Early recurrences after atrial fibrillation ablation: prognostic value and effect of early reablation

Prevention of atrial fibrillation recurrence with corticosteroids after radiofrequency catheter ablation: a randomized controlled trial

OBJECTIVES

We sought to clarify the efficacy of corticosteroid therapy for preventing atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI).

BACKGROUND

The inflammatory process may cause acute AF recurrence after PVI. However, no studies have examined the relationship between corticosteroid administration and AF recurrence after PVI.

METHODS

A total of 125 patients with paroxysmal AF were randomized to receive either corticosteroids (corticosteroid group) or a placebo (placebo group). In the corticosteroid group, intravenous hydrocortisone (2 mg/kg) was given the day of the procedure, and oral prednisolone (0.5 mg/kg/day) was administered for 3 days after the PVI. The body temperature and high-sensitivity C-reactive protein level were measured before and on each of the first 3 days after ablation.

RESULTS

The prevalence of immediate AF recurrence (≤3 days after the PVI) was significantly lower in the corticosteroid group (7%) than in the placebo group (31%). The maximum body temperature and C-reactive protein during the initial 3 days after ablation and the increase in the body temperature and C-reactive protein level from baseline were significantly lower in the corticosteroid group than in the placebo group. Corticosteroid treatment did not decrease AF recurrences between 4 and 30 days after ablation. The AF-free rate at 14 months post-ablation was greater in the corticosteroid group (85%) than in the placebo group (71%, p=0.032 by the log-rank test).

CONCLUSIONS

Transient use of small amounts of corticosteroids shortly after AF ablation may be effective and safe for preventing not only immediate AF recurrences but also AF recurrences during the mid-term follow-up period after PVI.

Chromosome 4q25 variants and atrial fibrillation recurrence after catheter ablation

OBJECTIVES

This study tested the hypothesis that chromosome 4q25 single-nucleotide polymorphisms (SNPs) associate with atrial fibrillation (AF) recurrence after catheter ablation.

BACKGROUND

Recent genome-wide association studies identified 2 SNPs on chromosome 4q25 associated with AF. Although the mechanisms underlying this increased risk are unknown, the closest gene, PITX2, is critical for myocardium development in the pulmonary veins.

METHODS

A total of 195 consecutive patients (mean age 56 +/- 12 years, 73% male) with drug-refractory paroxysmal (78%) or persistent (22%) AF who underwent AF catheter ablation were included. Two SNPs, rs2200733 and rs10033464, were genotyped using real-time polymerase chain reaction and fluorescence resonance energy transfer. Serial 7-day Holter electrocardiographic recordings were acquired to detect AF recurrences.

RESULTS

Early recurrence of atrial fibrillation (ERAF) (within the first 7 days) was observed in 37%, whereas late recurrence of atrial fibrillation (LRAF) (between 3 and 6 months) occurred in 21% of the patients. None of the clinical or echocardiographic baseline characteristics were associated with ERAF or LRAF. In contrast, the presence of any variant allele increased the risk for both ERAF (odds ratio [OR]: 1.994, 95% confidence interval [CI]: 1.036 to 3.837, p = 0.039) and LRAF (OR: 4.182, 95% CI: 1.318 to 12.664, p = 0.011). In patients with ERAF, 45% had LRAF, as opposed to 8% in patients without ERAF (OR: 9.274, 95% CI: 3.793 to 22.678, p < 0.001).

CONCLUSIONS

Polymorphisms on chromosome 4q25 modulate the risk for AF recurrence after catheter ablation. This finding points to a potential role for stratification of AF ablation therapy or peri-interventional management by genotype.

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 < or =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.

Electroanatomic mapping and radiofrequency ablation of porcine left atria and atrioventricular nodes using magnetic resonance catheter tracking

BACKGROUND

The MRI-compatible electrophysiology system previously used for MR-guided left ventricular electroanatomic mapping was enhanced with improved MR tracking, an MR-compatible radiofrequency ablation system and higher-resolution imaging sequences to enable mapping, ablation, and ablation monitoring in smaller cardiac structures. MR-tracked navigation was performed to the left atrium (LA) and atrioventricular (AV) node, followed by LA electroanatomic mapping and radiofrequency ablation of the pulmonary veins (PVs) and AV node.

