Atrial fibrillation after radiofrequency ablation of type I atrial flutter: time to onset, determinants, and clinical course

The characteristics of pre-excitation syndrome concomitant with atrial tachyarrhythmia and the effect of radiofrequency ablation

BACKGROUND

Wolff-Parkinson-White (WPW) concomitant with atrial tachyarrhythmia (ATA) has not been systemically characterized.

METHODS

Detailed electroanatomical mapping of the right atrium (RA) and/or left atrium (LA) was performed using three-dimensional mapping and the accessory pathway (AP) was mapped.

RESULTS

WPW syndrome with ATA was diagnosed in 11 patients (median age 60 years). The characteristic of unidirectional anterograde conduction over the AP was displayed in nine patients, six of whom were intermittent. Sustained atrial tachycardia, that is, counterclockwise atrial flutter (AFL) with a median tachycardia cycle length (TCL) of 225 (220-275) ms, was mapped in eight patients; furthermore, "figure 8" right atrial reentry was mapped with TCL 250 ms in one patient with a surgical history of ventricular septal defect repair. The remaining two patients underwent mitral annulus-dependent AT after paroxysmal atrial fibrillation (PAF) ablation and LA micro-reentry AT, respectively. In four patients, the location of the APs was left posterior. Left-lateral APs were identified in four patients. The locations of the APs in the remaining three patients were the right posterior and middle septum. All ATAs and APs were successfully ablated. After a median follow-up of 37 (15-72) months, no anterograde conduction over the AP was recorded, new onset of PAF was recorded in three patients, and all of them underwent circumferential pulmonary vein isolation.

CONCLUSIONS

WPW with concomitant ATA frequently had continuous anterograde conduction over the AP with a rapid ventricular rate. Most WPWs displayed the characteristic of unidirectional anterograde conduction.

Elevated Left Atrial Volume Index Predicts Incident Atrial Fibrillation After Typical Right Atrial Flutter Ablation

Purpose

Incident atrial fibrillation (AF) is common after cavotricuspid isthmus (CTI) dependent atrial flutter (AFL) ablation. Risk factors for the development of AF post ablation are not well understood. The purpose of this study was to identify patients undergoing CTI ablation for AFL most likely to develop AF.

Methods

Retrospective chart review identified 114 consecutive patients without a history of AF or prior cardiac surgery who underwent typical CTI dependent AFL ablation between December 2013 to November 2018, who also had a complete preoperative transthoracic echocardiogram, and at least 1 year of follow-up at our medical center. We evaluated baseline characteristics, electrophysiology study (EPS) data and echocardiographic data for incidence of AF within 3 years.

Results

Incident AF was identified in 46 patients (40%) during 600 + 405 days follow-up. Left atrial volume index (LAVI) was significantly greater in patients who developed AF compared to those that did not (37 ± 12.2 ml/m² vs 30 ± 13.4 ml/m², p=.004), with an area under the receiver operator characteristic curve based on the LAVI of 0.7 (p = 0.004). Kaplan-Meier estimated incidence of AF was significantly greater in patients with LAVI ≥ 30 ml/m² than LAVI < 30 ml/m² (66% vs 27%, p=0.004). Risk of incident AF in patients with LAVI > 40 mL/m2 was similar to that of LAVI 30-40 ml/m2 (67% vs 63%, respectively, p=0.97). In multivariable analysis LAVI remained the sole independent predictor of incidence AF after CTI AFL ablation.

Conclusions

LAVI ≥ 30 ml/m² is associated with significantly increased risk of incident AF following CTI ablation for typical AFL. HATCH <2 was notably not an independent predictor of AF after AFL ablation.

Prediction of Recurrent Atrial Tachyarrhythmia After Receiving Atrial Flutter Ablation in Patients With Prior Cardiac Surgery for Valvular Heart Disease

Background: Surgical scars cause an intra-atrial conduction delay and anatomical obstacles that facilitate the perpetuation of atrial flutter (AFL). This study aimed to investigate the outcome and predictor of recurrent atrial tachyarrhythmia after catheter ablation in patients with prior cardiac surgery for valvular heart disease (VHD) who presented with AFL.

Methods: Seventy-two patients with prior cardiac surgery for VHD who underwent AFL ablation were included. The patients were categorized into a typical AFL group (n = 45) and an atypical AFL group (n = 27). The endpoint was the recurrence of atrial tachyarrhythmia during follow-up. A multivariate analysis was performed to determine the predictor of recurrence.

