Importance of ablating all potential right atrial flutter circuits in postcardiac surgery patients

High-density mapping of upper loop macroreentry surrounding the superior vena cava: Substrate-evolved ablation strategy

BACKGROUND

The circuit of scar-related upper loop macroreentry atrial flutter (AFL) surrounding the superior vena cava (SVC) has been described by prior case reports. However, the correlation between the circuit and arrhythmogenic substrates and the corresponding optimized ablation strategy need to be further investigated.

OBJECTIVE

We aimed to identify the electrophysiologic substrate and corresponding ablation strategies of SVC-AFL using high-resolution mapping.

METHODS

From June 1, 2017, to May 1, 2023, consecutive patients with macroreentrant atrial tachycardias (ATs) from 7 institutions were retrospectively evaluated. Patients with SVC-AFL were enrolled and analyzed.

RESULTS

Of 1282 patients with macroreentrant ATs, 16 patients (1.2%; median age, 60.9 years; 8 male) had SVC-AFL (mean cycle length, 281.0 ± 55.1 ms), all identified during high-resolution activation mapping. All patients had prior cardiac surgery (14 [87.5%]) or catheter ablation (8 [50.0%]). A longitudinal surgical incision/scar extending from the SVC to the right atrium was observed in all patients, enabling macroreentry. SVC-AFLs with shorter circuits (<180 mm) had more slow conduction areas than those with longer circuits (>180 mm; 3.0 [2.0-4.0] vs 1.0 [1.0-1.5]; P = .023]. All ATs were terminated by ablating the channel between the surgical incision/scar and anatomic barriers. Cavotricuspid isthmus block was achieved in all patients. During a 21-month follow-up, all patients were free of atrial arrhythmias except for 4 patients experiencing short-lived paroxysmal ATs that did not require further ablation.

CONCLUSION

A surgical incision/scar extending from the SVC to right atrium promotes the development of SVC-AFL. Substrate-based linear lesions along with prophylactic cavotricuspid isthmus ablation afford favorable clinical outcomes.

High density mapping of atrial tachycardia in patients post cardiac surgery

Mapping and ablation of atrial tachycardia (AT) in patients who have had prior cardiac surgery can be a challenge for clinical electrophysiologists. High density mapping (HDM) technology has been widely used in these patients because it provides a better characterization of the substrate and the mechanisms with an unprecedented high resolution. In this review, we summarize how the latest HDM technologies can reveal the mechanism of AT in different types of patients post-cardiac surgery and guide a specifically tailored ablation strategy.

Is prophylactic ablation of the cavotricuspid and peri-incisional isthmus justified in patients with postoperative atrial flutter after right atriotomy?

BACKGROUND

The two most common postoperative atrial flutter (AFL) circuits after right atriotomy are the cavotricuspid isthmus (CTI) dependent and the lateral, peri-incisional. We investigated whether radiofrequency ablation (RFA) of both circuits results in more favorable long-term outcomes.

METHODS

Single-center retrospective cohort study of consecutive patients who underwent RFA of AFL after open-heart surgery. The effect of surgery type and RFA strategy on AFL recurrence was evaluated.

RESULTS

One hundred and forty-two patients (mean age 64.5 ± 12.7 years, 65.% male) were enrolled. Patients with right atrial (RA) flutter (n=124) were divided into two groups based on the index RFA procedure: only one RA circuit was ablated (Group 1, n= 84, 67.7%) or both the CTI and the peri-incisional circuit ablated (Group 2, n= 40, 32.3%). The previous open-heart surgery was categorized based on the extension of the RA incision: limited (Type A) or extended (Type B) atriotomy. After a mean follow-up of 36±28 months, flutter recurrence was not different among patients with limited RA atriotomy (25% vs. 22% in Group 1A and 2A, respectively, p=1.0). However, after type B surgery, ablation of both AFL circuits was associated with a reduced recurrence rate (63% vs. 26% in Group 1B and 2B, respectively, p=0.002).

CONCLUSIONS

In patients with postoperative RA flutter after extended right atriotomy, ablation of both the CTI and the peri-incisional isthmus significantly reduces the AFL recurrence rate. Prophylactic ablation of both isthmi, even if not proven to support reentry, is reasonable in this population. Keywords This article is protected by copyright. All rights reserved.