METHODS AND RESULTS

One ventricular ablation, 7 PV ablations, 3 LA mappings, and 3 AV node ablations were conducted. Three MRI-compatible devices (ablation/mapping catheter, torqueable sheath, stimulation/pacing catheter) were used, each with 4 to 5 tracking microcoils. Transseptal puncture was performed under x-ray, with all other procedural steps performed in the MRI. Preacquired MRI roadmaps served for real-time catheter navigation. Simultaneous tracking of 3 devices was performed at 13 frames per second. LA mapping and PV radiofrequency ablation were performed using tracked ablation catheters and sheaths. Ablation points were registered and verified after ablation using 3D myocardial delayed enhancement and postmortem gross tissue examination. Complete LA electroanatomic mapping was achieved in 3 of 3 pigs, Right inferior PV circumferential ablation was achieved in 3 of 7 pigs, with incomplete isolation caused by limited catheter deflection. During AV node ablation, ventricular pacing was performed, 3 devices were simultaneously tracked, and intracardiac ECGs were displayed. 3D myocardial delayed enhancement visualized node injury 2 minutes after ablation. AV node block succeeded in 2 of 3 pigs, with 1 temporary block.

CONCLUSIONS

LA mapping, PV radiofrequency ablation, and AV node ablation were demonstrated under MRI guidance. Intraprocedural 3D myocardial delayed enhancement assessed lesion positional accuracy and dimensions.

Ablation strategies for atrial fibrillation

Atrial fibrillation remains the most common arrhythmia in the USA and is associated with an increased risk for stroke, congestive heart failure and overall mortality. There has been a tremendous advance in the field of catheter ablation of atrial fibrillation that has resulted in better outcomes for patients. The approach for ablation of atrial fibrillation can be different depending on patients' presentation of paroxysmal or persistent atrial fibrillation. Pulmonary vein isolation remains the cornerstone of any ablation strategy for atrial fibrillation; however, further ablation, end points of the procedure, clinical end points for successful ablation and appropriate follow-up remain controversial. We aim to discuss these different approaches and the major controversies in catheter ablation of atrial fibrillation.

Long-term results and the predictors of outcome of catheter ablation of atrial fibrillation using steerable sheath catheter navigation after single procedure in 674 patients

AIMS

Identifying suitable candidates for circumferential left atrial pulmonary vein ablation (CPVA). CPVA is widely used as an ablation strategy in patients with atrial fibrillation (AF). Understanding the predictors of long-term success of single catheter ablation procedure of AF based on CPVA can help to identify those patients who have a high risk of recurrence based on this approach.

METHODS AND RESULTS

In this retrospective analysis 674 consecutive patients (464 male, mean age 57.3 +/- 10.8 years) with AF (84.8%, paroxysmal) treated with CPVA ablation between May 2005 and August 2007 using a manually controlled steerable sheath (Agilis((R)) St. Jude Medical Inc., St. Paul, MN, USA), were included. The endpoint of the ablation was the completion of predefined lesions (CPVA for paroxysmal, and CPVA+mitral isthmus and roof line ablation for persistent AF). Seven day Holter recordings were done immediately, 3, 6, and 12 month after ablation. AF longer than 30 s was considered as recurrence. The success was defined as lack of recurrence during 7-day Holter recordings done 3, 6, and 12 months after ablation. Early recurrence was defined as recurrence during the first 7-day Holter recording immediately after ablation. Forty-five and 20.8% of the patients received antiarrhythmic medications for the first 3 and 6 months after ablation procedure, respectively. After 6 months all antiarrhythmics were discontinued. About 51.5% experienced early recurrence. Twelve months success rate was 75.7% (paroxysmal: 75.7%, persistent: 75.0%, P = 1.0). Using multivariate analysis left atrial (LA) diameter > or =50 mm was the predictor of early recurrence {Hazard Ratio (HR) [95% confidence interval (CI)] = 5.1 (2.0-12.9)}. LA Diameter > or =50 mm [HR (95% CI) = 4.6 (2.6-9.1)]; early recurrence [HR (95% CI) = 4.3 (2.0-9.1)]; and arterial hypertension [HR (95% CI) = 4.6 (2.6-9.1)] were predictors of late recurrence.

