Long term follow-up after ventricular tachycardia ablation in patients with congenital heart disease.

Yang J, Brunnquell M, Liang JJ, Callans DJ, Garcia FC, Lin D, Frankel DS, Kay J, Marchlinski FE, Tzou W, Sauer WH, Liu B, Ruckdeschel ES, Collins K, Santangeli P, Nguyen DT. J Cardiovasc Electrophysiol. 2019 Sep;30(9):1560-1568. doi: 10.1111/jce.13996. Epub 2019 Jun 11. PMID: 31111602 Similar articles Select item 31115957   Take-Home Points:   This was a large two-center study of CHD VT ablation with 5-year follow up data. The mechanism of VT in congenital heart disease was primarily scar-related reentry (80%), followed by focal (15%) and non-scar related reentry (5%). Scar-related reentry was more commonly seen among patients with TOF vs other CHD anatomies. Acute complete procedural success could be achieved in 75% of patients overall, with recurrence in 20% of patients. Acute procedural success was strongly associated with ventricular arrhythmia-free survival. Commentary by Dr. Jeremy Moore (Los Angeles) Congenital and Pediatric Cardiac EP section editor:  This was a retrospective two-center study of VT catheter ablation outcomes over a 7-year period from 2010 to 2017. Forty-eight patients with variable CHD anatomy were identified, most commonly TOF in 29 (60%), Ebstein’s anomaly in 4 (8%), and bicuspid aortic valve in 4 (8%). Approximately three-quarters had an ICD in place and half had failed antiarrhythmic drugs. Overall, 77 unique VTs were induced, of which approximately half (52%) were hemodynamically stable and could be localized with activation or entrainment mapping. The remainder were identified by pace mapping. The mechanism was scar-related reentry in 81%, non-scar (His-Purkinje)-related reentry in 16%, and focal (mainly outflow tract in 73%) in the remaining 4%. His-Purkinje reentry (4) was seen only observed among patients with Ebstein’s anomaly (2) and TOF (2). Interestingly, the authors noted that VT CL was shorter for patients with preserved RV function versus RV dysfunction (286 ± 7 ms vs 322 ± 18 ms; P = .0246). In addition, TOF patients were more likely to manifest scar-related reentry. Acute success was achieved in 75% of patients, with recurrent VT in 21% over nearly 5-year follow up. Patients with acute success were less likely to experience recurrent VT (17% vs. 54%, p=0.02). Five of 10 patients with recurrence were taken for a second catheter ablation procedure. In 1 patient, the same anatomical isthmus was targeted; and in 2 others, a separate site was targeted (right coronary cusp in 1 and RBB in 1). The final 2 patients had no inducible VT at repeat catheter ablation and substrate-based ablation was pursued. There were no major complications from catheter ablation. At last follow up, only 8 patients remained on antiarrhythmic drugs. This study is notable as it is the largest series to date, describing catheter ablation outcomes in mixed CHD cohort with VT. The acute efficacy of 75% with no major complications suggest that this approach is a very reasonable therapeutic modality for affected patients. Similar to a smaller prior description from the Mayo Clinic [Martin et al. Heart Rhythm 2016;13:1449-1454), mechanisms were predominantly scar-related and anatomically based, with a significant number of focal VTs. Although reassuring, the issue of catheter ablation as a substitute for ICD placement was not fully resolved from this interesting experience.


Catheter Ablation for Atrial Tachycardia in Adults With Congenital Heart Disease: Electrophysiological Predictors of Acute Procedural Success and Post-Procedure Atrial Tachycardia Recurrence.