Ultra-high-density mapping and ablation strategy for multiple scar-related right atrial tachycardias in patients without previous cardiac surgery

BACKGROUND

Catheter ablation of right atrial (RA) tachycardia in patients who have extensive spontaneous RA scarring is challenging due to the complex substrate and the potential for multiple inducible atrial tachycardias (ATs).

METHODS

Eighteen patients with scar-related RA AT and no prior cardiac surgery were enrolled. A total of 52 different ATs (mean 3.2 ± 1.5 ATs per patient) were observed. We endeavored to complete activation maps for 45 ATs.

RESULTS

By analyzing activation maps, we classified ATs into six categories. The discrepant location and extension of ESAs were associated with different AT mechanisms.

CONCLUSIONS

Multiple scar-related RA ATs were observed in patients without previous cardiac surgery. The detailed activation patterns of these ATs could be clearly demonstrated by using an ultra-high-density mapping system.

Atrial flutter catheter ablation in adult congenital heart diseases

The important increase in life expectancy of adult patients with congenital heart disease (ACHD) has generated new challenges, including arrhythmias that represent one of the main late complications. Reentrant atrial arrhythmias are by far the main mechanism encountered, and catheter ablation has been now presented as a first-line therapy in this patient population. The number of procedures is expected to continuously increase year after year. The heterogeneity and complexity of phenotypes encountered require these cases to be performed by highly experienced operators, in specialized centers with multidisciplinary competencies. A thorough knowledge and understanding of anatomic specificities, vascular access issues, and main circuits encountered according to underlying phenotype is essential. Acute success rates have significantly improved and are now excellent, but recurrences remain a common issue, with different mechanisms or circuits frequently encountered. Observational data have suggested the interest of systematically targeting all inducible atrial arrhythmias, whether previously documented or not, and a lot of hope and research is based on the prediction of arrhythmia substrate before arrhythmia development by imaging or electroanatomic mapping to deliver a prophylactic patient tailored ablation approach. In this review, we summarize those different points in the most common or distinctive defects to offer a didactic overview of atrial flutter catheter ablation in ACHD patients.

Ablation Therapy as Management of Typical Atrial Flutter in the Early Period After Cardiac Surgery

Introduction

Available data on management of atrial flutter in the early postoperative setting after cardiac surgery are scarce. We aimed to investigate the safety and efficacy (profile) of flutter ablation in the early postoperative phase (30 days after cardiac surgery) in a cohort of 47 consecutive patients.

Methods

Between 2007 and 2016, 47 patients who underwent ablation for postoperative typical atrial flutter were retrospectively identified and analyzed. Follow-up data were acquired from patients’ records in case of rehospitalization and via follow-up calls.

Results

The median age of patients was 69 years, 89% male and with a median LV-EF of 55%. CAD was present in 80.8% of patients. The predominant conduction of atrial flutter was 2:1 (76.6%); 85.1% of patients had either undergone CABG, SAVR, or a combination of these two. Acute procedural success could be achieved in 100% of patients with one vascular pseudoaneurysm that was managed conservatively. No other complications occurred. After a median follow-up of 5.7 years, follow-up information regarding heart rhythm was available in 87.2% of patients. One patient (2.1%) had undergone repeat ablation for typical flutter. Two patients (4.2%) had developed atrial fibrillation, while 87.2% of patients were in sinus rhythm.

Conclusions

In this small cohort, early postoperative ablation of typical flutter was associated with a favorable short- and long-term safety and efficacy profile and can be considered part of heart rhythm management options in this setting.

Catheter ablation in adults with congenital heart disease: A 15-year perspective from a tertiary centre

BACKGROUND

With the growing adult congenital heart disease (ACHD) population, the number of catheter ablation procedures is expected to dramatically increase. Data reporting experience and evolution of catheter ablation in patients with ACHD, over a significant period of time, remain scarce.

AIM

We aimed to describe temporal trends in volume and outcomes of catheter ablation in patients with ACHD.

METHODS

This was a retrospective observational study including all consecutive patients with ACHD undergoing attempted catheter ablation in a large tertiary referral centre over a 15-year period. Acute procedural success rate and freedom from recurrence at 12 and 24 months were analysed.

