Chiriac, Anca

Abstract Objectives This study aimed to investigate the procedural characteristics, efficacy, and safety of atrioventricular junction (AVJ) ablation for atrial tachyarrythmia (AT) in patients with congenital heart disease (CHD). Background Although AVJ ablation is an established treatment option for intractable AT in the general population, there is no existing data on this treatment in patients with CHD. Methods Data were analyzed from an observational, retrospective, multicenter cohort, initiated jointly by the Pediatric and Congenital Electrophysiology Society and the International Society of Adult Congenital Heart Disease. Eleven centers contributed baseline, procedural and longitudinal data, including vital status, echocardiographic data, QRS duration, and NYHA class. Outcomes were assessed at early (3 months-1 year), and late follow-up (≥2 years) after AVJ ablation. Results A total of 66 patients (46.7 ± 20.2 years) underwent 71 AVJ ablations. In total, 58.5% had moderate or complex CHD, including 17.1% patients with a systemic RV or single ventricular circulation. The cumulative AVJ ablation success rate was 98.5%. An abnormal location of the atrioventricular conduction pathway was successfully targeted in 20.0% of the patients, which was significantly more common in patients with complex CHD compared to moderate or mild CHD (44.4%, 15.8%, and 3.6%, respectively; both P<0.05). Thirty-six patients (54.5%) underwent primary pacemaker implantation as part of the ‘pace and ablate’ strategy; final pacing modes were VVI pacing in 60.9%, and CRT/CSP in 39.1%. The transplant-free survival rates at 2, 5 and 10 years after AVJ ablation were 91.5%, 84.3%, and 69.0%, respectively. The acute and long-term complication rates were 3.0% and 13.6%, respectively. Conclusions AVJ ablation can be successfully performed in CHD patients with a high acute success rate and low complication rate. Anatomical challenges were common, which underscores the need for careful planning and operator experience. Given the acceptable long-term survival, these findings support the consideration of a ‘pace and ablate’ strategy in CHD patients with intractable AT.

Introduction: The incidence and risk factors for atrial arrhythmia (AA) [atrial fibrillation (AF) and atrial flutter (AFL)] in adults with systemic right ventricle (SRV), specifically congenitally corrected-TGA (cc-TGA) and D-TGA palliated with atrial switch procedures, is not well understood. This study aims to better define these risks. Methods: Adults with SRV presenting to the Mayo Clinic between 1971 and 2022 were identified. Clinical characteristics, ECG and echocardiographic parameters were recorded at first evaluation. Sustained AA (> 30s) incidence at follow-up was documented using ECG. Cox regression analysis identified associations of incident AA. Results: Among 447 patients with SRV (mean age 34.7±14.8, 55.9% male, cc-TGA n=247; D-TGA post-atrial baffle n=200), AA was documented in 231 (51.6%) at a mean age of 37.5±18.8y. Isolated AF was observed in 88 (38.1%), isolated AFL in 71 (30.7%), and both AF and AFL in 72 (31.2%) patients. Univariate analysis showed significant predictors of AA as: age (HR:1.03, p<0.001), male sex (HR:1.49, p=0.026), NYHA class≥2 (HR:1.98, p<0.001), ventricular pacing (HR:1.64, p=0.019), QRS duration (HR:1.008, p<0.001), SRV enlargement (HR:1.73, p=0.01), SRV ejection fraction (HR:0.979,p=0.012), left atrial enlargement (HR:1.947, p=0.006), hypertension (HR:1.57, p=0.047), CKD (HR:0.991, p=0.021), and obesity (HR:1.66, p=0.023). In multivariable analysis, age (HR:1.032, p<0.001) and QRS duration (HR:1.007, p=0.013) were significant predictors of AA. Kaplan Meier analysis of time from first evaluation to incidence of AA is shown in the figure. AA was associated with heart failure in 56 (26.7%) patients. During 11.2±10.5 years of follow-up, mortality occurred in 50 (21.6%) with AA and 19 (8.8%) without AA. Conclusion: Atrial arrhythmia occurred in more than half of patients with SRV, predominantly in the third decade of life. Significant associations of AA included advancing age, longer QRS duration, enlargement of pulmonary venous atrium, reduced SRV function, hypertension and obesity. AA was associated with heart failure in one-fourth of patients and higher mortality. Close monitoring and early intervention in patients with risk factors may help mitigate the development of AA.