Results: No significant difference was found in the recurrence rate of atrial tachyarrhythmia between the two groups. Patients with concomitant atrial fibrillation (AF) had a higher recurrence of typical AFL compared with those without AF (13 vs. 0%, P = 0.012). In subgroup analysis, typical AFL patients with concomitant AF had a higher incidence of recurrent atrial tachyarrhythmia than those without it (53 vs. 14%, P = 0.006). Regarding patients without AF, the typical AFL group had a lower recurrence rate of atrial tachyarrhythmia than the atypical AFL group (14 vs. 40%, P = 0.043). Multivariate analysis showed that chronic kidney disease (CKD) and left atrial diameter (LAD) were independent predictors of recurrence.

Conclusions: In our study cohort, concomitant AF was associated with recurrence of atrial tachyarrhythmia. CKD and LAD independently predicted recurrence after AFL ablation in patients who have undergone cardiac surgery for VHD.

Prospective Evaluation of a Standardized Screening for Atrial Fibrillation after Ablation of Cavotricuspid Isthmus Dependent Atrial Flutter

Aims: We aimed to prospectively investigate the effectiveness of a standardized follow-up for AF-detection after common atrial flutter (cAFL) ablation. Methods: A total of 309 patients after cAFL ablation without known AF, from 5 centers, and at least one completed, standardized follow-up at 3, 6 and 12 months, including a 24 h Holter-electrocardiogram (ECG), were included. The primary outcome was incident atrial fibrillation (AF), or atrial tachycardia (AT). Predictors were investigated by Cox proportional-hazards models. Results: The mean age was 67.9 years; 15.2% were female and the mean CHA₂DS₂-VASc (Congestive heart failure, Hypertension, Age, Diabetes, Stroke, Vascular disease, Sex category) score was 2.4 points. The great majority of patients (90.3%) were anticoagulated. Over a mean follow-up of 12.2 months with a standardized approach, AF/AT was detected in 73 patients, corresponding to 11.7% at 3 months, 18.4% at 6 months and 28.2% at 12 months of follow-up. AF was found in 64 patients, AT in 9 and both in 2 patients. Occurrence of AF was recorded in 40 (60.6%) patients by Holter-ECG and in the remaining 26 (39.4%) by clinical follow-up only. There was no difference in male versus female (p = 0.08), or in younger versus older patients (p = 0.96) for AF/AT detection. Only coronary artery disease (hazard ratio [95% confidence intervals] 1.03 [1.01–1.05], p = 0.01) was associated with the primary outcome. Conclusions: AF or AT was detected in a large proportion of cAFL patients after cavotricuspid-isthmus (CTI) ablation, using a standardized follow-up over 1 year. This standardized screening can be easily implemented with high patient acceptance. The high proportion of post-ablation AF needs to be taken into consideration when deciding on long-term oral anticoagulation.

Heart failure and atrial flutter: a systematic review of current knowledge and practices

While the interplay between heart failure (HF) and atrial fibrillation (AF) has been extensively studied, little is known regarding HF and atrial flutter (AFL), which may be managed differently. We reviewed the incidence, prevalence, and predictors of HF in AFL and vice versa, and the outcomes of treatment of AFL in HF. A systematic literature review of PubMed/Medline and EMBASE yielded 65 studies for inclusion and qualitative synthesis. No study described the incidence or prevalence of AFL in unselected patients with HF. Most cohorts enrolled patients with AF/AFL as interchangeable diagnoses, or highly selected patients with tachycardia‐induced cardiomyopathy. The prevalence of HF in AFL ranged from 6% to 56%. However, the phenotype of HF was never defined by left ventricular ejection fraction (LVEF). No studies reported the predictors, phenotype, and prognostic implications of AFL in HF. There was significant variation in treatments studied, including the proportion that underwent ablation. When systolic dysfunction was tachycardia‐mediated, catheter ablation demonstrated LVEF normalization in up to 88%, as well as reduced cardiovascular mortality. In summary, AFL and HF often coexist but are understudied, with no randomized trial data to inform care. Further research is warranted to define the epidemiology and establish optimal management.

