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Rate-responsive pacemakers (PM) provide meaningful information to permanently follow-up the physical status of implanted patients. We report the case of a CHF patient fitted with a CRT-P device.ELA Medical PMs feature accelerometer and minute ventilation sensors. Cross-check between both sensors allows the calculation of the activity duration (Ad). The accelerometer reflects the mean intensity of physical activity (Ai), and mean minute ventilation (MV) is calculated at rest (MVr) and during activity phases (MVa). A 52 y. old male (LVEF 16%, NYHA class III) received a Talent 3 MSP PM on Oct 2003. The patient had an out-hospital visit due to CHF aggravation on the 01/01/04, then was hospitalized for HF decompensation. CRT appeared to be ineffective, and was deactivated with an increase of drug therapy.Analysis of PM data: Period 1: stable phase. Ad and Ai increase slowly, up to a stable level. MVa/Ai increase independently from Ai level, suggesting that this indicator is independent from patient's daily-life activity. Period 2: hyperactivity. the patient develops unusual high levels of activity (Ai), with an important increase of MVa/Ai. In the same time, MVr, which was stable increases dramatically, which suggests a degradation of his pulmonary function even at rest. Period 3: Drop by 50% in Ai and MVr decrease suggest an impossible sustained exercise. Period 4: MVa/Ai still increases, and MVr increases again. MV vary now independently from Ai. The patient is hospitalized for HF.Data provided by the PM may help in predicting the degradation of the cardio-pulmonary status of CRT patients, allowing a better management of HF therapy. [ABSTRACT FROM PUBLISHER]

The first case report introducing the concept of cardiac resynchronisation therapy (CRT) was published less than 10 years ago, opening the way to the development of the first successful non-pharmacological treatment of congestive heart failure (CHF). The now routine implantation of CRT systems is applicable to multitudes of patients as adjunctive therapy in advanced CHF. This technique has transformed the traditional concepts associated with stimulation of the heart, and is now applied not only to restore an appropriate heart rate, but also to change the process of cardiac mechanical activation. Since it must be integrated within a comprehensive and multidisciplinary CHF management program, CRT has changed the practice of experts in the field of cardiac pacing. CRT in the management of CHF was ultimately validated in 2 randomised trials. MUSTIC, the first trial, compared in a single-blind, 3 × 3 months crossover design active versus inactive biventricular stimulation in a group of patients in sinus rhythm and another group in atrial fibrillation. Both phases of the trial were completed by 48 patients, with significant positive effects conferred by CRT on the distance walked in 6 min and on peak oxygen consumption. The number of hospitalizations for management of CHF was decreased by 2/3 (P < 0.05), and 85% of patients preferred the atrio-biventricular over the inactive stimulation mode (P < 0.001). These results were amply confirmed by the parallel-design MIRACLE trial. The current indications for CRT, dignostic tools to assist in its implementation, and limitations of this new therapeutic adjunct are further discussed in this review. [ABSTRACT FROM PUBLISHER]

Pulsed field ablation (PFA) is an emerging technology for the treatment of atrial fibrillation (AF), for which pre-clinical and early-stage clinical data are suggestive of some degree of preferentiality to myocardial tissue ablation without damage to adjacent structures. Here in the MANIFEST-17K study we assessed the safety of PFA by studying the post-approval use of this treatment modality. Of the 116 centers performing post-approval PFA with a pentaspline catheter, data were received from 106 centers (91.4% participation) regarding 17,642 patients undergoing PFA (mean age 64, 34.7% female, 57.8% paroxysmal AF and 35.2% persistent AF). No esophageal complications, pulmonary vein stenosis or persistent phrenic palsy was reported (transient palsy was reported in 0.06% of patients; 11 of 17,642). Major complications, reported for ~1% of patients (173 of 17,642), were pericardial tamponade (0.36%; 63 of 17,642) and vascular events (0.30%; 53 of 17,642). Stroke was rare (0.12%; 22 of 17,642) and death was even rarer (0.03%; 5 of 17,642). Unexpected complications of PFA were coronary arterial spasm in 0.14% of patients (25 of 17,642) and hemolysis-related acute renal failure necessitating hemodialysis in 0.03% of patients (5 of 17,642). Taken together, these data indicate that PFA demonstrates a favorable safety profile by avoiding much of the collateral damage seen with conventional thermal ablation. PFA has the potential to be transformative for the management of patients with AF., (© 2024. The Author(s).)