CONCLUSION

In our patients' cohort, a single catheter ablation procedure based on CPVA using steerable sheath for catheter navigation resulted in a 1 year success rate of 75.7% [without (91.0%) and with (58.6%) early recurrence, respectively, P = 0.0001]. Among those patients who are at high risk for recurrence after CPVA other ablation endpoints rather than completion of predefined lesions might be necessary to increase the success rate.

Outcomes in patients requiring cardioversion following catheter ablation of atrial fibrillation

INTRODUCTION

Early recurrence of atrial tachyarrhythmias is commonly noted after catheter ablation of atrial fibrillation (AF). The long-term outcomes of patients who require cardioversion for persistent AF after AF ablation is not known. This study reports the outcomes of patients who underwent cardioversion for persistent AF or atrial flutter following an AF ablation procedure.

METHODS

The patient population comprised 55 patients (mean age 58 +/- 10 years, 35% paroxysmal) who underwent catheter ablation of AF and subsequently required electrical cardioversion for persistent AF (45 patients) or atrial flutter (10 patients). Cardioversion was defined as early (within 90 days of the ablation procedure) or late (between 90 and 180 days following ablation).

RESULTS

The mean follow-up duration was 15 +/- 8 months. Forty-six of the 55 patients (84%) patients experienced recurrence during follow-up. The average time to recurrence after cardioversion was 37 days. Of the 55 patients, 8 (15%) patients had a complete success, 11 (20%) patients had a partial success and 36 patients (65%) had a failed outcome. Seven of the 43 patients (16%) who underwent early cardioversion had a complete success as opposed to one of 12 patients (8%) who underwent late cardioversion (P = 0.49).

CONCLUSIONS

This study shows that >80% of patients who undergo cardioversion for persistent AF or atrial flutter after AF ablation have recurrence. The timing of cardioversion did not affect the outcome. These findings allow clinicians to provide realistic expectations to patients regarding the long-term outcome and/or requirement for a second ablation procedure.

Cardiac ripple mapping: a novel three-dimensional visualization method for use with electroanatomic mapping of cardiac arrhythmias

BACKGROUND

Mapping of regular cardiac arrhythmias is frequently performed using sequential point-by-point annotation of local activation relative to a fixed timing reference. Assigning a single activation for each electrogram is unreliable for fragmented, continuous, or double potentials. Furthermore, these informative electrogram characteristics are lost when only a single timing point is assigned to generate activation maps.

OBJECTIVE

The purpose of this study was to develop a novel method of electrogram visualization conveying both timing and morphology as well as location of each point within the chamber being studied.

METHODS

Data were used from six patients who had undergone electrophysiological study with the Carto electroanatomic mapping system. Software was written to construct a three-dimensional surface from the imported electrogram locations. Electrograms were time gated and displayed as dynamic bars that extend out from this surface, changing in length and color according to the local electrogram voltage-time relationship to create a ripple map of cardiac activation.

RESULTS

Ripple maps were successfully constructed for sinus rhythm (n = 1), atrial tachycardia (n = 3), and ventricular tachycardia (n = 2), simultaneously demonstrating voltage and timing information for all six patients. They showed low-amplitude continuous activity in four of five tachycardias at the site of successful ablation, consistent with a reentrant mechanism.

CONCLUSION

Ripple mapping allows activation of the myocardium to be tracked visually without prior assignment of local activation times and without interpolation into unmapped regions. It assists the identification of tachycardia mechanism and optimal ablation site, without the need for an experienced computer-operating assistant.

Postprocedural care in patients undergoing catheter ablation for the treatment of atrial fibrillation

The high prevalence of atrial fibrillation has contributed to an increasing number of patients in need of treatment. International guidelines recognize the importance of a catheter-based approach for the curative treatment of atrial fibrillation and recommend its use in patients who have failed antiarrhythmic drug therapy. Physicians involved in the postprocedural care of these patients need to be familiar with common postoperative complications, proper use of antiarrhythmic agents and anticoagulation schemes, as well as, appropriate timing of reintervention.

Prevalence, predictors, and prognosis of atrial fibrillation early after pulmonary vein isolation: findings from 3 months of continuous automatic ECG loop recordings

INTRODUCTION

Following pulmonary vein isolation (PVI) for atrial fibrillation (AF), early recurrences are frequent, benign and classified as a part of a "blanking period." This study characterizes early recurrences and determines implications of early AF following PVI.

