Ablation of CTI-dependent flutter using different ablation technologies: acute and long-term outcome from the LEONARDO study

BACKGROUND

A novel ablation catheter has been released to map and ablate the cavo-tricuspid isthmus (CTI) in patients with atrial flutter (AFL), improving ablation efficiency.

METHODS

We evaluated the acute and long-term outcome of CTI ablation aiming at bidirectional conduction block (BDB) in a prospective, multicenter cohort study enrolling 500 patients indicated for typical AFL ablation. Patients were grouped on the basis of the AFL ablation method (linear anatomical approach, Conv group n = 425, or maximum voltage guided, MVG group, n = 75) and ablation catheter (mini-electrodes technology, MiFi group, n = 254, or a standard 8-mm ablation catheter, BLZ group, n = 246).

RESULTS

Complete BDB according to both validation criteria (sequential detailed activation mapping or mapping only the ablation site) was achieved in 443 patients (88.6%). The number of RF applications needed to achieve BDB was lower in the MiFi MVG group vs both the MiFi Conv group and the BLZ Conv group (3.2 ± 2 vs 5.2 ± 4 vs 9.3 ± 5, p < 0.0001 for all comparisons). Fluoroscopy time was similar among groups, whereas we observed a reduction in the procedure duration from the BLZ Conv group (61.9 ± 26min) to the MiFi MVG group (50.6 ± 17min, p = 0.048). During a mean follow-up of 548 ± 304 days, 32 (6.2%) patients suffered an AFL recurrence. No differences were found according to BDB achieved by both validation criteria.

CONCLUSIONS

Ablation was highly effective in achieving acute CTI BDB and long-term arrhythmia freedom irrespective of the ablation strategy or the validation criteria for CTI chosen by the operator. The use of an ablation catheter equipped with mini-electrodes technology seems to improve ablation efficiency.

CLINICAL TRIAL REGISTRATION

Atrial Flutter Ablation in a Real World Population. (LEONARDO).

CLINICALTRIALS

gov Identifier: NCT02591875.

Five waves of COVID-19 pandemic in Italy: results of a national survey evaluating the impact on activities related to arrhythmias, pacing, and electrophysiology promoted by AIAC (Italian Association of Arrhythmology and Cardiac Pacing)

BACKGROUND

The subsequent waves of the COVID-19 pandemic in Italy had a major impact on cardiac care.

METHODS

A survey to evaluate the dynamic changes in arrhythmia care during the first five waves of COVID-19 in Italy (first: March-May 2020; second: October 2020-January 2021; third: February-May 2021; fourth: June-October 2021; fifth: November 2021-February 2022) was launched.

RESULTS

A total of 127 physicians from arrhythmia centers (34% of Italian centers) took part in the survey. As compared to 2019, a reduction in 40% of elective pacemaker (PM), defibrillators (ICD), and cardiac resynchronization devices (CRT) implantations, with a 70% reduction for ablations, was reported during the first wave, with a progressive and gradual return to pre-pandemic volumes, generally during the third-fourth waves, slower for ablations. For emergency procedures (PM, ICD, CRT, and ablations), recovery from the initial 10% decline occurred in most cases during the second wave, with some variability. However, acute care for atrial fibrillation, electrical cardioversions, and evaluations for syncope showed a prolonged reduction of activity. The number of patients with devices which started remote monitoring increased by 40% during the first wave, but then the adoption of remote monitoring declined.

CONCLUSIONS

The dramatic and profound derangement in arrhythmia management that characterized the first wave of the COVID-19 pandemic was followed by a progressive return to the volume of activities of the pre-pandemic periods, even if with different temporal dynamics and some heterogeneity. Remote monitoring was largely implemented during the first wave, but full implementation is needed.

Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator? Results From the Multicenter Randomized PARTITA Trial

BACKGROUND

Optimal timing for catheter ablation of ventricular tachycardia is an important unresolved issue. There are no randomized trials evaluating the benefit of ablation after the first implantable cardioverter defibrillator (ICD) shock.