Implantable loop recorder for augmenting detection of new-onset atrial fibrillation after typical atrial flutter ablation

Background

Patients with typical atrial flutter (AFL) undergoing successful cavotricuspid isthmus ablation remain at risk for future development of new-onset atrial fibrillation (AF). Conventional monitoring (CM) techniques have shown AF incidence rates of 18%–50% in these patients.

Objectives

To evaluate whether continuous monitoring using implantable loop recorders (ILRs) would enhance AF detection in this patient population.

Methods

Veteran patients undergoing AFL ablation between 2002 and 2019 who completed at least 6 months of follow-up after the ablation procedure were included. We compared new-onset AF detection between those who underwent CM and those who received ILRs immediately following AFL ablation.

Results

A total of 217 patients (age: 66 ± 9 years; all male) participated. CM was used in 172 (79%) and ILR in 45 (21%) patients. Median follow-up duration after ablation was 4.1 years. Seventy-nine patients (36%) developed new-onset AF, which was detected by CM in 51 and ILR in 28 (30% vs 62%, respectively, P < .001). AF detection occurred at 7.7 months (IQR: 4.7–17.5) after AFL ablation in the ILR group vs 41 months (IQR: 23–72) in the CM group (P < .001). Eleven patients (5%) experienced cerebrovascular events (all in the CM group) and only 4 of these patients (36%) were on long-term anticoagulation.

Conclusion

Patients undergoing AFL ablation remain at an increased risk of developing new-onset AF, which is detected sooner and more frequently by ILR than by CM. Improving AF detection may allow optimization of rhythm management strategies and anticoagulation in this patient population.

Oral Anticoagulation Discontinuation Following Catheter Ablation of Typical Atrial Flutter

Catheter ablation (CA) of typical atrial flutter (AFL) is the preferred treatment for typical AFL due to its excellent long-term success rate. However, current guidelines recommend pursuing oral anticoagulation (OAC) based on established indices of stroke regardless of the perceived success of ablation. We conducted a retrospective study of all patients who underwent typical AFL ablation at our institute from 2011 to 2017. All patients continued OAC for at least six weeks post-CA and underwent 24-hour Holter monitoring. OAC was discontinued if there was no evidence of recurrence at six weeks. In patients with low left ventricular ejection fraction or prior atrial fibrillation episodes, OAC was continued for six months with repeat Holter monitoring at six months. A total of 106 patients were included in our analysis, with a mean age of 64 ± 14 years and 78.3% of whom were male. The mean CHA₂DS₂-VASc score was 3 ± 1 points. OAC was discontinued by six weeks in 17% and at one year in 55.7% of patients, respectively, but was continued indefinitely in 44.3%. Over a mean follow-up period of 28.6 ± 27.3 months, there was one ischemic stroke in the OAC discontinuation group and no ischemic events in the continued OAC group. There were a total of three major bleeding events, all in the OAC group. In patients undergoing successful AFL ablation, a strategy of OAC discontinuation with close rhythm monitoring appears feasible. The benefit of continued OAC in this cohort may be outweighed by an adverse risk of bleeding. Further studies examining rhythm-guided OAC can minimize unnecessary exposure to long-term anticoagulation.

Frequency of atrial arrhythmias after atrial flutter ablation and the effect of presenting rhythm on the day of ablation

Radiofrequency catheter ablation of the cavotricuspid isthmus is a proven therapy for typical atrial flutter (AFl); however, in some patients, new atrial arrhythmias (AA) may occur after AFl ablation. This study explored the difference in the occurrence of spontaneous AA after AFl ablation as a function of the patient's presenting rhythm on the day of the AFl ablation. A retrospective study of consecutive patients who underwent AFl ablation at Baylor University Medical Center at Dallas was performed. A total of 188 subjects were included; 50% (94) presented in AFl (Group AFl) on the day of the ablation procedure and 94 presented in sinus rhythm (SR; Group SR). Group AFl patients were older (P < 0.001), more likely to have diabetes (P = 0.03), and more likely to have undergone previous heart surgery (P = 0.03). The median size of the left atrium was 4 cm (range 2.8-6.8) in Group AFl compared with 3.8 cm (range 2.6-5.6) in Group SR (P = 0.009). Atrial fibrillation was induced during the ablation procedure in 7.5% and 21.3% of patients in Groups AFl and SR, respectively (P = 0.007). Overall, 29 of 188 (15.4%) patients developed new AA within 1 year of the procedure, 13.8% in Group AFl vs 17.0% in Group SR (P = 0.57). In conclusion, patients presenting for AFl ablation in SR were younger and healthier but had more atrial fibrillation induced during their ablation procedure, with a trend toward more postablation AA due to additional arrhythmia substrate.