Aims: Catheter ablation is a widely accepted intervention for atrial fibrillation (AF) management. Prior to undertaking this procedure, thorough patient education on its efficacy and potential complications is crucial. Additionally, educating patients about stroke risk management and anticoagulant therapy is imperative. At Mater Private Hospital in Dublin, we implemented a solution, integrating a customized treatment pathway and a mobile application. This patient-centred approach aims to optimize the clinical management of AF catheter ablation candidates, focusing on knowledge gaps and adherence to guideline-based care to enhance overall outcomes., Methods and Results: The application automates pre-operative assessments and post-operative support, facilitating seamless patient-clinician communication. During the observation period (September 2022-April 2023), 63 patients installed the app. Patient adherence to the pathway was strong, with 98% of patients actively engaging in the treatment pathway and with 81% completing all pre-operative tasks. The average enrolment-to-admission duration was 14 days, and post-ablation tasks were fulfilled by 62% of patients within an average of 36 days. Operators perceived the solution as user-friendly and effective in enhancing patient connectivity. Patient satisfaction was high, and knowledge about AF improved notably through the solution, particularly concerning the recognition of symptoms and anticoagulation therapy-related complications., Conclusion: Our findings demonstrate the successful implementation of the app-based Ablation Solution, showcasing widespread patient use, improved adherence, and enhanced understanding of AF and its treatments. The system effectively connects healthcare providers with patients, offering a promising approach to streamline AF catheter ablation management and improve patient outcomes., Competing Interests: Conflict of interest: N.F. reports institutional educational support from Biosense Webster and Synapse Medical as well as speakers fees from Daiichi Sankyo, unrelated to the submitted work. G.S. reports personal fees from Abbott, Bayer, Boston Scientific, Bayer, Johnson and Johnson Medical, and Luma Vision, not related to the present study, and consulting fees from Boston Scientific related to the present study. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Low voltage areas (LVAs) have been proposed as surrogate markers for left atrial (LA) scar. Correlation between voltages in sinus rhythm (SR) and atrial fibrillation (AF) have previously been measured via point-by-point analysis. We sought to compare LA voltage composition measured in SR to AF, utilizing a high-density automated voltage histogram analysis (VHA) tool in those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF)., Methods: We retrospectively analyzed patients with PeAF undergoing de novo PVI. Maps required ≥ 1,000 voltage points in each rhythm and had a standardized procedure (mapped in AF then remapped in SR post-PVI). We created six anatomical segments (AS) from each map: anterior, posterior, roof, floor, septal and lateral AS. These were analyzed by VHA, categorizing atrial LVAs into 10 voltage aliquots 0 - 0.5 mV. Data were analyzed using SPSS v.26., Results: We acquired 58,342 voltage points (n = 10 patients, mean age: 67 ± 13 years, three females). LVA burdens of ≤ 0.2 mV, designated as "severe LVAs", were comparable between most AS (except on the posterior wall) with good correlation. Mapped voltages between the ranges of 0.21 and 0.5 mV were labeled as "diseased LA tissue", and these were found significantly more in AF than SR. Significant differences were seen on the roof, anterior, posterior, and lateral AS., Conclusions: Diseased LA tissue (0.21 - 0.5 mV) burden is significantly higher in AF than SR, mainly in the anterior, roof, lateral, and posterior wall. LA "severe LVA" (≤ 0.2 mV) burden is comparable in both rhythms, except with respect to the posterior wall. Our findings suggest that mapping rhythm has less effect on the LA with voltages < 0.2 mV than 0.2 - 0.5 mV across all anatomical regions, excluding the posterior wall., Competing Interests: No conflict of interest to report., (Copyright 2023, Mannion et al.)

