of 8-hydroxy-2′-deoxyguanosine and biopyrrin in atrial fibrillation: Effect of sinus rhythm restoration

Background

Oxidative stress is considered to contribute to the pathological consequences of atrial fibrillation (AF). We examined the level of oxidative stress in AF patients and changes in its level following sinus rhythm restoration.

Methods

Oxidative stress level was evaluated by urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, and urinary biopyrrin, an oxidative metabolite of bilirubin. In Study 1, we compared 8-OHdG/creatinine levels between patients with permanent AF (AF-group, n = 40) and sinus rhythm (SR-group, n = 133). In Study 2, we examined the changes in 8-OHdG and biopyrrin levels in 36 patients with persistent AF following sinus rhythm restoration by electrical or pharmacological cardioversion (n = 15) and radiofrequency catheter ablation (n = 21).

Results

In Study 1, 8-OHdG/creatinine levels were significantly higher in AF-group than in SR-group (19.1 ± 8.6 vs. 12.3 ± 5.5 ng/mg, p < 0.001). Multivariate analysis showed that the presence of AF was an independent factor that significantly correlated with 8-OHdG/creatinine level after adjustment for other covariates to oxidative stress (β = 0.36, p < 0.001). Sinus rhythm was maintained at the chronic phase in patients of all Study 2 (7.2 ± 5.8 months after cardioversion or catheter ablation). 8-OHdG/creatinine and biopyrrin/creatinine levels at the chronic phase were significantly lower than those before cardioversion or catheter ablation (8.7 ± 3.2 vs. 21.7 ± 15.1 ng/mg, p < 0.0001 and 1.7 ± 1.1 vs. 3.0 ± 1.9 mU/mg, p < 0.0001).

Conclusions

Oxidative stress level is significantly increased in AF patients, but can be improved by restoration of sinus rhythm. The results suggest that the pathogenic process of AF is promoted by AF itself through the production of oxidative stress.     

Optimal observation time after completion of circumferential pulmonary vein isolation for atrial fibrillation to prevent chronic pulmonary vein reconnections

Purpose

To identify predictors of chronic pulmonary vein (PV) reconnection (CPVR) after successful circumferential PV isolation (CPVI) for atrial fibrillation (AF).

Materials and methods

A total of 718 PVs from 181 consecutive AF patients (141 males, median age 61 years, 92 paroxysmal AF) who underwent a second ablation procedure for recurrent AF were retrospectively analyzed.

Results

During the second procedure, a CPVR was observed in 477 PVs (66.4%) among 169 patients. In a multiple logistic regression analysis, the observation time after the final completion of the PVI (OT-final) was a significant negative predictor (odds ratio 0.980; P < 0.001). A receiver operating characteristic analysis demonstrated that the greatest area under the curve was for the OT-final (0.670). At an optimal cutoff of 35 min, the sensitivity and specificity for predicting a CPVR were 66.9% and 60.6%, respectively. By Kaplan Meier analysis, CPVR was more frequent in PVs with an OT-final of < 35 min than ≥ 35 min (log-rank test, P = 0.018). In a vessel-by-vessel analysis, the OT-final at all PV sites was a significant negative predictor, while male gender in the right PVs and left-inferior PV, number of RF applications for the ipsilateral CPVI in the right PVs and left-superior PV, and major PV diameter in the left-superior PV were significant positive predictors of a CPVR (all P < 0.05).

Conclusions

An optimal observation time (≥ 35 min in this study) to determine whether PVI is successfully completed during the initial CPVI for AF may be needed to prevent a CPVR and subsequent AF recurrence thereafter.     

Infiltrated atrial fat characterizes underlying atrial fibrillation substrate in patients at risk as defined by the ARIC atrial fibrillation risk score

Background

It is known that expanded epicardial fat is associated with atrial fibrillation (AF). However, infiltrated intraatrial fat has not been previously quantified in individuals at risk as determined by the ARIC AF risk score.

Methods

Patients in sinus rhythm (N = 90, age 57 ± 10 years; 55 men [63.2%]), in 3 groups at risk of AF as determined by the ARIC AF risk score [low (≤ 11 points; n = 15), moderate (12–18 points; n = 40), high (≥ 19 points; n = 23) risk of AF], and paroxysmal AF (n = 12) underwent cardiac magnetic resonance study. Intraatrial and epicardial fat was analyzed with a Dark-blood DIR-prepared Fat-Water-separated sequence in the horizontal longitudinal axis. OsiriX DICOM viewer (Geneva, Switzerland) was used to quantify the intraatrial fat area. Width of the cephalad portion of the interatrial septum was measured at the level of the fossa ovalis.