METHODS

We conducted a 2-phase, prospective, multicenter, randomized clinical trial. Patients with ischemic or nonischemic dilated cardiomyopathy and primary or secondary prevention indication for ICD were enrolled in an initial observational phase until first appropriate shock (phase A). After reconsenting, patients were randomly assigned 1:1 in phase B to immediate ablation (within 2 months from shock delivery) or continuation of standard therapy. The primary end point was a composite of death from any cause or hospitalization for worsening heart failure. Amiodarone intake was not allowed except for documented atrial tachyarrhythmias. On July 23, 2021, phase B of the trial was interrupted as a result of the first interim analysis on the basis of the Bayesian adaptive design.

RESULTS

Of the 517 patients enrolled in phase A, 154 (30%) had ventricular tachycardia, 56 (11%) received an appropriate shock over a median follow-up of 2.4 years (interquartile range, 1.4-4.4), and 47 of 56 (84%) agreed to participate in phase B. After 24.2 (8.5-24.4) months, the primary end point occurred in 1 of 23 (4%) patients in the ablation group and 10 of 24 (42%) patients in the control group (hazard ratio, 0.11 [95% CI, 0.01-0.85]; P=0.034). The results met the prespecified termination criterion of >99% Bayesian posterior probability of superiority of treatment over standard therapy. No deaths were observed in the ablation group versus 8 deaths (33%) in the control group (P=0.004); there was 1 worsening heart failure hospitalization in the ablation group (4%) versus 4 in the control group (17%; P=0.159). ICD shocks were less frequent in the ablation group (9%) than in the control group (42%; P=0.039).

CONCLUSIONS

Ventricular tachycardia ablation after first appropriate shock was associated with a reduced risk of the combined death or worsening heart failure hospitalization end point, lower mortality, and fewer ICD shocks. These findings provide support for considering ventricular tachycardia ablation after the first ICD shock.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01547208.

Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator? Results From the Multicenter Randomized PARTITA Trial

BACKGROUND

Optimal timing for catheter ablation of ventricular tachycardia is an important unresolved issue. There are no randomized trials evaluating the benefit of ablation after the first implantable cardioverter defibrillator (ICD) shock.

METHODS

We conducted a 2-phase, prospective, multicenter, randomized clinical trial. Patients with ischemic or nonischemic dilated cardiomyopathy and primary or secondary prevention indication for ICD were enrolled in an initial observational phase until first appropriate shock (phase A). After reconsenting, patients were randomly assigned 1:1 in phase B to immediate ablation (within 2 months from shock delivery) or continuation of standard therapy. The primary end point was a composite of death from any cause or hospitalization for worsening heart failure. Amiodarone intake was not allowed except for documented atrial tachyarrhythmias. On July 23, 2021, phase B of the trial was interrupted as a result of the first interim analysis on the basis of the Bayesian adaptive design.

RESULTS

Of the 517 patients enrolled in phase A, 154 (30%) had ventricular tachycardia, 56 (11%) received an appropriate shock over a median follow-up of 2.4 years (interquartile range, 1.4-4.4), and 47 of 56 (84%) agreed to participate in phase B. After 24.2 (8.5-24.4) months, the primary end point occurred in 1 of 23 (4%) patients in the ablation group and 10 of 24 (42%) patients in the control group (hazard ratio, 0.11 [95% CI, 0.01-0.85]; P=0.034). The results met the prespecified termination criterion of >99% Bayesian posterior probability of superiority of treatment over standard therapy. No deaths were observed in the ablation group versus 8 deaths (33%) in the control group (P=0.004); there was 1 worsening heart failure hospitalization in the ablation group (4%) versus 4 in the control group (17%; P=0.159). ICD shocks were less frequent in the ablation group (9%) than in the control group (42%; P=0.039).

CONCLUSIONS

Ventricular tachycardia ablation after first appropriate shock was associated with a reduced risk of the combined death or worsening heart failure hospitalization end point, lower mortality, and fewer ICD shocks. These findings provide support for considering ventricular tachycardia ablation after the first ICD shock.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01547208.

