John K. Triedman

Long-Term Survival, Modes of Death, and Predictors of Mortality in Patients With Fontan Surgery

Background— To better define determinants of mortality in patients with univentricular physiology, a database registry was created of patients born in 1985 or earlier with Fontan surgery who were followed up at Children’s Hospital Boston. Methods and Results— A total of 261 patients, 121 of whom (46.4%) were women, had a first Fontan surgery at a median age of 7.9 years: right atrium–to–pulmonary artery connection in 135 (51.7%); right atrium to right ventricle in 25 (9.6%); and total cavopulmonary connection in 101 (38.7%). Over a median of 12.2 years, 76 (29.1%) died, 5 (1.9%) had cardiac transplantation, 5 (1.9%) had Fontan revision, and 21 (8.0%) had Fontan conversion. Perioperative mortality decreased steadily over time and accounted for 68.4% of all deaths. In early survivors, actuarial freedom from death or transplantation was 93.7%, 89.9%, 87.3%, and 82.6% at 5, 10, 15, and 20 years, respectively, with no significant difference between right atrium to pulmonary artery versus total cavopulmonary connection. Late deaths were classified as sudden in 7 patients (9.2%), thromboembolic in 6 (7.9%), heart failure–related in 5 (6.7%), sepsis in 2 (2.6%), and other in 4 (5.2%). Most sudden deaths were of presumed arrhythmic origin with no identifiable predictor. Independent risk factors for thromboembolic death were lack of antiplatelet or anticoagulant therapy (hazard ratio [HR], 91.6; P=0.0041) and clinically diagnosed intracardiac thrombus (HR, 22.7; P=0.0002). Independent predictors of heart failure death were protein-losing enteropathy (HR, 7.1; P=0.0043), single morphologically right ventricle (HR, 10.5; P=0.0429), and higher right atrial pressure (HR, 1.3 per 1 mm Hg; P=0.0016). Conclusion— In perioperative survivors of Fontan surgery, gradual attrition occurs predominantly from thromboembolic, heart failure–related, and sudden deaths.

Results of a multicenter retrospective implantable cardioverter-defibrillator registry of pediatric and congenital heart disease patients.

OBJECTIVES We sought to determine the implications of implantable cardioverter-defibrillator (ICD) placement in children and patients with congenital heart disease (CHD). BACKGROUND There is increasing frequency of ICD use in pediatric and CHD patients. Until recently, prospective registry enrollment of ICD patients was not available, and children and CHD patients account for only a small percentage of ICD recipients. Therefore, we retrospectively obtained collaborative data from 4 pediatric centers, aiming to identify implant characteristics, shock frequency, and complications in this unique population. METHODS Databases from 4 centers were collated in a blinded fashion. Demographic information, implant electrical parameters, appropriate and inappropriate shock data, and complications were recorded for all implants from 1992 to 2004. RESULTS A total of 443 patients were included, with a median age of 16 years (range 0 to 54 years) and median weight of 61 kg (range 2 to 130 kg), with 69% having structural heart disease. The most common diagnoses were tetralogy of Fallot (19%) and hypertrophic cardiomyopathy (14%). Implant indication was primary prevention in 52%. Shock data were available on 409 patients, of whom 105 (26%) received appropriate shocks (mean 4 shocks/patient, range 1 to 29 shocks/patient). Inappropriate shocks occurred in 87 of 409 patients (21%), with a mean of 6 per patient (range 1 to 60), mainly attributable to lead failure (14%), sinus or atrial tachycardias (9%), and/or oversensing (4%). CONCLUSIONS Children and CHD ICD recipients have significant appropriate and inappropriate shock frequencies. Optimizing programming, medical management, and compliance may diminish inappropriate shocks. Despite concerns regarding generator recalls, lead failure remains the major cause of inappropriate shocks, complications, and system malfunction in children. Prospective assessment of ICD usage in this population may identify additional important factors in pediatric and CHD patients.

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

OBJECTIVES The goal of this study was to identify factors associated with radiofrequency catheter ablation (RFCA) outcomes of intra-atrial re-entrant tachycardia (IART). BACKGROUND Radiofrequency catheter ablation of IART is difficult. The influence of patient and procedural factors and novel technologies on outcomes is unknown. METHODS Acute 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. RESULTS A total of 177 procedures were performed in 134 patients; 139 procedures (79%) resulted in RFCA of > or =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. CONCLUSIONS Improvement 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.

Radiofrequency Ablation of Intra-Atrial Reentrant Tachycardia After Surgical Palliation of Congenital Heart Disease

BACKGROUND 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. METHODS AND RESULTS 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. CONCLUSIONS 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.

A multicenter experience with novel implantable cardioverter defibrillator configurations in the pediatric and congenital heart disease population.

