Recurrence of Atrial Arrhythmias Following Ablation in Adults with Congenital Heart Disease: New Substrate Formation or Late Procedural Failure?

Recurrence of Atrial Arrhythmias Following Ablation in Adults with Congenital Heart Disease: New Substrate Formation or Late Procedural Failure? J. Shuplock MD, G. Barker MD, A. Radbill MD, P. Kannankeril MD MSCI, F. Fish MD Jacqueline Shuplock, MD Pediatric Cardiology Fellow, PGY 6 Vanderbilt Children s Hospital

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Background Arrhythmias in adults with congenital heart disease (CHD) are a growing problem Most develop late, suggesting an evolving substrate Atrial arrhythmias cause significant morbidity & mortality 3 times increased risk of cardiac intervention 50% increase in mortality In univentricular hearts, atrial arrhythmias may herald and hasten declining ventricular function Bouchardy, J et. Al; Atrial Arrhythmias in Adults with Congenital Heart Disease; Circ 2009;120:1679 1686

Background Ablation is challenging Lower success rates vs. normal cardiac anatomy Complex anatomy & arrhythmia substrates Multiple circuits are common High acute success with current electroanatomic mapping and ablation tools Success rates range from 55 90% Recurrences remain common (not clearly defined) Triedman, J; Arrhythmias in Adults with Congenital Heart Disease; Heart 2002; 87:383 389 Walsh, E.P.; Arrhythmias in Adult Patients with Congenital Heart Disease; Circ; 2007;115:534 545 Kannankeril, P.J.; Frequency of Late Recurrence of Intra Atrial Reentry Tachycardia after Radiofrequency Catheter Ablation in Patients with Congenital Heart Disease; Am J Card;92; 10/1/03

Objective and Hypothesis Examine the outcomes of radiofrequency catheter ablation (RFA) in adults with repaired CHD at our institution Examine the nature of recurrence Risk factors for recurrence Hypothesis Recurrences often represent the development of new substrates

Methods Retrospective chart review All adolescents & adults with repaired CHD undergoing RFA at our institution from Jan. 2003 to Nov. 2013 Statistical analysis Mann Whitney U test for continuous variables Pearson Chi Square for categorical variables

Methods CHD Type Tetralogy type TOF, PA/VSD, DORV (non single ventricle), Rastelli Single Ventricle Atrial switch (TGA) Senning, Mustard Other Septal defects, Coarctation, Anomalous veins, PS/AS, BAV, AVSD, Arterial switch, Shone s, cctga, Scimitar, OHT Triedman, J; Arrhythmias in Adults with Congenital Heart Disease; Heart 2002; 87:383 389

Methods Circuit Type Cavo tricuspid isthmus (CTI) dependent Counterclockwise (Common or type 1) atrial flutter Clockwise atrial flutter Scar Non isthmus dependent scar related macro reentry Focal Mostly micro reentrant Atrioventricular reciprocating tachyarrhythmias (AVNRT/AP)

Methods Acute procedural success = ablation of all circuits Recurrences warranting clinical intervention Medications Anti tachycardia pacing Cardioversion Repeat EPS/catheter ablation Surgical ablation Specific recurrence type Original substrate New substrate Unmapped recurrence Atrial fibrillation (AFib)

Results 118 patients 156 ablation procedures Median age of 35 years Range 12 64 years 33% 33% Tet Type Single Ventricle Atrial Switch Other Types 13% 21%

Circuit Type 252 tachyarrhythmia circuits were targeted CTI & Scar most common Combination of circuits CTI/Scar 16% 6% Focal 13% CTI CTI/Focal 6% 29% 29% Scar Combination CTI/AVNRT/AP Focal/Scar 2% 4% 23% AVNRT/AP CTI/Focal/Scar 1%

CHD Type & Circuit Type 50% 40% 30% 20% Focal CTI Scar Combination AVNRT/AP 10% 0% Tet Type Single Ventricle Atrial Switch Other