Grubb CS, Lewis M, Whang W, Biviano A, Hickey K, Rosenbaum M, Garan H. JACC Clin Electrophysiol. 2019 Apr;5(4):438-447. doi: 10.1016/j.jacep.2018.10.011. Epub 2019 Jan 30. PMID: 31000097 Free Article Similar articles Select item 30895757   Take Home Points: Atrial tachycardia is a common complication in adults with congenital heart disease leading to increased morbidity and mortality. The majority of atrial tachycardia is macro reentrant (93%) followed by focal (7%). Nearly half (45%) had typical cavo-tricuspid isthmus (CTI) flutter. Acute procedural success for CTI dependent flutter was high at 98.4% but success for > 1 arrhythmia mechanism or a single complex mechanism was only 80%. Only a single arrhythmia mechanism was associated with acute procedural success Recurrence after the first ablation procedure was common (44%) with a median time to recurrence of ~4 years. Recurrence after the second procedure was common (55%) with a median time to recurrence of ~4.7 years. Recurrence was often due to different atrial tachycardia (52%). Presence of prior maze and failed initial procedure were associated with recurrence of atrial tachycardia . Improvements in surgical and catheter-based ablation will likely improve acute and long-term outcomes in ACHD patients but there may be a continued need for repeat procedures to disease evolution over time. Comment from Dr. Akash Patel (San Francisco), section editor of Congenital Electrophysiology Journal Watch  Atrial tachycardias are a common complication in patients with congenital heart disease. These include atrial fibrillation, focal atrial tachycardias, and macro reentrant atrial tachycardia (flutter/IART).  Presence of atrial fibrillation/atrial flutter/IART have been shown to increase morbidity (heart failure, stroke) and mortality. This has resulted in the increased use of catheter ablation as primary therapy due to the long-term side effects and efficacy of medical management. The overall acute success rates have improved over time and reported to be between 70-90% but recurrence rates continue to be high (40-60%). The predictors for acute and long-term success are limited and the focus has been on IART. This single center study (Columbia University, NY) aimed to describe the spectrum of atrial tachycardia referred for ablation, determine predictors for acute success, and determine risk factors for atrial tachycardia free survival in adult patients with congenital heart disease. This was a retrospective single tertiary center study of all consecutive patients with congenital heart disease who underwent ablation procedure for atrial tachycardia from December 2005 to July 2017.  Subjects were excluded if the primary indication for the procedure was for SVT due to AV node reentry, SVT due to accessory pathway, or VT. Baseline clinical, electrocardiographic, ablation and mapping data were included.   Electrophysiology studies were conducted using a standard approach and 3-D electroanatomic mapping in all patients. Irrigated (open/closed) or non-irrigated radiofrequency ablation catheters were used for all cases. For irrigated catheters, temperature and power were limited to 43-45°C and 25 to 40 W. For non-irrigated catheters, the temperature and power were limited to 60 °C and 50 W. Pulmonary vein isolation for atrial fibrillation ablation was not performed in these patients and cardioversion was used to convert sustained episodes. Ablation success was defined as termination of all atrial tachycardias during radiofrequency ablation and non-inducibility with programmed stimulation after ablation. For patients with macro-reentrant atrial tachycardia with a critical isthmus, bidirectional conduction block was confirmed. The study group included 140 patients (51% male) with a mean age of 45.0 ± 1.2  years. The most common diagnoses were atrial septal/ventricular septal defects (31%), tetralogy of Fallot  (27%), Fontan (14%), Mustard/Senning (9%), Aortic Stenosis/BAV (5%), AV Canal (5%), Ebstein (2%), and other (6%).  Medications included beta-blockers (57%), amiodarone (16%), sotalol (10%), calcium channel blockers (6%), sodium channel blockers (1%).  Prior surgical maze was done in 6%.  Prior cardioversion was required in 39%. The baseline cardiac rhythm was atrial tachycardia in 66%.   There was no mention of prior atrial fibrillation.  The atrial tachycardia cycle length was 275 ± 5 msec . There were 180 atrial tachycardias (spontaneous or induced) noted in 140 patients. 23% had 2 mechanisms and 3% had > 2 mechanisms. 93% (n=170) were macro-reentry and 7% (n=12) were focal.  Of the macro-reentry arrhythmia types, 84 (49%) were cavotricuspid isthmus (CTI)-dependent and 19 (11%)  were mitral isthmus–dependent.  45% of patients had  CTI dependent flutter as the only mechanism.   Acute success was seen in 124 (89%) of the overall cohort. Acute success for CTI dependent flutter was high at 98.4% but the success for > 1 mechanism or complex single mechanism was lower at 80%. On multivariate analysis, presence of a single arrhythmia mechanism was associated with acute procedural success (HR 0.27, p=0.03) but not CTI dependent flutter.   On multivariate analysis, presence of a Senning/Mustard (HR 4.46, p=0.05)  and non CTI-Dependent flutter (HR 3.74, p=0.04) were associated with procedural failure. See Figure Below.   Atrial tachycardia recurrence after the first procedure was common and seen in 44% with a median time to recurrence of 49.9 months (IQR: 6.7 -73.7). See Figure Below. Recurrence occurred in 40% of biventricular patients and 65% of Fontan patients. Recurrence occurred much sooner in Fontan than non-Fontan patients (12.5 vs. 50.1 months, p=0.01). On multivariate analysis,  prior surgical maze (HR3.34, p=0.03) and lack of acute procedural success at first ablation (HR 2.16, p=0.04) were associated with recurrence. See Figure Below. A second procedure was attempted in 68% of patients who had recurrence.  The baseline cardiac rhythm was atrial tachycardia in 69%.   There was no mention of prior atrial fibrillation. There were 57 atrial tachycardias (spontaneous or induced) noted in 42 patients. Of these patients, 52% had a new atrial tachycardia. 93% (n=53) were macro-reentry and 7% (n=4) were focal. Recurrence after the second procedure was seen in 55% with a median time to recurrence of 56.0 months (IQR: 22.0 – 90.9). See Figure Below. Catheter ablation for atrial tachycardias in ACHD patients was safe in this cohort. The incidence of major complications was low at 1.4% (n=2). There was one patient with post-procedure AV block requiring a pacemaker and one patient who died of an acute stroke 1 month after procedure. Of note, the overall incidence of death or transplant in this cohort was significant at 7% over  the 8 year study period. 8 patients died a median of 9.2 months after the procedure and 2 had heart transplant. There are no details of who these patients are but this is consistent with known data on atrial arrhythmias and morbidity and mortality in ACHD patients.  It would be important with the authors detailed if these patients were procedural success or failure, the arrhythmia mechanisms noted, and if they had recurrence despite ablation attempts. This study demonstrates that the acute success rates for atrial tachycardias are comparable to published data at 89%  and the majority are macro-reentrant.   Risk factors for acute procedural failure were noted to be Mustard/Senning patients and non-CTI dependent IART. As other studies have demonstrated, Mustard/Senning patients pose technical challenges for ablation but success can be improved with ablation techniques and approach.  In addition, this patient cohort will continue to shrink with the advent of the arterial switch operation as demonstrated by this cohort (9%). The risk of recurrence as expected is dependent on acute procedural success. However, like other recent studies have shown,  the majority of recurrence was due to new arrhythmia mechanisms.  The use of ablation and need for repeat procedures may be common but long term success without the need for chronic antiarrhythmic medications may be achievable in this relatively young adult old cohort.  Of note, this study did not assess the impact of atrial fibrillation which is important.  Other recent studies have shown this to be a risk factor for acute procedural failure and recurrence.  It is unclear what portion of the cohort had atrial fibrillation but 39% required cardioversion. The impact of this arrhythmia on acute procedural success and recurrence would be important.  In particular, there was an acute stroke noted in one patient 1 month after an ablation that resulted in death. Overall, this studies adds to the growing data that ablation can be successful,  but recurrence is common and repeat procedures are often needed.  With continued advances in mapping and ablation strategies for catheter and surgical approaches,  hopefully there can be continued improvements in the acute and long-term success of ablation for atrial arrhythmias in ACHD patients.    