Aims: Incorporating a steerable sheath that can be visualized using an electroanatomical mapping (EAM) system may allow for more efficient mapping and catheter placement, while reducing radiation exposure, during ablation procedures for atrial fibrillation (AF). This study evaluated fluoroscopy usage and procedure times when a visualizable steerable sheath was used compared with a non-visualizable steerable sheath for catheter ablation for AF., Methods and Results: In this retrospective, observational, single-centre study, patients underwent catheter ablation for AF using a steerable sheath that is visualizable using the CARTO EAM (VIZIGO; n = 57) or a non-visualizable steerable sheath (n = 34). The acute procedural success rate was 100%, with no acute complications in either group. Use of the visualizable sheath vs. the non-visualizable sheath was associated with a significantly shorter fluoroscopy time [median (first quartile, third quartile), 3.4 (2.1, 5.4) vs. 5.8 (3.8, 8.6) min; P = 0.003], significantly lower fluoroscopy dose [10.0 (5.0, 20.0) vs. 18.5 (12.3, 34.0) mGy; P = 0.015], and significantly lower dose area product [93.0 (48.0, 197.9) vs. 182.2 (124.5, 355.0) μGy·m2; P = 0.017] but with a significantly longer mapping time [12.0 (9.0, 15.0) vs. 9.0 (7.0, 11.0) min; P = 0.004]. There was no significant difference between the visualizable and non-visualizable sheaths in skin-to-skin time [72.0 (60.0, 82.0) vs. 72.0 (55.5, 80.8) min; P = 0.623]., Conclusion: In this retrospective study, use of a visualizable steerable sheath for catheter ablation of AF significantly reduced radiation exposure vs. a non-visualizable steerable sheath. Although mapping time was longer with the visualizable sheath, the overall procedure time was not increased., Competing Interests: Conflict of interest: N.F. reports institutional educational support from Biosense Webster and Synapse Medical as well as speakers fees from Daiichi Sankyo, unrelated to the submitted work. G.S. reports personal fees from Abbott, Bayer, Boston Scientific, and Biosense Webster Inc. outside the submitted work. All remaining authors have declared no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Ablation index (AI) is a novel catheter-based parameter that has improved the outcome and safety of radiofrequency (RF) ablation of pulmonary vein isolations (PVIs). This index incorporates contact force (CF) (g), time (s), and power (W) parameters. The role of AI in redo ablations for persistent atrial fibrillation (peAF) has not been fully investigated. Hence, the impact of AI on the success of the redo PVI during the short-term follow-up period is the aim of this study., Methods: A retrospective analysis of 39 consecutive patients who underwent redo PVI ablations for peAF was carried out between January 2016 and December 2018. Target values for AI were 500 - 550 for anterior and roof and 400 - 380 for posterior and inferior regions. We compared outcomes between AI-guided and catheter CF ablations (i.e., forced time integral (FTI) of more than 400 g/s) during a follow-up of 24 months., Results: Pulmonary vein reconnections at redo procedure were similar in both groups (P = 0.1). AF free burden period was non-significant (mean 15.53 ± 2.4 months in AI group vs. 15.22 ± 1.9 months in CF group, P = 0.79) at 24 months. The AI group demonstrated greater numbers of patients for whom anti-arrhythmic therapy could be de-escalated over 1 year (n = 11 (65%) in AI vs. n = 6 (27%) in CF, P = 0.02). Fewer patients underwent escalation of their anti-arrhythmic therapy (n = 2 (12%) in AI vs. n = 7 (32%) in CF, P = 0.15). The AI group trended towards a shorter procedure time (111.6 ± 27 min) compared to the CF group (133 ± 40 min) (P = 0.06). Other procedural details were comparable., Conclusion: Redo PVI interventions using AI lead to a significant de-escalation in medication during follow-up. Procedure time and radiation dose using AI tends to be shorter. Both techniques are safe with minimal complications., Competing Interests: Limited financial support from J&J to cover the publication fee of the manuscript., (Copyright 2022, Lennon et al.)