RESULTS

From November 2004 to November 2019, 302 catheter ablations were performed in 221 patients with ACHD (mean age 43.6±15.0 years; 58.9% male sex). The annual number of catheter ablations increased progressively from four to 60 cases per year (P<0.001). Intra-atrial reentrant tachycardia/focal atrial tachycardia was the most common arrhythmia (n=217, 71.9%). Over the study period, acute procedural success rate increased from 45.0% to 93.4% (P<0.001). Use of irrigated catheters (odds ratio [OR] 4.03, 95% confidence interval [CI] 1.86-8.55), a three-dimensional mapping system (OR 3.70, 95% CI 1.72-7.74), contact force catheters (OR 3.60, 95% CI 1.81-7.38) and high-density mapping (OR 3.69, 95% CI 1.82-8.14) were associated with acute procedural success. The rate of freedom from any recurrence at 12 months increased from 29.4% to 66.2% (P=0.001). Seven (2.3%) non-fatal complications occurred.

CONCLUSIONS

The number of catheter ablation procedures in patients with ACHD has increased considerably over the past 15 years. Growing experience and advances in ablative technologies appear to be associated with a significant improvement in acute and mid-term outcomes.

Electrophysiological Characteristics and Outcomes of Radiofrequency Catheter Ablation of Atrial Flutter in Children with or Without Congenital Heart Disease

There are scarce studies on radiofrequency catheter ablation (RFCA) of atrial flutter (AFL) in the pediatric population. This study therefore aimed to investigate the clinical features and RFCA of AFL in children with or without congenital heart disease. Data from 72 consecutive children (44 males; mean age, 6.1 ± 3.8 [0.9-15.0] years; and mean weight, 23.6 ± 13.9 [8.1-72.0] kg) undergoing RFCA for AFL from 2009 to 2019 were retrospectively reviewed. Thirty-three patients had normal cardiac structure and 39 had congenital heart disease (CHD) of whom 29 had undergone surgical repair and developed AFL at a mean of 3.1 ± 2.5 years later. Fifty-nine patients (84%) presented with persistent AFL. Five patients (7%) had cardiac dysfunction with LVEF of 30-48%, which normalized after ablation. Overall, acute success rate of ablation was 99% and recurrence rate was 18% at 0.5-10 years of follow-up. No procedure-related complications were identified. All 33 patients with normal cardiac structure had cavotricuspid isthmus (CTI)-dependent AFL. Among patients who had undergone corrective surgery for CHD, 15 (52%) had CTI-dependent AFL, 4 (14%) had surgical incisional scar reentrant AFL and the remaining 10 (34%) had both CTI-dependent and scar reentrant AFL. Success rate (100% vs. 97%, P = 1.0000) and recurrence rate (21% vs. 16%, P = 0.7008) were similar between patients with and without CHD. Overall, sick sinus syndrome (SSS) was found in 42% (30/72) of patients with AFL, with an incidence of 39% (13/33) among patients with normal cardiac structure and 59% (17/29) among those who underwent surgery for congenital defects. Permanent pacemakers (PM) were implanted in 53% (16/30) of patients with SSS after ablation. RFCA therefore appeared efficacious and safe for treatment of pediatric AFL. The mechanisms underlying AFL after corrective surgery for CHD are complex, including CTI-dependent macro-reentrant, scar reentrant, or a combination of both. SSS is not rare among pediatric AFL cases, with approximately half of patients needing PM implantation.

Dynamic voltage threshold adjusted substrate modification technique for complex atypical atrial flutters with varying circuits

BACKGROUND

Atypical atrial flutter (AFL) is common in patients with postsurgical atrial scar, with macro- or microscopic channels in the scar acting as substrate for reentry. Heterogeneous atrial scarring can cause varying flutter circuits, which makes mapping and ablation challenging, and recurrences common.

AIM

We hypothesize that dynamically adjusting voltage thresholds can identify heterogeneous atrial scarring, which can then be effectively homogenized to eliminate atypical AFLs.

METHODS

We studied consecutive patients who presented to Electrophysiology laboratory for atypical AFL ablation with history of atriotomy and included the patients with multiple, varying flutter circuits during mapping in our study. We excluded patients with stable flutter circuit that was sustained and could be localized using traditional entrainment and activation mapping strategy. In the included patients, we performed detailed high-density voltage map of the atrium of interest. We adjusted voltage thresholds as needed to identify heterogeneity and channels in the scarred regions. A thorough scar homogenization was performed with irrigated smart-touch ablation catheter. Re-inducibility of tachycardia, and immediate and long-term outcomes were studied.

RESULTS

Of five studied cases, one was female; age 66 ± 10 years. All five had prior surgical substrate. All the patients had multiple flutter morphologies, which varied as we mapped the AFL. After scar homogenization, tachycardia was not inducible in any patient. No recurrence of flutter was noted during a mean follow-up duration of 450 ± 27 days.