Interest of waiting time for spontaneous early reconnection after cavotricuspid isthmus ablation: A monocentric randomized trial

INTRODUCTION

The aim of this study was to determine the rate of recurrent atrial flutter (AFl) after isolated cavotricuspid isthmus (CTI) ablation and to evaluate the impact of a waiting period with the search for early resumption of the CTI block on the long-term outcome.

METHOD

Three hundred and nineteen consecutive patients referred for typical AFl ablation were randomly assigned to CTI ablation with continuous reevaluation of the CTI block during 30 minutes and early reablation if needed (waiting time [WT] + group, n  =  155) or to CTI ablation with no waiting period after proven bidirectional CTI block (WT - group, n  =  164). All patients were regularly followed-up.

RESULT

In the WT+ group, 10 patients (6%) presented a recovery across the CTI (time to recovery: 17 ± 7') and were reablated at the end of the waiting period. After a median follow-up of 21 months, the rate of recurrent AFl was significantly higher in the WT - group as compared to the WT+ group (11.6% [19/164] vs 2.5% [4/155], respectively; P  =  0.007). However, no significant differences in the subsequent rate of AF were observed between the two groups (29% [WT -] vs 32% [WT+], P  =  0.66). During the follow-up, 28 patients from the WT - group underwent a second ablation procedure (16 AFl redo and 12 AF ablation) versus 10 patients form the WT+ group (three AFl redo and seven AF ablation).

CONCLUSION

Waiting 30 minutes after CTI ablation to check for early resumption and early reablation allows for decreasing significantly the rate of recurrent atrial flutter.

Atrial Flutter, Typical and Atypical: A Review

Clinical electrophysiology has made the traditional classification of rapid atrial rhythms into flutter and tachycardia of little clinical use. Electrophysiological studies have defined multiple mechanisms of tachycardia, both re-entrant and focal, with varying ECG morphologies and rates, authenticated by the results of catheter ablation of the focal triggers or critical isthmuses of re-entry circuits. In patients without a history of heart disease, cardiac surgery or catheter ablation, typical flutter ECG remains predictive of a right atrial re-entry circuit dependent on the inferior vena cava-tricuspid isthmus that can be very effectively treated by ablation, although late incidence of atrial fibrillation remains a problem. Secondary prevention, based on the treatment of associated atrial fibrillation risk factors, is emerging as a therapeutic option. In patients subjected to cardiac surgery or catheter ablation for the treatment of atrial fibrillation or showing atypical ECG patterns, macro-re-entrant and focal tachycardia mechanisms can be very complex and electrophysiological studies are necessary to guide ablation treatment in poorly tolerated cases.

Risk and outcome after ablation of isthmus-dependent atrial flutter in elderly patients

Purpose of the research

To study the influence of age on the clinical presentation and long-term outcome of patients referred for atrial flutter (AFL) ablation. Age-related differences have been reported regarding the prognosis of arrhythmias.

Methods

A total of 1187 patients with a mean age 65±12 years consecutively referred for AFL ablation were retrospectively analyzed in the study.

Results

445 (37.5%) patients were aged ≥70 (range 70 to 93) among which 345 were aged 70 to 79 years (29.1%) and 100 were aged ≥80 (8.4%). In multivariable analysis, AFL-related rhythmic cardiomyopathy and presentation with 1/1 AFL were less frequent (respectively adjusted OR = 0.44, 0.27–0.74, p = 0.002 and adjusted OR = 0.29, 0.16–0.52, p<0.0001). AFL ablation-related major complications were more frequent in patients ≥70 although remained lower than 10% (7.4% in ≥70 vs. 4.2% in <70, adjusted OR = 1.74, 1.04–2.89, p = 0.03). After 2.1±2.7 years, AFL recurrence was less frequent in patients ≥70 (adjusted OR = 0.54, 0.37–0.80, p = 0.002) whereas atrial fibrillation (AF) occurrence was as frequent in the 70–79 and ≥80 age subsets. As expected, cardiac mortality was higher in older patients. Patients aged ≥80 also had a low probability of AFL recurrence (5.0%) and AF onset (19.0%).

