Electrogram morphology discriminators in implantable cardioverter defibrillators: A comparative evaluation.

Background: Morphology algorithms are currently recommended as a standalone discriminator in single-chamber implantable cardioverter defibrillators (ICDs). However, these proprietary algorithms differ in both design and nominal programming.

Objective: To compare three different algorithms with nominal versus advanced programming in their ability to discriminate between ventricular (VT) and supraventricular tachycardia (SVT).

Assessment of cardiac resynchronisation therapy in patients with wide QRS and non-specific intraventricular conduction delay: rationale and design of the multicentre randomised NICD-CRT study.

Introduction: Cardiac resynchronisation therapy (CRT) was initially developed to treat patients with left bundle branch block (LBBB). However, many patients with heart failure have a widened QRS but neither left-BBB nor right-BBB; this is called non-specific intraventricular conduction delay (NICD). It is unclear whether CRT is effective in this subgroup of patients.

Role of patient education in the perception and acceptance of home monitoring after recent implantation of cardioverter defibrillators: the EDUCAT study.

Background: Much attention is being paid to the education of and provision of medical information to patients, to optimize their understanding and acceptance of their disease.

Aims: To ascertain the impact of educating recent recipients of an implantable cardioverter defibrillator (ICD) on their perception and acceptance of a home monitoring (HM) system.

Methods: Questionnaire 1, completed one month after ICD implantation, was designed to assess: the quality of patient preparation for HM; patient comprehension of HM; and patient anxiety experienced during its installation.

Impact of pacing site on QRS duration and its relationship to hemodynamic response in cardiac resynchronization therapy for congestive heart failure.

Introduction: Recent studies have demonstrated that left ventricular (LV) pacing site is a critical parameter in optimizing cardiac resynchronization therapy (CRT). The present study evaluates the effect of pacing from different LV locations on QRS duration (QRSd) and their relationship to acute hemodynamic response in congestive heart failure patients.

Methods And Results: Thirty-five patients with nonischemic dilated cardiomyopathy and left bundle branch block referred for CRT device implantation were studied.

Contributions of a hemodynamic sensor embedded in an atrial lead in a porcine model.

Introduction: Preliminary studies have revealed a high correlation between peak endocardial acceleration (PEA) measured with a sensor embedded in a ventricular lead and human cardiac contractility. In this study we assessed (1) the contributions made by measurements of PEA1, an index of ventricular systolic contraction, from the right atrium, and (2) the feasibility of recording a fourth component of PEA (PEA4), coincident with atrial contraction and corresponding to the phonocardiographic fourth heart sound.

Methods: We placed a PEA sensor embedded at the tip of a right atrial lead in 9 pigs.

Addition of a second LV pacing site in CRT nonresponders rationale and design of the multicenter randomized V(3) trial.

Background: Cardiac resynchronization therapy (CRT) is an effective treatment of heart failure (HF) in presence of a depressed left ventricular (LV) ejection fraction and a wide QRS complex. It is limited by a high proportion of nonresponders. Attempts have been made, in small studies, to increase the number of stimulation sites to optimize the resynchronization therapy.

Left ventricular endocardial stimulation for severe heart failure.

Biventricular resynchronization, a therapy recommended for patients presenting with left ventricular (LV) dysfunction and ventricular dyssynchrony, requires the implantation of an LV lead, usually placed in a lateral or posterolateral tributary of the coronary sinus. Despite important progress made in the development of dedicated instrumentation, the procedure remains sometimes challenging and unsuccessful in a minority of patients. In the rare instances of unsuccessful transvenous implantations occurring in the presence of major surgical contraindications, a few operators have implanted the LV lead transseptally, an approach limited by technical difficulties and by the thromboembolic risk associated with the presence of a lead inside the LV cavity.

Extraction of old pacemaker or cardioverter-defibrillator leads by laser sheath versus femoral approach.

Background: Some operators routinely extract chronically implanted transvenous leads from a femoral, whereas others prefer a superior approach. This prospective study compared the safety and effectiveness of laser sheaths versus femoral snare extractions.

Methods And Results: The single-center study comprised 101 patients referred for unequivocal indications to extract > or =1 transvenous lead(s).

