Intra-atrial Re-entrant Tachycardia Ablation Research Articles

Catheter ablation of atrial fibrillation using 2nd-generation cryoballoon in congenital heart disease patients — significance of RF ablation of additional atrial macro-reentrant tachycardia

BackgroundPrevalence of atrial fibrillation (AF) is increasing in adult patients with congenital heart disease (CHD). Experience using the cryoballoon to achieve pulmonary vein isolation (PVI) in adult CHD patients is limited. The aim of the present study was to assess the value of PVI by cryoballoon in adult CHD patients and to evaluate the significance of additional radiofrequency (RF) ablation of atrial tachycardia (AT).Patients and methodsProspective data analysis; all patients with CHD and AF and PVI using the cryoballoon from January 2017 through November 2021 were included.ResultsNineteen patients with various types of CHD were included. Median age was 58 (IQR 47–63) years. A total of 12/19 (63%) patients had had RF ablation of right atrial AT before. Median procedure duration was 225 (IQR 196–261) min. Median fluoroscopy time was 12.3 (IQR 5.2–19.5) min and median freeze time was 32 (IQR 28–36.3) min. Procedural success was achieved in all patients. Additional RF catheter ablation of intraatrial reentrant tachycardia within the left atrium was performed in 3/19 (16%) subjects and within the right atrium in 6/19 (32%) patients. Median follow-up was 26 (IQR 9–49) months. Excluding a 90-day blanking period, recurrence of AF was observed in 6/19 subjects (32%). After one redo procedure deploying RF energy only, 84% of all patients remained free from recurrence. Phrenic nerve palsy was observed in 1 subject.ConclusionResults after PVI using the cryoballoon plus additional RF ablation of AT were promising (84% success including one redo procedure). Success of AF ablation was unsatisfactory in all patients who had no additional AT ablation. Ablation of any AT in these patients should therefore be considered in addition to PVI.

Catheter ablation of intra-atrial re-entrant tachycardia in adult congenital heart disease: Value of final programmed atrial stimulation

While outcomes of intra-atrial re-entrant tachycardia (IART) catheter ablation have considerably improved in adult congenital heart disease (ACHD), recurrences remain common with different circuits frequently encountered. We aimed to assess the value of programmed atrial stimulation after successful clinical IART catheter ablation in ACHD patients. Retrospective study including all ACHD patients undergoing IART catheter ablation in a large tertiary centre. After successful catheter ablation of the clinical arrhythmia, survival free from arrhythmia recurrence was analysed according to whether all inducible IART were targeted. From 2004 to 2020, 238 IART catheter ablations were performed (mean age 44.1 ± 15.0 years, 61.3% males). Acute procedural success of clinical arrhythmia was achieved in 208 (87.4%) procedures. Among 122 (58.7%) patients with programmed atrial stimulation, at least one other IART was induced in 61 (50%) patients. All inducible IART were ablated in 54 (88.5%) patients whereas 7 (11.5%) patients had at least one non-targeted inducible IART. Patients with non-targeted inducible IART had a higher risk of atrial arrhythmia recurrence compared to inducible patients with ablation of all IART (HR = 5.7, 95% CI: 1.7–18.4), with 12-month survival rates of 22.9% and 77.7%, respectively. Inducible patients with successful ablation of all IART had a similar risk of atrial arrhythmia recurrence compared to non-inducible patients (HR = 0.6, 95% CI: 0.3–1.3) ( Fig. 1 ). Our findings suggest that final programmed atrial stimulation is associated with improved outcomes in ACHD patients referred for IART ablation when all inducible IART are targeted and successfully ablated.

Extensive scar modification for the treatment of intra-atrial re-entrant tachycardia in patients after congenital heart surgery.

