Is a dual-sensor pacemaker appropriate in patients with sino-atrial disease? Results from the DUSISLOG study.

Background: Rate-responsive pacemakers (PMs) are often supplied with accelerometer (XL) and minute ventilation (MV) sensors to provide a physiologic rate response according to patient needs. No information is available about the real benefit of dual-sensor rate-responsive pacing on the daily life of patients.

Methods: DUSISLOG (Dual Sensor vs Single Sensor comparison using patient activity LOGbook) is a two-arm prospective, randomized, multicenter study that enrolled 105 patients who received a rate-responsive PM (Insignia), Guidant Corp.

Digital technology in cardiac pacing: methods for morphology analysis of sensed endocavitary signals.

Unlabelled: Proper functioning of a pacemaker depends exclusively on the detection of intrinsic cardiac signals. Conventional devices merely establish the presence of an endocavitary potential, but do not evaluate it qualitatively. The recent incorporation of digital signal processing of sensed events in pacemaker permits diagnostic characterization heretofore impossible.

Effects of cardiac resynchronization therapy on the mechanisms underlying functional mitral regurgitation in congestive heart failure.

Aims: Functional mitral regurgitation (FMR) improvement induced by cardiac resynchronization therapy (CRT) has been related to left ventricular (LV) remodeling reversal and contractility enhancement. The effects induced by the changes of LV synchronicity indexes on FMR severity have not been investigated.

Methods And Results: In 30 patients with CRT for heart failure (HF) and QRS>130 ms, LV function parameters, FMR severity as mitral jet regurgitation/left atrial area ratio (JA/LAA) and standard deviation (SD) of the time to the systolic peak velocity at 6-basal and mid-LV segments as asynchrony indexes were evaluated (echo/tissue Doppler) before and 6 months after implant.

Evolution and prognostic significance of diastolic filling pattern in cardiac resynchronization therapy.

Background: Cardiac resynchronization therapy (CRT) is an emerging treatment for heart failure patients with left bundle branch block; in these patients left ventricle filling pattern (LVFP) abnormalities are recognized as cause of symptoms and predictors of outcome. We investigated the effects of CRT on diastolic function and the prognostic value of LVFP in patients on CRT.

Methods: 65 patients treated with CRT were studied over a 12 months period.

Monitored atrial fibrillation duration predicts arterial embolic events in patients suffering from bradycardia and atrial fibrillation implanted with antitachycardia pacemakers.

Objectives: The aim of our study was to evaluate arterial embolism (AE) occurrence rates and predictors in patients suffering from bradycardia and wearing a pacemaker with antitachycardia pacing therapies.

Background: Atrial fibrillation (AF) is associated with a high incidence of AE.

Methods: A total of 725 patients (360 men, age 71 +/- 11 years) were implanted with a DDDRP pacemaker (Medtronic AT500, Medtronic Inc.

Pacemaker selection: time for a rethinking of complex pacing systems?

Evidence from randomized trials indicates that the clinical benefits of dual-chamber (DDD) pacing are modest: (i) no significant differences exist between physiological pacing and single-chamber pacing in mortality and stroke; (ii) ventricular desynchronization resulting from chronic right-ventricular pacing in DDD mode, induces a significantly increased incidence of atrial fibrillation (AF) and heart failure hospitalizations; (iii) AF pacing prevention and therapy algorithms have shown a modest to minimal or absent efficacy; (iv) the widespread use of physiological pacemakers is not an economically attractive strategy. Thus, these data provide a reliable body of evidence on which to make more rationale clinical decisions for individual patients and policy decisions for health costs saving. The cheaper single-chamber AAI(R) or VVI(R) has been shown to satisfy both conditions in most cases of sinus node disease and AV block.

Long-term reduction of atrial tachyarrhythmia recurrences in patients paced for bradycardia-tachycardia syndrome.

Background: Atrial tachyarrhythmias (AT) are considered progressive diseases. Several rhythm control therapies for treatment of AT have been proposed.

Objectives: The Italian AT500 Registry was designed to prospectively study long-term AT evolution in patients paced for the brady-tachy form of sinus node disease (BT-SND).

Resynchronization of mitral valve annular segments reduces functional mitral regurgitation in cardiac resynchronization therapy.