CONCLUSION

High-density voltage mapping and homogenization of the scar can be an effective strategy in eliminating complex scar-mediated atypical AFL with multiple circuits.

Identification of critical isthmus using coherent mapping in patients with scar-related atrial tachycardia

INTRODUCTION

Accurate identification of slow conducting regions in patients with scar-related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs.

METHODS

Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three-dimensional EAMs using CARTO 3 system with CONFIDENSE and a high-resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System-defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval < 20 ms), CV < 0.3 m/s and local fractionated electrograms were evaluated.

RESULTS

Twenty-six complex ATs were mapped (mean: 1.3 ± 0.7 maps/pt; 4 focal, 22 isthmus-dependent). Coherent mapping was better in identifying CI/breakout sites where ablation terminated the tachycardia (96.2% vs 69.2%; P = .010) and identified significantly more CI (mean/chamber 2.0 ± 1.1 vs 1.0 ± 0.7; P < .001) with narrower width (19.8 ± 10.5 vs 43.0 ± 23.9 mm; P < .001) than conventional mapping. Ablation at origin and CI sites was successful in 25 (96.2%) with long-term recurrence in 25%.

CONCLUSIONS

Coherent mapping with conduction velocity vectors derived from adjacent mapping sites significantly improved the identification of CI sites in scar-related ATs with isthmus-dependent re-entry better than conventional mapping. It may be used in conjunction with conventional mapping strategies to facilitate recognition of slow conduction areas and critical sites that are important targets of ablation.

Long-Term Follow-Up After Ablation of Intra-Atrial Re-Entrant Tachycardia in Patients With Congenital Heart Disease: Types and Predictors of Recurrence

OBJECTIVES

The aim of this study was to analyze the long-term outcomes after intra-atrial re-entrant tachycardia (IART) ablation in congenital heart disease (CHD).

BACKGROUND

IART increases morbidity and mortality in CHD patients. Radiofrequency catheter ablation has evolved into the first-line treatment of this complication.

METHODS

This was a prospective, single-center study of all consecutive CHD patients who underwent first ablation for IART from January 2009 to December 2015 (n = 94, 39.4% female, age 36.55 ± 14.9 years, follow-up 44.45 ± 22.7 months).

RESULTS

During the study period, 130 procedures were performed (n = 94, 1.21 ± 0.41 IART/patient). In the first procedure, 114 IART were ablated (short-term success 74.66%). Forty-nine percent of the patients whose IART was ablated had non-cavotricuspid isthmus (CTI)-related IART (alone or with concomitant CTI IART). After the first ablation, 54.3% maintained sinus rhythm (SR), 23.9% presented with recurrence of the ablated IART, 14.2% developed new IART, and 7.6% presented with atrial fibrillation (AF). After the second radiofrequency catheter ablation, 78.3% were in SR, 8.7% presented with AF, and 23.0% presented with IART (50% new IART). Multivariate predictors of recurrences were non-CTI IART (hazard ratio [HR]: 5.06; 95% confidence interval [CI]: 1.6 to 15.9; p = 0.006), PR interval >200 ms (HR: 4.02; 95% CI: 1.9 to 11.3; p = 0.009), AF induction (HR: 3.11; 95% CI: 1.1 to 9.1; p = 0.04). and previous AF (HR: 3.08; 95% CI: 1.1 to 9.3; p = 0.04). A risk score according multivariate model identified 3 levels of recurrence risk: 5.8%, 20%, and 58.5% (area under the receiver-operating characteristic curve 0.8 ± 0.03; p < 0.0001).

CONCLUSIONS

Ablation of IART in CHD is a challenging procedure, but after ablation in experienced centers, SR can be maintained in 78.3%. Predictors of recurrences are non-CTI-related IART, long PR interval, and previous or induced AF. A risk score based on these factors can be useful for recurrence prediction.

Intra-atrial re-entrant tachycardia in congenital heart disease: types and relation of isthmus to atrial voltage

BACKGROUND

Intra-atrial re-entrant tachycardia (IART) is a frequent and severe complication in patients with congenital heart disease (CHD). Cavotricuspid isthmus (CTI)-related IART is the most frequent mechanism. However, due to fibrosis and surgical scars, non-CTI-related IART is also frequent.

OBJECTIVE

The main objective of this study was to describe the types of IART and circuit locations and to define a cut-off value for unhealthy tissue in the atria.

