Andrea Colella

Interatrial septum pacing: A new approach to prevent recurrent atrial fibrillation.

Background. There are a variety of approaches to the prevention of atrial fibrillation (AF) with pacing. Aim of this study was to test the safety and feasibility of interatrial septum pacing at the posterior triangle of Koch for AF prevention and to exclude potential arrhythmic effects.Matherial and Methods.Interatrial septum pacing was performed in 34 patients (21 males, 13 females, mean age 69±12 years): 9 without a history and clinical evidence of atrial fibrillation (AF) (6 with sinus bradycardia, 2 with second-degree AV block, and 1 with carotid sinus hypersensitivity) and 25 with sinus bradycardia and paroxysmal atrial fibrillation (PAF) (mean symptomatic episodes/month 6.2±10). In all patients a screw-in bipolar lead was positioned in the interatrial septum superiorly to the coronary sinus.Results.At implant the mean P wave amplitude was 2.5±1.5 mV, the pacing threshold was 1±0.6 V and the impedance was 907±477 Ohm. Mean P wave duration was 118±17 ms in sinus rhythm and 82±15 during interatrial septum pacing (p < 0.001). During a mean follow-up period of 10±7 months, no patients without atrial tachyarrhythmias before implantation experienced AF. During a 9±6 months follow-up we observed only 2 symptomatic arrhythmia recurrences between AF patients (mean symptomatic episodes/month 0.006±0.0022) (p < 0.01 vs before implant period).Conclusions. Our data indicate that interatrial septal pacing is safe and feasible. A significant less incidence of arrhythmic episodes has been observed during follow-up. Further controlled randomized prospective studies are necessary to establish the exact role of this technique respect to conventional or multisite stimulation when patients with paroxysmal AF need to be permanently paced.

Evaluation of Clotting and Fibrinolytic Activation after Protracted Physical Exercise

The behavior of hemostatic system activation during protracted physical exercise is well known, but the duration of its modification is not yet defined. In order to evaluate the time of hemostatic system activation after prolonged strenuous endurance physical exercise (typical marathon race: 42.195 km, v=15.35 km/h; mean length of time run 2.45+/-0.15 hours) 12 well-trained long-distance male runners (mean age: 35+/-7, range 25-47 years) were investigated. Blood samples were drawn in the morning on the day before the performance, immediately after the race, and 24 hours and 48 hours after the end of run. With respect of baseline, immediately after the race, a significant decrease of fibrinogen (-25%) and significant increases of prothrombin fragment 1+2 (+633%) and thrombin-antithrombin complex (+848%) were observed. A significant acceleration of euglobulin lysis time (-41%), and rises of plasma levels of tissue plasminogen activator antigen (+361%), plasminogen activator inhibitor type 1 antigen (+235%), d-dimer (+215%), and plasma fibrinogen degradation products (+1200%) were also found. Only a slight, yet not significant, decrease in plasminogen activator inhibitor type 1 activity was observed. One day after the end of marathon different parameters were still unchanged. Forty-eight hours after the competition all parameters investigated returned to baseline values. These results indicate a persistence of clotting as well as fibrinolysis activation up to 24 hours after the end of the race.

P Wave Assessment: State of the Art Update

Diagnostic (mapping) and therapeutic (ablation, pacing) advances have provided insight into atrial depolarization processes and new developments in P wave analysis. Information about interatrial pathways is important to the understanding of interatrial conduction delay. A standardized method for P wave analysis is necessary for the development of a clinical role for management of patients with paroxysmal atrial fibrillation using signal-averaged P wave analysis and P wave dispersion. Algorithms for predicting localization of ectopic P waves may facilitate catheter ablation. P wave changes due to pacing at different atrial sites may be useful for permanent pacing for prevention of atrial fibrillation. Introduction of these developments into clinical practice should allow better prevention and treatment of atrial arrhythmias and could have considerable impact in view of their high frequency especially in the older population.

