Cristiano Pisani

Selective Atrial Vagal Denervation Guided by Evoked Vagal Reflex to Treat Patients With Paroxysmal Atrial Fibrillation

Background— The aim of this study was to evaluate whether selective radiofrequency (RF) catheter ablation of the atrial sites in which high-frequency stimulation induces vagal reflexes prevents paroxysmal atrial fibrillation (AF). Methods and Results— Ten patients with episodes suggestive of vagal-induced paroxysmal AF and no heart disease were selected for percutaneous epicardial and endocardial mapping of the atria to search for sites in which high-frequency transcatheter stimulation (20 Hz,) induced vagal reflexes. A vagal response defined as AV block of >2 seconds was elicited in 7 of 10 patients (70%) with an average of 5±2.4 (range, 2 to 9) sites per patient, and RF pulses (21.0±12.0 per patient) were applied at those sites to eliminate all evoked vagal reflexes. The 3 patients in whom evoked vagal reflexes were not obtained underwent circumferential pulmonary vein ablation with an average of 58.0±13.9 RF pulses per patient (P=0.022). Autonomic evaluation was performed before and 48 hours and 3 months after the procedure and was consistent with vagal withdrawal in all patients. Two of the 7 patients who underwent denervation remained asymptomatic without the use of antiarrhythmic medication at a mean follow-up of 8.3±2.8 months (range, 5 to 15 months); 4 had frequent recurrences and were referred for circumferential pulmonary vein ablation; and 1 had few AF episodes without antiarrhythmic medication. The 3 patients without evoked vagal reflexes who underwent circumferential pulmonary vein ablation remained asymptomatic without antiarrhythmic medication. One patient had acute delayed gastric emptying after atrial vagal denervation. Conclusions— RF catheter ablation of selected atrial sites in which high-frequency stimulation induced vagal reflexes may prevent AF recurrences in selected patients with apparently vagal-induced paroxysmal AF.

Atrial-oesophageal fistula following percutaneous radiofrequency catheter ablation of atrial fibrillation: the risk still persists

Aims Atrial‐oesophageal fistula is a serious complication related to ablation of atrial fibrillation. As its occurrence is rare, there is a great lack of information about their mechanisms, incidence, presentations, and treatment. The objective of this manuscript is to present a series of cases of atrial‐oesophageal fistula in Brazil, focusing on incidence, clinical presentation, and follow‐up. Methods and results This is a retrospective multicentre registry of atrial‐oesophageal fistula cases that occurred in eight Brazilian centres from 2003 to 2015. Ten cases (0.113%) of atrial‐oesophageal fistula were reported in 8863 ablation procedures in the period. Most of the subjects were male (70%) with age 59.6 ± 9.3 years. Eight centres were reference units in atrial fibrillation ablation with an experience over than 200 procedures at the time of fistula occurrence. Oesophageal temperature monitoring was performed in eight cases using coated sensors in six. The first atrial‐oesophageal fistula clinical manifestation was typically fever (in six patients), with a median onset time of 16.5 (12‐43) days after ablation. There was a delay of 7.8 ± 3.3 days between the first manifestation and the diagnosis in five patients. The treatment was surgical in six cases, clinical in three and stenting in one. Seven patients died (70%) and two developed permanent neurological sequelae. Conclusion Atrial‐oesophageal fistula remains a serious complication following AF ablation despite the incorporation of protective measures and increased technical experience of the groups. The high morbidity and mortality despite the treatment indicates the need to develop adequate preventive strategies.

Selective Vagal Denervation of the Sinus and Atrioventricular Nodes, Guided by Vagal Reflexes Induced by High Frequency Stimulation, to Treat Refractory Neurally Mediated Syncope

A 15‐year‐old female patient presented with frequent episodes of vasovagal syncope refractory to non‐pharmacological and pharmacological measures. Two tilt‐table tests performed before and after conventional therapy were positive and reproduced the patients clinical symptoms. Selective vagal denervation, guided by HFS, was performed. Six radiofrequency pulses were applied on the left and right sides of the interatrial septum, abolishing vagal responses at these locations. Basal sinus node and Wenckebach cycle lengths changed significantly following ablation. A tilt test performed after denervation was negative and revealed autonomic tone modification. The patient reported significant improvement in quality of life and remained asymptomatic for 9 months after denervation. After this period, three episodes of NMS occurred during a 4‐month interval and a tilt test performed 11 months after the procedure demonstrated vagal activity recovery.

Percutaneous Transatrial Access to the Pericardial Space for Epicardial Mapping and Ablation

Background—Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results—An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P=0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions—Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings.