Conclusions

Older patients represent 37.5% of patients referred for AFL ablation and displayed a <10% risk of ablation-related complications. Importantly, AFL recurrences were less frequent in patients ≥70 while AF occurrence was as frequent as in patients <70. Similar observations were made in patients ≥80 years. AFL ablation appears to be safe and efficient and should not be ruled out in elderly patients.

New-onset atrial fibrillation after cavotricuspid isthmus ablation: identification of advanced interatrial block is key

AIMS

A significant proportion of patients develop atrial fibrillation (AF) following cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl). The objective of this study was to assess whether the presence of advanced interatrial block (aIAB) was associated with an elevated risk of AF after CTI ablation in patients with typical AFl and no prior history of AF.

METHODS AND RESULTS

This study included patients with typical AFl and no prior history of AF that were referred for CTI ablation. Patients were excluded when they had received repeat ablations or did not demonstrate a bidirectional block. In all patients, a post-ablation electrocardiogram (ECG) in sinus rhythm was evaluated for the presence of aIAB, defined as a P-wave duration ≥120 ms and biphasic morphology in the inferior leads. New-onset AF was identified from 12-lead ECGs, Holter monitoring, and device interrogations. The cohort comprised 187 patients (age 67 ± 10.7 years; ejection fraction 55.8 ± 11.2%). Advanced interatrial block was detected in 18.2% of patients, and left atrium was larger in patients with aIAB compared with those without aIAB (46.2 ± 5.9 vs. 43.1 ± 6.0 mm; P = 0.01). Over a median follow-up of 24.2 months, 67 patients (35.8%) developed new-onset AF. The incidence of new-onset AF was greater in patients with aIAB compared with those without aIAB (64.7 vs. 29.4%; P < 0.001). After a comprehensive multivariate analysis, aIAB emerged as the strongest predictor of new-onset AF [odds ratio (OR) 4.2, 95% confidence interval (CI): 1.9-9.3; P < 0.001].

CONCLUSION

Advanced interatrial block is a key predictor for high risk of new-onset AF after a successful CTI ablation in patients with typical AFl.

Prognostic value of atrial fibrillation inducibility after right atrial flutter ablation

BACKGROUND

Patients with typical right atrial flutter (AFL) may also have underlying atrial fibrillation (AF) or be at high risk of developing AF. Inducibility of AF among patients undergoing AFL ablation may be an important predictor of future occurrence of AF and may be useful in guiding management of this patient population.

OBJECTIVE

This study aimed to determine whether inducibility of AF at the time of AFL ablation is independently associated with the risk of future AF.

METHODS

Attempt at induction of AF by burst pacing was performed in consecutive patients who underwent AFL ablation. Time to incidence of AF after AFL ablation was examined using multivariable Cox proportional hazards models. All analyses were stratified by a history of AF.

RESULTS

A total of 175 patients were retrospectively evaluated over a median follow-up period of 482 days. In patients without a documented history of AF (n = 93), the incidence of AF after AFL ablation was 18.7 per 100 person-years. In these patients, inducible AF was strongly associated with the future development of AF (adjusted hazard ratio 15.99; 95% confidence interval 5.10-50.12). In contrast, in patients with a documented history of AF (n = 82), the incidence of AF after AFL ablation was 59.3 per 100 person-years and inducible AF was not associated with the future development of AF (adjusted hazard ratio 1.26; 95% confidence interval 0.74-2.14).

CONCLUSION

Inducibility of AF after AFL ablation is strongly and independently associated with the risk of future AF among patients without a history of AF but not among patients with a history of AF.

Impact of a 4q25 genetic variant in atrial flutter and on the risk of atrial fibrillation after cavotricuspid isthmus ablation

BACKGROUND

The prediction of atrial fibrillation (AF) following catheter ablation of atrial flutter (Afl) would be helpful to facilitate targeted arrhythmia monitoring and anti-coagulation strategies. A single nucleotide polymorphism, rs2200733, is strongly associated with AF. We sought to characterize the association between rs2200733 and prevalent Afl and to determine if the variant could predict AF after cavotricuspid isthmus ablation.