Catheter ablation is an important therapeutic option for atrial tachycardias in patients with CHD. As a result of extensive scarring and surgical repair, multiple intra-atrial re-entrant tachycardia circuits develop and serve as a substrate for arrhythmias. The best ablation approach for patients with multiple intra-atrial re-entrant tachycardias has not been investigated. Here, we compared substrate-based ablation using extensive scar modification to conventional ablation. The present study included patients with surgically corrected CHD that underwent intra-atrial re-entrant tachycardia ablation. Extensive scar modification was defined as substrate ablation based on a dense voltage map, aimed to eliminate all potentials in the scar region. The control group had activation mapping-based ablation. A clinical composite endpoint was assessed. Points were given for type, number, and treatment of intra-atrial re-entrant tachycardia recurrence. In 40 patients, 63 (extensive scar modification 13) procedures were performed. Acute procedural success was achieved in 78%. Procedural duration was similar in both groups. Forty-nine percent had a recurrence within 1 year. During a 5-year follow-up (2.5-7.5 years), 46% required repeat catheter ablation. Compared to baseline, clinical composite endpoint significantly decreased by 46% after 12 months (p = 0.001). Acute procedural success, procedural parameters, recurrence and repeat ablation were similar between extensive scar modification and activation mapping-based ablation. Catheter ablation using extensive scar modification for intra-atrial re-entrant tachycardias occurring after surgically corrected CHD illustrated similar short- and long-term outcomes and procedural efficiency compared to catheter ablation using activation mapping-based ablation. The choice of ablation approach for multiple intra-atrial re-entrant tachycardia should remain at the discretion of the operator.

Mechanisms of Intra-Atrial Re-Entrant Tachycardias in Congenital Heart Disease: Types and Predictors

Intra-atrial re-entrant tachycardia (IART) is a 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 frequent. The main objective of this study was to describe the types of IART, circuit locations, and to analyze predictors of CTI versus non-CTI-related IART. This is an observational study that includes all consecutive patients with CHD who underwent a first IART ablation in a single referral tertiary hospital from January 2009 to December 2015 (94 patients; 39.4% women; 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). CTI-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 the two types of IART. Severe dilation of the systemic ventricle, absence of severe dilation of the venous atrium, highly complex cardiac defects, and nontypical electrocardiography (ECG) were related to non-CTI-related IART in univariate analysis. In multivariate analysis, nontypical ECG (odds ratio 3.64; 1.01 to 4.9; p = 0.049) and grade III CHD complexity (odds ratio 9.43; 1.44 to 11.7; p = 0.001) were predictors of non-CTI-related IART. In 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% (alone or with concomitant CTI-related IART). High-grade CHD complexity and nontypical ECG were strongly related to non-CTI IART.

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

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). IART increases morbidity and mortality in CHD patients. Radiofrequency catheter ablation has evolved into the first-line treatment of this complication. 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). 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). 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. Arisk score based on these factors can be useful for recurrence prediction.

Intra-atrial re-entrant tachycardia in patients with congenital heart disease: factors associated with disease severity.

Intra-atrial re-entrant tachycardia (IART) is a common complication in patients with congenital heart disease (CHD) and is related to increased morbidity and mortality. Few reports have been published about factors associated to IART severity. The aim of this study is to analyse factors associated to severe clinical presentation of IART. Observational study of all consecutive CHD patients who underwent a first IART ablation from January 2009 to December 2015 (94 patients, 39.4% female, and age: 36.55 ± 14.9 years). Severe clinical presentation was defined as heart failure, syncope, shock, electromechanical dissociation (EMD), or aborted sudden death. The majority of patients had moderately or highly complex cardiac defect (90.4%). Types of IART included cavotricuspid isthmus(CTI) dependent in 51% (48), non-CTI-related in 22.3% (20), and both types in 27.7% (26). In 38 patients (40.4%), a severe event occurred and in 16 (17%), the symptoms included shock, syncope, sudden death, or EMD. In 21 (22.3%), severe symptoms were the first manifestation of IART. In multivariate analysis, transposition of the great arteries (TGA) with right systemic ventricle (OR 5.32, 95% C.I. 1.6-7.02, P = 0.0005) and severe dilation of the venous atrium (VsA) (OR 4.17; 95% CI 1.4-8.12, P = 0.0009) were factors independently associated with severity. In our series of 94 CHD patients with a high proportion of moderately to highly complex cardiac defects, severe consequences of IART were frequent. Transposition of the great arteries with systemic right ventricle and severe dilation of VsA were independently associated to severity. Early invasive procedures should be considered for these high-risk patients.

Recurrences at long-term follow-up after flutter ablation in patients with congenital heart disease: types and predictors