METHODS AND RESULTS

This observational study included all consecutive patients with CHD who underwent a first ablation procedure for IART from January 2009 to December 2015 (94 patients, 39.4% female, age: 36.55 ± 14.9 years, 40.4% with highly complex cardiac disease). During the study, 114 IARTs were ablated (1.21 ± 0.41 IARTs per patient). Cavotricuspid isthmus-related IART was the only arrhythmia in 51% (n = 48) of patients, non-CTI-related IART was the only mechanism in 27.7% (n = 26), and 21.3% of patients (n = 20) presented both types of IART. In cases of non-CTI-related IART, the most frequent location of IART isthmus was the lateral or posterolateral wall of the venous atria, and a voltage cut-off value for unhealthy tissue in the atria of 0.5 mV identified 95.4% of IART isthmus locations.

CONCLUSION

In our population with a high proportion of complex CHD, CTI-related IART was the most frequent mechanism, although non-CTI-related IART was present in 49% of patients (alone or with concomitant CTI-related IART). A cut-off voltage of 0.5 mV could identify 95.4% of the substrates in non-CTI-related IART.

Anatomical Substrates and Ablation of Reentrant Atrial and Ventricular Tachycardias in Repaired Congenital Heart Disease

Advances in surgical repair techniques for various types of congenital heart disease have improved survival into adulthood over the past decades, thus exposing these patients to a high risk of atrial and ventricular arrhythmias later in life. These arrhythmias arise from complex arrhythmogenic substrates. Substrate formation may depend on both pathological myocardial remodelling and variable anatomical boundaries, determined by the type and timing of prior corrective surgery. Accordingly, arrhythmogenic substrates after repair have changed as a result of evolving surgical techniques. Radiofrequency catheter ablation offers an important therapeutic option but remains challenging due to the variable anatomy, surgically created obstacles and the complex arrhythmogenic substrates. Recent technical developments including electroanatomical mapping and image integration for delineating the anatomy facilitate complex catheter ablation procedures. The purpose of this review is to provide an update on the changing anatomical arrhythmogenic substrates and their potential impact on catheter ablation in patients with repaired congenital heart disease and tachyarrhythmias.

Atrial fibrillation and flutter following coronary artery bypass graft surgery: A retrospective study and review

Introduction and objectives

Atrial fibrillation is a common arrhythmia following coronary artery bypass graft surgery. Its incidence can range from 10 to 60% of patients undergoing coronary artery bypass graft. This rhythm can result in shorter or longer intervals between beats.

Methods

Medical records of 143 patients from the Queen’s Medical Center, Kuakini Medical Center, Saint Francis Medical Center, and Straub Hospital and Clinic, all of which are located in Honolulu, Hawaii were reviewed. An additional 39 records of patients who did not develop these complications were also reviewed as a control group. Patients were selected according to the ICD codes for atrial fibrillation/flutter and coronary artery bypass graft. Both anomalies can lead to increased health care costs, morbidity, and mortality. In this study, possible predisposing factors to these complications were investigated. The time of onset, weight gain, elapsed time, fluid status (in/out), hematocrit, and drug regimens were compared between the two groups.

Results

The differences in weight gain, fluid status, and hematocrit between the groups were not significant. There were a total of 17 different drugs prescribed to the group as a whole but not every patient received the same regimen.

Conclusions

Atrial fibrillation and flutter were found to be more common in males, particularly between the ages of 60 and 69 years. There were no other significant findings.

Arrhythmia diagnosis and management throughout life in congenital heart disease

Arrhythmias, covering bradycardia and tachycardia, occur in association with congenital heart disease (CHD) and as a consequence of surgical repair. Symptomatic bradycardia can occur due to sinus node dysfunction or atrioventricular block secondary to either unrepaired CHD or surgical repair in the area of the conduction system. Tachyarrhythmias are common in repaired CHD due to scar formation, chamber distension or increased chamber pressure, all potentially leading to abnormal automaticity and heterogeneous conduction properties as a substrate for re-entry. Atrial arrhythmias occur more frequently, but ventricular tachyarrhythmias may be associated with an increased risk of sudden cardiac death, notably in patients with repaired tetralogy of Fallot or aortic stenosis. Defibrillator implantation provides life-saving electrical therapy for hemodynamically unstable arrhythmias. Ablation procedures with 3D electroanatomic mapping technology offer a viable alternative to pharmacologic or device therapy. Advances in electrophysiology have allowed for successful management of arrhythmias in patients with congenital heart disease.