Introduction: The incidence and risk factors for sudden cardiac death (SCD) in patients with systemic right ventricle (sRV) and D-TGA palliated with atrial switch procedures is not well understood. Methods: This cohort was examined retrospectively for the composite end point of SCD, sustained ventricular tachycardia (VT) >30 s or appropriate ICD therapy for VT. Clinical characteristics of those with and without the end point were compared using the Kruskal-Wallis or Chi-square test as appropriate. Results: The composite end point occurred in 15 of 148 (10%) patients (63.5% male) at a mean age of 36.4 (SD 10.3) years. SCD occurred in 6 patients (n=2 successfully resuscitated), sustained VT in 6 patients and ICD therapy for VT in 3 patients who had previously received a primary prevention ICD. Patients with SCD/VT had lower sRV ejection fraction (EF) compared to patients without SCD/VT [28±11 vs 40±10%, P<0.001]. The odds ratio of SCD/VT in patients with sRVEF≤35% compared to sRVEF>35% was 13.3 (95% CI 2.8 - 64.4). Kaplan Meier analysis of time to SCD/VT stratified by sRV EF is presented in figure. QRS duration, QRS fragmentation, QTc and history of systemic AV valve surgery were not significantly associated with SCD/VT. Non-sustained ventricular tachycardia (NSVT) on Holter monitoring occurred more frequently in SCD/VT patients (80 vs 39%, p=0.003). All 11 survivors of SCD/VT received an ICD; appropriate ICD therapy occurred in 27% of these patients during follow-up. Conclusion: SCD or VT occurred in one-tenth of D-TGA patients palliated with atrial switch, predominantly in 3 rd and 4 th decade of life. Reduced sRV EF was the most important association and ICD implantation for primary prevention of SCD is a reasonable consideration in those with reduced sRV EF.

BACKGROUND: The outcomes of catheter ablation for atrial fibrillation in adults with congenital heart disease are not well described. METHODS: In a retrospective study of adult patients with congenital heart disease who underwent catheter ablation for atrial fibrillation between 2000 and 2020 at Mayo Clinic, procedural characteristics and outcomes were collected. The primary outcomes were atrial arrhythmia (AA) recurrence following a 3-month blanking period and repeat ablation. An arrhythmia clinical severity score was assessed pre- and post-ablation based on the duration of arrhythmia episodes, symptoms, cardioversion frequency, and antiarrhythmic drug use. RESULTS: One hundred forty-five patients (age, 57±12 years; 28% female; 63% paroxysmal atrial fibrillation) underwent 198 ablations with a median follow-up of 26 months (interquartile range, 14–69). One hundred ten, 26, and 9 patients had simple, moderate, and complex congenital heart disease, respectively. All patients underwent pulmonary vein isolation, and non–pulmonary vein targets were ablated in 79 (54%). AA recurrence at 12 months was 37% (95% CI, 29%–45%). On univariate analysis, increasing left atrial volume index was associated with higher odds of AA recurrence (odds ratio, 1.03 [1.00–1.06] per 1 mL/m 2 increment; P =0.05). Noninducibility of atrial flutter was predictive of decreased odds of AA recurrence (odds ratio, 0.43 [0.21–0.90]; P =0.03). A second ablation was performed in 43 patients after a median of 20 (interquartile range, 8–37) months. Arrhythmia clinical severity scores improved following ablation, reflecting a decrease in symptoms, cardioversions, and antiarrhythmic drugs. CONCLUSIONS: Catheter ablation of atrial fibrillation is feasible and effective in patients with adult congenital heart disease and reduces symptoms. Recurrence of AA frequently requires repeat ablation.

Background: Patients with ccTGA have a high incidence of atrial arrhythmias and premature failure of the systemic right ventricle. We sought to better define this risk. Methods: A retrospective review of all clinical data for patients with ccTGA followed at a large tertiary care institution was performed. The primary outcome was a composite of death and cardiac transplantation. Results: A cohort of 165 patients (age 41±16 years, 53% male) were followed for 11±8 years; 41 patients died, 7 underwent cardiac transplantation, and 4 underwent VAD placement. Male sex (HR 2.7, p=0.002), older age (HR 1.04, p<0.001), clinical heart failure symptoms (HR 7, p<0.001), heart failure hospitalization (HR 4.9, p<0.001), syncope (HR 1.8, p=0.04) and pulmonary hypertension (HR 2.77, p<0.001) were significant predictors of the primary outcome. Atrial fibrillation (HR 3.5, p=0.002), atrial flutter (HR 3.05, p=0.04), and prolonged QRS duration (HR 1.01, p=0.004) on the first ECG, as well as right and left atrial enlargement (HR 4, p<0.001 and 3.7, p<0.003) and severe systemic AV valve regurgitation (HR 3.8, p=0.03) on the first echocardiogram were associated with poor outcomes. Atrial arrhythmias occurred in 110(67%) patients: atrial fibrillation in 75(45%), atrial flutter in 50(30%), and supraventricular tachycardia in 16(9.7%) patients. Arrhythmias were largely asymptomatic in 109(66%) patients, while 25(14.5%) experienced palpitations, dizziness or presyncope, and 10(6%) presented with decompensated heart failure. Cardioversion and antiarrhythmic therapy were utilized in 53(32%) patients. Surgical pulmonary vein isolation or atrial MAZE were performed in 15(9%) patients, cryoablation of the CTI in 3 patients, and surgical ablation of an accessory pathway in 2 patients. One or more catheter ablation procedures were also performed in 18(11%) patients. Conclusions: Atrial fibrillation and flutter, heart failure, prolonged QRS duration, systemic AV valve regurgitation and pulmonary hypertension predict worse outcomes in ccTGA. Although asymptomatic in a majority of patients, atrial arrhythmias are associated with significant morbidity and mortality. Whether a rhythm control strategy even in asymptomatic patients may improve outcomes remains unknown.

