Atrial fibrillation and sympatho-vagal imbalance: from the choice of the antiarrhythmic treatment to patients with syncope and ganglionated plexi ablation.

For several years, the autonomic nervous system has played a central role in the pathophysiological mechanism of atrial fibrillation (AF), so much so that it has been considered one of the cornerstones of Coumel's triangle. The clinical and therapeutic management of AF secondary to sympatho-vagal imbalance represents one of the most important examples of how precision medicine should be applied. Increasing knowledge of this kind of arrhythmias has made it possible to select specific antiarrhythmic drugs and to diversify their use according to vagal or adrenergic AF forms. Ablative strategies, such as cardioneuroablation and non-direct cardiac neuromodulation methods (such as renal denervation and peripheral vagal stimulation), have gradually emerged. In the possibly near future, there will be a development of new acquisitions regarding new pharmacological therapeutic strategies and gene therapy. Finally, finding an AF in patients experiencing syncopal episodes opens a whole chapter regarding interesting, but also complex, diagnostic and therapeutic strategies, ranging from neurally mediated forms to convulsive seizure that could also increase the risk of sudden death.

Ganglionated plexi ablation in the right atrium for the treatment of cardioinhibitory syncope.

Neurocardiogenic syncope, also called vasovagal syncope, represents one of the clinical manifestations of neurally mediated syncopal syndrome. Generally, the prognosis of the cardioinhibitory form of neurocardiogenic syncope is good, but quality of life is seriously compromised in patients who experience severe forms. Drug therapy has not achieved good clinical results and very heterogeneous data come from studies regarding permanent cardiac pacing. In this scenario, the ganglionated plexi ablation has been proposed as an effective and safe method in patients with cardioinhibitory neurocardiogenic syncope, especially in young patients in order to avoid or prolong, as much as possible, the timing of definitive cardiac pacing. Certainly, making this procedure less extensive and limiting the ablation in the right atrium (avoiding the potential complications of a left atrial approach) and at level of anatomical regions of the most important ganglionated plexy, considered 'gateway' of the sino-atrial and atrio-ventricular node function (through the recognition of specific endocardial potentials), could be very advantageous in this clinical scenario. Finally, randomized, multicentre, clinical trials on a large population are needed to better understand which is the best ablation treatment (right-only or bi-atrial) and provide evidence for syncope guidelines.

The Complex but Fascinating Relationship between Sport and Atrial Fibrillation: From Pathophysiology to the Clinical Scenario.

Atrial fibrillation (AF) is the most common cause of hospital admission among all arrhythmias in the general population. Moreover, AF represents the most common arrhythmia in the athletic population as well. The complex but fascinating relationship between sport and atrial fibrillation has not yet been fully clarified. Although the benefits of moderate physical activity in controlling cardiovascular risk factors and in reducing the risk of atrial fibrillation have been widely demonstrated, some concerns have been raised about the potential adverse effects of physical activity. Endurance activity in middle-aged men athletes appears to increase the risk of AF. Several different physiopathological mechanisms may explain the increased risk of AF in endurance athletes, including the imbalance of the autonomic nervous system, changes in left atrial size and function and presence of atrial fibrosis. The goal of this article is to review the epidemiology, pathophysiology and clinical management for AF in athletes, including pharmacological and electrophysiological strategies.

Atrial fibrillation and sport: need for monitoring.

Historically, regular exercise contributed to reduce the arrhythmic burden and improve cardiovascular outcomes in the general population. However, a heightened risk of atrial fibrillation (AF) seems to occur mainly amongst endurance athletes. The exact mechanisms are not fully elucidated, but dynamic interactions between electro-anatomical changes induced by exercise, the autonomic system, variable triggers, along individual genetic predisposition are the main contributors to AF development in athletes. The type and training load of sports are also crucial in determining the arrhythmogenic milieu predisposing to AF insurgence and perpetuation. Moreover, a sex difference seems to influence an increased risk of AF only in men undergoing strenuous exercise, whereas women appear protected even during more vigorous training. In the absence of solid evidence, the advent of modern technologies could help to monitor and deep investigate the peculiar aspects of AF in these athletes. This review aims to describe the pathophysiology, diagnosis, and management of AF in athletes, shedding light on possible future strategies to face AF in this population.

Ivabradine versus bisoprolol in the treatment of inappropriate sinus tachycardia: a long-term follow-up study.