Very long-term outcome of catheter ablation of post-incisional atrial tachycardia: Role of incisional and non-incisional scar

BACKGROUND

The arrhythmogenicity of right atrial (RA) incisional scar after cardiac surgery could result in atrial tachycardia (AT). Radiofrequency catheter ablation is effective in the treatment of such tachycardia. However, data regarding long-term outcomes are limited.

METHODS AND RESULTS

A total of 105 patients with prior RA incision who underwent radiofrequency catheter ablation of AT were included. In the first procedure, electroanatomic mapping (EAM) revealed a total of 139 ATs in 105 patients, including 88 cavotricuspid isthmus dependent atrial flutters (IDAFs), 5 mitral annulus reentrant tachycardias (MARTs), 44 intra-atrial reentrant tachycardias (IARTs) and 2 focal ATs (FATs). AT was successfully eliminated in 101 (96.1%) patients. During a mean follow-up period of 90 ± 36 months, recurrent AT was observed in 23 patients and 21 underwent a second ablation. A total of 23 ATs were identified in redo procedures including 4 IDAFs, 2 MARTs, 12 IARTs and 5 FATs. The time to recurrence was significantly different among various AT types. Acute success was achieved in 20 of 23 redo procedures. Taking a total of 21 patients presenting atrial fibrillation during follow-up into account, 85 patients (81.9%) were in sinus rhythm. No complications except for a case of RA compartmentation occurred.

CONCLUSION

RA incisional scar played an essential role in promoting both IDAF and IART, while non-incisional scar contributed to a substantial rate of late recurrent AT in forms of both macroreentry and small reentry. Catheter ablation using EAM system resulted in a high success rate during long-term follow-up.

Long-Term Outcome After Ablation of Right Atrial Tachyarrhythmias After the Surgical Repair of Congenital and Acquired Heart Disease

Atrial myopathy, atriotomies, and fibrotic scars are the pathophysiological substrate of lines of conduction block, promoting atrial macroreentry. The aim of this study was to determine the acute and long-term outcome of radiofrequency catheter ablation (RFCA) for right atrial tachyarrhythmia (AT) in adults after cardiac surgery for congenital heart disease (CHD) and acquired heart disease (AHD) and predictors of these outcomes. Clinical records of adults after surgery for heart disease undergoing RFCA of right-sided AT were analyzed retrospectively. Multivariate analyses identified clinical and procedural factors predicting acute and long-term outcomes. A total of 372 patients (69% men; age 61 ± 15 years) after surgical repair of CHD (n = 111) or AHD (n = 261) were studied. Cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) was observed in 300 patients and non-CTI-AFL in 72 patients. Ablation was successful in 349 cases (94%). During a mean follow-up of 51 ± 30 months, recurrences were observed in 24.5% of patients. Multivariate analysis showed that non-CTI-AFL (hazard ratio [HR] 1.78, 95% confidence interval [CI] 1.1 to 2.9) and CHD (HR 1.75, 95% CI 1.07 to 2.9) were independent predictors of long-term recurrences. Multivariate analysis showed that female gender (HR 2.29, 95% CI 1.6 to 3.3), surgery for AHD (HR 95% 2.31, 95% CI 1.5 to 3.7), and left atrial dilatation (HR 2.1, 95% CI 1.3 to 3.2) were independent predictors of long-term atrial fibrillation. In conclusion, RFCA of right-sided AT after cardiac surgery is associated with high acute success rates and significant long-term recurrences. Non-CTI-dependent AFL and surgery for CHD are at higher risk of recurrence. Atrial fibrillation is common during follow-up, particularly in patients with AHD and enlarged left atrium.

Postoperative arrhythmias after cardiac surgery: incidence, risk factors, and therapeutic management

Arrhythmias are a known complication after cardiac surgery and represent a major cause of morbidity, increased length of hospital stay, and economic costs. However, little is known about incidence, risk factors, and treatment of early postoperative arrhythmias. Both tachyarrhythmias and bradyarrhythmias can present in the postoperative period. In this setting, atrial fibrillation is the most common heart rhythm disorder. Postoperative atrial fibrillation is often self-limiting, but it may require anticoagulation therapy and either a rate or rhythm control strategy. However, ventricular arrhythmias and conduction disturbances can also occur. Sustained ventricular arrhythmias in the recovery period after cardiac surgery may warrant acute treatment and long-term preventive strategy in the absence of reversible causes. Transient bradyarrhythmias may be managed with temporary pacing wires placed at surgery, but significant and persistent atrioventricular block or sinus node dysfunction can occur with the need for permanent pacing. We provide a complete and updated review about mechanisms, risk factors, and treatment strategies for the main postoperative arrhythmias.