CHD Type & Circuit Type 50% p<0.001 40% 30% 20% Focal CTI Scar Combination AVNRT/AP 10% 0% Tet Type Single Ventricle Atrial Switch Other

CHD Type & Circuit Type 50% p=0.004 40% 30% 20% Focal CTI Scar Combination AVNRT/AP 10% 0% Tet Type Single Ventricle Atrial Switch Other

CHD Type & Circuit Type 50% p=0.013 40% 30% 20% Focal CTI Scar Combination AVNRT/AP 10% 0% Tet Type Single Ventricle Atrial Switch Other

Acute Success 94% (147/156) procedures acutely successful 94% (237/252) targeted tachyarrhythmia circuits

Acute Success 9 procedures 7 patients 1 patient accounted for 3 acutely unsuccessful ablations 2 procedures were not followed by recurrence 6 repeat ablations were performed 4 in the same patient 2 of the 6 repeat ablations were unsuccessful (both in same patient)

Recurrence Median follow up: 31 months 10% lost to follow up Recurrence in 49.4% (77/156) No recurrence in 50.6% (79/156) Median time to recurrence: 6 months

Recurrence Of those with recurrence Not mapped in 40% Original substrates in 25% New tachycardia substrates in 23% AFib accounted for 12% 35% were a known new substrate Including AFib 25% 40% Original New 23% 12% Afib Not Mapped

Age & Recurrence Overall recurrence (p=0.257) No recurrence: 34 years Recurrence: 36 years Specific type of recurrence Original substrate (28y vs. 40y; p<0.001) AFib (47y vs. 36y; p<0.001)

CHD Type & Recurrence Single Ventricle (81% recurrence) Tet Type (38.5% recurrence) Atrial switch (40% recurrence) Other types (44% recurrence) 80% 60% 40% p<0.001 20% 0% Tet Type Single Ventricle Atrial Switch Other

Conclusions 94% overall acute success rate Nearly 50% recurrence rate Single ventricle patients had the highest recurrence (81%) Of the recurrences undergoing repeat mapping, a new substrate was found nearly as often as as the original substrate 23% vs. 25% respectively Including AFib as a new substrate, 35% of recurrences represented a known new substrate

Conclusions Type of recurrence was influenced by age Original substrate recurred in significantly younger patients AFib developed in significantly older patients Initial circuit ablated relates to underlying CHD Tet Type: more CTI related arrhythmias Single Ventricle: more focal arrhythmias Atrial Switch: more scar related arrhythmias

Conclusions Despite high acute procedural success, adults with repaired CHD have frequent recurrences Substantial proportion are attributable to new or evolving substrates Repeat ablation may be warranted New target for ablation may be identified

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References 1. Triedman, J; Arrhythmias in Adults with Congenital Heart Disease; Heart 2002; 87:383 389 2. Huang, J et. al; Management of Late Arrhythmias in Adults with Repaired Congenital Heart Disease; Current Treatment Options in Cardiovascular Medicine (2013) 15:615 631 3. Oliver Ruiz, J.M.; Congenital Heart Disease in Adults: Residua, Sequelae, and Complications of Cardiac Defects Repaired at an Early Age; Rev Esp Cardiol 2003;56(1):73 88 4. Walsh, E.P.; Arrhythmias in Adult Patients with Congenital Heart Disease; Circulation 2007;115:534 545 5. Bouchardy, J et. Al; Atrial Arrhythmias in Adults with Congenital Heart Disease; Circulation 2009;120:1679 1686 6. Triedman, J; Influence of Patient Factors and Ablative Technologies on Outcomes of Radiofrequency Ablation of Intra Atrial Re Entrant Tachycardia in Patients with Congenital Heart Disease; Journal of the American College of Cardiology; Vol 39, No 11, 2002 7. Kannankeril, P.J.; Frequency of Late Recurrence of Intra Atrial Reentry Tachycardia after Radiofrequency Catheter Ablation in Patients with Congenital Heart Disease; The American Journal of Cardiology; Vol 92; Oct 1, 2003 8. http://www.cdc.gov/ncbddd/heartdefects/data.html