Eligibility for subcutaneous implantable cardioverter defibrillators in the adult congenital heart disease population.

Garside H, Leyva F, Hudsmith L, Marshall H, de Bono J. Pacing Clin Electrophysiol. 2019 Jan;42(1):65-70. doi: 10.1111/pace.13537. Epub 2018 Dec 4. PMID: 30394548 Similar articles Select item 30394546   Take Home Points: Adult congenital heart disease (ACHD) patients may need implantable cardioverter-defibrillators (ICDs) due to concerns for life-threatening arrhythmias and increased risk for sudden cardiac arrest. The use of traditional transvenous ICD systems may not be a viable option in a subset of ACHD patient due to lack of vascular access associated with underlying anatomy or concerns for short and long term procedural risks. Subcutaneous ICDs (S-ICD) provide a new and less invasive approach to provide similar protection in these complex patients, but its use has been limited. Factors that have reduced the use of S-ICDs include the need for concurrent pacing. This study showed that 25% of patient with ACHD - TOF, TGA, Fontan - are deemed ineligible for S-ICD placement due to failure to pass the S-ICD ECG screening test which is required for the device to appropriately detect arrhythmias. 9 out of 10 Fontan patients meet S-ICD screening eligibility which is encouraging for a population with limited vascular access and negative long-term implantations associated with a transvenous ICD system. The presence of TOF, RBBB, and prolonged QRS duration were associated with ineligibility. The R wave sensing varied significantly with position. Prior studies have shown that exercise also negatively impacted appropriate sensing which was seen here. Rigorous pre-screening for S-ICD eligibility should be performed to avoid the risk of inappropriate shock delivery or withholding. Commentary by Dr. Akash Patel (San Francisco, CA) Congenital and Pediatric Cardiac EP section editor:  Based on the 2014 HRC/PACES Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease recommends ICD implantation in ACHD patients with prior cardiac arrest, hemodynamically significant ventricular arrhythmias, significantly depressed ventricular function, and in select high-risk patient groups such as TOF.  The vast majority of adult patients requiring ICD therapy have structurally normal hearts with normal cardiac position in the chest for whom the S-ICD was developed.  This may not be the case for ACHD patients with complex anatomy, abnormal cardiac position, and abnormalities in conduction system that may impact the efficacy of the S-ICD.  Prior small series have looked at ACHD patients who have received S-ICD which as you expect consisted of small heterogeneous populations. The aim of this study was to determine the proportion ACHD patients with TOF, D-TGA, or Fontan Palliation who met the ECG screening criteria for an S‐ICD in a larger cohort. The secondary aim was to determine factors that may impact eligibility status. The study was a single center prospective cohort study conducted at a specialized ACHD Center (UK). All patient ≥ 16 years of age with tetralogy of Fallot, d-transposition of the great arteries, or Fontan palliation were included.   All subjects underwent screening ECG via the S-ICD manufacturer’s protocol using modified electrode positions. Three vectors were analyzed - primary, secondary, and alternate (See below) in three positions- supine, sitting, and standing. The external screening ECG was recorded for up to 10s at 25 mm/s with gains of 5, 10, or 20 mm/mV.   This was repeated post-exercise for patients who had an exercise test as a part of their routine ACHD care. Based on the analyzed signal, the obtained screening ECG would be deemed acceptable or not based on the manufacturer algorithm (see below). In addition, 12-lead ECG data was extracted. This included assessment of the R:Tmax which was defined as the ratio of the R wave to T wave in the lead with the largest amplitude T wave. There were 102 of 107 recruited subjects who had complete data.  The average age was 30.7 ± 6 years. At baseline, 77 (75%) passed screening eligibility for S-ICD and 25 (25%) were deemed ineligible.  There were only 14% of patients who had screening repeated post-exercise. Comparison between eligible and ineligible patients showed no difference in age, sex, or BMI. The underlying anatomy included Fontan (22%), TGA (34 %), TOF (38%), Fontan+TGA (5%), TOF + Fontan (1%).  There was no difference between eligible and ineligible groups for TGA , Fontan+TGA ,and TOF+Fontan group.   TOF resulted in more ineligible patients (56% vs 33%).  Fontan palliation resulted in more eligible patients (27% vs 4%). Of note, 5% had dextrocardia. (See Below) The baseline ECG characteristics showed 69% had a bundle branch block (BBB) of which 84% were Right BBB. Prolonged QRS duration (149 msec vs. 122 msec) and RBBB (68% vs 44%) were significantly associated with the ineligible group.  Narrow QRS duration (<120 msec) was significantly associated with the eligible group (47% vs 20%). (see below) The R wave amplitude varied significaly with position with larger R waves seen in the eligible group.  (See below) Eligibility was noted in 77 (75%) of patients with at least one suitable vector. One suitable vector was seen in 38%,  two suitable vectors in 47%, and all there in 16%. The primary vector was suitable in 62% (see initial figure). Ineligibility was noted in 25% of patients and differed by anatomy as mentioned. (see below). The main reason for differences was felt due to the R:T max changes with position.  The reasons for ineligibility, if they failed all 3 vectors was due to a Tall T waves . Of the 14 patient who were rescreened after exercise stress tests, 1 failed to maintain eligibity. This patient had TOF. There was no multivariate analysis to further delineate the variable associated with eligibility status. This study showed that 25% of ACHD patients with TOF, Fontan, TGA or some combination of these select anatomies failed to meet S-ICD eligibility criteria. Patients with TOF were the group that failed the screening in the highest proportion (36%) which is likely due to the presence of a prolonged QRS and RBBB. Fontan patients on the other had were deemed eligible in the vast majority (90%).  Due to the impact of anatomy, positional changes and exercise on R/T wave analysis,  presence of BBB,  and secondary abnormal repolarization (i.e. Tall T waves), the eligibility for S-ICD in ACHD is limited. Additional work on refining algorithms, use of  additional screening ECG vectors and alternative device position placement, and more rigor at time of patient selection will ultimately provide for increased eligibility  and better patient selection of S-ICDs in ACHD patients.