Catheter Ablation of Atrial Fibrillation in Patients with Previous Lobectomy or Partial Lung Resection: Long-Term Results of an International Multicenter Study

INTRODUCTION

Data regarding the efficacy of catheter ablation in patients with atrial fibrillation (AF) and patients' previous history of pulmonary lobectomy/pneumonectomy are scanty. We sought to evaluate the efficacy and long-term follow-up of catheter ablation in this highly selected group of patients.

MATERIAL AND METHODS

Twenty consecutive patients (8 females, 40%; median age 65.2 years old) with a history of pneumonectomy/lobectomy and paroxysmal or persistent AF, treated by means of pulmonary vein isolation (PVI) at ten participating centers were included. Procedural success, intra-procedural complications, and AF recurrences were considered.

RESULTS

Fifteen patients had a previous lobectomy and five patients had a complete pneumonectomy. A large proportion (65%) of PV stumps were electrically active and represented a source of firing in 20% of cases. PVI was performed by radiofrequency ablation in 13 patients (65%) and by cryoablation in the remaining 7 cases. Over a median follow up of 29.7 months, a total of 7 (33%) AF recurrences were recorded with neither a difference between patients treated with cryoablation or radiofrequency ablation or between the two genders.

CONCLUSIONS

Catheter ablation by radiofrequency ablation or cryoablation in patients with pulmonary stumps is feasible and safe. Long-term outcomes are favorable, and a similar efficacy of catheter ablation has been noticed in both males and females.

[An up-to-date telemedicine integrated clinical pathway for adult patients with congenital heart disease]

Clinical management of adult patients with congenital heart disease (GUCH) is a difficult task for multiple reasons, which include their own pathology and clinical history complexity, diagnostic complexity and organization of care. GUCH specialists are present in very small numbers and are concentrated in few centers, thus generating considerable transfer problems for patients. During the COVID-19 pandemic, telemedicine has become the standard of care, ensuring health assistance continuity, and implementing communication channels between patients and health professionals. We suggest to stratify GUCH patients into three groups, which correspond to different levels of risk (low, moderate and high, respectively) to develop complications over time, using a GUCH-specific multiparametric complexity score; so, each patient pathway will be defined according to the specific group, with indication of site, timing and type of clinical and instrumental evaluations, including virtual visits and consults. In conclusion, practical tools are provided for the implementation of updated care pathways for GUCH patients, who finally are inserted in a new model of care in which even if in-person visit still represents the crucial moment of each patient care pathway, on the other hand, telemedicine incorporation could contribute to improving and making even more complete and effective GUCH patient care.

281 Home delivery of the communicator for remote monitoring of cardiac implantable devices: a multicentre experience during the COVID-19 lockdown

Aims

During the COVID-19 pandemic in-person visits for patients with cardiac implantable electronic devices should be replaced by remote monitoring (RM), in order to prevent viral transmission. A direct home-delivery service of the RM communicator has been implemented at 49 Italian arrhythmia centres.

Methods and results

According to individual patient preference or the organizational decision of the centre, patients were assigned to the home-delivery group or the standard in-clinic delivery group. In the former case, patients received telephone training on the activation process and use of the communicator. In June 2020, the centres were asked to reply to an ad hoc questionnaire to describe and evaluate their experience in the previous 3 months. RM was activated in 1324 patients: 821 (62%) received the communicator at home and the communicator was activated remotely. Activation required one additional call in 49% of cases, and the median time needed to complete the activation process was 15 min (25th–75th percentile: 10–20). 753 (92%) patients were able to complete the correct activation of the system. At the time when the questionnaire was completed, 743 (90%) communicators were regularly transmitting data. The service was generally deemed useful (96% of respondents) in facilitating the activation of RM during the COVID-19 pandemic and possibly beyond.