Ablation of intra-atrial reentrant tachycardia (IART), either isthmus-dependent (CTI-F) or scar-related flutter (SC-F) can be a challenging procedure in patients with congenital heart disease (CHD). Few data is published about long-term follow-up (FU) and predictors of recurrence. We describe ablation success, type and predictors of recurrences in a tertiary care hospital. Methods: Between 1999 an 2012 we performed 81 flutter ablation procedures (RF) in 58 patients (age 34,1±15,5 years, mean 1,39 procedures per patient, flutter type: 50% CTI-F, 20.7% SC-F and 29,3% CTI-F and SC-F) with surgically repaired CHD. The most frequent CHD was transposition of great arteries (TGA, 17p, 29%) with atrial switch procedure, repaired atrial septal defect (11pt.,19%) and Tetralogy of Fallot (11pt., 19%). Cardiac history (specially arrhythmia burden), imaging and RF procedure details were analysed. Results: After a FU of more than 3 years (38.09±34,4 months), 76.4% of the patients were in sinus rhythm (23 pts. with more than one procedure). The most frequent arrhythmia in the recurrences was a flutter different than the one that was ablated (44%), followed by the same kind of flutter (40%) and atrial fibrillation (AFib, 16%). Predictors of any kind of arrhythmia recurrence at the end of FU were: acute RF failure (45.5% vs. 15%, p=0.08), QRS width >120 ms (21.2 vs. 0%, p=0.05), number of arrhythmia episodes before RF (1.7±1.38 vs. 0.82±1.05 months, p=0.019) and time between the first arrhythmia and RF procedure (RF Delay) (80.41±106 vs. 25.69±42 months, p=0.009). Previous Afib (80 vs. 42.2%, p=0.04) and SC-F (76.5 vs. 36.8%, p=0.009) were specific predictors of recurrence after a single procedure but were not related with overall recurrence at the end of FU. Predictors of recurrence of the same arrhythmia after a single procedure were: previous Afib (40 vs. 15.5%, p=0.09), acute RF failure (50 vs. 13.5%, p=0.021) and RF delay (97.8±115.7 months vs. 22.5±31.6 months, p=0.005). None of the parameters related with echocardiogram neither with the RF procedure were predictors of recurrence. Conclusions: Despite the complexity and cardiac disease progression, after a flutter ablation procedure a high proportion of CHD patients maintain sinus rhythm after long-term FU. Parameters related not only with acute success but also with arrhythmia burden and with not aggressive treatment at the beginning of arrhythmia appearance were predictors of recurrence during FU. Our data suggests that an early invasive arrhythmia treatment in these patients could decrease the recurrences, but more studies are needed in this field.

Percutaneous right ventricular support during catheter ablation of intra-atrial reentrant tachycardia in an adult with a mustard baffle—A novel use of the Impella device

Late sequelea following a Mustard operation for transposition of the great arteries (TGA) include atrial arrhythmias and dysfunction of the systemic right ventricle. Catheter mapping and ablation of atrial tachycardia in the setting of significant right ventricular dysfunction may result in hemodynamic compromise. We report the novel use of the Impella percutaneous microaxial flow pump to support cardiac output in an adult patient with a Mustard operation for TGA who experienced a cardiac arrest during a prior ablation attempt. The Impella device was placed via a retrograde approach across the aortic valve into the right ventricle providing hemodynamic stability for successful mapping and ablation of intra-atrial reentrant tachycardia.

Irrigated-tip catheter ablation of intraatrial reentrant tachycardia in patients late after surgery of congenital heart disease

The aim of this study was to evaluate irrigated-tip catheter for ablation of intraatrial reentrant tachycardias late after surgical repair of congenital heart disease. In congenital heart disease patients, the right atrium can be markedly enlarged with areas of low blood flow. Radiofrequency (RF) lesion creation may be hampered by insufficient electrode cooling at sites with low blood flow. Thirty-six consecutive patients with intraatrial reentrant tachycardia refractory to antiarrhythmic therapy from two centers were included in the study. Entrainment pacing and electroanatomic mapping (CARTO) were used to delineate reentrant circuits and critical isthmus sites. RF ablation was performed using an irrigated-tip catheter (Navistar Thermocool). Fifty-two intraatrial reentrant tachycardia circuits were identified, and 48 were targeted with RF ablation. RF ablation was performed using a mean of 13 +/- 11 irrigated RF applications per tachycardia isthmus with a mean power of 36 +/- 8 W. In a historical control group of congenital heart disease patients managed with conventional catheter ablation, the number of lesions per isthmus was higher (23 +/- 11) and mean power was lower (27 +/- 14 W). Acute success was achieved in 45 intraatrial reentrant tachycardias (94% of targeted tachycardias and 87% of all tachycardias). After a mean follow-up of 17 +/- 7 months, 33 (92%) of 36 patients were free of recurrence. Five patients (14%) developed paroxysmal atrial fibrillation. The combination of modern techniques including electroanatomic mapping and catheter irrigation allows safe and highly effective ablation of intraatrial reentrant tachycardia in patients with surgically repaired congenital heart disease.