Purpose: Transseptal puncture (TSP) is widely used in catheter-based cardiac procedures to gain left atrial access, but its workflow has remained largely unchanged in the last 50 years. This study evaluated the safety and efficacy of a novel, simplified technique for TSP with a radiofrequency (RF)-powered guidewire that eliminates multiple exchanges required with standard needles., Methods: TSP was performed in 84 patients undergoing left-sided procedures (72 atrial fibrillation ablations [32 RF, 40 cryoballoon], 4 atrial tachycardia ablations, 2 ventricular arrhythmia ablations, 6 left atrial appendage closure) utilizing a stiff, exchange length RF guidewire. Under fluoroscopic and echocardiographic guidance, the RF guidewire was used to facilitate septal puncture with RF energy and provide a rail for advancing catheters to the left atrium without exchange. All procedures were performed under general anesthesia or sedation., Results: TSP was achieved in all patients with no complications. The RF guidewire allowed catheters to be tracked back up to the superior vena cava without exchange in cases where another dropdown was desired to locate a preferred puncture site. The stiffness of the wire provided adequate support to advance all sheaths to the left side regardless of outer diameter., Conclusion: TSP was performed safely and successfully for various left heart procedures with a RF guidewire that served as an RF transseptal device and a stiff guidewire. This allowed for a more efficient and potentially safer technique without the need for re-wiring or an over the wire sheath exchange. This provides substantial savings in both time and materials.

Introduction: This study aimed to evaluate the safety and efficacy of utilising an innovative radiofrequency (RF) powered flexible needle to achieve transseptal puncture (TSP)., Methods and Results: A RF powered flexible needle (Toronto catheter, Baylis Medical Company Inc.) associated with a stiffer dilator (Torflex Superstrong, Baylis Medical Company Inc.) was used in 125 consecutive patients referred for left sided ablations (mean age=55.6, male=86.5%) and compared with a standard transseptal set (BRK needle, SL0 sheath and dilator, St Jude Medical, Inc.) used in the previous 100 patients (mean age=56, male 82%). TSP was achieved in 95/100 patients in the Brockenbrough group and in all 125 patients in the Toronto group (p=0.01) despite an equivalent proportion of difficult situations (8 and 9% respectively) and patients with a prior TSP (17% vs 24%). 7/100 needle related events (failure, aborted attempt or pericardial effusion) occurred in the Brockenbrough group and none in the Toronto group (p=0.01). The Toronto needle crossed the septum at the first attempt in 123/125 (98.4%) patients and the Brockenbrough needle in 84/95 (88%) patients (p<0.001)., Conclusion: Our data suggest that the Toronto RF powered flexible needle is safer and more efficient than a standard Brockenbrough needle and can be used not only in difficult situations but routinely to achieve TSP., (Copyright © 2014 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Aims: SafeR performance versus DDD/automatic mode conversion (DDD/AMC) and DDD with a 250-ms atrioventricular (AV) delay (DDD/LD) modes was assessed toward ventricular pacing (Vp) reduction., Methods: After a 1-month run-in phase, recipients of dual-chamber pacemakers without persistent AV block and persistent atrial fibrillation (AF) were randomly assigned to SafeR, DDD/AMC, or DDD/LD in a 1:1:1 design. The main endpoint was the percentage of Vp (%Vp) at 2 months and 1 year after randomization, ascertained from device memories. Secondary endpoints include %Vp at 1 year according to pacing indication and 1-year AF incidence based on automatic mode switch device stored episodes., Results: Among 422 randomized patients (73.2±10.6 years, 50% men, sinus node dysfunction 47.4%, paroxysmal AV block 30.3%, bradycardia-tachycardia syndrome 21.8%), 141 were assigned to SafeR versus 146 to DDD/AMC and 135 to DDD/LD modes. Mean %Vp at 2 months was 3.4±12.6% in SafeR versus 33.6±34.7% and 14.0±26.0% in DDD/AMC and DDD/LD modes, respectively (P<0.0001 for both). At 1 year, mean %Vp in SafeR was 4.5±15.3% versus 37.9±34.4% and 16.7±28.0% in DDD/AMC and DDD/LD modes, respectively (P<0.0001 for both). The proportion of patients in whom Vp was completely eliminated was significantly higher in SafeR (69%) versus DDD/AMC (15%) and DDD/LD (45%) modes (P<0.0001 for both), regardless of pacing indication. The absolute risk of developing permanent AF or of remaining in AF for >30% of the time was 5.4% lower in SafeR than in the DDD pacing group (ns)., Conclusions: In this selected patient population, SafeR markedly suppressed unnecessary Vp compared with DDD modes., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)

Background: Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP)., Methods: The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year., Results: Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF., Conclusions: In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.