Simplified progressive approach for the ablation of scar related atrial macroreentrant tachycardias

INTRODUCTION

Radiofrequency ablation of scar related right atrial flutter is challenging. Long procedures, prolonged fluoroscopic times and high percentages of recurrences are of concern. We present a simple and progressive approach based on a single electroanatomic map of the right atrium.

METHODS

Twenty-two consecutive patients with atrial flutter and history of cardiac surgery were included. An electrophysiologic study was performed to define localization (left or right) and cavo-tricuspid isthmus participation using entrainment mapping. After a critical isthmus was localized, ablation was performed with an external irrigated tip catheter with a power limit of 30 W. Potential ablation sites were confirmed by entrainment.

RESULTS

The predominant cardiopathy was atrial septal defect. All arrhythmias were localized in the right atrium; mean cycle length of the clinical flutter was 274 ± 31 ms. Only 40% had cavo-tricuspid isthmus participation. None of the patients with successful ablation had recurrences after 13 ± 9.4 months of follow-up.

CONCLUSIONS

A progressive approach with only one activation/voltage CARTO(®) map of the atrium and ablation of all potential circuits is a highly effective method for ablating scar related macroreentrant atrial arrhythmias.

Surgical technique and the mechanism of atrial tachycardia late after open heart surgery

INTRODUCTION

Diverse atrial tachycardias (ATs) can develop after open heart surgery. The aim of our study was to examine the determinants of the mechanism of postoperative AT.

METHODS AND RESULTS

One hundred patients with AT occurring at least 3 months after open heart surgery were studied. Patients were grouped according to the atrial incision applied at the time of surgery. During 127 electrophysiology procedures, 151 ATs were studied. Eighty-eight patients had cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), 49 patients had at least one non-CTI-dependent AFL and 11 patients had focal AT. While CTI-dependent AFL was equally prevalent across groups, the finding of a non-CTI-dependent AFL was progressively more common as more extensive atriotomy was applied (p < 0.001). Among patients who had right atrial (RA) operations, RA incisional tachycardia was the most common non-CTI-dependent circuit, while the finding of perimitral or left atrial (LA) roof-dependent AFL was associated with LA atriotomy (p = 0.002 and p = 0.041, respectively). After adjustment for possible confounders, surgical group remained independent predictor of non-CTI-dependent AFLs (p < 0.001). No predictor was identified for focal AT, which originated from typical predilection sites and in 36% from the vicinity of surgical scar. Radiofrequency ablation was highly effective for all ATs, but the recurrence rate of AFL and atrial fibrillation was high at 22% and 27%, respectively, during 19 ± 15 months of follow-up.

CONCLUSION

While CTI-dependent AFL is the most common AT late after open heart surgery, atypical AFL becomes progressively more common with more extensive atriotomy. Right atrial incisional tachycardia is the dominant non-CTI-dependent AFL after opening of the RA, while a perimitral or roof-dependent LA circuit can be expected after LA operations.

Higher rate of recurrent atrial flutter and atrial fibrillation following atrial flutter ablation after cardiac surgery

INTRODUCTION

Atrial flutter (AFL) is common after cardiac surgery. However, the types of post-cardiac surgery AFL, its response to catheter-based radiofrequency ablation, and its relationship to atrial fibrillation (AF) are unknown.

METHODS AND RESULTS

We retrospectively studied all patients who underwent mapping and ablation for AFL after cardiac surgery from January 1990 to July 2004. One hundred randomly selected patients without prior cardiac surgery (PCS) who underwent mapping and ablation of AFL served as the control population. A total of 236 patients formed the study population (mean age 62 + 13 years, 22% female) and 100 patients formed the control population (mean age 60 + 13 years, 25% female). The majority of patients without PCS had cavo-tricuspid isthmus (CTI)-dependent AFL when compared to patients with PCS (93% vs 72%, respectively, P < 0.0001). In contrast, scar-related AFL was more common in patients with PCS as compared to patients without PCS (22% vs 3%, P < 0.0001). Predictors of scar related AFL in multivariable regression analysis included PCS and left-sided AFL. Acute success rates and complications were similar between the groups. When compared to patients with AFL ablation without PCS, those that had AFL after PCS had higher rates of recurrence of both AFL (1% vs 12%, P < 0.0001; mean time to recurrence 1.85 years) and AF (16% vs 28%, P = 0.02; mean time to recurrence 2.67 years).