A19-1 Electroanatomic mapping and irrigated tip catheter ablation of intra-atrial re-entrant tachycardia in patients after surgery of congenital heart disease

A19-1 Electroanatomic mapping and irrigated tip catheter ablation of intra-atrial re-entrant tachycardia in patients after surgery of congenital heart disease

Influence of patient factors and ablative technologies on outcomes of radiofrequency ablation of intra-atrial re-entrant tachycardia in patients with congenital heart disease

ObjectivesThe goal of this study was to identify factors associated with radiofrequency catheter ablation (RFCA) outcomes of intra-atrial re-entrant tachycardia (IART). BackgroundRadiofrequency catheter ablation of IART is difficult. The influence of patient and procedural factors and novel technologies on outcomes is unknown. MethodsAcute and chronic RFCA outcomes were studied in patients with congenital heart disease and IART. Clinical status was measured using a multiaxis severity score. Multivariate analyses identified associations of clinical, procedural and technological factors with outcomes. ResultsA total of 177 procedures were performed in 134 patients; 139 procedures (79%) resulted in RFCA of ≥1 IART circuit and 117 (66%) in RFCA of all targeted circuits. Multivariate analysis associated acute success with irrigated ablation and absence of atrial fibrillation. Twenty-two complications were noted, nine related to vascular access. Electroanatomic mapping failed to decrease procedure or fluoroscopy time. Improvement in clinical status occurred in most patients (severity score preablation: 6.2 ± 1.6, postablation: 3.0 ± 2.3, p < 0.0001). At mean follow-up of 25 ± 11 months, 42% of patients had IART recurrence and 28% required cardioversion. Six deaths occurred (1.8%/patient-year), and two patients underwent transplant. Chronic outcomes were associated with higher right atrial saturations, use of electroanatomic mapping, fewer IART circuits encountered and acute procedural success. ConclusionsImprovement of acute RFCA outcomes was contemporaneous with introduction of novel technologies. Intra-atrial re-entrant tachycardia recurrence was common, and no effect on mortality was discerned, but most patients had effective palliation of symptoms. Chronic outcome predictors included the underlying disease severity, application of novel technologies and successful ablation of all targeted arrhythmia circuits.

Location of acutely successful radiofrequency catheter ablation of intraatrial reentrant tachycardia in patients with congenital heart disease

Intraatrial reentrant tachycardia (IART) is common after surgery for congenital heart disease (CHD). Radiofrequency (RF) catheter ablation of IART targets anatomic areas critical to the maintenance of the arrhythmia circuit, areas that have not been well defined in this patient population. The purpose of this study was to determine the anatomic areas critical to IART circuits, defined by activation mapping and confirmed by an acutely successful RF ablation at the site. A total of 110 RF ablation procedures in 88 patients (median age 23.4 years, range 0.1 to 62.7) with CHD were reviewed. Patients were grouped according to surgical intervention: Mustard/Senning (n = 15), other biventricular repaired CHD (n = 24), Fontan (n = 43), and palliated CHD (n = 6). In first-time ablation procedures, ≥1 IART circuits were acutely terminated in 80% of Mustard/Senning, 71% of repaired CHD, and 72% of Fontan (p = NS). The palliated CHD group underwent 1 of 6 successful procedures (17%), and this patient was excluded. The locations of acutely successful RF applications in Mustard/Senning patients (n = 14 sites) were at the tricuspid valve isthmus (57%) and at the lateral right atrial wall (43%). In patients with repaired CHD (n = 18 sites), successful RF sites were at the isthmus (67%) and the lateral (22%) and anterior (11%) right atria. In the Fontan group (n = 40 sites), successful RF sites included the lateral right atrial wall (53%), the anterior right atrium (25%), the isthmus area (15%), and the atrial septum (7%). Location of success was statistically different for the Fontan group (p = .002). In conclusion, the tricuspid valve isthmus is a critical area for ablation of IART during the Mustard/Senning procedure and in patients with repaired CHD. IART circuits in Fontan patients are anatomically distinct, with the lateral right atrial wall being the more common area for successful RF applications. This information may guide RF and/or surgical ablation procedures in patients with CHD and IART.