Conclusions

Home delivery of the communicator proved to be a successful approach to system activation, and received positive feedback from clinicians. The increased use of a RM protocol will reduce risks for both providers and patients, while maintaining high-quality care.

A reliable fossa ovalis impedance mapping for safer transseptal puncture: A new vision beyond voltage

INTRODUCTION

Transseptal puncture (TSP) is widely used in clinical practice but is negatively affected by a nonneglectable rate of complications and X-ray exposure. To address these problems, we investigated whether or not impedance mapping could correctly identify fossa ovalis (FO) and safely guide TSP.

METHODS AND RESULTS

Electroanatomic mapping was performed with CARTO 3 system version 7 and a ThermoCool® SmartTouch® mapping catheter was employed. In each patient, an impedance map and a bipolar voltage map of the whole interatrial septum were collected, acquiring at least 150 points with a contact force ≥2 g and using the pattern matching filter. Thirty-five patients were enrolled. A low impedance area was clearly identified in 34 of them. In 30 patients (88%), the FO was located in the low impedance area. The map was obtained in sinus rhythm in 17 cases (50%); in 15 of these (88%), the TSP site, the patent foramen ovale, or the FO tenting area fell inside the low impedance area. The same numbers were observed when mapping during atrial fibrillation.

CONCLUSION

To the best of our knowledge, this is the first study that provides the reliability and reproducibility of impedance mapping in identifying FO, an affordable and feasible tool that could be potentially introduced into clinical practice.

AV junction ablation and cardiac resynchronization for patients with permanent atrial fibrillation and narrow QRS: the APAF-CRT mortality trial

AIMS 

In patients with atrial fibrillation (AF) and heart failure (HF), strict and regular rate control with atrioventricular junction ablation and biventricular pacemaker (Ablation + CRT) has been shown to be superior to pharmacological rate control in reducing HF hospitalizations. However, whether it also improves survival is unknown.

METHODS AND RESULTS 

In this international, open-label, blinded outcome trial, we randomly assigned patients with severely symptomatic permanent AF >6 months, narrow QRS (≤110 ms) and at least one HF hospitalization in the previous year to Ablation + CRT or to pharmacological rate control. We hypothesized that Ablation + CRT is superior in reducing the primary endpoint of all-cause mortality. A total of 133 patients were randomized. The mean age was 73 ± 10 years, and 62 (47%) were females. The trial was stopped for efficacy at interim analysis after a median of 29 months of follow-up per patient. The primary endpoint occurred in 7 patients (11%) in the Ablation + CRT arm and in 20 patients (29%) in the Drug arm [hazard ratio (HR) 0.26, 95% confidence interval (CI) 0.10-0.65; P = 0.004]. The estimated death rates at 2 years were 5% and 21%, respectively; at 4 years, 14% and 41%. The benefit of Ablation + CRT of all-cause mortality was similar in patients with ejection fraction (EF) ≤35% and in those with >35%. The secondary endpoint combining all-cause mortality or HF hospitalization was significantly lower in the Ablation + CRT arm [18 (29%) vs. 36 (51%); HR 0.40, 95% CI 0.22-0.73; P = 0.002].

CONCLUSIONS 

Ablation + CRT was superior to pharmacological therapy in reducing mortality in patients with permanent AF and narrow QRS who were hospitalized for HF, irrespective of their baseline EF.

STUDY REGISTRATION

ClinicalTrials.gov Identifier: NCT02137187.

Home delivery of the communicator for remote monitoring of cardiac implantable devices: A multicenter experience during the covid-19 lockdown

Background

During the COVID‐19 pandemic in‐person visits for patients with cardiac implantable electronic devices should be replaced by remote monitoring (RM), in order to prevent viral transmission. A direct home‐delivery service of the RM communicator has been implemented at 49 Italian arrhythmia centers.

Methods

According to individual patient preference or the organizational decision of the center, patients were assigned to the home‐delivery group or the standard in‐clinic delivery group. In the former case, patients received telephone training on the activation process and use of the communicator. In June 2020, the centers were asked to reply to an ad hoc questionnaire to describe and evaluate their experience in the previous 3 months.