Minimally invasive surgical treatment of lone atrial fibrillation: Early results of hybrid versus standard minimally invasive approach employing radiofrequency sources

BACKGROUND We compared short-term results of a hybrid versus a standard surgical bilateral thoracoscopic approach employing radiofrequency (RF) sources in the surgical treatment of lone atrial fibrillation (LAF). METHODS Between January 2008 and July 2010 sixty-three consecutive patients with LAF underwent minimally invasive surgery. Thirty-five (55.5%) underwent surgery with the hybrid approach whereas 28 (45.5%) underwent bilateral thoracoscopic standard procedure (no-hybrid group). All patients underwent continuous 7-day Holter Monitoring (HM) at 3 months, 6 months and 1 year. RESULTS At 1 year, 91.4% and 82.1% (time-related prevalence 5.2% vs.6.0% [p=0.56]) of the patients were free of AF and AAD. The hybrid group yielded better results in long standing persistent AF (8.2% [time related prevalence 81.8% vs. 44.4%, p=0.001] vs.14.9%, p=0.04). One-year success rates were 87.5% vs. 100% (p=0.04) in persistent [time related prevalence 3.8% vs. 0%, p<0.001] and 87.5% vs. 100% (p=0.04) in paroxysmal AF [time related prevalence 3.2% vs. 0%, p<0.001] in the two groups. One-year prevalence of Warfarin use was significantly higher in the hybrid group (29.0% [26.2-33.1] and 13.4% [9.9-16.3]) with no difference by AF type. LA reverse remodeling occurred in 81.7% (n=30) of hybrid patients and 67.8% (n=19) of no-hybrid patients at latest control (p=0.02). Left atrial emptying fraction increased in both groups (50 ± 14%, p<0.001 and 52 ± 12%, p=0.004 in hybrid and no-hybrid, respectively) without differences between groups (p=0.6). CONCLUSIONS The hybrid procedure yielded excellent results in long-standing persistent AF. Our findings need to be confirmed by further larger studies.

Minimal invasive surgery for atrial fibrillation: an updated review

AIMS Despite its proven efficacy, the Cox-Maze III procedure did not gain widespread acceptance for the treatment of stand-alone atrial fibrillation (SA-AF) because of its complexity and technical difficulty. Surgical ablation for SA-AF can now be successfully performed utilizing minimally invasive surgery (MIS). This study provides an overview of state-of-the-art MIS for the treatment of SA-AF. METHODS AND RESULTS Studies selected for this review were identified on PUBMED and exclusion and inclusion criteria were applied to select the publication to be screened. Twenty-eight studies were included; 27 (96.4%) were observational in nature whereas 1 was prospective non-randomized. The total number of patients was 1051 (range 14-114). Mean age ranged from 45.3 to 67.1 years. Suboptimal results were obtained when employing microwave and high focused ultrasound energies. In contrast, MIS ablation of SA-AF achieved satisfactory 1-year results when the bipolar radiofrequency was employed as energy source, with antiarrhythmic drug-free success rate comparable to percutaneous catheter ablation (PCA). The success rate in paroxysmal was even higher than in PCA. In contrast, ganglionated plexi ablation and left atrial appendage removal seem not to influence the recurrence of AF and the occurrence of postoperative thromboembolic events. CONCLUSION Minimally invasive surgery ablation of SA-AF achieved satisfactory 1-year results when the bipolar radiofrequency was employed. Nevertheless, the relatively high complication rate reported suggest that such techniques require further refinement. Finally, the preliminary results of the hybrid approach are promising but they need to be confirmed.

Cardiac resynchronization therapy : Gender related differences in left ventricular reverse remodeling

Cardiac resynchronization refers to pacing techniques that change the degree of atrial and ventricular electromechanical asynchrony in patients with major atrial and ventricular conduction disorders. Atrial and ventricular resynchronization is usually accomplished by pacing from more than one site in an electrical chamber--atrium or ventricle--and occasionally by stimulation at a single unconventional site. Resynchronization produces beneficial hemodynamic and antiarrhythmic effects by providing a more physiologic pattern of depolarization. Atrial resynchronization may prevent atrial fibrillation in selected patients with underlying bradycardia or interatrial block. Its antiarrhythmic effect in the absence of bradycardia is unclear. Ventricular resynchronization is of far greater clinical value than atrial resynchronization. Biventricular (or single-chamber left ventricular) pacing is beneficial for patients with congestive heart failure, severe left ventricular systolic dysfunction, dilated cardiomyopathy (either ischemic or idiopathic), and a major left-sided intraventricular conduction disorder, such as left bundle branch block. The change in electrical activation from resynchronization, which has no positive inotropic effect as such, is translated into mechanical improvement with a more coordinated left ventricular contraction. Several recent randomized trials and a number of observational studies have demonstrated the long-term effectiveness of ventricular resynchronization in the above group of patients. The high incidence of sudden death among these patients has encouraged ongoing clinical trials to evaluate the benefit of a system that combines biventricular pacing and cardioversion-defibrillation into a single implantable device.Aim: Gender related differences in epidemiology, treatment, and prognosis of heart failure (HF) have been reported. We examined the sex influence in patients treated with cardiac resynchronization therapy (CRT).