Mapping and radiofrequency ablation of intraatrial reentrant tachycardia after the senning or mustard procedure for transposition of the great arteries

The Senning and Mustard procedures are offen associated with the development of atrial tachyarrhythmias, which may be a cause of sudden death. We hypothesized that atrial surgery creates barriers to impulse propagation, establishing potential routes for atrial reentry, and that mapping combined with knowledge of the surgical anatomy could identify zones that are critical to the tachycardia to be targeted for radiofrequency catheter ablation. Patients underwent mapping to identify early sites of atrial activation that were related to anatomic or surgically created obstacles, with confirmation by pacing to demonstrate concealed entrainment. Radiofrequency lesions were placed to connect these obstacles, while observing for tachycardia termination. Thirteen tachycardias were attempted in 10 patients, 10 successfully. Three patients had 2 distinct tachycardias. Successful sites were in right atrial tissue, although in many, a retrograde approach to the pulmonary venous atrium was necessary. Ablation of the clinically documented tachycardia was successful in 9 of 10 patients. The most common successful site was the region of the coronary sinus mouth, approached antegrade or retrograde. Ablation of intraatrial reentrant tachycardias after the Senning or Mustard procedure is feasible using concealed entrainment mapping techniques, but requires a detailed knowledge of the individual surgical anatomy and the ability to approach the pulmonary venous atrium. Radiofrequency ablation offers significant advantages over other management modalities in this patient group.

Ablation of 'incisional' reentrant atrial tachycardia complicating surgery for congenital heart disease. Use of entrainment to define a critical isthmus of conduction.

Intra-atrial reentrant tachycardia occurs frequently after surgery for congenital heart disease and is difficult to treat. We tested the hypotheses that intra-atrial reentrant tachycardia in patients who had undergone prior reparative surgery for congenital heart disease could be successfully ablated by targeting a protected isthmus of conduction bounded by natural and surgically created barriers and that entrainment techniques could be used to identify these zones. Eighteen consecutive patients with 26 intra-atrial reentrant tachycardias complicating surgery for congenital heart disease (9 atrial septal defect repair, 4 Fontan, 2 Mustard, 2 Senning, and 1 Rastelli procedure) underwent electrophysiological study and ablation attempts. Mapping of activation was facilitated by the deployment of catheters with multiple electrodes. Sites for ablation were sought that demonstrated entrainment with concealed fusion and at which the postpacing interval minus the tachycardia cycle length and the stimulus to P wave minus the activation time were < 30 ms. These sites were considered to be within a narrow isthmus critical to the tachycardia mechanism. Anatomic barriers bordering the critical isthmus of conduction were identified on anatomic grounds, by the presence of areas of electrical silence or by the demonstration of split potentials signifying a line of block. Success was achieved in 15 patients with 21 arrhythmias. The median number of radiofrequency applications was 5. There was a wide range of activation times at successful sites (-30 to -250 ms). At a mean duration of follow-up of 17 +/- 8 months, 11 patients were asymptomatic and 9 did not require antiarrhythmia therapy. Successful ablation of intra-atrial reentrant tachycardia complicating surgery for congenital heart disease may be achieved by creation of an ablative lesion in a critical isthmus of conduction bounded by anatomic barriers. This isthmus may be identified by the presence of entrainment with concealed fusion and an analysis of the relationship between the postpacing interval and the tachycardia cycle length and between the activation time and the stimulus time. Because this isthmus is invariably confined on at least one aspect by a surgical repair site that is of central importance to the tachycardia mechanism, we suggest that this type of arrhythmia be given the descriptive designation of "incisional reentry."

Radiofrequency ablation of intra-atrial reentrant tachycardia after surgical palliation of congenital heart disease.

Intra-atrial reentrant tachycardia (IART), also called atrial flutter, is a common and potentially lethal complication of surgical correction of congenital heart disease. Medical management of IART is often problematic, which prompts an investigation of the utility of radiofrequency (RF) ablation for management of these arrhythmias. Ten consecutive patients referred for treatment of recurrent IART after surgery for congenital heart disease were studied. Median age was 18.4 years, and median duration of arrhythmia was 6.4 years; a median of three antiarrhythmic drugs had been tried. Surgical procedures used were Fontan (6), Mustard/Senning (2), and biventricular repair (2). Intracardiac electrophysiological study demonstrated 30 distinct IART circuits, defined by activation sequence and cycle length. Mean IART cycle length was 323 +/- 114 ms. Cycle length was significantly longer in IART circuits that were successfully ablated compared with those that were not (381 versus 248 ms, P < .001). RF ablation was attempted in 22 of these circuits. Ablation sites were targeted to presumed exit points from zones of slow conduction by electrophysiological criteria. Sites chosen in this manner clustered in four distinct areas of the right atrium. Of 22 IART circuit ablations attempted, 17 (77%) resulted in acute termination of the tachycardia. In 8 of 10 patients in whom at least one IART circuit was successfully ablated, 4 are free of clinical tachycardia and 3 are improved over short-term follow-up. No complications were encountered. Multiple IART circuits may be present in patients after surgery for congenital heart defects. Activation sequences observed were diverse and different from those observed in atrial flutter in patients with normal anatomy. Interruption of IART circuits by RF ablation is feasible using mapping techniques aimed at identifying an exit point from a zone of slow conduction. Short-term follow-up suggests that RF ablation may be a useful adjunct in management of IART in these difficult patients.