Results

RM was activated in 1324 patients: 821 (62%) received the communicator at home and the communicator was activated remotely. Activation required one additional call in 49% of cases, and the median time needed to complete the activation process was 15 min [25th‐75th percentile: 10–20]. 753 (92%) patients were able to complete the correct activation of the system. At the time when the questionnaire was completed, 743 (90%) communicators were regularly transmitting data. The service was generally deemed useful (96% of respondents) in facilitating the activation of RM during the COVID‐19 pandemic and possibly beyond.

Conclusions

Home delivery of the communicator proved to be a successful approach to system activation, and received positive feedback from clinicians. The increased use of a RM protocol will reduce risks for both providers and patients, while maintaining high‐quality care.

Challenging ST elevation during night shift

•

Every ST segment elevation is suspicious of acute myocardial infarction and the diagnosis should be reached in a short time.

•

Electrolyte imbalance (i.e. hyperkaliemia) and Ph alterations should always be considered.

•

The treatment of electrolyte imbalance should be performed promptly, even before considering interventional treatments.

•

Brugada syndrome should be considered as a diagnosis, especially in patients with syncope and a coved type ST elevation in the right precordial leads.

•

Even a diagnostic type 1 Brugada pattern could be a phenocopy due to electrolyte imbalance.

•

When Brugada syndrome is presumed and electrolyte imbalance is present, an Ajmaline test is required to confirm the diagnosis.

P1448Ablation of cti-dependent flutter using a novel advanced mini-electrodes technology: preliminary results from Leonardo registry

Funding Acknowledgements

NO FUNDING

OnBehalf

LEONARDO study group

Background

Ablation of cavotricuspid isthmus (CTI) represents the standard therapeutic approach for the creation of bidirectional conduction block (BDB) across the isthmus and the prevention of recurrences, yet recurrence of arrhythmia is common.

Objective

To evaluate the acute and long-term outcome of CTI ablation through a novel ablation catheter equipped with three radially distributed mini-electrodes (ME) compared with standard ablation catheter technology (ST).

Methods

Atrial Flutter Ablation in a Real World Population (LEONARDO) is a prospective, multicenter cohort study aimed at providing an estimate of acute to long-term outcome in a large population of pts indicated for AFL ablation from 2015 to 2017. The procedural endpoint was the creation of a BDB. Presence of widely split double potentials (DP) along the ablation line and assessment of the atrial activation sequence (AAS) were used as criteria for complete BDB. Recurrence of AFL and complications were assessed at 12-month follow-up.

Results

  205 consecutive pts undergoing typical AFL ablation were included (74% male, 50.6% with history of AF, median of 7[4–11] ablation lesions, median ablation time of 20[10-30] min). Complete BDB was achieved in 175 (85.4%) pts (10 pts had DP only criterion, 19 pts had AAS only criterion whereas in 1 pt we failed to reach a BDB). 15 (7.3%) pts experienced AFL recurrence during follow-up. 102 pts (49.8%) underwent ablation procedure with ME catheters whereas 103 (50.2%) pts were treated by ST catheters. The median number of lesions/pt was significantly lower in the ME group compared to the ST one (4[3-6] vs 8.5[6-12], p &lt; 0.0001), whereas no differences were found in terms of fluoroscopy time (10.5[7-15] min vs 10[5.8 ± 15] min, p = NS) or ablation time (22.5[10-30.5] min vs 18[10-26] min, p = NS). No complications were reported. The acute procedural success was comparable between groups (81.4% vs 89.2%, p = NS) whereas the time to AFL recurrence was significantly longer among pts targeted with ME catheters (HR = 0.343; 0.12 to 0.97; log-rank p = 0.044).

Conclusions

In our preliminary experience, the use of the ME technology seemed safe and effective. It resulted in fewer lesions/pt and a lower AFL recurrence rate at 1-year follow-up compared with ST ablation catheters.

