Boris Schmidt

Initial Experience Using a Forward Directed, High-Intensity Focused Ultrasound Balloon Catheter for Pulmonary Vein Antrum Isolation in Patients with Atrial Fibrillation

Background: A high‐intensity‐focused ultrasound balloon catheter (HIFU‐BC) is designed to isolate pulmonary veins (PV) outside the ostia (PV antrum). This catheter uses a parabolic CO2 balloon (behind water balloon) to focus a 20‐, 25‐, or 30‐mm diameter ring of ultrasound forward of the balloon (parallel to catheter shaft). The purpose of this study is to test the safety and efficacy of the HIFU‐BC for PV antrum isolation in patients with atrial fibrillation (AF).

Pulmonary vein isolation using a visually guided laser balloon catheter: the first 200-patient multicenter clinical experience.

Background— Because of the technical difficulty with achieving pulmonary vein (PV) isolation in the treatment of patients with paroxysmal atrial fibrillation, novel catheter designs to facilitate the procedure are in development. A visually guided laser ablation (VGLA) catheter was designed to allow the operator to directly visualize target tissue for ablation and then deliver laser energy to perform point-to-point circumferential ablation. Single-center studies have demonstrated favorable safety and efficacy. We sought to determine the multicenter feasibility, efficacy, and safety of performing PV isolation using the VGLA catheter. Methods and Results— This study includes the first 200 paroxysmal atrial fibrillation patients treated with the VGLA catheter (33 operators, 15 centers). After transseptal puncture, the VGLA catheter was used to perform PV isolation. Electric isolation was assessed using a circular mapping catheter. Using the VGLA catheter, 98.8% (95% confidence interval, 97.8%–99.5%) of targeted PVs were isolated using a mean of 1.07 catheters per patient. Fluoroscopy and procedure times were 31±21 (mean±SD) and 200±54 minutes, respectively, and improved with operator experience. There were no instances of stroke, transient ischemic attack, atrioesophageal fistulas, or significant PV stenosis. There was a 2% incidence of cardiac tamponade and a 2.5% incidence of phrenic nerve palsy. At 12 months, the drug-free rate of freedom from atrial arrhythmias after 1 or 2 procedures was 60.2% (95% confidence interval, 52.7%–67.4%). Conclusions— In this multicenter experience of the first 200 patients treated with the VGLA catheter, PV isolation can be achieved in virtually all patients using a single VGLA catheter with an efficacy similar to radiofrequency ablation.Background—Because of the technical difficulty with achieving pulmonary vein (PV) isolation in the treatment of patients with paroxysmal atrial fibrillation, novel catheter designs to facilitate the procedure are in development. A visually guided laser ablation (VGLA) catheter was designed to allow the operator to directly visualize target tissue for ablation and then deliver laser energy to perform point-to-point circumferential ablation. Single-center studies have demonstrated favorable safety and efficacy. We sought to determine the multicenter feasibility, efficacy, and safety of performing PV isolation using the VGLA catheter. Methods and Results—This study includes the first 200 paroxysmal atrial fibrillation patients treated with the VGLA catheter (33 operators, 15 centers). After transseptal puncture, the VGLA catheter was used to perform PV isolation. Electric isolation was assessed using a circular mapping catheter. Using the VGLA catheter, 98.8% (95% confidence interval, 97.8%–99.5%) of targeted PVs were isolated using a mean of 1.07 catheters per patient. Fluoroscopy and procedure times were 31±21 (mean±SD) and 200±54 minutes, respectively, and improved with operator experience. There were no instances of stroke, transient ischemic attack, atrioesophageal fistulas, or significant PV stenosis. There was a 2% incidence of cardiac tamponade and a 2.5% incidence of phrenic nerve palsy. At 12 months, the drug-free rate of freedom from atrial arrhythmias after 1 or 2 procedures was 60.2% (95% confidence interval, 52.7%–67.4%). Conclusions—In this multicenter experience of the first 200 patients treated with the VGLA catheter, PV isolation can be achieved in virtually all patients using a single VGLA catheter with an efficacy similar to radiofrequency ablation.

Catheter ablation of multiple unstable macroreentrant tachycardia within the right atrium free wall in patients without previous cardiac surgery.