METHODS AND RESULTS

Seventy-two consecutive patients (59.8 +/- 10.7 years, 69% male) were studied following PVI for paroxysmal or persistent AF. Subjects were fitted with an external loop recorder for automatic, continuous detection of AF recurrence for 3 months. AF prevalence was highest 2 weeks after PVI (54%) and declined to an eventual low of 22%. A significant number (488, 34%) of recurrences were asymptomatic; however, all patients with > or =1 AF event had > or =1 symptomatic event. No clear predictor of early recurrence was identified. Forty-seven (65%) patients had at least 1 AF episode, predominantly (39 of 47 patients, 83%) within 2 weeks of PVI. Of the 33 patients who did not experience AF within the first 2 weeks, 85% (28/33) were complete responders (P = 0.03) at 12 months. Recurrence at any time within 3 months was not associated with procedural success or failure.

CONCLUSIONS

Early AF recurrence peaks within the first few weeks after PVI, but continues at a lower level until the completion of monitoring. A blanking period of 3 months is justified to identify patients with AF recurrences that do not portend procedure failure. Freedom from AF in the first 2 weeks following ablation significantly predicts long-term AF freedom.

Comparison of characteristics and significance of immediate versus early versus no recurrence of atrial fibrillation after catheter ablation

Atrial fibrillation (AF) recurrences after catheter ablation are common within the first month after AF ablation, and inflammatory processes may be related to AF genesis. This study aimed to clarify the relation between inflammatory processes and recurrence of AF after ablation and to characterize AF recurring within 3 days after ablation (immediate AF recurrence).The study included 186 patients with drug-refractory paroxysmal AF who underwent extensive pulmonary vein isolation. Body temperature and C-reactive protein level were measured before and consecutively on the first 3 days after ablation. Signs of pericarditis or atrial arrhythmias within 3 days after ablation were also monitored. Forty-five patients (24%) had immediate AF recurrence (immediate-AF-recurrence group), 27 (14%) had early recurrence 4 to 30 days after ablation (early-AF-recurrence group), and the remaining 114 (61%) had no AF recurrence within 1 month after ablation (no-AF-recurrence group). Increases in body temperature and C-reactive protein level from baseline in the immediate-AF-recurrence group were the highest among the 3 groups, and signs of pericarditis were observed in 15 of the 45 patients (33%) in the immediate-AF-recurrence group. Atrial premature contractions and nonsustained AF occurred most frequently in the early-AF-recurrence group. After 6-month follow-up, the AF-free rate was greater in the immediate-AF-recurrence group (76%) than in the early-AF-recurrence group (30%). In conclusion, immediate AF recurrence has an apparently different mechanism and impact on midterm outcomes than does early AF recurrence. Acute inflammatory changes after ablation may be responsible for immediate AF recurrence.

Recurrence of atrial fibrillation correlates with the extent of post-procedural late gadolinium enhancement: a pilot study

OBJECTIVES

We sought to evaluate radiofrequency (RF) ablation lesions in atrial fibrillation (AF) patients using cardiac magnetic resonance (CMR), and to correlate the ablation patterns with treatment success.

BACKGROUND

RF ablation procedures for treatment of AF result in localized scar that is detected by late gadolinium enhancement (LGE) CMR. We hypothesized that the extent of scar in the left atrium and pulmonary veins (PV) would correlate with moderate-term procedural success.

METHODS

Thirty-five patients with AF, undergoing their first RF ablation procedure, were studied. The RF ablation procedure was performed to achieve bidirectional conduction block around each PV ostium. AF recurrence was documented using a 7-day event monitor at multiple intervals during the first year. High spatial resolution 3-dimensional LGE CMR was performed 46 +/- 28 days after RF ablation. The extent of scarring around the ostia of each PV was quantitatively (volume of scar) and qualitatively (1: minimal, 3: extensive and circumferential) assessed.

RESULTS

Thirteen (37%) patients had recurrent AF during the 6.7 +/- 3.6-month observation period. Paroxysmal AF was a strong predictor of nonrecurrent AF (15% with recurrence vs. 68% without, p = 0.002). Qualitatively, patients without recurrence had more completely circumferentially scarred veins (55% vs. 35% of veins, p = NS). Patients without recurrence more frequently had scar in the inferior portion of the right inferior pulmonary vein (RIPV) (82% vs. 31%, p = 0.025, Bonferroni corrected). The volume of scar in the RIPV was quantitatively greater in patients without AF recurrence (p < or = 0.05) and was a univariate predictor of recurrence using Cox regression (p = 0.049, Bonferroni corrected).