The long-term relationship between cardiac arrhythmias and sleep apnoea in myotonic dystrophy (DM1) is unknown. Pacemakers enabling the long-term monitoring of electrocardiographic and ventilation parameters were implanted in 20 patients with DM1 (mean age = 42+/-11.6 years), followed 40+/-12.3 months. Arrhythmias were recorded by the pacemaker in 17 patients (85%): 14 developed arrhythmic episodes that occurred either in absence or in presence of concomitant sleep apnoea. Conversely, among these 14 patients, the majority of sleep apnoea episodes were not associated with concomitant arrhythmias. In the other three patients who developed arrhythmias, simultaneous sleep apnoea was never observed. Episodes of sleep apnoea were observed in all patients, though only 85% presented with sleep apnoea syndrome. In conclusion, a high incidence of arrhythmias and sleep apnoea was observed. While arrhythmias are generally attributable to an organic substrate, they are sometimes precipitated by functional triggers, as in the case of sleep apnoea.

Aims: To examine the performance of AAIsafeR2, a new pacing mode to minimize the cumulative proportion of ventricular pacing in patients who do not need regular ventricular support., Methods and Results: The safety of AAIsafeR2 was examined in 123 recipients (73 +/- 12 years old, 51% men) of dual chamber pacemakers implanted for sinus node dysfunction, paroxysmal AV block or the bradycardia-tachycardia syndrome. Data were collected from pacemaker diagnostics, and the first 43 patients underwent 24-h Holter recordings before being discharged from the hospital with AAIsafeR2 activated. No adverse event related to AAIsafeR2 was observed. All ventricular pauses detected on Holter tapes triggered immediate back-up ventricular pacing. Appropriate switches to DDD occurred in 97 of 123 patients. In 69 of 123 devices (56%) switches to DDD were non-sustained, and the average % ventricular pacing in this group was 0.2+/-0.5%., Conclusion: AAIsafeR2 mode seems to be safe and reliable in patients with infrequent slowing or pauses in ventricular activity, while maintaining ventricular pacing below 1%.

Automatic beat-by-beat capture functions are designed to minimize the pacing energy delivered, while maintaining the highest safety by delivering an immediate back-up stimulus in case of loss of capture. The objective of this study was to estimate the lowering of ventricular pacing amplitude allowed by such a function, compared to amplitudes usually set manually in routine practice. An automatic ventricular pacing threshold test is launched every 6 hours to measure the automatic capture threshold (AT). From AT the function calculates: (1) the"capture amplitude"(V(c)) = AT + 0.5 V at a minimum output of 1 V and (2) the"safety amplitude" (V(s)) = twice AT at a minimum output of 2.5 V. The function preferentially uses V(c) and verifies capture after each paced beat. In case of loss of capture, a back-up spike is delivered and V(s) is implemented until the next threshold measurement. We estimated the ventricular amplitude delivered by the pacemaker from data stored in the pacemaker memory. We compared these values with the pacing amplitude typically programmed manually (MPA) by physicians at twice AT and a minimum of 2.5 V. Data from 57 recipients of Talent 3 DR pacemakers were analyzed. Complete data sets were available in 25 patients at 1 day, 28 at 1 month, and 39 between 1 day and 1 month. No loss of capture or ventricular pause was observed on 53 ambulatory electrocardiograms (ECG); and pulse amplitude automatically delivered by the device was significantly lower than the MPA at each of the three time points analyzed. This new beat-by-beat capture function allows a significant lowering of the pacing amplitude compared to manual settings, while preserving a 100% safety.

