Magnetic resonance imaging abnormalities in the basal interventricular septum of patients with left ventricular outflow tract arrhythmias.

Introduction: Concealed structural abnormalities were detected by delayed enhancement - magnetic resonance imaging (DE-MRI) in patients with apparently idiopathic tachycardia of left ventricular (LV) origin. Basal septal fibrosis was evaluated as a potential arrhythmia substrate in patients with left ventricular outflow tract (LVOT) arrhythmias.

Methods And Results: A total of 22 patients with LVOT arrhythmias, including frequent monomorphic premature ventricular complexes (PVCs) in 15 patients and ventricular tachycardia (VT) in 7 patients, underwent catheter ablation and DE-MRI.

Electrocardiographic criteria of epicardial ventricular tachycardia with anterior origin.

Background: ECG criteria for identifying an epicardial origin of ventricular tachycardia (VT) have mainly been described for VTs with basal-superior and lateral origin.

Objective: The aim of this study was to determine ECG criteria for epicardial VTs with anterior origin as a guide for trans-pericardial ablation.

Results: Among 22 patients undergoing successful ablation of VTs from the anterior myocardial wall, 14 patients underwent endocardial ablation and 8 patients underwent epicardial ablation.

Impact of intraoperative mechanical ventilation on left ventricular lead function in cardiac resynchronization therapy.

Background: Intraoperative controlled mechanical ventilation (CMV) changes the intrathoracic geometry and may impact postoperative left ventricular (LV) lead function after CRT implantation. This multicenter study investigates the effect of intraoperative ventilation setting (spontaneous breathing [SB] vs CMV) on postoperative LV lead function taking into account patients' body mass index (BMI).

Methods: CRT implantation was performed at two centers during SB in 92 and during CMV in 73 patients.

Left ventricular outflow tract arrhythmias with divergent QRS morphology: mapping of different exits and ablation strategy.

Background: Ventricular arrhythmias (VAs) from the left ventricular outflow tract (LVOT) can have multiple exits exhibiting divergent ECG features.

Methods: In a series of 131 patients with VAs with LVOT origin, 10 patients presented with divergent QRS morphologies. Multisite endo- and epicardial mapping of different exit sites was performed.

Atypical Surface ECG Complicating the Diagnosis of Bundle Branch Reentry Tachycardia.

Background: Typical left bundle branch block (LBBB) during ventricular tachycardia (VT) is a diagnostic criterion of bundle branch reentry tachycardia (BBRT) with activation of the right bundle in the anterograde direction.

Methods And Results: Eleven patients (seven male, 60 ± 12 years) with nonischemic cardiomyopathy (left ventricular ejection fraction 37 ± 16%) presenting with BBRT were successfully treated by ablation of the right bundle. Among them, five patients had atypical surface electrocardiograms (ECGs) differing from a typical LBBB during the VT.

Epicardial ventricular tachycardia substrate visualized by magnetic resonance imaging: need for a transpericardial ablation approach?

Background: Sustained ventricular tachycardia (VT) in patients with nonischemic cardiomyopathy (NICM) often involves midmyocardial and epicardial structures. Delayed-enhancement magnetic resonance imaging (DE-MRI) of scar and fibrosis is the method of choice to define the substrate of monomorphic VT.

Objective: The aim of the study was to compare the outcome of endocardial vs.

Incidence and relevance of nonreentrant monomorphic ventricular tachycardia in patients with frequent implantable cardioverter defibrillator interventions.

Background: Nonreentrant ventricular tachycardia (VT) originates in hearts without structural disease but occasionally can occur in patients with different cardiomyopathies equipped with an implantable cardioverter defibrillator (ICD).

Methods: In a series of 142 ICD recipients with structural heart disease undergoing ablation for recurrent or incessant monomorphic VT, nonreentrant VTs were identified.

Results: Nonreentrant VTs were the cause of appropriate ICD interventions in 12 patients (8.

Findings on magnetic resonance imaging of fascicular ventricular tachycardia.

Background: Idiopathic left ventricular tachycardia (ILVT) with right bundle branch block and left axis deviation originates from the left posterior fascicle--Purkinje fiber network. Scar-related ventricular tachycardias (VTs) with Purkinje fibers as a part of the reentry circuit have also been described in patients with structural heart disease.