Results

Intraatrial fat monotonically increased with growing AF risk in study groups (low AF risk 16 ± 4 vs. moderate AF risk 32 ± 18 vs. high AF risk 81 ± 83 mm²; ANOVA P = 0.012). Log-transformed intraatrial fat predicted ARIC AF risk score in multivariate ordered probit regression after adjustment for sex, race, left and right atrial area indices, and body mass index (β-coefficient 0.50 [95% CI 0.03–0.97]; P = 0.037), whereas epicardial fat did not. Interatrial septum width showed similar association (3.0 ± 1.4 vs. 5.0 ± 1.8 vs. 7.1 ± 2.7 mm; ANOVA P < 0.001; adjusted β-coefficient 2.80 [95% CI 1.19–4.41]; P = 0.001).

Conclusions

Infiltrated intraatrial fat characterizes evolving substrate in individuals at risk of AF.     

Radiofrequency ablation of left atrial flutter mediated with double potentials in a seemingly normally structured heart

Background

Left atrial flutter (left AFL) is common in patients who undergo atrial fibrillation ablation and cardiac surgery; however, few reports describe left AFL in detail in a seemingly normally structured heart, and the mechanisms of the occurrence of such arrhythmia are still not clear. We describe left AFL in patients without prior cardiac surgery or catheter ablation and discuss the electrophysiological characteristics that may explain the preferential generation and perpetuation of such tachycardia.

Methods and results

Eleven patients with left AFL, who had no history of cardiac surgery or interventions, underwent electrophysiological studies and 3-dimensional electroanatomic mapping studies. Echocardiography revealed a relatively mild dilation of the left atrium, mild to moderate mitral regurgitation, and a normal left ventricular ejection fraction. The electroanatomic mapping during tachycardia showed a “reentrant” activation pattern in all patients. The mean tachycardia cycle length was 266 ± 17 ms. A single-loop reentrant circuit was identified in 7 patients. A counterclockwise left atrial flutter evolved around the mitral valve annulus in 6 patients. The tachycardia rotated around the left atrial anterior wall in 1 patient. Four patients exhibited a double-loop reentrant circuit with a “figure of 8” pattern reentry. Double potentials as the critical isthmus of the circuit were identified in the left atrial anterior wall near the mitral annulus which displayed a low-voltage area matched with the left atrium–aorta contiguity. The conduction velocity was significantly slower in the double-potential recording area than in the lateral mitral annulus (0.36 ± 0.03 m/s vs 0.74 ± 0.12 m/s; P < 0.05). Successful ablation around the double-potential recording site caused an interruption of the tachycardia, and remained free of recurrence during a 12-month follow-up in all patients.

Conclusion

Left AFL in patients without a history of surgery or ablation is rarely observed in clinical practice. The successful site of ablation was within the anterior wall near the mitral annulus showing the double potentials as the critical part of the reentrant circuit. This suggests that perhaps a double potential-targeted ablation may be effective for these patients.     

Don't move during ablation of atrial fibrillation!

Background

Restless patient is recalcitrant during ablation of atrial fibrillation (AF). We aimed to assess the association between patient movements during AF ablation and its outcome.

Methods

We examined the body movement during AF ablation in 78 patients with the use of a novel portable respiratory monitor, the SD-101, which also has the ability to quantify the frequency of body movements.

Results

The body movement index, defined as the number of the units of time with body movement events divided by the recording time (11.4 ± 6.5 events/h), was significantly correlated with the ablation time defined as the time from the first point of the ablation to the end of the procedure (1.2 ± 0.3 h) (r = 0.35; p = 0.0014) and a total radiofrequency energy applied (56.6 ± 17.7 kW) (r = 0.36; p = 0.0015). A multiple linear regression analysis showed that non-paroxysmal AF (β = 0.25; p = 0.036) and the body movement index (β = 0.36; p = 0.0019) were independent determinants of the ablation time. The body movement index was similar in patients with and without recurrence of AF.

Conclusions

Keeping patients motionless may be important to reduce the procedural duration of AF ablation.     

Distinct prognostic impacts of both atrial volumes on outcomes after radiofrequency ablation of nonvalvular atrial fibrillation: Three-dimensional imaging study using multidetector computed tomography

Background

Left atrial (LA) enlargement is associated with atrial fibrillation (AF) recurrence after radiofrequency ablation (RFA). However, impact of right atrial (RA) size on outcomes after RFA is unclear.

Methods

Patients who underwent RFA of AF (n = 242, 197 men, 57 ± 11 years) were enrolled (159 paroxysmal [PaAF] and 83 persistent [PeAF]). Three-dimensional RA and LA volumes were measured before RFA with multidetector computed tomography and indexed to body surface area (RAVI and LAVI).