Background: Patients with D-transposition of the great arteries and atrial switch have a high incidence of atrial arrhythmias. We sought to analyze the arrhythmia substrate, ablation strategies, and outcomes for catheter ablation in this population. Methods: An in-depth analysis of all clinical and procedural data in patients with D-transposition of the great arteries, atrial baffles, and atrial arrhythmia ablation was performed. Results: A cohort of 32 patients (72% male, mean age 38±7 years) underwent ablation for non-AV nodal reentrant tachycardia atrial arrhythmias, and 4 patients underwent AV nodal reentrant tachycardia ablation. Cavotricuspid isthmus flutter (CTI-flutter) was the most common arrhythmia, encountered in 75% of patients, followed by scar-related intraatrial reentrant tachycardia (non-CTI intraatrial reentrant tachycardia, 53%) and focal atrial tachycardia (focal atrial tachycardia, 6%). Among the 32 patients, 26 underwent 31 procedures at our institution. For patients with prior outside intervention, the index ablation at our institution revealed CTI-dependent flutter in 3/5 cases. However, redo ablation after an index ablation with demonstrated bidirectional CTI block revealed different/new arrhythmia substrates (80% non-CTI intraatrial reentrant tachycardia, 40% focal atrial tachycardia). Achieving bidirectional block across the CTI often required ablating on both sides of the baffle (retroaortic access, 81%; using a baffle leak, 11.5%; or transbaffle puncture, 7.7%). Combined approaches were necessary in 19% to reach the critical tissue. Acute procedural success was 81%, and recurrence was documented in 58% of patients. Despite recurrence, clinical arrhythmia burden was significantly reduced post-ablation ( P <0.001), with rare episodes, amenable to antiarrhythmic therapy. Redo ablation was required in 5 (19%) patients and uncovered new arrhythmia substrates. AV nodal reentrant tachycardia ablation also required transbaffle approaches in 3/4 patients. Conclusions: CTI-dependent flutter was the most common arrhythmia in patients with Dextro-Transposition of the Great Arteries and atrial switch. Transbaffle approaches were often necessary, and, provided that bidirectional CTI block was achieved at the index ablation, late recurrence was due to different arrhythmia mechanisms. Despite recurrence, ablation was associated with significant clinical improvement.

Introduction: Atrial arrhythmias are common in patients with D-TGA and atrial switch. We sought to analyze the arrhythmia substrate and catheter ablation approaches and outcomes. Methods: We performed a retrospective review of all clinical and procedural data in patients with D-TGA followed at a large tertiary care center. Results: In a cohort of 152 patients (mean age 30±11 years), atrial tachycardia was present in 69(45%) patients. Ablations were performed in 39(26%) patients: macro-reentrant atrial flutter (N=37), atrial fibrillation (N=4), and focal automatic atrial tachycardia (N=3). Detailed electrophysiology study data was available for 34 patients. At first ablation (N=28), cavo-tricuspid isthmus dependent flutter (CTI, 23(82%)) was most common, followed by right atriotomy-related flutter (IART, 16(57%)) and focal atrial tachycardia (FAT, 1(3.5%)). Bidirectional CTI block often required ablation on both sides of the baffle to complete the isthmus line. Access to the pulmonary venous atrium was obtained in 82% of first-time ablations (via retrograde aortic access, 74%, baffle puncture, 6%, or baffle fenestration, 12%) and in 100% of redo procedures. The first ablation was acutely successful in 25 (89%) patients; the other 3 patients had either partial procedural success (1), failed ablation (1), or underwent an empirical ablation (1). Long-term arrhythmia recurrence occurred in 13(46%) after the first ablation and class III antiarrhythmic medications were utilized in 12 patients. At least one long-term recurrence occurred in 11(44%) patients. Importantly, clinical arrhythmia burden was significantly reduced post-ablation, with rare and short-limited episodes amenable to antiarrhythmic drugs or cardioversion. Repeat ablation was required in 3 cases. Long-term arrhythmia recurrence after a previously completed CTI line involved different arrhythmia mechanisms: scar-related reentry (80%) and automatic atrial tachycardia (40%). Conclusions: Atrial arrhythmia in patients with D-TGA often involves the CTI and atriotomy scars. Ablation of the CTI typically requires access to the pulmonary venous atrium to achieve bidirectional block. Despite late recurrence, the clinical arrhythmic burden is substantially improved.