Early and Late Effects of Cardiac Resynchronization Therapy in Adult Congenital Heart Disease.

Yanrong Yin, MD1; Konstantinos Dimopoulos, MD, PhD2; Eriko Shimada, MD3; Karen Lascelles, PGDip2; Samuel Griffiths, MSc2; Tom Wong, MD, PhD2; Michael A. Gatzoulis, MD, PhD2; Sonya V. Babu‐Narayan, MBBS, BSc, PhD2; Wei Li, MD, PhD*,2 J Am Heart Assoc. 2019 Dec 17;8(24):e014507. doi: 10.1161/JAHA.119.014507. Epub 2019 Dec 10. No abstract available. PMID: 31818210 Free Article Similar articles Select item 31842676   Take Home Points: Heart failure and systemic ventricular dysfunction are a growing problem in older ACHD patients Cardiac Resynchronization Therapy (CRT) was effective in improving NYHA Class in 1-2 (Early) and 4-5 years (Late) after CRT placement in ACHD patients CRT was effective in improving systemic left ventricular function 1-2 years and 4-5 years after CRT placement in ACHD patients CRT was not effective in improving systemic right ventricular function 1-2 years and 4-5 years after CRT placement in ACHD patients QRS duration was the only predictor of CRT response though systemic LV morphology appears to important as well. CRT implantation can be achieved in biventricular circulation but does carry a high rate of device implant complications (20%). CRT should be considered in patients who meet criteria from the 2014 PACES/HRS Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease. Comment from Dr. Akash Patel (San Francisco), section editor of Congenital Electrophysiology Journal Watch.  As congenital heart disease patients continue to survive into older adulthood, the population of patients at risk for developing heart failure will continue to increase.  The use of cardiac resynchronization therapy (CRT) for the treatment of heart failure in adults with congenital heart disease (ACHD) is poorly understood due to the limited number of patients, heterogeneity of congenital heart disease lesions, morphology of the systemic failing ventricle (right vs. left), impact of single ventricle vs. biventricular circulation, and short duration of follow-up.  This study aimed to assess the impact of early and late effects of CRT in ACHD. This was a retrospective single center study of all patients with ACHD who had reduced systemic ventricular function (LV Ejection Fraction (LVEF) < 40% or RV Fractional Area Change (RV FAC) < 35%), received CRT between 2004 and 2017, and had >90% biventricular pacing.  The clinical practice for determining who underwent CRT placement during this time period was made on an individual basis through a multidisciplinary team approach (ACHD Cardiologist, Electrophysiologist, and Congenital Surgeon).  After implantation, optimization of device programming was based on routine clinical practice.  Baseline clinical, device, electrocardiographic, and echocardiographic data were obtained. Follow-up data was obtained during two time periods: early (1-2 years after CRT) and late (4-5 years after CRT).  Outcome measures included death, heart transplantation, and positive response to CRT defined as a ≥ 5% absolute increase in LVEF or RVFAC at follow-up. The study group included 54 patients who had reduced systemic ventricular function, a CRT device implanted with BiV pacing >90%, and acceptable imaging.  The majority of patients had systemic left ventricles (72%). The lesions included were LVOT lesions (31%), ccTGA (24%), TOF (20%), others systemic LV (20%), and other systemic RV (4%). See figure below. The mean age of the cohort was 46 ± 13 years with 74% male and a mean follow-up of 5.7± 3.0 years after CRT. 96% had NYHA Class II-IV heart failure. Baseline demographic in Table below. Demographic and clinical characteristics   Age at CRT implantation (Years) 46 ± 13 Men 40 (74%) Follow-up duration  5.7 ± 3.0 SBP at CRT implantation, mmHg 112 ± 15 DBP at CRT implantation, mmHg 70 ± 10 BMI, kg/m2 25.7 (22.9–29.7) Biochemical parameters   Urea, mmol/L 7.1 (5.2–7.9) Creatinine, Imol/L 84 (76–94) NYHA functional class I 3 (6%) II 20 (37%) III 28 (51%) IV 3 (6%) Drug treatment ACEI or ARB 52 (96%) Beta-Blocker 48 (89%) Aldosterone antagonist 35 (65%) Loop diuretic 28 (52%) Amiodarone  11 (20%) Anticoagulation  36 (67%) Digoxin  5 (9%)   The majority of patients were in sinus rhythm (81%) with the remainder in permanent atrial fibrillation which effected pacing modality (VVIR/DDIR in 15%).  As expected, the majority of ACHD patients had a non-LBBB QRS morphology (72%).  See table below.   ECG Sinus rhythm  44 (81%) Atrial fibrillation 10 (19%) QRS duration, ms 174 ± 27 QRS morphological characteristics LBBB 15 (28%) Non-LBBB 39 (72%)   Retrospective review of device indications for CRT based on the 2014 PACES/HRS Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease showed the majority met criteria. 44 (81%) had systemic dysfunction (LVEF/RVFAC ≤ 35%), clinical heart failure (NYHA Class II-IV), and electrical dyssynchrony (QRS ≥ 120 msec).   There were 8 (15%) patients who has >40% pacing (5 with systemic LVEF > 35% and 3 with NYHA Class I). There were 2 (4%) patients who had systemic LVEF > 35% and broadening QRS duration. Device implantation occurred due to high grade heart block in 61%.  The majority of patients had an existing device (57%).  A CRT-D was implanted in 85% and CRT-P in 15%. See figure below.   Device implantation Permanent Pacemaker/ICD upgrade to CRT 31 (57%)    Permanent Pacemaker 21    ICD 10 CRT de novo 23 (43%) CRT-D 46 (85%) CRT-P  8 (15%)   Implantation approach varied based on congenital heart lesion.  