Results

After a 3-month blanking period, 66 patients (27%) failed to maintain sinus rhythm during follow-up (556 ± 322 days). Despite similar clinical characteristics, LAVI was larger (77 ± 21 vs. 91 ± 27 ml/m², P < 0.001) and RAVI showed a trend to be greater (85 ± 26 vs. 92 ± 25 ml/m², P = 0.06) in patients with future recurrence than without recurrence. Additionally, patients with larger RA or LA experienced recurrences more frequently and earlier during follow-up (log rank, P < 0.05 for all). In Cox regression analysis, LAVI was independently associated with outcomes (10 ml/m² increase; HR: 1.22, 95% CI: 1.09–1.36, P < 0.001), whereas RAVI was not. In subgroup analysis, 25 PaAF patients (16%) experienced recurrence and both atrial volumes failed to predict the outcome independently, despite borderline significance of RAVI (10 ml/m² increase; HR: 1.21, 95% CI: 1.00–1.48, P = 0.05). Meanwhile, 41 patients (49%) in PeAF group experienced AF recurrence and LAVI was an independent prognosticator (10 ml/m² increase; HR: 1.19, 95% CI: 1.03–1.36).

Conclusions

RA size might affect the outcome after RFA in PaAF patients. LA enlargement, rather than RA size, influence outcomes after RFA, especially in PeAF.     

Short stature and ischemic stroke in nonvalvular atrial fibrillation: New insight into the old observation

Background

For decades, repeated epidemiologic observations have been made regarding the inverse relationship between stature and cardiovascular disease, including stroke. However, the concept has not been fully evaluated in patients with atrial fibrillation (AF). We investigated whether patient’s height is associated with ischemic stroke in patients with nonvalvular AF and attempted to ascertain a potential mechanism.

Methods

All 558 AF patients were enrolled: 211 patients with ischemic stroke (144 men, 68 ± 10 years) and 347 no-stroke patients (275 men, 56 ± 11 years) as a control group. Clinical characteristics and echocardiographic parameters were compared between the two groups.

Results

(1) Stroke patients were shorter than those in the control group (164 ± 8, vs. 169 ± 8 cm, p < 0.001). However, body mass index failed to predict ischemic stroke; (2) Short stature (OR 0.93, 95% CI 0.91– 0.95, p < 0.001) along with left atrial (LA) anterior-posterior diameter and diastolic mitral inflow velocity (E) to diastolic mitral annuls velocity (E’) (E/E’) were independent predictor of stroke; (3) Height showed inverse correlation with E/E’ independently, even after adjusting for other variables, including age, sex, and body weight, and comorbidities β − 0.20, p = 0.003); (4) LA size showed no correlation with stature (R = − 0.06, p = 0.18), whereas left ventricular size increases according to height of patients.

Conclusions

Short stature is associated with occurrence of ischemic stroke and diastolic dysfunction in patients with AF and preserved systolic function. Height is a non-modifiable risk factor of stroke and might be more important than obesity in Asian AF patients, who are relatively thinner than western populations.     

Heart failure epicardial fat increases atrial arrhythmogenesis

Background

Obesity is an important risk factor for atrial fibrillation (AF) and heart failure (HF). The effects of epicardial fat on atrial electrophysiology were not clear. This study was to evaluate whether HF may modulate the effects of epicardial fat on atrial electrophysiology.

Methods

Conventional microelectrodes recording was used to record the action potential in left (LA) and right (RA) atria of healthy (control) rabbits before and after application of epicardial fat from control or HF (ventricular pacing of 360–400 bpm for 4 weeks) rabbits. Adipokine profiles were checked in epicardial fat of control and HF rabbits.

Results

The LA 90% of AP duration was prolonged by control epicardial fat (from 77 ± 6 to 87 ± 7 ms, p < 0.05, n = 7), and by HF epicardial fat (from 78 ± 3 to 98 ± 4 ms, p < 0.001, n = 9). However, control or HF epicardial fat did not change the AP morphology in RA. HF epicardial fat increased the contractility in LA (61 ± 11 vs. 35 ± 6 mg, p = 0.001), but not in RA. Control fat did not change the LA or RA contractility. Moreover, control and HF epicardial fat induced early and delayed afterdepolarizations in LA and RA, but only HF epicardial fat provoked spontaneous activity and burst firing in LA (n = 3/9, 33.3% vs. n = 0/7, 0%, n = 0/9, 0%, p < 0.05). Compared to control fat, HF epicardial fat, had lower resistin, C-reactive protein and serum amyloid A, but similar interluekin-6, leptin, monocyte chemotactic protein-1, adiponectin and adipsin.

Conclusions

HF epicardial fat increases atrial arrhythmogenesis, which may contribute to the higher atrial arrhythmia in obesity.