Targets and End Points in Cardiac Autonomic Denervation Procedures

Background— Autonomic denervation is an alternative approach for patients with symptomatic bradycardia. No consensus exists on the critical targets and end points of the procedure. The aim of this study was to identify immediate end points and critical atrial regions responsible for vagal denervation. Methods and Results— We enrolled 14 patients (50% men; age: 34.0±13.8 years) with cardioinhibitory syncope, advanced atrioventricular block or sinus arrest, and no structural heart disease. Anatomic mapping of ganglionated plexuses was performed, followed by radiofrequency ablation. Heart rate, sinus node recovery time, Wenckebach cycle length, and atrial-His (AH) interval were measured before and after every radiofrequency pulse. Wilcoxon signed-rank test was used for comparison. Significant shortening of the R-R interval (P=0.0009), Wenckebach cycle length (P=0.0009), and AH intervals (P=0.0014) was observed after ablation. The heart rate elevation was 23.8±12.5%, and the Wenckebach cycle length and AH interval shortening was 18.1±11% and 24.6±19%, respectively. Atropine bolus injection (0.04 mg/kg) did not increase heart rate further. Targeting a single spot of the left side (64% of the patients) or right side (36%) of the interatrial septum was observed to be responsible for ≥80% of the final R-R and AH interval shortening during ablation. Conclusions— Targeting specific sites of the interatrial septum is followed by an increase in heart rate and atrioventricular nodal conduction properties and might be critical for vagal attenuation. The R-R interval, Wenckebach cycle length, and AH interval shortening, associated with a negative response to atropine, could be considered immediate end points of the procedure.

Spectral characteristics of atrial electrograms in sinus rhythm correlates with sites of ganglionated plexuses in patients with paroxysmal atrial fibrillation

AIMS To verify whether spectral components of atrial electrograms (AE) during sinus rhythm (SR) correlate with cardiac ganglionated plexus (GP) sites. METHODS AND RESULTS Thirteen patients undergoing atrial fibrillation (AF) ablation were prospectively enrolled. Prior to radio frequency application, endocardial AE were recorded with a sequential point-by-point approach. Electrical stimuli were delivered at 20 Hz, amplitude 100 V, and pulse width of 4 ms. A vagal response was defined as a high-frequency stimulation (HFS) evoked atrioventricular block or a prolongation of RR interval. Spectral analysis was performed on single AE during SR, sampling rate of 1000 Hz, Hanning window. Overall, 1488 SR electrograms were analysed from 186 different left atrium sites, 129 of them corresponding to negative vagal response sites, and 57 to positive response sites. The electrogram duration and the number of deflections were similar in positive and negative response sites. Spectral power density of sites with vagal response was lower between 26 and 83 Hz and higher between 107 and 200 Hz compared with negative response sites. The area between 120 and 170 Hz normalized to the total spectrum area was tested as a diagnostic parameter. Receiver operating characteristic curve analysis demonstrated that an area 120-170/area(total) value >0.14 identified vagal sites with 70.9% sensitivity and 72.1% specificity. CONCLUSION Spectral analysis of AE during SR in sites that correspond to the anatomical location of the GP is feasible and may be a simpler method of mapping the cardiac autonomic nervous system, compared with the HFS technique.

Epicardial ablation for cardiac arrhythmias: techniques, indications and results.

Purpose of review To review the most relevant published data on epicardial ablation of cardiac arrhythmias in the last few years. Recent findings Several studies performing epicardial and endocardial ablation have demonstrated that epicardial ablation may improve the results of ventricular tachycardia (VT) ablation in almost all cardiomyopathies. New imaging techniques have been recently applied, refining the identification of patients who actually benefit from epicardial ablation and increasing its safety. Summary Epicardial VT ablation is an important tool for electrophysiologists to deal with the challenge of scar-related ventricular arrhythmias.

Redução da densidade de extrassístoles e dos sintomas relacionados após administração de magnésio por via oral

BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE: We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260mg of Mg element. None of the patients had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the premature complexes frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.

Accessory atrioventricular pathways refractory to catheter ablation: role of percutaneous epicardial approach.

Background—Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed. Methods and Results—We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access. Conclusions—Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial–epicardial approach.

Monitoring risk for oesophageal thermal injury during radiofrequency catheter ablation for atrial fibrillation: does the characteristic of the temperature probe matter?

This editorial refers to ‘Comparison between single- and multi-sensor oesophageal temperature probes during atrial fibrillation ablation: thermodynamic characteristics’ by C.M. Tschabrunn et al ., doi: 10.1093/europace/euu356. Atrioesophageal fistula as a complication of radiofrequency (RF) catheter ablation of atrial fibrillation (AF) was first described in 2004, shortly after strategies for pulmonary vein isolation moved from ostial to circumferential antral ablation.1,2 Atrioesophageal fistula was initially interpreted as a transitory technical problem that could be prevented by recognizing the oesophagus position and titrating RF energy during ablation in the proximity to the oesophagus. After more than 10 years of development, AF ablation has become the most common catheter ablation procedure performed worldwide. However, atrioesophageal fistula has remained a serious and unpredictable complication occurring in 0.03–0.2% of the ablation procedures even in experienced centres,3 without a convincing demonstration that a specific strategy might prevent it. The crucial problem is that atrioesophageal fistula is often unexpected, and when it occurs, the risk of death or severe neurologic sequelae is around 80%. Moreover, the incidence of atrioesophageal fistula may increase in the next years because technical improvements have been implemented in order to obtain ‘better RF lesions’ to prevent pulmonary vein reconnections and the increasing number of new operators. Thermal injury is the postulated mechanism for oesophageal injury during RF ablation due to the close anatomical relationship between the left atrium and the oesophagus. Radiofrequency energy delivery may extend beyond the atrial myocardium and may reach the oesophagus leading to distinctive grades of ischaemic necrosis of the mucosal layers with different consequences.4 In the past years, many interventions have being proposed …