METHODS AND RESULTS

We performed a genetic association study of 295 patients with Afl and/or AF and 469 controls using multivariable logistic regression. The variant was then assessed as a predictor of incident AF after cavotricuspid isthmus ablation in 87 consecutive typical Afl patients with Cox proportional hazards models. The rs2200733 rare allele was associated with an adjusted 2.06-fold increased odds of isolated Afl (95% CI: 1.13-3.76, P = 0.019) and an adjusted 2.79-fold increased odds of a combined phenotype of AF and Afl (95% CI: 1.81-4.28, P < 0.001). Following catheter ablation for Afl, carrier status of rs2200733 failed to predict an increased risk of AF either among all subjects (adjusted HR: 0.94; 95% CI: 0.58-1.53, P = 0.806) or among those with isolated Afl (adjusted HR: 1.29; 95% CI: 0.51-3.26, P = 0.585).

CONCLUSIONS

Our study demonstrates that Afl, whether occurring in isolation or along with AF, is associated with the rs2200733 AF risk allele. Genetic carrier status of rs2200733 failed to predict an increased risk of incident or recurrent AF following catheter ablation for Afl. These findings suggest that the causal mechanism associated with rs2200733 is germane to both AF and Afl.

Predictors of the atrial fibrillation following catheter ablation of typical atrial flutter

Background:

Despite technical refinements and improved long-term efficacy of the ablation procedure for treating AFL (AFL), the subsequent occurrence of AF (AF) following this procedure remains a significant clinical problem.

Objectives:

To determine long-term incidence and predictors of AF after catheter ablation of typical AFL.

Material and Methods:

Between March 2005 and February 2010, a total of 84 consecutive patients who underwent catheter ablation of documented typical AFL were enrolled.

Results:

Cavotricuspid isthmus ablation was successful in terminating and preventing the re-induction of AFL in all 84 patients (100%). The mean follow-up duration for study was 26± 22 months. During the follow-up period, early AF occurred in 5% after successful catheter ablation of AFL and late AF in 11% of the patients. The clinical variables associated with the occurrence of AF after catheter ablation of AFL were female, a history of AF before AFL ablation, body mass index (BMI), and left atrial abnormality. However, logistic multivariate analysis demonstrated that only BMI was independently associated with the late AF (OR 1.36, 95% CI 1.11-1.70, P = 0.004).

Conclusions:

Catheter ablation of flutter circuit will not prevent later manifestation of AF in 16% of the patients undergoing catheter ablation of the typical AFL. BMI was the only independent predictor of AF following catheter ablation of the typical AFL.

Structural and functional inverse cardiac remodeling after cavotricuspid isthmus ablation in patients with typical atrial flutter

INTRODUCTION AND OBJECTIVES

The purpose of the present study is to determine the structural and functional cardiac changes that occur in patients at 1-year follow-up after ablation of typical atrial flutter.

METHODS

We enrolled 95 consecutive patients referred for cavotricuspid isthmus ablation. Echocardiography was performed at ≤6h post-procedure and 1-year follow-up.

RESULTS

Of 95 patients initially included, 89 completed 1-year follow-up. Hypertensive cardiopathy was the most frequently associated condition (39%); 24% of patients presented low baseline left ventricular systolic dysfunction. We observed a significant reduction in right and left atrial areas, end-diastolic and end-systolic left ventricular diameters, and interventricular septum. We observed substantial improvement in right atrium contraction fraction and left ventricular ejection fraction, and a reduction in pulmonary hypertension. Changes in diastolic dysfunction pattern were observed: 60% of patients progressed from baseline grade III to grade I; at 1-year follow-up, this improvement was found in 81%. We found no structural differences between paroxysmal and persistent atrial flutter at baseline and 1-year follow-up, exception for basal diastolic function.

CONCLUSIONS

In patients with typical atrial flutter undergoing cavotricuspid isthmus catheter ablation, we found inverse structural and functional cardiac remodeling at 1-year follow-up with much improved left ventricular ejection fraction, right atrium contraction fraction, and diastolic dysfunction pattern. Full English text available from:www.revespcardiol.org.

Long-term outcome following ablation of atrial flutter occurring late after atrial septal defect repair

AIMS

In patients with surgical atrial septal defect (ASD) repair, late atrial flutters (AFLs), including cavotricuspid isthmus (CTI)-dependent and non-CTI-dependent scar-related flutter (AFL), are common. Radiofrequency ablation (RFA) of these arrhythmias has a high acute success rate. We aimed to characterize the long-term freedom from atrial arrhythmias in this population.