CONCLUSION

Despite ablation of AFL, patients with PCS have a higher rate of AFL and AF when compared to patients without PCS who underwent ablation of atrial flutter during long-term follow-up.

Scar-related right atrial macroreentrant tachycardia in patients without prior atrial surgery: Electroanatomic characterization and ablation outcome

BACKGROUND

Few descriptions of right atrial macroreentrant atrial tachycardia involving regions of spontaneous "scar" have been reported.

OBJECTIVES

We describe the electrocardiographic, electrophysiologic, and electroanatomic characteristics of an unusual RA macroreentrant atrial tachycardia in eight patients with spontaneous RA scarring.

METHODS

Eight of 286 patients with macroreentrant atrial tachycardia treated with radiofrequency ablation had RA spontaneous scarring and underwent conventional electrophysiologic studies and electroanatomic mapping.

RESULTS

Eight patients (age 53 +/- 12 years) had symptoms for 58 +/- 62 months and had not responded to 2.5 +/- 0.8 antiarrhythmic drugs and 1.0 +/- 0.9 DC cardioversions. All patients had overall normal systolic function, and five had mild atrial enlargement. Scarring was present in the posterolateral wall extending from the crista terminalis toward the tricuspid annulus. The proportion of RA classified as scar was 31% +/- 14% (range 11%-46%). Stable circuits were around scar in seven patients, through a "channel" within the scar in four, and typical cavotricuspid isthmus-dependent flutter in five. Radiofrequency ablation sites included the cavotricuspid isthmus; between the inferior vena cava, superior vena cava, or crista terminalis and scar; or a channel in the scar. ECG morphology of the RA free wall tachycardias varied, depending upon whether cavotricuspid isthmus block was present. Radiofrequency ablation of all inducible circuits was successful in six patients and of all clinical circuits in seven. At follow-up of 20 +/- 13 months, six patients are free from macroreentrant atrial tachycardia, one has infrequent nonsustained macroreentrant atrial tachycardia, and one is controlled with previously ineffective medication. Five had sinus node dysfunction requiring permanent pacemaker implant.

CONCLUSIONS

Extensive spontaneous scarring of the RA is an unusual cause of macroreentrant atrial tachycardias, both cavotricuspid isthmus dependent and independent in the same patient. Radiofrequency ablation is an effective treatment. Sinus node dysfunction requiring permanent pacemaker is common. The cause is unknown.

The need for atrial flutter ablation following pulmonary vein antrum isolation in patients with and without previous cardiac surgery

OBJECTIVES

The aim of this study was to assess the incidence of atrial flutter (AFL) after pulmonary vein antrum isolation (PVAI) in patients with previous cardiac surgery (PCS) in comparison to patients without PCS and to assess the need for AFL ablation in both groups.

BACKGROUND

Atrial fibrillation (AF) and AFL often co-exist. Pulmonary vein antrum isolation may be sufficient to control both arrhythmias. However, in patients with PCS, atrial incisions, cannulations, and scar areas may cause AFL recurrence despite elimination of pulmonary vein triggers.

METHODS

Data from 1,345 patients who had PVAI were analyzed. Patients with a history of AFL ablation and patients who had concomitant AFL ablation during PVAI were excluded from analysis. Sixty-three patients constituted the PCS group (Group 1, age 57 +/- 13 years, 12 female) and 1,062 patients constituted the non-PCS group (Group 2, age 55 +/- 12 years, 212 female). Patients in Group 1 had larger left atria, higher incidence of AFL pre-PVAI, and lower ejection fraction.

RESULTS

There was no significant difference in post-PVAI AF recurrence between Groups 1 and 2, but AFL incidence after PVAI was higher in Group 1 (33% vs. 4%, p < 0.0001). Ablation of AFL in Group 1 patients resulted in an 86% acute success rate and 11% recurrence over a mean follow-up of 357 +/- 201 days.

CONCLUSIONS

In patients with PCS, post-PVAI AF recurrence is similar to patients without PCS. However, history of PCS is associated with a higher recurrence of AFL after PVAI. In a significant number of patients with PCS, AFL ablation is required to achieve a cure.