Methods And Results: Nine patients with fascicular VT (left posterior, n = 8; left anterior, n = 1) with preserved left ventricular ejection fraction (60 ± 10%) underwent cardiac magnetic resonance imaging (MRI) including functional analysis and delayed enhancement magnetic resonance imaging (DE-MRI).

The risk of delayed atrioventricular and intraventricular conduction block following ablation of bundle branch reentry.

Background: The aim of the study was to determine the long-term reliability of atrioventricular and intraventricular conduction and the implications for cardiac resynchronization therapy (CRT-D) following catheter ablation of bundle branch reentry tachycardia (BBRT) and interfascicular tachycardia.

Methods And Results: Fourteen patients with recurrent monomorphic ventricular tachycardia (VT) (n = 11) and incessant VT (n = 3) underwent catheter ablation of BBRT (n = 7), interfascicular tachycardia (n = 5) or both arrhythmias (n = 2). Successful ablation was achieved in all patients without intraprocedural atrioventricular (AV) block.

Recording of low-amplitude diastolic electrograms through the coronary veins: a guide for epicardial ventricular tachycardia ablation.

Aims: The purpose of the study was to evaluate the role of coronary venous mapping to identify epicardial ventricular tachycardia (VT) in patients with structural heart disease.

Methods And Results: Epicardial mapping of the electrophysiological substrate through the coronary vein branches using a 2.2F, 16-pole microelectrode catheter was performed in 33 consecutive patients undergoing VT ablation.

Recurrent torsades de pointes after catheter ablation of incessant ventricular bigeminy in combination with QT prolongation.

A 45-year-old woman, who had received a single-chamber implantable cardioverter defibrillator (ICD) due to ventricular fibrillation 5 years ago, was admitted for catheter ablation of incessant right ventricular outflow tract bigeminy. After successful ablation recurrent torsades de pointes associated with a prolonged corrected QT (QTc) interval were initiated by polymorphic premature ventricular complexes. Genetic testing revealed a heterozygous missense mutation in the SCN5A-gene (p.

Outcome of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation.

Objectives: The aim of this study was to determine the long-term results of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation.

Methods: A history of atrial fibrillation was documented in 25 of 111 patients (23%) with focal atrial tachycardias. We studied the results of focal ablation during a follow-up of 27 +/- 22 months.

Complete loss of ICD programmability after magnetic resonance imaging.

The purpose of this case report is to describe the effects of an MRI performed on a patient without realizing that an ICD has been previously implanted. After a few seconds of imaging the adversity was recognized and the examination was stopped immediately. The patient was not pacemaker dependent and had neither physical complaints nor electrocardiographic changes in the surface ECG.

Application of radiofrequency energy in surgical and interventional procedures: are there interactions with ICDs?

During surgical and interventional procedures, interference may occur between ICDs and electrical cautery or with the application of RF energy. This may lead to the false induction of ICD therapies or could even result in device malfunction, which represents a potential perioperative hazard for the patient. This study analyzed the intraoperative interactions in 45 consecutive ICD patients in reference to different surgical and interventional procedures.

Radiofrequency catheter ablation: different cooled and noncooled electrode systems induce specific lesion geometries and adverse effects profiles.

The success and safety of standard catheter radiofrequency ablation may be limited for ablation of atrial fibrillation and ventricular tachycardia. The aim of this study was to characterize and compare different cooled and noncooled catheter systems in terms of their specific lesion geometry, incidence of impedance rise, and crater and coagulum formation to facilitate appropriate catheter selection for special indications. The study investigated myocardial lesion generation of three cooled catheter systems (7 Fr, 4-mm tip): two saline irrigation catheters with a showerhead-type electrode tip (sprinkler) and a porous metal tip and an internally cooled catheter.

Transvenous defibrillation leads: high incidence of failure during long-term follow-up.

Introduction: Patients with implantable cardioverter defibrillators (ICD) critically depend on correct functioning of their system. The aim of this study was to determine the incidence and clinical presentation of transvenous ICD lead failures during long-term follow-up.

Methods And Results: The study group consisted of 261 consecutive patients who received Medtronic right ventricular polyurethane transvenous leads (models 6884, 6966, 6936) between 1990 and 1998 as part of an abdominal (n = 70) or pectoral (n = 191) ICD system.