Both slowed and regularized ventricular rate provide hemodynamic benefits to patients with atrial fibrillation and thus constitute a primary therapeutic goal. The return to sinus rhythm obviously reaches this goal and has been the preferred strategy over several decades. Given that recurrence of atrial fibrillation is frequent in the face of both pharmacological and ablation-based invasive therapy, and that side effects may limit their use, rhythm control approaches may frequently fall short of expected clinical benefits. In that situation, rate control becomes the alternate strategy. In fact, a number of recent clinical trials comparing rhythm and rate control strategies consistently reported net benefits of rate control therapy (see1,2 for review). Accordingly, for many patients rate control is becoming the preferred strategy while rhythm control is being targeted when needed and/or possible.1 Rate control is primarily achieved by drug-induced conduction impairment of the AV node. When this approach fails, ablation-induced third-degree AV block coupled with ventricular pacing may be considered.3,4 Several other approaches are currently under scrutiny: ventricular pacing without AV block, slow pathway ablation, gene therapy, and selective ganglionic parasympathetic stimulation.3 The modulation of AV nodal function by cardiac ganglionic stimulation may prove to be of significant value in heart failure patients in whom antiarrhythmic drug-induced depression of ventricular function must be avoided.5-8 An added benefit is that a normal ventricular activation sequence is maintained. Selective ganglionic stimulation combined with ventricular pacing may provide further benefits by achieving a slowed and regularized ventricular rate in spite of persistent atrial fibrillation.9 The Soos et al. study in the current issue10 raises the possibility that ganglionic stimulation may be feasible with currently available pacemaker technology. The concept of rate control through parasympathetic stimulation is derived from pioneering experimental work showing that selective AV node conduction slowing can be achieved through local cardiac nerve stimulation.11-15 Effective parasympathetic ventricular rate slowing during atrial fibrillation has been reached in animals with nerve stimulation applied endocardially in the vicinity of AV node,16 transvenous catheter stimulation from the coronary sinus,5 and local electrical stimulation of inferior interatrial parasympathetic ganglionated plexus.7-10 In humans, transvenous

Cardiac resynchronization therapy (and multisite pacing) in pediatrics and congenital heart disease: five years experience in a single institution.

Introduction: Clinical evidence supports the use of cardiac resynchronization therapy (CRT) in adults with heart failure, but experience in pediatrics and congenital heart disease (CHD) is limited in terms of patient numbers and follow‐up. We sought to determine the functional assessment and clinical outcomes in pediatric and CHD CRT patients followed uniformly at one institution.

Efficacy of Radiofrequency Ablation for Control of Intraatrial Reentrant Tachycardia in Patients With Congenital Heart Disease

BACKGROUND Intraatrial reentrant tachycardia (IART) is a common problem in patients with congenital heart disease (CHD). The progression of clinical symptoms of IART and their response to radiofrequency (RF) ablation are not yet well described. OBJECTIVES The objective of the study was to determine the early and midterm success rates of RF ablation in effecting a reduction of clinical arrhythmic events in patients with IART and CHD. METHODS Clinical records of patients undergoing early, successful RF ablation were analyzed retrospectively to document the occurrence and frequency of documented IART, cardioversion and arrhythmia-related hospital visits before and after ablation. RESULTS Fifty-five catheterizations for intended RF ablation of IART were performed in 45 patients (mean [+/-SD] age 24.5 +/- 10.5 years, 40 after surgical palliation of CHD). Early success was achieved for one or more IART circuits in 33 patients (73%). Mean clinical follow-up of those patients with successful ablation is 17.4 +/- 11.3 months (total 574 patient-months). Documented IART recurrence was noted after 21 (53%) of 40 early, successful catheterizations in 17 (52%) of 33 patients, with a mean time to recurrence of 4.1 months, often with electrocardiographically novel configurations. A more prolonged and frequent history of IART was a univariate risk factor for recurrence. Seven patients underwent repeat RF ablations, and eight patients were restarted on antiarrhythmic medications after ablation. Two patients who had severe ventricular dysfunction before RF ablation died 1.5 and 11 months after RF ablation without known arrhythmia recurrence. Clinical events related to IART increased steadily in frequency for 24 months before RF ablation. Radiofrequency ablation resulted in a reduction of event frequency to levels significantly lower than those in the 12-month period before RF ablation and not significantly different from those levels observed at baseline 3 to 4 years before RF ablation. CONCLUSIONS In patients with successful RF ablation, the frequency of subsequent events was reduced compared with the 2 preceding years. However, recurrence of IART in patients who showed clinical improvement was frequent, and often revealed the presence of new IART configurations.

EHRA/HRS/APHRS expert consensus on ventricular arrhythmias.

Christian Torp Pedersen (EHRA Chairperson, Denmark), G. Neal Kay (HRS Chairperson, USA), Jonathan Kalman (APHRS Chairperson, Australia), Martin Borggrefe (Germany), Paolo Della-Bella (Italy), Timm Dickfeld (USA), Paul Dorian (Canada), Heikki Huikuri (Finland), Youg-Hoon Kim (Korea), Bradley Knight (USA), Francis Marchlinski (USA), David Ross (Australia), Frédéric Sacher (France), John Sapp (Canada), Kalyanam Shivkumar (USA), Kyoko Soejima (Japan), Hiroshi Tada (Japan), Mark E. Alexander (USA), John K. Triedman (USA), Takumi Yamada (USA), and Paulus Kirchhof (Germany)

PACES/HRS Expert Consensus Statement on the Management of the Asymptomatic Young Patient with a Wolff-Parkinson-White (WPW, Ventricular Preexcitation) Electrocardiographic Pattern

C PACES/HRS Expert Consensus Statement on the Management of the Asymptomatic Young Patient with a Wolff-Parkinson-White (WPW, Ventricular Preexcitation) Electrocardiographic Pattern Developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology Foundation (ACCF), the American Heart Association (AHA), the American Academy of Pediatrics (AAP), and the Canadian Heart Rhythm Society (CHRS)

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, > or = 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.