AIM: The aim of our study was to compare ivabradine versus bisoprolol in the short-term and long-term treatment of inappropriate sinus tachycardia. METHODS: From this prospective, parallel-group, open-label study, consecutive patients affected by inappropriate sinus tachycardia received ivabradine or bisoprolol and were evaluated with Holter ECG, ECG stress test, European Heart Rhythm Association score and Minnesota Living With Heart Failure Questionnaire at baseline, after 3 and 24 months. RESULTS: Overall, 40 patients were enrolled. Baseline parameters were comparable in the ivabradine and bisoprolol subgroups. Two patients had transient phosphenes with ivabradine and two others interrupted the drug after 3 months as they planned to become pregnant. Eight individuals treated with bisoprolol experienced hypotension and weakness, which caused drug discontinuation in five of them. Ivabradine was superior to bisoprolol in reducing Holter ECG mean heart rate (HR) and mean HR during daytime at short- and long-term follow-up. Moreover, ivabradine but not bisoprolol significantly reduced Holter ECG mean HR during night-time as well as maximal and minimal HR and significantly increased the time duration and maximal load reached at ECG stress test. The quality of life questionnaires significantly improved in both subgroups. CONCLUSION: This study suggests that ivabradine is better tolerated than bisoprolol and seems to be superior in controlling the heart rate and improving exercise capacity in a small population of individuals affected by inappropriate sinus tachycardia during a short-term and long-term follow-up.

Atrial fibrillation and autonomic nervous system: A translational approach to guide therapeutic goals.

The autonomic nervous system (ANS) is known to play an important role in the genesis and maintenance of atrial fibrillation (AF). Biomolecular and genetic mechanisms, anatomical knowledges with recent diagnostic techniques acquisitions, both invasive and non-invasive, have enabled greater therapeutic goals in patients affected by AF related to ANS imbalance. Catheter ablation of ganglionated plexi (GP) in the left and right atrium has been proposed in varied clinical conditions. Moreover interesting results arise from renal sympathetic denervation and vagal nerve stimulation. Despite all this, in the scenario of ANS modulation translational strategies we necessary must consider the treatment or correction of dynamic factors such as obesity, obstructive sleep apnea, lifestyle, food, and stress. Finally, new antiarrhythmic drugs, gene therapy and "ablatogenomic" could be represent exciting future therapeutic perspectives.

Catheter ablation of right atrial ganglionated plexi to treat cardioinhibitory neurocardiogenic syncope: a long-term follow-up prospective study.

PURPOSE: Several reports have focused on biatrial ganglionated plexi (GP) transcatheter ablation to treat cardioinhibitory neurocardiogenic syncope (CNS). Considering that anatomical studies showed a significant number of GP in the right atrium (RA), we hypothesized that RA "cardioneuroablation" could be an effective treatment for CNS. METHODS: Eighteen consecutive patients (mean age: 36.9 ± 11.2 years) with severe CNS were submitted to transcatheter ablation of GPs in the RA alone using an anatomical approach. Head up tilt test evaluation was performed during the follow-up period at 6, 12, and 24 months and in case of significant symptoms, while heart rate variability parameters were evaluated at patients discharge at 1, 3, 6, 12, 24, and 36 months after ablation. RESULTS: At a mean follow-up of 34.1 ± 6.1 months, 3 (16.6%) patients experienced syncopal episodes and 5 patients (27.7%) only prodromal episodes. Syncopal and prodromal recurrences were significantly decreased both in overall population (P = 0.001) and in symptomatic patients after ablation (P = 0.003). Heart rate variability analysis showed the loss of autonomic balance secondary to a reincrease of sympathetic tone after the acute phase faster than vagal tone more evident at 12 months (LF/HF vs preablation, P < 0.001) and persistent until 24 months. Finally, a good correlation was observed between symptomatic events and the extension of RF lesions in supero-, middle-, and infero-posterior RA areas (r = 0.73, P = 0.03; r = 0.85, P = 0.02; r = 0.87, P = 0.004, respectively). CONCLUSIONS: Cardioneuroablation in the RA can be considered safe and an effective technique to treat CNS episodes.

Ventricular arrhythmias and risk stratification of cardiac sudden death in athletes.

Sudden cardiac death (SCD) of young athletes is an unexpected and tragic event that could occur during sport activities and is frequently related to ventricular arrhythmias. Identifying athletes at risk of SCD remains a major challenge. While specific characteristics of premature ventricular contractions are considered common and benign, other "uncommon" features should require more accurate investigations, in order to determine eligibility for competitive sports. The most common type of idiopathic premature ventricular contractions originates from ventricular outflow tract and is characterized by an ECG pattern with left bundle branch block and inferior QRS axis (infundibular pattern). Another pattern associated with a good prognosis is the "fascicular" morphology, characterized by a typical right bundle branch block, superior QRS axis morphology and QRS duration <130 ms. Conversely, other morphological features (such as left bundle branch block /intermediate or superior axis or right bundle branch block/intermediate or superior axis and wide QRS) correlate to an underlying substrate. In risk stratification setting, cardiac magnetic resonance plays a key role allowing an accurate identification of myocardial tissue abnormalities, which could affect athletes' prognosis. This review focuses on characteristics of premature ventricular contractions characteristics in terms of morphology, distribution, complexity and response to exercise and describes the possible underlying myocardial substrates. This review also critically analyzes the evaluation process of athletes with premature ventricular contractions necessary for an accurate risk stratification.