We have designed a prospective observational study to analyze the incidence and predictive factors of atrial fibrillation (AF) during a long follow-up, in a large population. Atrial fibrillation episodes were documented by the fallback mode switch (FMS) provided by implanted pacemakers. We have included 377 patients (61% men). The pacing indications were atrioventricular (AV) block (49%), sinus node disease (SND, 16%), bradycardia-tachycardia syndrome (BTS, 5%), AV block + SND (19%), AV block + BTS (6%), and BTS + SND (5%). The mean age at implant was 75 +/- 12 (range 28-95). Atrial fibrillation before inclusion was documented in 10% of patients. Drug therapy at first follow-up included beta-adrenergic blockers (17% of the patients), amiodarone (13%), and others (16%). The mean follow-up was 30 +/- 24 weeks. At least one AF episode was stored during follow-up in the memory of 169 pacemakers (45%). Among patients without history of AF at implant, 46% had documented FMS during follow-up. Patients with AF received more antiplatelet medications than patients without AF (P = 0.03). In patients with AF, New York Heart Association functional class was slightly higher, amiodarone and sotalol were more often prescribed, and the proportion of hypertension was higher than in patients without AF. However, these trends were not statistically significant. A significant higher incidence of premature atrial beats was observed in patients with AF than patients without AF (P < 0.0002). Patients with AF had a lower atrial percentage of paced events (55%) than patients without AF (63%, P < 0.02). These preliminary results confirm the high incidence of AF in paced patients and suggest a preventive effect of atrial pacing. The effects of other clinical variables may be confirmed with a longer follow-up in a larger population.

Atrial conduction disorders are frequent in elderly subjects and/or those with structural heart diseases, mainly mitral valve disease, hyperthrophic cardiomyopathies, and hypertension. The resultant electrophysiological and electromechanical abnormalities are associated with a higher risk of paroxysmal or persistent atrial tachyarrhythmias, either atrial fibrillation, typical or atypical flutter or other forms of atrial tachycardias. Such an association is not fortuitous because intra- and interatrial conduction abnormalities delays disrupt (spatial and temporal dispersion) electrical activation, thus promoting the initiation and perpetuation of reentrant circuits. Preventive therapeutic interventions induce variable, sometimes paradoxical effects as with the proarrhythmic effect of class I antiarrhythmic drugs. Similarly, atrial pacing may promote proarrhythmias or an antiarrhythmic effect according to the pacing site(s) and mode. Multisite atrial pacing was conceived to correct, as much as possible, abnormal activation induced by spontaneous intra- or interatrial conduction disorders or by single site atrial pacing, which are situations responsible for commonly refractory arrhythmias. Atrial electrical resynchronization can also be used to correct mechanical abnormalities like left heart AV dyssynchrony resulting from intraatrial conduction delays.

The evaluation of multisite stimulation with a haemodynamic aim has since its origin clashed with the absence of definition of a simple method of identifying candidates and of evaluation of the effects of treatment. In this pilot work, 66 patients were selected on electromechanical criteria obtained from a desynchronisation model identified from simple echographic parameters. The short term results demonstrate important modifications, differing according to the type of patient undergoing implantation. These results reject the basis of a prospective multicentric study aimed at validating the concept of ventricular resynchronisation.

Introduction: Results of previous studies suggest that atrial resynchronization by multisite atrial pacing may contribute to prevention of recurrences in patients with drug-refractory atrial tachyarrhythmias and significant intra-atrial conduction delay., Methods and Results: To verify this hypothesis, a prospective noncontrolled study of 86 patients (mean age 66 +/- 10 years) was conducted in a single center between January 1989 and February 1998. Inclusion criteria were P wave duration > or = 120 msec with interatrial conduction time > or = 100 msec, and history of multiple recurrences of atrial tachyarrhythmias (mean 7 +/- 4.8 episodes) evolving in a persistent mode for at least 6 months despite optimized drug treatment (mean 2.7 +/- 1.8 drugs/patient). Patients were chronically implanted with a pacing system that ensured permanent biatrial pacing using two atrial leads, one placed in the high right atrium and the other one into the mid or the distal part of the coronary sinus. P wave duration decreased from a mean value of 187 +/- 29 msec before implant to 106 +/- 14 msec (P < 0.0001) under biatrial pacing. After a 33-month mean follow-up (range 6 to 109), 55 patients (64%) remained in sinus rhythm, including 28 patients (32.6%) without any documented recurrence and 27 patients with one or more recurrences in a paroxysmal or in a persistent form. In these 55 patients, drug treatment was significantly reduced in relation to the preimplantation period (1.4 +/- 0.6 vs 1.7 +/- 0.5 drugs/patient; P = 0.011). The other 31 patients went into chronic atrial arrhythmia after a mean period of 26 months. The only predictive factor of positive response was a spontaneous P wave duration < 160 msec at baseline., Conclusion: The results are consistent with a preventive effect of permanent biatrial pacing on recurrent and drug-refractory atrial arrhythmias associated with intra-atrial conduction delay.