Optimizing hemodynamics in heart failure patients by systematic screening of left ventricular pacing sites: the lateral left ventricular wall and the coronary sinus are rarely the best sites.

Objectives: We sought to evaluate the impact of the left ventricular (LV) pacing site on hemodynamic response to cardiac resynchronization therapy (CRT).

Background: CRT reduces morbidity and mortality in heart failure patients. However, 20% to 40% of eligible patients may not fully benefit from CRT device implantation.

Electrocardiogram-based algorithm to predict the left ventricular lead position in recipients of cardiac resynchronization systems.

Introduction: Biventricular pacing is associated with various electrocardiographic patterns depending on the position of the left ventricular (LV) lead. We aimed to develop an electrocardiogram-based algorithm to predict the position of the LV lead.

Methods: The algorithm was developed in 100 consecutive recipients of cardiac resynchronization therapy (CRT) systems.

Predictors of a positive response to biventricular pacing in patients with severe heart failure and ventricular conduction delay.

Background: Cardiac resynchronization therapy (CRT) is recommended in patients with ejection fraction <35%, QRS width> 120 ms, and New York Heart Association (NYHA) functional class III or IV despite optimal medical therapy. We aimed to define demographic, clinical, and electrocardiographic predictors of positive clinical response to CRT.

Methods And Results: Hundred consecutive patients fulfilling the recommended criteria were implanted with a CRT device.

High prevalence of sleep apnea syndrome in patients with long-term pacing: the European Multicenter Polysomnographic Study.

Background: Cardiovascular diseases leading to pacemaker implantations are suspected of being associated with a high rate of undiagnosed sleep apnea syndrome (SAS). We sought to determine the prevalence and consequences of SAS in pacemaker patients according to pacing indications: heart failure, symptomatic diurnal bradycardia, and atrioventricular block.

Methods And Results: Ninety-eight consecutive patients (mean age, 64+/-8 years) not known to have sleep apnea were included; 29 patients were paced for dilated cardiomyopathy (29%), 33 for high-degree atrioventricular block (34%), and 36 for sinus node disease (37%).

Outcome after implantation of a cardioverter-defibrillator in patients with Brugada syndrome: a multicenter study.

Background: Brugada syndrome is an arrhythmogenic disease characterized by an increased risk of sudden cardiac death (SCD) by ventricular fibrillation. At present, an implantable cardioverter-defibrillator (ICD) is the recommended therapy in high-risk patients. This multicenter study reports the outcome of a large series of patients implanted with an ICD for Brugada syndrome.

Dynamic ventricular dyssynchrony: an exercise-echocardiography study.

Objectives: We sought to assess the effects of exercise on ventricular dyssynchrony in patients with normal and depressed left ventricular (LV) function.

Background: Asynchronous myocardial contraction adversely influences ventricular function and is associated with a poor prognosis in heart failure. Exercise-induced changes in ventricular dyssynchrony may be an important determinant of dynamic changes in cardiac output and mitral regurgitation.

Echocardiographic assessment during exercise of heart failure patients with cardiac resynchronization therapy.

This prospective echocardiographic study investigated the respective impacts of left ventricular (LV) pacing and simultaneous and sequential biventricular pacing (BVP) on ventricular dyssynchrony during exercise in 23 patients with compensated heart failure and ventricular conduction delays. During exercise, LV pacing and BVP significantly (p <0.05) improved mitral regurgitation and LV dyssynchrony compared with spontaneous activation.

Cardiovascular effects and risk of syncope related to donepezil in patients with Alzheimer's disease.

Background: When otherwise unexplained, syncope in patients with Alzheimer's disease may be attributed to bradycardia caused by cholinesterase inhibitors. We studied prospectively the clinical events and cardiovascular changes occurring during treatment with donepezil in patients with Alzheimer's disease.

Methods: Consecutive patients presenting with mild-to-moderate Alzheimer's disease were included in the study.

Clinical predictors of noninducibility of sustained atrial fibrillation after pulmonary vein isolation.

Background: Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI.

Methods And Results: Data were collected prospectively from 181 patients (153 male; age 54 +/- 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration < or =7 days).