Aim: Cardiac resynchronization therapy (CRT) reduces the severity of functional mitral regurgitation (FMR) in patients with heart failure and left bundle branch block. Our hypothesis was that the induction of a more synchronous mitral valve anulus contraction can be a mechanism of FMR reduction in CRT patients.

Methods: An echo tissue Doppler imaging (TDI) examination was performed at baseline and 6 months after biventricular pacing system implant in 30 patients (4 females and 26 males, 74.

Rate stabilization by right ventricular apex or His bundle pacing in patients with atrial fibrillation.

Aims: In patients with atrial fibrillation right ventricular pacing can block antegrade conduction at pacing intervals longer than the shortest spontaneous R-R interval, causing the stabilization of ventricular rhythm. In this study the effects of pacing at two sites were compared in order to evaluate the role of conduction times in determining the stabilization of ventricular rhythm.

Methods: In eight patients with permanent atrial fibrillation, the ventricular rate was recorded before and during pacing at the right ventricular apex and the His bundle with different cycle lengths.

Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device.

Unlabelled: Predictors of ATP efficacy in brady/tachy patients.

Background: Recent options to treat atrial tachyarrhythmias (ATA) include implantable devices delivering antitachycardia pacing therapies (ATP). No prospective study selected patients with higher chances of episode termination by ATP or indicated the most effective ATP use.

Sample size estimates for atrial fibrillation endpoints.

This article reviews the current sample size requirements for studies evaluating the efficacy of atrial therapies. Sample sizes for several study designs and endpoints are presented. However, emphasis is given to studies conducted in patients with implantable devices in the light of new available data from recent trials involving such patients.

Echocardiographic examination of atrioventricular and interventricular delay optimization in cardiac resynchronization therapy.

In 21 patients implanted with a biventricular pacing device with programmable interventricular delay (VVd), the myocardial performance index (MPI) was evaluated during spontaneous sinus rhythm, simultaneous biventricular pacing, and sequential biventricular pacing at different VVds and atrioventricular delays (AVds). The AVd-VVd combination associated with the minimum MPI defined patient-tailored biventricular pacing. Simultaneous biventricular pacing significantly improved MPI compared with spontaneous sinus rhythm.

Digital technology for cardiac pacing.

Digital technology transforms analog signals into digital signals. Digitalization translates data into a numerical sequence of 0 seconds and 1 second or off and on (binary system). Thus encoded, differing signals (static or moving images, sounds, written texts) become homogeneous and can be handled simultaneously in a rapid and flexible manner while maintaining quality and stability.

Temporal variability of atrial tachyarrhythmia burden in bradycardia-tachycardia syndrome patients.

Aims: Several studies have tested non-pharmacological therapies for atrial tachyarrhythmias (ATs) by measuring the cumulative time (burden) the patient spends in arrhythmia. Contradictory results questioned either therapy efficacy or statistical power of the trials. We studied AT burden variability in patients paced for sinus node disease (SND) in order to interpret currently published data appropriately and to evaluate reliable sample sizes.

[Prevalence of cardiovascular manifestations in Marfan syndrome].

Background: Marfan syndrome is an inherited connective tissue disorder with an autosomic dominant transmission. The prevalence is 1:5000-10 000 and the clinical major criteria involve the skeletal and ocular apparatus and the cardiovascular and central nervous system. The main cause of morbidity is represented by the thoracic aortic dissection/aneurysm that is responsible for 80% of the deaths.

Far-field R wave oversensing in dual chamber pacemakers designed for atrial arrhythmia management: effect of pacing site and lead tip to ring distance.

INAMA, G., et al.: Far-Field R Wave Oversensing in Dual Chamber Pacemakers Designed for Atrial Arrhythmia Management: Effect of Pacing Site and Lead Tip to Ring Distance.

Atrial fibrillation and cardiac resynchronization therapy: the MASCOT study.

Atrial fibrillation (AF) and congestive heart failure (CHF) share several characteristics and often coexist in the same patient. Both are responsible for significant morbidity and mortality, are increasing in prevalence, and are major sources of health expenditure. The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) study is a European, single-blind, prospective, controlled, multicentre, randomized clinical trial designed to examine whether adding the AF Suppression Algorithm to cardiac resynchronization therapy (CRT) improves the prognosis of patients with CHF.

Atrial septal pacing: a new approach to prevent atrial fibrillation.