Radiofrequency catheter ablation of supraventricular arrhythmias in patients with congenital heart disease: Results and technical considerations

Objectives. The aim of this study was to report the results and techniques of radiofrequency ablation for treatment of supraventricular arrhythmias in patients with congenital structural heart disease.Background. The management of patients with congenital and other structural heart disease may be complicated by serious arrhythmias due to Wolff-Parkinson-White syndrome or by atrial arrhythmias after cardiac surgery. Ablation techniques using radiofrequcncy current are revolutionizing the management of arrhythmias, but reports have included few with structural heart disease.Methods. Fifteen patients with significant heart disease underwent radiofrequency ablation: 11 with Wolff-Parkinson-White syndrome and 4 with intraatrial reentrant tachycardia after atrial surgery. Seven had Ebstein's anomaly, complex in two, and the rest had other defects. Coexistence of structural defects introduced significant technical difficulties to radiofrequency ablation in patients with the Wolff-Parkinson-White syndrome and was accomplished by adaptation of current techniques. Ablation of intraatrial reentrant tachycardia was performed by finding early atrial activation sites with electrogram fractionation for radiofrequency application.Results. Radiofrequency ablation was initially successful in 14 of 15 patients, with cure in 10 and clinical improvement in 14. Two patients subsequently underwent cardiac surgery without perioperative arrhythmias.Conclusions. Radiofrequency ablation in patients with congenital heart disease and arrhythmias is both safe and effective and may be the preferred approach to treatment in some patients. In patients who are to undergo surgical correction or palliation, preoperative radiofrequency ablation of the tachycardia substrate is effective and may be preferred to operative accessory pathway division. The ablation of intraatrial reentrant tachycardia shows promise in the management of patients who have undergone extensive atrial surgery, and it may eventually become the preferred approach, particularly when there are contraindications to the use of antiarrhythmic agents.

Radiofrequency catheter ablation of sustained intra-atrial reentrant tachycardia in adult patients. Identification of electrophysiological characteristics and endocardial mapping techniques.

Information about electrophysiological characteristics and radiofrequency ablation of intra-atrial reentrant tachycardia has not been reported before. We proposed that induction and termination of intra-atrial reentrant tachycardia by atrial extrastimuli or rapid atrial pacing and resetting the response pattern by atrial extrastimuli during intra-atrial reentrant tachycardia could ensure the mechanism of reentry and that the earliest site of endocardial activation and concealed entrainment pace mapping with the shortest stimulus-P wave interval could localize a critical area responsible for intra-atrial reentrant tachycardia and radiofrequency ablation. Seven patients with refractory atrial tachycardia were referred for electrophysiological studies and radiofrequency ablation. Electrophysiological studies and endocardial mapping found (1) 10 atrial foci with atrial tachycardia cycle length of 406 +/- 41 ms; (2) atrial tachycardia had induction and termination by atrial extrastimuli (8 of 10) or rapid atrial pacing (10 of 10); (3) atrial tachycardia had increasing (6 of 10) or mixed (flat and increasing, 4 of 10) resetting response pattern, with resetting interval of 57 +/- 13 ms (14 +/- 4% of atrial tachycardia cycle length); (4) exit sites of atrial tachycardia in right atrial free wall (6 of 10), right atrial septum (3 of 10), and midposterior left atrium (1 of 10); and (5) earliest activation site had timing relative to P wave by -37 +/- 7 ms, and concealed entrainment pace mapping had shortest stimulus-P interval 23 +/- 3 ms. By the endocardial activation pace-mapping technique, radiofrequency energy (8 +/- 1 pulses, 31 +/- 3 W, 101 +/- 11 seconds) successfully eliminated the 10 atrial foci without recurrence (follow-up, 16 +/- 5 months). Mechanism of intra-atrial reentrant tachycardia could be confirmed by the electrophysiological characteristics, and radiofrequency ablation energy delivered to a critical area in the atrial reentrant circuit is safe and effective for the treatment of intra-atrial reentrant tachycardia.