Background—Macroreentrant atrial tachycardia (AT) involving the right atrial free wall (RAFW) has been reported in patients without atriotomy. Catheter ablation of these ATs remains challenging due to the multiple morphologies of ATs with unstable reentrant circuits in some patients. The purpose of this study was to clarify the electrophysiological characteristics of these ATs and attempt the novel approach for catheter ablation. Methods and Results—Electrophysiological study and catheter ablation were performed in 17 patients (14 men; 71 [quartile 1, 67; quartile 3, 76] years) with reentrant ATs originating from the RAFW using 3D mapping. All patients had no history of cardiac surgery. Clinical ATs with stable cycle length and atrial activation were identified in 11 patients (group A). All ATs were successfully ablated. In the remaining 6 patients, clinical tachycardia continuously changed, with a different cycle length and P-wave morphology and atrial activation sequence during mapping or entrainment study (group B). A complete isolation of the RAFW was attempted in group B. After complete isolation was achieved in 5 of 6 patients, ATs were not induced in these 6 patients. The number of previous failed catheter ablations and induced ATs were higher in group B than in group A. During 31 (19; 37) months of follow-up, AT recurrence developed in 27% patients from group A and 33% from group B. Conclusions—Multiple and unstable macroreentrant ATs from the RAFW can occur in patients without a history of cardiac surgery. The RAFW isolation has the potential to abolish all ATs.

Ventrikuläre Tachykardien mit Ursprung im spezifischen Reizleitungssystem

ZusammenfassungVentrikuläre Tachykardien (VT) mit Ursprung im His-Purkinje-System können bei Patienten mit und ohne strukturelle Herzerkrankung auftreten. Bei Ersteren stellen die Schenkeltachykardien (englisch „bundle branch reentrant ventricular tachycardia“) die häufigste Form dieser VT dar. Diese Makroreentrytachykardien entstehen auf dem Boden einer Leitungsverzögerung im His-Purkinje-System (vorbestehender Linksschenkelblock) und können durch Ablation des rechten Tawara- Schenkels kuriert werden. Die weitere Prognose hängt von der kardialen Grunderkrankung ab.Bei herzgesunden Patienten treten idiopathische linksventrikuläre Tachykardien auf, die Ausdruck eines Reentrys im Purkinje-Netzwerk des posterioren Faszikels sind. Typisch sind der relativ schmale QRS-Komplex und die Rechtsschenkelblockmorphologie mit superiorer Achse. Die Gabe von Verapamil oder die kurative Katheterablation im Bereich des mittleren Septums stellen die therapeutischen Alternativen dar.Bei Patienten ohne strukturelle Herzerkrankung mit überlebtem plötzlichen Herztod können „Trigger“ aus dem Purkinje-Netzwerk vorzeitig ein fallende Extrasystolen generieren, die dann idiopathisches Kammerflimmern induzieren. Die Katheterablation stellt eine sehr effektive Methode zur Reduktion von ICD-Interventionen (implantierbarer Kardioverter-Defibrillator) bei diesen Patienten dar.AbstractVentricular tachycardias (VT) associated with the His-Purkinje system may occur in patients with and without organic heart disease. The former may encounter bundle branch reentrant VT, a macroreentrant VT utilizing the specific conduction system. It frequently occurs in patients with preexisting conduction disturbance such as complete left bundle branch block and may be eliminated by catheter ablation of the right bundle branch. After successful ablation, patient’s prognosis depends on the presence or absence of structural heart disease.In patients without structural heart disease, VT with right bundle branch block pattern and superior axis, referred to as idiopathic left ventricular tachycardia, is observed. It is a reentrant VT utilizing the posterior left fascicle and the Purkinje network. The two treatment options include antiarrhythmic drug therapy with verapamil or curative catheter ablation.Another form of ventricular arrhythmia originating in the Purkinje network is idiopathic ventricular fibrillation (IVF). Focal triggers from the right and left ventricular Purkinje network induce premature ventricular contractions inducing IVF. This is amenable to catheter ablation leading to a significant reduction in ICD (implantable cardioverter defibrillator) interventions in sudden cardiac death survivors.Ventricular tachycardias (VT) associated with the His-Purkinje system may occur in patients with and without organic heart disease. The former may encounter bundle branch reentrant VT, a macroreentrant VT utilizing the specific conduction system. It frequently occurs in patients with preexisting conduction disturbance such as complete left bundle branch block and may be eliminated by catheter ablation of the right bundle branch. After successful ablation, patients prognosis depends on the presence or absence of structural heart disease.In patients without structural heart disease, VT with right bundle branch block pattern and superior axis, referred to as idiopathic left ventricular tachycardia, is observed. It is a reentrant VT utilizing the posterior left fascicle and the Purkinje network. The two treatment options include antiarrhythmic drug therapy with verapamil or curative catheter ablation.Another form of ventricular arrhythmia originating in the Purkinje network is idiopathic ventricular fibrillation (IVF). Focal triggers from the right and left ventricular Purkinje network induce premature ventricular contractions inducing IVF. This is amenable to catheter ablation leading to a significant reduction in ICD (implantable cardioverter defibrillator) interventions in sudden cardiac death survivors.