96% had a standard CRT approach with leads placed in the right atrium, non-systemic ventricle, and systemic ventricle via coronary sinus branch.  4% had an epicardial or hybrid approach. Device complication were noted in 19% with infection as the most common complication. See Table below. Device-related complications Infection 5 (9%) Lead dislodgement  3 (6%) Venous obstruction  1 (2%) Pneumohemothorax and pulmonary embolism  1 (2%)   The effects of CRT were assessed at 1.8 ± 0.8 years (Early Period) and 4.7 ± 0.8 years (Late Period).   CRT was associated with improved cardiothoracic ratio, QRS duration, and NYHA Functional Class (p<0.05) during the Early Period.  Only NYHA Functional Class improved in the Late Period. See figure below. NYHA Functional Class improved in the Early and Late Period with CRT (See Below). In the Early Period, improvement in functional class was seen 65%, no change was seen in 33%, and worsening was seen in 2%.  In the Late Period when compared to the Early Period, further improvement in functional class was seen in 2%, no change was seen in 37%, and worsening from prior class in 31%. Of note, only Late Period data on NYHA Functional Class was available in 70%. See figure below. Response to CRT with a ≥ 5% increase in LVEF or RVFAC was seen in 65%.  Most responders had a systemic LV (74%) compared to systemic RV (40%).  There was significant improvement in ejection fraction at both the early and late period for systemic left ventricles. However, there was no significant improvement in RV fractional area change in the systemic right ventricles. See figures below. On further echocardiographic assessment of systemic left ventricles, improved LVEF and LV End systolic volume persisted in Late Period follow-up. On further echocardiographic assessment of systemic right ventricles, there was no significant improvement in RV function that persisted in the Late Period follow-up. Predictors of CRT response on multivariate analysis showed only baseline QRS duration was a significant predictor (OR: 1.4 per every 10-msec increase in QRS duration; 95% CI, 1.042– 1.838; p= 0.025). The QRS duration for responders vs non-responders was 182 ±23 msec vs. 159 ± 29 msec (p<0.007). There was no difference in QRS duration in those without or without a pre-existing pacemaker and prior pacemaker was not shown to be a risk factor.  See figure below. Overall, 20% died from all-cause mortality between 4.2 and 11.8 years after CRT. Below are Kaplan-Meier curves depicting freedom from death and heart transplantation from CRT in patients with systemic left and right ventricles. Of note, 2 patients listed for transplant were removed from the list due to clinical improvement with CRT. This study demonstrates the efficacy of CRT in an older cohort of heterogenous ACHD patients with improvement in both NYHA Functional Class and systemic ventricular function. The design of this study allowed for analysis of early and late effects of CRT which had not previously been reported. The improvements in ventricular function were seen at both short and long-term follow-up in those with systemic left ventricles but were not seen in those with systemic right ventricles. This lack of response may be reflective of the small sample size, heterogeneity of cardiac lesions, or ventricular morphology.  Overall, the majority of patients had an improvement (65%) or no change (33%) in NYHA Class early after CRT but a subsequent decline in NYHA Class was seen overtime in 31% raising concern for the long-term effectiveness of CRT in these patients. The response to CRT was dependent on QRS duration consistent with data from adults without ACHD. However, bundle branch block morphology was not associated with response. In addition, left ventricular morphology plays an important role in those with the highest likelihood to respond. Despite the positive effects of CRT in this population, 20% died of all-cause mortality. Identifying and improving methods to treat heart failure in the ACHD population is therefore critically important. This study raises the importance of using CRT in ACHD with systemic ventricular dysfunction and heart failure. In particular, the study demonstrated minimal deleterious effects on cardiac function with significant potential benefits.  Clearly there are important anatomic and procedural aspects to consider as device complications were seen in 19%.  However, increased experience should result in reducing these issues. Ultimately, more data is needed with larger sample sizes, more homogenous populations, and longer term follow-up to determine the response to CRT and better identify predictors to refine existing guidelines.  In addition, the cohort in this study focused only on the failing systemic RV and LV in biventricular circulation.  Further consideration is needed in those with failing single ventricles (RV vs. LV) or failing subpulmonary ventricles. Management of heart failure in ACHD patients is important to reduce deaths, need for transplantations, reduce comorbidities, need for hospitalization, and improve quality of life. Similar to this study, a multidisciplinary individualistic approach is needed when determining CRT placement in ACHD patients until additional data is available.


The entirely subcutaneous ICDTM system in patients with congenital heart disease: experience from a large single-centre analysis.