Cardiac resynchronization therapy: Part 2--issues during and after device implantation and unresolved questions.

Encouraged by the clinical success of cardiac resynchronization therapy (CRT), the implantation rate has increased exponentially, although several limitations and unresolved issues of CRT have been identified. This review concerns issues that are encountered during implantation of CRT devices, including the role of electroanatomical mapping, whether CRT implantation should be accompanied by simultaneous atrioventricular nodal ablation in patients with atrial fibrillation, procedural complications, and when to consider surgical left ventricular lead positioning. Furthermore, (echocardiographic) CRT optimization and assessment of CRT benefits after implantation are highlighted.

Cardiac resynchronization therapy: Part 1--issues before device implantation.

Cardiac resynchronization therapy (CRT) has been used extensively over the last years in the therapeutic management of patients with end-stage heart failure. Data from 4,017 patients have been published in eight large, randomized trials on CRT. Improvement in clinical end points (symptoms, exercise capacity, quality of life) and echocardiographic end points (systolic function, left ventricular size, mitral regurgitation) have been reported after CRT, with a reduction in hospitalizations for decompensated heart failure and an improvement in survival.

Spectral analysis identifies sites of high-frequency activity maintaining atrial fibrillation in humans.

Background: The identification of sites of dominant activation frequency during atrial fibrillation (AF) in humans and the effect of ablation at these sites have not been reported.

Methods And Results: Thirty-two patients undergoing AF ablation (19 paroxysmal, 13 permanent) during ongoing arrhythmia were studied. Electroanatomic mapping was performed, acquiring 126+/-13 points per patient throughout both atria and coronary sinus.

Causes of syncope in patients with Alzheimer's disease treated with donepezil.

Introduction: Treatment of Alzheimer's disease (AD) with cholinesterase inhibitors carries a theoretical risk of precipitating bradycardia. Though syncope occurs in patients with AD, its aetiology is unclear. The aim of this study was to determine the causes of syncope in patients with AD who were treated with donepezil and hospitalised for evaluation of syncope.

Effect of catheter ablation on quality of life of patients with paroxysmal atrial fibrillation.

Background: Although improved quality of life is one of the primary aims of catheter ablation for paroxysmal atrial fibrillation, there is a paucity of published data on this topic.

Objectives: The purpose of this study was to determine the effect of curative catheter ablation on the quality of life of patients with symptomatic, drug-refractory paroxysmal atrial fibrillation.

Methods: This was a prospective nonrandomized study of 63 consecutively enrolled patients (49 men and 14 women, age 56 +/- 7 years).

Electrophysiologic and clinical consequences of linear catheter ablation to transect the anterior left atrium in patients with atrial fibrillation.

Objectives: To evaluate the feasibility and outcome of ablation to transect the anterior left atrium (LA) in patients with atrial fibrillation (AF).

Background: While the Maze procedure is effective in maintaining sinus rhythm in patients with AF, it is associated with significant morbidity. This prospective clinical study evaluates the feasibility and consequences of limited LA linear ablation to transect the anterior LA in patients with AF.

Left atrial linear ablation to modify the substrate of atrial fibrillation using a new nonfluoroscopic imaging system.

Linear left atrial ablation is performed in combination with pulmonary vein (PV) isolation to improve the clinical results of atrial fibrillation (AF) ablation. These procedures require long procedures and fluoroscopic exposure. The aim of the present study was to evaluate the performance of a new, nonfluoroscopic, real-time, three-dimensional navigation system for linear ablation at the left atrial roof and mitral isthmus.

Biventricular pacing and left ventricular pacing in heart failure: similar hemodynamic improvement despite marked electromechanical differences.

Introduction: We conducted an acute echocardiographic study comparing hemodynamic and ventricular dyssynchrony parameters during left ventricular pacing (LVP) and biventricular pacing (BVP). We sought to clarify the mechanisms responsible for similar hemodynamic improvement despite differences in electrical activation.

Methods And Results: Thirty-three patients underwent echocardiography prior to implantation with a multisite pacing device (spontaneous rhythm [SR]) and 2 days after implantation (BVP and LVP).