METHODS

Twenty consecutive patients undergoing RFA for AFL late after ASD repair were included. Electrophysiological assessment included multipolar activation, entrainment, and electroanatomic mapping. Clinical, electrocardiograph, and Holter monitoring follow-up was conducted every 6 months.

RESULTS

Mean age was 53 ± 13 years. Time from surgical repair to RFA was 29 ± 15 years. All patients had CTI-dependent AFL (20/20). There were 1.6 ± 0.7 arrhythmias per patient; other arrhythmias included non-CTI-dependent AFL (14), focal atrial tachycardia (two), and atrioventricular nodal reentry tachycardia (two) . Acute success was obtained in 100%. Five patients with recurrent AFL (three CTI dependent, two non-CTI dependent) at 13 ± 8 months had successful repeat RFA. At 3.2 ± 1.6 years follow-up since the last procedure, 90% of patients with successful RFA for AFL remained free of their clinical arrhythmia. However, 30% of the original 20 patients had documented atrial fibrillation (AF) 2.1 ± 1.6 years after the last procedure; five (25%) required AF intervention. One stroke (5%) occurred in the context of late AF.

CONCLUSION

RFA of AFL occurring late after surgical ASD repair has a low long-term risk of recurrence, although 25% of patients required two procedures. However, there is a high late incidence of AF (30%), with an additional 25% of patients requiring intervention for AF.

Characterization of atrial remodeling studied remote from episodes of typical atrial flutter

Atrial electrical remodeling has been shown after termination of atrial flutter (AFL); however, whether abnormalities persist beyond an arrhythmic episode is not known. We aimed to characterize the atrial substrate, remote from arrhythmia, in patients with typical AFL. We compared 20 patients, studied remote from episodes of typical AFL and without a history of atrial fibrillation, to 20 reference patients. Multipolar catheters placed at the lateral right atrium (RA), coronary sinus, crista terminalis, and septal RA measured the effective refractory period at 5 sites; conduction characteristics at the crista terminalis; and the conduction time along the lateral RA and coronary sinus. Electroanatomic right atrial maps were created to determine regional differences in voltage and conduction. Patients with AFL demonstrated the following compared to the reference patients: a larger right atrial volume (121 +/- 30 vs 83 +/- 24 ml, p = 0.005); a prolonged P-wave duration (122 +/- 18 vs 102 +/- 11 ms, p = 0.007); a longer right atrial activation time (107 +/- 23 vs 85 +/- 14 ms, p = 0.02); a prolonged conduction time along the lateral RA (67 +/- 4 vs 47 +/- 3 ms, p <0.001); a slower mean conduction velocity (1.2 +/- 0.2 vs 2.1 +/- 0.6 mm/ms, p <0.001); a greater proportion of fractionated electrographic findings (16 +/- 4% vs 10 +/- 6%, p = 0.006); more frequent abnormal electrographic findings at the crista terminalis (4.1 +/- 2.6 vs 1.0 +/- 1.1, p = 0.001); a prolonged corrected sinus node recovery time (318 +/- 71 vs 203 +/- 94 ms, p = 0.02); a trend toward greater effective refractory period (232 +/- 29 vs 213 +/- 12 ms, p = 0.06); and a lower voltage (2.1 +/- 0.5 vs 3.0 +/- 0.5 mV, p <0.001). In conclusion, studied remote from arrhythmia, patients with AFL demonstrated significant and diffuse atrial abnormalities characterized by structural changes, conduction abnormalities, and sinus node dysfunction. These persisting abnormalities characterize the substrate underlying typical AFL and may account for the subsequent development of atrial fibrillation.

The place of hybrid therapies with drugs to supplement nonpharmacological therapies in atrial fibrillation

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias, and its prevalence continues to rise as the aged population increases. Comparative studies of rhythm control and rate control have been equivocal; however, the benefits of rhythm control may have been offset by the limitations of antiarrhythmic drugs. More recently, nonpharmacological therapies have emerged that provide hope of more effective rhythm control. Catheter ablation techniques have gained favour with high success rates in specialized centers, although these techniques are not without complications and require considerable expertise. Pacing therapies designed to reduce harmful right ventricular pacing and increase physiological pacing have shown benefit in AF patients with bradycardia. Despite this progress, no single modality confers benefit for all patients. Strategies to combine these treatment modalities in a hybrid approach has shown increasing promise for subgroups of AF patients.