Introduction: Patients with D-TGA palliated with atrial switch operations have the morphologic right ventricle in the systemic position. There is increased risk of atrial arrhythmias and systemic right ventricle (SRV) failure. We sought to analyze the long term outcomes of these patients. Methods: All patients with D-TGA and SRV followed in the Adult Congenital Heart Disease Clinic of a large tertiary care institution were reviewed. A comprehensive retrospective analysis of the medical record was performed, including consult notes, ECGs, echocardiograms and electrophysiology reports. Results: A total of 154 patients (63% male) aged 29±11 years were followed for a mean of 10±9 years (range 0-51). During follow-up, 3 patients underwent cardiac transplantation and 15 died; 5 had sudden death, 2 had cardiogenic shock, 5 had non-cardiac death (i.e., infective endocarditis, sepsis) and 3 had unknown causes of death. Heart failure symptoms were present in 53(34%) patients. Severe SRV systolic dysfunction occurred in 37(24%) patients, with a mean EF of 23±5.5%; moderate SRV dysfunction occurred in 67(44%) patients, mean EF 35±4%. Sinus node dysfunction was present in 75(49%) patients, complete AV block in 9(5%) patients, and a pacemaker placed in 60(39%) patients, with cardiac resynchronization therapy in 5. Atrial arrhythmias occurred in 94(61%) patients and ablations were performed in 47(31%) patients. An ICD was implanted in 37 patients; 5 patients had appropriate shocks, but 7 had inappropriate shocks due to atrial arrhythmias. Age (HR 1.07, p=001), heart failure symptoms (HR 4.9, p= 0.007), severe SRV enlargement (HR 3.7, p=0.03), severe systolic dysfunction (HR 5.4, p=0.003), severe systemic AV valve regurgitation (HR 5.2, p=0.002) and a QRS duration> 122ms (HR 3.7, p=0.02) were significant predictors of mortality. The 15 year probability of sudden death was 3.2%(95% CI 0-6.9%). Conclusions: Atrial arrhythmias are common after atrial switch operations secondary to atriotomy scars. Further studies will need to determine whether restoration of sinus rhythm or cardiac synchrony may prevent further deterioration of the systemic right ventricle. Severe SRV dysfunction and prolonged QRS duration >122ms were significantly correlated with mortality.

Background Patients with Eisenmenger syndrome are known to have a high incidence of sudden cardiac death ( SCD ), yet the underlying causes are not well understood. We sought to define the predictors of SCD in this population. Methods and Results A retrospective analysis of all patients with Eisenmenger syndrome from 2 large tertiary referral centers was performed. ECGs, prolonged ambulatory recordings, echocardiograms, and clinical histories were reviewed; and the cause of death was identified. A total of 246 patients (85 [34.6%] men) with a mean age of 37.3 (±14.2) years were followed up for a median of 7 years. Over the study period, 136 patients died, with 40 experiencing SCD and 74 experiencing cardiac death (sudden and nonsudden). Age, atrial fibrillation, prolonged QRS duration, complete heart block, right atrial enlargement, right bundle branch block, increased right atrial pressure, impaired biventricular function, and the presence of a pacemaker were associated with increased risk of SCD , whereas advanced pulmonary hypertension therapies were protective. Atrial fibrillation (11.45‐fold increased risk; P <0.001) and QRS duration ≥120 ms (2.06‐fold increased risk; P =0.034) remained significant predictors of SCD in the multivariate analysis, whereas advanced pulmonary hypertension therapies were strongly protective against SCD ( P <0.001). Conclusions Atrial arrhythmias, impaired ventricular function, and conduction system disease were associated with increased risk of SCD in this cohort of patients with Eisenmenger syndrome, providing an opportunity for early risk stratification and potential intervention. Clinical heart failure symptoms (New York Heart Association class ≥ II ) were predictive of increased mortality but not of SCD , suggesting a potential arrhythmic cause behind SCD .