Willy K, Reinke F, Bögeholz N, Köbe J, Eckardt L, Frommeyer G. Europace. 2019 Jul 13. pii: euz190. doi: 10.1093/europace/euz190. [Epub ahead of print] PMID: 31302706 Similar articles Select item 31302722   Take Home Points:   ACHD patients who are not candidates for transvenous systems (i.e. cyanotic or single ventricular heart disease) are overrepresented in cohorts of ACHD SICD studies such as this one. The SICD appears to be effective and safe in the ACHD population, with an acceptable rate of inappropriate shocks during short term follow up. The long-term outcome of ACHD patients undergoing SICD placement is not well-described and larger studies are still needed. Commentary by Dr. Jeremy Moore (Los Angeles) Congenital and Pediatric Cardiac EP section editor:  This was a single-center retrospective study evaluating the authors’ experience with the SICD in 20 patients with adult congenital heart disease. The first SICD was implanted at this center in June 2010, shortly after the CE mark approval in Europe. The mean age was 40.5 ± 11.5 years and the youngest patient was 19 years of age. The SICDs were implanted in a heterogenous population of ACHD patients, however at least 5 (25%) patients had single ventricle anatomy and 3 (15%) were palliated and/or cyanotic. Device implantation was most commonly secondary prevention in 70% and primary prevention in 30%. Only one patient had a preexisting cardiac device at the time of implant. Acute testing was notable for successful defibrillation in 18 of 20 at 65J, one at 70J, and deferred in one.   The study follow up period was 3 years, during which time 3 (15%) patients experienced appropriate shocks and 2 (10%) experienced inappropriate shocks (IAS). Appropriate shocks for monomorphic VT were observed in one TOF and one DTGA-Mustard patient, and multiple appropriate shocks for polymorphic VT were observed in a patient with HLHS who had undergone a TCPC operation. IAS were due to T wave oversensing in both cases, and could be avoided with programming changes (i.e. One managed by changing the sensing vector, the other by turning on SMARTPASS filter). During follow up, 3 patients died from non-arrhythmic causes. One system required explantation for wound infection that could not be treated with antibiotics. Although this is not the largest study of the SICD in ACHD to date, this report benefits from nearly complete data acquisition and relatively long follow up, compared to other similar studies. Overall, this report supports the SICD as a useful technological strategy for ACHD patients, particularly those with single ventricle anatomy or cyanotic congenital heart disease as demonstrated previously.1 As opposed to other similar studies in this population, issues such as concomitant cardiac electronic devices (common in the Fontan population) and IAS were less commonly seen. As for the latter, recent improvements in this technology such as improvements in bandpass filtering, may partially explain this discrepancy. Also, the absence of unprotected brady-asystole was not observed in this study, which is encouraging (although implanters should remain vigilant for this possibility). Moore JP, Mondésert B, Lloyd MS, Cook SC, Zaidi AN, Pass RH, John AS, Fish FA, Shannon KM, Aboulhosn JA, Khairy P; Alliance for Adult Research in Congenital Cardiology (AARCC). Clinical Experience with the Subcutaneous Implantable Cardioverter-Defibrillator in Adults with Congenital Heart Disease. Circ Arrhythm Electrophysiol. 2016 Sep;9(9). pii: e004338. doi: 10.1161/CIRCEP.116.004338.


Improvement in ventricular function with rhythm control of atrial arrhythmias may delay the need for atrioventricular valve surgery in adults with congenital heart disease.