Atrial pacing may prevent the onset of atrial fibrillation (AF) because of: (1) prevention of the relative bradycardia that triggers paroxysmal AF; (2) prevention of the bradycardia induced dispersion of refractoriness; (3)suppression or reduction of premature atrial contractions that initiate reentry and predispose to AF; (4) preservation of AV synchrony, which might prevent switch induced changes in atrial repolarization predisposing to AF. Atrial pacing locations that decrease atrial activation and dispersion of refractoriness may be preferable in patients with a history of AF. Two different interatrial septum sites have been proposed: the Bachmann's bundle and the coronary sinus ostium.

Methods for testing automatic mode switching in patients implanted with DDD(R) pacemakers.

The assessment of automatic mode switching (AMS) algorithms is impossible in vivo, due to a low chance of seeing the patient at the onset of a spontaneous episode of atrial fibrillation (AF). As the induction of AF to test AMS has clinical concerns, three alternative and non-invasive techniques may be proposed for this purpose: myopotentials, chest wall stimulation, and an external supraventricular arrhythmia simulator. The first method is simple and does not require additional equipment, even though in some patients adequate signals cannot be generated with a soft effort such as handgrip or hand compression.

Atrial tachyarrhythmia recurrence temporal patterns in bradycardia patients implanted with antitachycardia pacemakers.

Introduction: New-generation pacemakers allow continuous atrial tachyarrhythmia (AT) monitoring that provides accurate information about AT type, frequency, burden, and temporary evolution.

Methods And Results: We performed a prospective multicenter study to describe AT temporal patterns in patients with sinus bradycardia and AT. Two hundred forty patients (123 men; age 71 +/- 8 years) were implanted with a DDDRP pacemaker (model AT500, Medtronic Inc.

A perspective on atrioventricular delay optimization in patients with a dual chamber pacemaker.

Atrioventricular delay (AVD) is critical in patients with DDD pacemakers (PM). Echo/Doppler evaluation of AVD providing the longest left ventricular filling time (FT) or the highest cardiac output (CO) is used for AVD optimization. Recently myocardial performance index (MPI) has been shown to improve by optimizing AVD.

Myocardial perfusion imaging using gated SPECT in heart failure patients undergoing cardiac resynchronization therapy.

Unlabelled: Cardiac resynchronization therapy (CRT) by biventricular pacing is indicated in patients with severe heart failure and left bundle branch block who remain symptomatic despite optimal medical therapy. The relationship between baseline resting perfusion pattern and hemodynamic response to CRT has not been fully investigated. We tested the usefulness of perfusion gated SPECT for baseline evaluation and follow-up of these patients.

Combined efficacy of atrial septal lead placement and atrial pacing algorithms for prevention of paroxysmal atrial tachyarrhythmia.

Introduction: The combined role of atrial septal lead location and atrial pacing algorithms in the prevention of atrial tachyarrhythmias (AT/AF), including both atrial fibrillation and flutter, is unknown. We tested the hypothesis that atrial prevention pacing algorithms could decrease AT/AF frequency in patients with atrial septal leads, bradycardia, and paroxysmal AT/AF.

Methods And Results: A total of 298 patients (age 70 +/- 10 years; 61% male) from 35 centers were implanted with a DDDRP pacing system including three AT/AF prevention pacing algorithms.

[Normal and abnormal atrial activation. An update with special reference to surface electrocardiogram].

Surface electrocardiogram is commonly used to evaluate the normal and abnormal activation of the atria. Interatrial conduction appears as the most important factor determining P wave duration and morphology during sinus rhythm. A good estimation of the interatrial conduction time can be obtained by a simple esophageal recording or by P wave duration on the surface electrocardiogram.

Prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia: role of right atrial linear ablation and pacing site.

Introduction: Right atrial linear lesions (RALL), either alone or in combination with antiarrhythmic drug therapy, may modify the substrate for maintenance of atrial fibrillation (AF). The aim of this prospective randomized study was to determine whether RALL provides additional benefit to right atrial appendage pacing (RAAP) and/or interatrial septum pacing (IASP) and drug therapy in patients with symptomatic paroxysmal AF and sinus bradycardia requiring permanent atrial pacing.

Methods And Results: Sixty-four patients (33 men and 31 women, mean age 73 +/- 10 years) completed the 6-month follow-up.