Dual-site left ventricular cardiac resynchronization therapy.

Simultaneous stimulation of 2 left ventricular (LV) sites could enhance the effectiveness of cardiac resynchronization therapy (CRT). The aim of this study was to evaluate the acute hemodynamic response to dual-site LV CRT. Two LV pacing leads were successfully implanted in 12 CRT candidates (New York Heart Association classes III to IV, QRS >or=120 ms). Target positions were the lateral or posterolateral vein (site A) and anterior or anterolateral vein (site B). A conductance catheter was placed in the left ventricle for pressure-volume measurements. Tested CRT configurations were alternated by atrial overdrive pacing at a fixed rate and included site A and B single-site CRT and dual-site LV CRT (2 LV sites plus right ventricular apex) at 4 atrioventricular intervals. Overall, single-site LV CRT significantly enhanced stroke volume, stroke work, maximum pressure derivative, and conductance-derived indexes of LV synchrony when delivered in site A, whereas no significant changes were noticed with pacing in site B. Specifically, site-A pacing resulted in a higher stroke volume increase (LV pacing site associated with the best hemodynamic response [best-LV]) in 8 patients, and site-B pacing, in 4 patients. At intermediate atrioventricular intervals, dual-site LV CRT resulted in improved stroke volume, stroke work, maximum pressure derivative, and LV synchrony with respect to single-site CRT when delivered at the best-LV (all p <0.05). However, single-site CRT at best-LV produced results similar to dual-site LV CRT when the atrioventricular interval was optimized in each patient. In conclusion, adding a second LV lead does not result in further improvement in acute hemodynamic response with respect to standard CRT when the single LV pacing site and atrioventricular interval are optimal.

Atrioventricular interval optimization in the right atrial appendage and interatrial septum pacing: a comparison between echo and peak endocardial acceleration measurements.

PADELETTI, et al.: Atrioventricular Interval Optimization in the Right Atrial Appendage and Interatrial Septum Pacing: A Comparison Between ECHC and Peak Endocardial Acceleration. Interatrial septum pacing (IASP) reduces interatrial conduction time and consequently may interfere with atrioventricular delay (AVD) optimization. We studied 14 patients with an implanted BEST Living system device able to measure peak endocardial acceleration (PEA) signal. The aims of our study were to compare the (1) optimal AVD (OAVD) in right atrial appendage pacing (RAAP) and IASP, and (2) OAVD derived by the PEA signal versus OAVD derived by Echo/Doppler evaluation of the left ventricular filling time (LVFT) and cardiac output (CO). Measurements were performed in DDD VDD modes Eight patients (group A) had RAAP and six patients (group B) had IASP. In group A, OAVD measured by LVFT, CO, and PEA was 185 ± 23 ms, 177 ± 19 ms, and 192 ± 23 ms in DDD and 147 ± 19 ms, 135 ± 27 ms, and 146 ± 20 ms in VDD, respectively. OAVD measured by LVFT, CO, and PEA was significantly longer in DDD mode than in VDD (P < 0.01, P < 0.01, P < 0.001). In group B, OAVD measured by LVFT, CO, and PEA was 116 ± 19 ms, 113 ± 10 ms, and 130 ± 30ms in DDD and 106 ± 16 ms, 96 ± 15 ms, and 108 ± 26 ms in VDD, respectively. No statistical differences were observed between DDD and VDD. Significant correlations between OAVDs PEA derived and OAVDs LVFT and CO derived were observed (r = 0.71, r = 0.69, respectively). When new techniques of atrial stimulation, as IASP, are used an OAVD shorter and similar in VDD and DDD has to be considered. The BEST Living system could provide a valid method to ensure, in every moment, the exact required OAVD to maximize atrial contribution to CO.

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 Bachmanns bundle and the coronary sinus ostium. The results of two prospective randomized studies indicate that septal pacing, when compared to the traditional right atrial appendage pacing, significantly reduces : (1) paroxysmal AF recurrences and burden; and (2) progression to chronic AF. (PACE 2004; 27[Pt. II]:850–854)

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.