Zielonka B, Kim YY, Supple GE, Partington SL, Ruckdeschel ES, Marchlinski FE, Frankel DS. Congenit Heart Dis. 2019 Aug 5. doi: 10.1111/chd.12833. [Epub ahead of print] PMID: 31385437 Similar articles Select item 31380593   Take Home Points: Atrial arrhythmias in ACHD patients is known to increase with age, disease severity and hemodynamic burden (i.e. atrioventricular valve regurgitation - AVVR). Improvements in hemodynamic burden can reduce arrhythmia burden but not always due to adverse atrial remodeling. Rhythm control of atrial arrhythmias in ACHD patients with moderate to severe AVVR resulted in improved ventricular function – increase in LV EF of ~5% or reduction of 1 grade of qualitative RV function severity. Overall, rhythm control was superior to rate control for avoidance of surgery at 4 years (89% vs 33%). Use of catheter ablation and/or AADs for rhythm control resulted in a reduction in arrhythmia burden of 67% (no recurrence or conversion from persistent to paroxysmal) in this cohort. Overall recurrence of arrhythmias still remained high at 75%. Atrial arrhythmia management with the goal of rhythm control may provide an alternative treatment approach to delay the need for surgical intervention in a subset of patients. Comment from Dr. Akash Patel (San Francisco), section editor of Congenital Electrophysiology Journal Watch.  Atrial arrhythmias are a common complication in patients with adult congenital heart disease and increase with age, lesion severity, and hemodynamic burden such as atrioventricular valvar regurgitation (AVVR).  Correction of underlying hemodynamic burden (i.e. AV valve surgery) has classically been thought to improve arrhythmia burden but this is not always true due to adverse atrial remodeling.  Conversely, it remains unclear if there is benefit of arrhythmia control for improvement on atrioventricular valvar regurgitation in ACHD patients which could potentially delay the need for AV valve surgery. This study aimed to assess the impact of rhythm control of atrial arrhythmias in AVVR in adults with congenital heart disease. This was a retrospective single center study of all patients with adult congenital heart disease who were seen by both, electrophysiology and adult congenital heart disease specialists, with at least moderate to severe AVVR and atrial arrhythmias from January 2004 to July 2017.  The rhythm control group was defined as those who underwent catheter ablation or on antiarrhythmic medications (Class I or Class III).  The rate control group was defined as all others. Baseline clinical, arrhythmia, echocardiographic and follow-up data were included.   The study group included 24 patients who had at least moderate-severe AVVR out of 229 ACHD patients with atrial arrhythmias.  There were 9 patients in the rhythm control group of whom 8 (89%) were free from valve surgery at last follow-up. There were 15 patients in the rate control group of whom 5 (33%) were free from valve surgery at last follow-up.  See Figure Below. The mean age of the cohort was 47 years with no difference in gender, age, congenital heart disease, lesion severity, prior operations, CEIDs, and comorbidities between the rhythm and rate control groups. See Table Below. The most common cardiac diagnoses were atrial septal/ventricular septal defects (25%), tetralogy of Fallot (25%), D-TGA (17%), AV Canal (13%), Ebstein (8%), and other (13%). The atrial arrhythmias were IART (58%), atrial fibrillation (58%),] focal atrial tachycardia (29%), and AVNRT (4%).  There were significantly more patients with IART in the rhythm control group which is likely more amenable to antiarrhythmic therapies.  The arrhythmias were paroxysmal (<7 days) in 38% and persistent (≥ 7 days or cardioversion) in 63%. There was no difference in average heart rate between the groups.  See Table Below. There was some form of recurrence (paroxysmal or persistence) seen in 75% overall with no difference between the rhythm and rate control groups. There was a significant reduction in arrhythmia burden in the rhythm control group, 6 (67%) vs. 3(20%), p =0.04. Reduction was defined as no recurrence or a decrease in pattern from persistence to paroxysmal.   The antiarrhythmics used in the rhythm control group included dofetilide (78%), amiodarone (44%), sotalol (33%), and propafenone (11%) with 1.8±1.1 antiarrhythmic drugs used.   Echocardiographic findings showed that baseline atrial sizes, ventricular sizes, ventricular function, and AVVR were the same in both groups.  There was moderate to severe left atrial dilation in 46%, right atrial dilation 63%. There was tricuspid valve regurgitation in 79% and mitral valve regurgitation in 21% with moderate-severe regurgitation in 54% and severe in 46%. See Table Below. Follow echocardiographic data at a mean of ~2 years showed overall atrial sizes, ventricular sizes, ventricular function, and AVVR were the same in both groups.  There was moderate to severe left atrial dilation in 42%, right atrial dilation 63%. There was moderate-severe regurgitation in 38% and severe in 38%. See Table Below. In the rhythm control group, the mean LV ejection fraction improved from 54.4 ± 12.4% to 60.0 ± 11.5%, p=0.02 and the mean RV  systolic function improved ~ 1 grade classification, p=0.02. There was no significant change in LV ejection fraction or RV systolic function in the rate control group. (See Below).  There was also no significant change in AVVR severity. The overall AV valve operation and transplant free survival at 4 years was 88% in the rhythm group and 31% in the rate control group (log-rank p=0.04). See Figure Below. This study demonstrates an association between rhythm control and a small but significant increase in ventricular function without change in AVVR severity.  This was associated with the need for less AVV surgery in the rhythm control group (11% vs. 60%).   Clearly, atrial arrhythmias are associated with increased comorbidities including heart failure. This study demonstrated that even a reduction in arrhythmia burden despite a high recurrence rate of 75% still resulted in change ventricular function and reinforces the importance of sinus rhythm and AV synchrony in the setting of moderate to severe AVVR. This study raises an interesting option for patients with significant AVVR and adds to the data supporting the importance of rhythm control over rate control in ACHD patients. Clearly more data is needed in a larger sample size to determine the impact on ventricular function as the change in this study was only noted ~5% increase in LV EF or qualitative RV function.  In addition, it is unclear based on the sample size, if the impact would be the same for failing systemic RV vs LV in biventricular circulation, single ventricle (RV vs LV), or failing subpulmonary ventricle with concordant AVVR.  In addition, it remains unclear the impact how the anatomic valve morphology plays in the tolerance of AVVR as this population skewed heavily toward tricuspid regurgitation (79% of total cohort). Finally, the type of arrhythmia such as atrial fibrillation which is less amenable to rhythm control vs flutter and impact of persistence vs paroxysmal arrhythmias requires further evaluation.   Management of atrial arrhythmias in ACHD patients is critically important to reduce associated comorbidities such as stroke, heart failure and death.   Further improvements in ablation therapy may provide more long-term success and potentially could show even more benefit than was noted in this study in whom patients had a  high recurrence rate.


Establishment of Specialized Clinical Cardiovascular Genetics Programs: Recognizing the Need and Meeting Standards: A Scientific Statement From the American Heart Association.