CONCLUSIONS

Among patients undergoing PV isolation, AF recurrence during the first year is associated with a lesser degree of PV and left atrial scarring on 3-dimensional LGE CMR. This finding was significant for RIPV scar and may have implications for the procedural technique used in PV isolation.

Recurrence of atrial fibrillation correlates with the extent of post-procedural late gadolinium enhancement: a pilot study

OBJECTIVES

We sought to evaluate radiofrequency (RF) ablation lesions in atrial fibrillation (AF) patients using cardiac magnetic resonance (CMR), and to correlate the ablation patterns with treatment success.

BACKGROUND

RF ablation procedures for treatment of AF result in localized scar that is detected by late gadolinium enhancement (LGE) CMR. We hypothesized that the extent of scar in the left atrium and pulmonary veins (PV) would correlate with moderate-term procedural success.

METHODS

Thirty-five patients with AF, undergoing their first RF ablation procedure, were studied. The RF ablation procedure was performed to achieve bidirectional conduction block around each PV ostium. AF recurrence was documented using a 7-day event monitor at multiple intervals during the first year. High spatial resolution 3-dimensional LGE CMR was performed 46 +/- 28 days after RF ablation. The extent of scarring around the ostia of each PV was quantitatively (volume of scar) and qualitatively (1: minimal, 3: extensive and circumferential) assessed.

RESULTS

Thirteen (37%) patients had recurrent AF during the 6.7 +/- 3.6-month observation period. Paroxysmal AF was a strong predictor of nonrecurrent AF (15% with recurrence vs. 68% without, p = 0.002). Qualitatively, patients without recurrence had more completely circumferentially scarred veins (55% vs. 35% of veins, p = NS). Patients without recurrence more frequently had scar in the inferior portion of the right inferior pulmonary vein (RIPV) (82% vs. 31%, p = 0.025, Bonferroni corrected). The volume of scar in the RIPV was quantitatively greater in patients without AF recurrence (p < or = 0.05) and was a univariate predictor of recurrence using Cox regression (p = 0.049, Bonferroni corrected).

CONCLUSIONS

Among patients undergoing PV isolation, AF recurrence during the first year is associated with a lesser degree of PV and left atrial scarring on 3-dimensional LGE CMR. This finding was significant for RIPV scar and may have implications for the procedural technique used in PV isolation.

A deductive mapping strategy for atrial tachycardia following atrial fibrillation ablation: importance of localized reentry

BACKGROUND

Atrial tachycardia (AT) occurring following catheter ablation of persistent atrial fibrillation (AF) may be challenging to map and ablate because their mechanism and location is unpredictable and may be multiple in an individual patient.

METHODS AND RESULTS

A prospective cohort of 128 consecutive patients presenting 246 AT in the context of prior AF ablation was investigated. Using activation and entrainment mapping and applying the consensus definition of AT, we evaluated a deductive diagnostic approach based on up to three steps: (1) cycle length regularity, (2) search for macroreentry (i.e., involving >2 separate atrial segments), and (3) if macroreentry excluded, search for focal origin giving a centrifugal activation of the atria. A total of 238/246 (97%) sustained AT (mean cycle length [CL] 284 +/- 87 ms) were successfully mapped (single AT, 51 pts; multiple AT, 77 pts) with a diagnostic time of 10 +/- 8 min per tachycardia. AT were macroreentrant in 109 (46%) and focal in 129 (54%). Of the latter, only 34 focal AT originated from a discrete point site fulfilling the consensus criteria, while a distinct mechanism, localized reentry (AT that was neither macro reentry nor focal), was identified in 95. Localized reentry was defined by (1) electrograms covering >or=75% of the cycle length of AT within an area covering a single or 2 contiguous segments, (2) postpacing interval (PPI) < 30 ms at the site, (3) an identifiable zone of slow conduction, and (4) centrifugal activation of the atrium from the area.

CONCLUSIONS

This prospective study demonstrates the feasibility of rapid and accurate identification of all types of postablation AT in a large cohort of patients and describes the dominant role of localized reentry as a novel mechanism of AT.