[Catheter ablation of typical atrial flutter]

Atrial flutter is one of the most common supraventricular arrhythmic diseases and occurs with an incidence of 88/100,000. The high risk for thromboembolic events is similar to that for atrial fibrillation and also has the risk for fast conduction to the ventricle. Pharmacological treatment is not significantly effective. Catheter ablation of common atrial flutter offers an alternative with a high quality outcome ranging from 90-96% and a low recurrence rate of 2-6%. Radiofrequency catheter ablation of the cavotricuspidal isthmus is an established treatment for common atrial flutter. Modern techniques like cryo-ablation show nearly the same results and will be an alternative to the RF ablation in the future.

Effect of radiofrequency ablation of atrial flutter on the natural history of subsequent atrial arrhythmias

Flutter Ablation and Subsequent Arrhythmia.

INTRODUCTION

Patients with atrial flutter (AFL) treated medically are at high risk for subsequent development of atrial fibrillation (AF). Whether curative radiofrequency ablation of AFL can modify the natural history of arrhythmia progression is not clear. We aimed to determine whether ablation of AFL decreases the subsequent development of AF in patients without previous AF.

METHODS AND RESULTS

Patients with AFL as the sole atrial arrhythmia were selected from patients who underwent successful AFL ablation at Mayo Clinic between 1997 and 2003 (N = 137). The cohort was divided by presence (n = 50) or absence (n = 87) of structural heart disease. A control group comprised 59 patients with AFL and no history of paroxysmal AF, who received only medical therapy. Occurrence of AF after AFL ablation was compared among study groups and controls. Symptomatic AF occurred in 49 patients during 5 years of follow-up after AFL ablation, with similar frequency in both study groups. The cumulative probability of paroxysmal and chronic AF was similar in controls and each study group. By multivariate analysis, the AFL ablation procedure carries significant risk of AF occurrence during follow-up. Fifty patients discontinued antiarrhythmic drugs after AFL ablation, and the rate of cardioversions decreased.

CONCLUSION

Successful ablation of AFL does not improve the natural history of atrial arrhythmia progression; postablation AF is frequent. This suggests that AFL may be initiated by bursts of AF and that in the absence of AFL substrate the AF continues to progress.

Atrial fibrillation is common after ablation of isolated atrial flutter during long-term follow-up

BACKGROUND

Previous studies have shown that the incidence of atrial fibrillation after atrial flutter ablation is approximately 20% among patients presenting with typical atrial flutter and no history of fibrillation. However, studies involving this population have been small, with follow-up typically less than 2 years.

OBJECTIVE

The purpose of this study was to provide a more accurate perspective on the long-term risk of atrial fibrillation in patients presenting with isolated typical flutter.

METHODS

Clinical records of consecutive patients who had flutter ablations at Presbyterian Medical Center between 1999 and 2004 were assessed (n = 254). Patients with no apparent history of atrial fibrillation before their flutter ablation were identified. Retrospective follow-up data on these patients were obtained by review of medical records from our institution, from patients' cardiologists and primary care physicians, and by direct patient questionnaires. Postablation atrial fibrillation and other arrhythmias were identified by electrocardiography, Holter monitoring, and subsequent clinical records.

RESULTS

Postablation atrial fibrillation was identified in 40 (50%) of 80 patients, and an additional three patients presented with atypical atrial flutter, after a mean follow-up of 29.6 +/- 21.7 months. The incidence of atrial fibrillation was progressive, with 49% occurring after 2 years. There was no difference in age, left atrial size, hypertension, structural heart disease, or left ventricular dysfunction in patients who developed atrial fibrillation compared with those who did not.

CONCLUSION

Atrial fibrillation occurs in over half of patients who present with isolated typical flutter after cavotricuspid isthmus ablation. Asymptomatic patients should be screened for recurrent arrhythmias indefinitely after ablation. In certain patients, atrial fibrillation and flutter may be different expressions of the same electrical disease, and eradication of the flutter circuit will not prevent the eventual manifestation of atrial fibrillation.