Ahmad F, McNally EM, Ackerman MJ, Baty LC, Day SM, Kullo IJ, Madueme PC, Maron MS, Martinez MW, Salberg L, Taylor MR, Wilcox JE; American Heart Association Council on Genomic and Precision Medicine; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Basic Cardiovascular Sciences; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; and Stroke Council. Circ Genom Precis Med. 2019 May 23:HCG0000000000000054. doi: 10.1161/HCG.0000000000000054. [Epub ahead of print] PMID: 31117808 Similar articles Select item 31136304 Take Home Points: Cardiovascular genetics is evolving as a new frontier with advances in genome sequencing, genetic testing with application to a wide variety of cardiac conditions. The next big leap is to integrate clinical cardiovascular findings with genetic information to allow for improved diagnosis, prognostication of genetically vulnerable families with identification of proband. This scientific statement outlines current best practices for establishing clinical cardiovascular genetics programs (CVGPs) and on delivering cardiovascular genetic evaluation and care in both the pediatric and the adult settings, with a focus on a heart team approach along with a medical geneticist. It would be interesting to see the evolution of the medicolegal aspect of CV genetics given the vast information from genetic testing. Genetic Information Nondiscrimination Act (GINA) provides protection against denial of employment or health insurance based on genetic test results. Prediagnosis with genetic studies, antemortem imaging or invasive studies and postmortem information when needed constitutes a full spectrum analysis of a heritable cardiac condition. Depending on the heritable CVD under consideration, genetic testing can impact diagnostic, prognostic, and therapeutic decision making. In some disorders, such as LQTS, FH, and aortopathies, the impact is robust in all three respects, whereas in other disorders such as familial atrial fibrillation, the impact is limited perhaps to identification of potential at-risk family members by cascade testing. Despite the effort by the American College of Medical Genetics and Genomics to standardize guidelines for interpretation, genetic testing laboratories may not agree on variant interpretation. Misclassification of variants has serious clinical implications.   The American College of Medical Genetics and Genomics identified 59 genes as medically actionable, indicating that variants in these genes should prompt follow-up medical care. Thirty-one of the 59 genes are linked to CVDs, including cardiomyopathies, heritable arrhythmias, aortopathies, and FH. The use of multigene panels is standard for most clinical cardiovascular genetic testing because of the extent of locus and allelic heterogeneity in cardiac conditions. The development of formal CVGP clinics is a relatively new phenomenon. Detailed studies of their impact, resource needs, funding models, patient outcomes, and overall roles and value within the healthcare system generally have not been conducted. Core personnel include cardiologists, medical geneticists, genetic counselors, nurse managers, and clinical coordinators.   Comment from Dr. Khyati Pandya  (Mississippi), section editor of Congenital Electrophysiology Journal Watch:  Major advances in the field of molecular genetics have expanded our ability to identify genetic substrates underlying the pathogenesis of various disorders that follow Mendelian inheritance patterns. Included among these disorders are the potentially lethal and heritable channelopathies and cardiomyopathies for which the underlying genetic basis has been identified and is now better understood (Ackerman et al). Inherited cardiac conditions (ICCs) comprise a broad range of syndromes that affect the heart and major blood vessels, including cardiomyopathies, arrhythmias, aortopathies, familial hypercholesterolemia (FH), and congenital structural heart defects. Collectively, these disorders are relatively common and are associated with adverse clinical outcomes such as sudden cardiac death (SCD), heart failure, and premature coronary heart disease (CHD). Advances in sequencing technology have expanded testing panels for inherited cardiac conditions and driven down costs, further improving the cost-effectiveness of genetic testing. However, this expanded testing requires great rigor in the identification of pathogenic variants, with domain-specific knowledge required for variant interpretation (Walsh et al). The table below is a comprehensive list of the major genes associated with various inheritable cardiac disorders. (Walsh et al; Clinical Chemistry 63:1 116–128 (2017) ) There are significant challenges to the establishment of clinical cardiovascular genetics programs (CVGPs) in smaller programs, as these require presence of on-site clinical geneticist, genetic counselors and a significant time commitment from multiple specialties for effective coordination. The presence of remote support from genetic counselors via telemedicine may serve to mitigate this problem. A lot more remains to be desired regarding insurance coverage for genetic testing, although, it has considerably improved compared to previous.   Illustrative workflow for evaluation and management in a cardiovascular genetics program clinic of new patients who do not have a known pathogenic variant.   Illustrative workflow for evaluation and management in a cardiovascular genetics program clinic of members of families with a known pathogenic variant. The principal benefit of clinical genetic testing in the current era, is the cascade screening of family members of patients with a pathogenic variant, enabling targeted follow up of presymptomatic genotype-positive individuals and discharge of genotype-negative individuals to health. For the proband, diagnostic sequencing can also be useful in discriminating inherited disease from alternative diagnoses, directing treatment, and for molecular autopsy in cases of sudden unexplained death. Advances in sequencing technology have expanded testing panels for inherited cardiac conditions and driven down costs, further improving the cost-effectiveness of genetic testing. However, this expanded testing requires great rigor in the identification of pathogenic variants, with domain-specific knowledge required for variant interpretation. Diagnostic sequencing can potentially become an integral part of the clinical management of patients with inherited cardiac conditions. However, to move beyond just confirmatory and predictive testing, a much greater understanding is needed of the genetic basis of these conditions, the role of the environment, and the underlying disease mechanisms. With this additional information it is likely that genetic testing will increasingly be used for stratified and preventative strategies in the era of genomic medicine. The establishment of CVGPs is probably the most effective and comprehensive method for diagnosis and treatment of a wide array of heritable cardiac conditions, that, heretofore, remained somewhat elusive. These programs are up and running in some major/ tertiary institutions. However, making this a routine practice for diagnosis of heritable cardiac conditions, would be the standard of care. Till such time, that the creation of CVGPs is made uniform practice, a primary need, is establishing screening programs. These maybe in the form of community screening which in turn maybe achieved by distributing screening questionnaires to identify individuals at risk for sudden cardiac death, premature atherosclerosis or heart failure. Once identified, these patients can then be referred to CVGPs for further investigations. Genetic counselors form the cornerstone of CVGPs and serve as a liaison between the clinician and the patient. As of today, cardiogenetics largely remains underutilized due to various factors. A fully established CVGP is an exciting frontier for identification and management of heritable cardiac conditions. Collaborating with the coroner for cascade screening of families of young individuals who have suffered sudden cardiac death cannot be overemphasized.


Modified Lung Ultrasound Examinations in Assessment and Monitoring of Positive End-Expiratory Pressure-Induced Lung Reaeration in Young Children With Congenital Heart Disease Under General Anesthesia.

Wu L, Hou Q, Bai J, Zhang J, Sun L, Tan R, Zhang M, Zheng J. Pediatr Crit Care Med. 2019 May;20(5):442-449. doi: 10.1097/PCC.0000000000001865. PMID:  31058784 Similar articles   Take Home Points: The most prevalent region of post-intubation atelectasis in...

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