Electrocardiographic markers of structural heart disease and predictors of death in 2332 unselected patients undergoing outpatient Holter recording.

AIMS: To test the hypothesis that the QS interval of ventricular ectopic beats (VEBs) (ventricular ectopic QS interval, VEQSI) would provide a marker for the presence of structural heart disease and a predictor of mortality. METHODS AND RESULTS: We interviewed and examined 2332 patients undergoing Holter ECG monitoring for clinical indications. In persons with VEBs, the morphologies were counted and the QS interval was measured for each of these morphologies. The duration of the broadest VEB, measured from the QRS onset in the derivation showing the earliest onset to its end in the derivation showing the latest termination, was taken as that patient's VEQSI. Survival was ascertained from public health records. Of 15 electrocardiographic variables pre-selected as potential prognostic indicators, VEQSI demonstrated the strongest association with the presence of structural heart disease (P = 0.013). Thirty-four persons died in 16 +/- 4 months follow-up. Univariate predictors of mortality are age, history of myocardial infarction, maximum heart rate, QS interval, the number of VEB morphologies, and the VEQSI. On multivariate analysis, only age (P < 0.001) and the number of VEB morphologies (P = 0.02) predicted mortality. CONCLUSION: VEQSI predicts the presence of structural heart disease. The number of VEB morphologies in a Holter recording predicts all-cause mortality.

Safety and efficacy of a new magnetic resonance imaging-compatible pacing system: early results of a prospective comparison with conventional dual-chamber implant outcomes.

BACKGROUND: A new pacing system has been designed and tested preclinically for safe use in the magnetic resonance imaging (MRI) environment. Experience with this innovative system has not yet been reported. OBJECTIVE: The purpose of this study was to verify the safety and effectiveness of this newly designed system compared to conventional DDD implant outcomes. METHODS: Over an 11-month period, 107 consecutive patients (71 men and 36 women; age 72.6 +/- 8.5 years) were implanted with either the MRI system (n = 50; MRI group) or a dual-chamber, active-fixation lead (Medtronic 4076) non-MRI system (n = 57; DDD group). Data were collected at implant and during postoperative follow-up at 1, 3, 6, and 12 months. Procedural and fluoroscopic times at implant, as well as lead measurements, handling characteristics, and procedural-related complications, were prospectively analyzed. RESULTS: The implantation success rate in both groups was 100%. Cephalic access was 63% for MRI patients and 70% for DDD patients (P = NS). Follow-up was obtained for all patients (median 6.8 months, range 3-12 months). At implant and at the end of follow-up, stimulation thresholds, sensing, and impedance were acceptable. No cases of high pacing thresholds or inadequate sensing were noted. No complications occurred, and no patient experienced subsequent lead displacement. CONCLUSION: This prospective, controlled study provides strong evidence that the feasibility and safety of this novel technology compare favorably with those of the conventional technique.

Feasibility and safety of a simplified draping method for pacing procedures.

AIMS: Traditional draping for pacing procedures is time-consuming. We evaluated prospectively the safety of a simplified method using a single adhesive drape intended for use in cardiac catheterization. METHODS AND RESULTS: A single disposable adhesive drape was used in each of 250 consecutive pacing procedures by the same operator including 200 device implants and 50 revision procedures. We compared the results with those of 114 procedures performed in the same cardiac catheterization laboratory by three other operators using traditional draping methods for most cases. In the study group, no wound or pacemaker pocket infection, device erosion, or endocarditis was observed within the first 6 months after the procedure (0%, 95% CI 0-1.2%). One suspected infection occurred at 10 months (0.4%, 95% CI 0.1-2.2%). In the control group, there were two cases of early infection or suspected infection (2 of 114 procedures, 1.8%, 95% CI 0.27-6.1%), four cases of confirmed or suspected infection more than 6 months after the procedure giving an overall infection rate (6 of 114, 5.3%, 95% CI 2.1-11.0%) significantly higher than in the study group (P = 0.014, Fisher's exact test). CONCLUSION: A simplified draping method involving a single adhesive fenestrated drape can be used for pacemaker or ICD implantation or revision procedures without an excessively elevated risk of infective complications.