Barry Love

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.

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.

Electroanatomic Characterization of Conduction Barriers in Sinus/Atrially Paced Rhythm and Association with Intra‐Atrial Reentrant Tachycardia Circuits Following Congenital Heart Disease Surgery

Conduction Barriers in Sinus Rhythm and IART. Introduction: The electrophysiologic mechanism of intra‐atrial reentrant tachycardia (IART) is generally thought to be a macroreentrant circuit revolving around a nonconductive or highly anisotropic barrier. However, the electrical and anatomic substrate that supports these circuits has been incompletely defined. Our objectives were to characterize the atria of patients with IART using electroanatomic mapping in sinus or atrially paced rhythm and to determine whether electrical barriers identified in sinus/atrially paced rhythm are associated with IART circuits.

Supraventricular arrhythmias in children and young adults with implantable cardioverter defibrillators.

SVT in Pediatric ICD Recipients. Introduction: Rapidly conducted supraventricular tachycardias (SVTs) can lead to inappropriate device therapy in implantable cardioverter defibrillator (ICD) patients. We sought to determine the incidence of SVTs and the occurrence of inappropriate ICD therapy due to SVT in a pediatric and young adult population.

Percutaneous Transhepatic Venous Access for Catheter Ablation Procedures in Patients With Interruption of the Inferior Vena Cava

Background— Catheter ablation of left-sided atrial arrhythmias generally is performed using a transfemoral venous approach through the inferior vena cava (IVC). In this report, we assessed the feasibility of a percutaneous transhepatic approach to ablation of left-sided atrial arrhythmias in 2 patients with interruption of the IVC. Methods and Results— Patient 1 had atrial flutter in the setting of complex congenital heart disease and prior Fontan for univentricular physiology and a single atrium. Patient 2 had atrial fibrillation. Percutaneous hepatic vein access was obtained with ultrasound and fluoroscopic guidance. Transseptal catheterization was performed in patient 2. After the procedure, the hepatic tract in patient 1 was cauterized using a bipolar radiofrequency catheter, and an Amplatzer vascular plug was used in patient 2 to obtain hemostasis. Percutaneous hepatic vein access was achieved without complications. After electroanatomical mapping, a linear lesion was placed between the single atrioventricular valve and the confluence of the hepatic veins in patient 1; this terminated the flutter, and bidirectional block was achieved. In patient 2, the pulmonary veins were electrically isolated using an extraostial approach, isolating the ipsilateral veins in pairs. Additionally, ablation of right-side atrial flutter was achieved by obtaining bidirectional block across a linear lesion between the tricuspid valve and confluence of the hepatic veins. Hemostasis of the transhepatic tract was attained in both patients. Conclusions— In patients with interrupted IVCs, a percutaneous transhepatic approach is a feasible alternative for performing catheter ablation of complex left-sided arrhythmias.

Staged repair of tetralogy of Fallot and diminutive pulmonary arteries with a fenestrated ventricular septal defect patch

OBJECTIVES Patients with tetralogy of Fallot and diminutive pulmonary arteries are at risk for suprasystemic right ventricular pressure and right ventricular failure after complete repair. We report the short-term outcome and medium-term follow-up after using a fenestrated ventricular septal defect patch as a component of staged repair in selected patients. METHODS We reviewed 47 patients with tetralogy of Fallot and diminutive pulmonary arteries whose ventricular septal defect patch was fenestrated, either electively or as a rescue technique, at a single institution between 1984 and 2001. RESULTS Early mortality was 10.6% and occurred only in patients who underwent rescue fenestration. Review of medium-term follow-up (median, 39 months) revealed 4 late deaths; an additional 4 patients experienced right ventricular failure despite fenestration. Most (7/8) of these late events occurred in patients who underwent planned fenestration. Excessive left-to-right shunt through the fenestration developed in only 2 patients. CONCLUSIONS Fenestrated patch closure of the ventricular septal defect in patients with tetralogy of Fallot and diminutive pulmonary arteries resulted in 10.6% early mortality. Used preemptively in selected patients, this technique is associated with no surgical mortality and a low incidence of excessive left-to-right shunt (4%). Early survivors remain at risk for late death and right ventricular failure despite fenestration.

Transcatheter occlusion of pulmonary arteriovenous malformations using the Amplatzer Vascular Plug II.

Pulmonary arteriovenous malformations (PAVMs) are a relatively uncommon but potentially life‐threatening condition manifested by cyanosis, paradoxical embolization, brain abscess, and rupture. A variety of transcatheter closure devices have been used to occlude PAVMs however risks of device embolization, incomplete closure, or large delivery systems have made each of these methods sub‐optimal. The Amplatzer Vascular Plug II (AVP II) is a new multisegmented, woven nitinol cylinder that can be deployed through a small delivery catheter. The AVP II differs from the original AVP in having a finer, more tightly woven nitinol frame and three, rather than one occlusive segment. The authors report the first use of the AVP II for occlusion of bilateral large arteriovenous malformations in a patient with hereditary hemorrhagic telangiectasia.

Evaluation and management of the adult patient with transposition of the great arteries following atrial-level (Senning or Mustard) repair

Atrial-level repair for transposition of the great arteries is one of the greatest achievements of modern cardiovascular medicine, transforming a once fatal congenital heart condition into one with excellent long-term survival. Although atrial-level repair has been supplanted by the arterial switch, there remains a population of patients who underwent atrial-level repair as children and now require ongoing care as adults. Survival slowly continues to decline in this population mainly owing to systemic right ventricular dysfunction and sudden death. Other problems include sinus node dysfunction, atrial arrhythmias, systemic atrioventricular valve regurgitation, baffle problems, and pulmonary hypertension. Evaluation and management of these late complications is addressed.

Transatrial septal catheterization using a new radiofrequency probe

Percutaneous therapeutic techniques requiring transseptal catheterization have increased in recent years. The traditional and current method for transseptal catheterization involves needle puncture, an effective but complicated technique, which is associated with a small but significant incidence of both perforation of structures adjacent to the atrial septum and pericardial tamponade. Enhanced imaging has reduced but not eliminated the risk of these complications. We have used an alternative method for transseptal access to the left atrium, which employs a novel radiofrequency catheter system. In this report, we describe the system and its use in our initial series of patients.

Transfemoral Snaring and Stabilization of Pacemaker and Defibrillator Leads to Maintain Vascular Access During Lead Extraction

Background: Lead extraction is an effective method for removing pacemaker and defibrillator leads and to obtain venous access when central veins are occluded.