P1009Procedural success and long-term outcome of CTI ablation targeted with maximum voltage-guided approach: preliminary results from an Italian multicenter registry

Background

Ablation technique targeting high-amplitude signals (maximum voltage guided - MVG -) on the cavotricuspid isthmus (CTI) has emerged as viable alternative option compared to standard anatomical approach (ST) for the creation of bidirectional conduction block (BDB) across the isthmus but limited data are available to date.

Purpose

To evaluate the effectiveness of acute and long-term outcome of CTI ablation through MVG technique for AFL compared to standard linear (SL) lesion ablation.

Methods

Atrial Flutter Ablation in a Real World Population (LEONARDO) is a prospective, multicenter cohort study aimed at providing an estimate of acute to long-term outcome in a large population of patients (pts) indicated for AFL ablation. Recurrence of AFL were retrieved at 12-month follow-up. Complete BDB was defined by agreement with the presence of widely split double potentials (DP) along the ablation line and assessment of the atrial activation sequence (AAS). For MVG technique the ablation catheter was positioned at the site of maximum local electrogram voltage.

Results

Two-hundred fifteen consecutive pts were included (mean age 68 years, 73% male). A median of 4 [2–6] ablation lesions were required. Median follow up was 359 [192–443] days. Complete BDB was achieved in 175 (81.4%) pts (9 pts had DP only criterion, 30 pts had AAS only criterion whereas in 1 pt we failed to reach a BDB). In the 106 pts with complete data at 1-year follow-up, 10 (9.4%) had a recurrence of AFL. 171 pts (79%) underwent a SL ablation whereas 44 pts (21%) were treated by MVG approach. The median number of lesions/pt was significantly lower in the group of pts targeted with MVG compared to the SL approach (3 [2–4] vs 4 [2–8], p<0.01), whereas no differences were found in terms of fluoroscopy time (16 [12–18] min vs 12 [7–22] min, p=NS) or proportion of pts with BDB achievement (86.4% of the cases for MVG vs 80.1% of the cases for ST, p=NS). No complications were reported. AFL recurrence was comparable during follow-up between groups (8.3% for MVG vs 9.8% for SL ablation; p=NS).

Conclusion

Ablation of a targeted site through MGV approach seems to be safe and effective as standard anatomical ablation technique. This strategy may avoid unnecessary ablation of the entire anatomic isthmus.

Acknowledgement/Funding

None

Ajmaline Challenge To Unmask Infrahisian Disease In Patients With Recurrent And Unexplained Syncope, Preserved Ejection Fraction, With Or Without Conduction Abnormalities On Surface ECG

Background: Pharmacological challenge with class I antiarrhythmic drug is a recommended diagnostic test in patients with unexplained syncope only in the presence of bundle branch block, when non-invasive tests have failed to make the diagnosis. Its role in patients with minor or no conduction disturbances on 12-leads ECG has not been evaluated yet. It is also not clear which are the values of His-Ventricular interval to be considered diagnostic. We sought to evaluate the role of ajmaline challenge in unmasking the presence of an infrahisian disease in patients with recurrent and unexplained syncope, regardless of the existence of conduction disturbances on surface ECG. Materials And Methods: Patients with history of recurrent syncope, preserved EF and a negative first level workup were enrolled. Conduction disturbances on ECG were not considered as an exclusion criteria. During EPS, basal HV conduction was determined. In the presence of a HV >70 msec the study was interrupted and the patient was implanted with a pacemaker. If the HV was ≤ 70 msec, ajmaline was infused and HV was reassessed. The maximum value of HV was considered. A prolongation ≥ 100 msec was considered as diagnostic and indicative of conduction disease, and the patient underwent pacemaker implantation. Patients with an HV <100 msec were implanted with an ILR. Results: Sixteen consecutive patients were studied (age 76±5.2 years). Nine patients had conduction disturbances at baseline ECG (group ECG+). Among them, 5 had a basal diagnostic HV interval and 4 had a non-diagnostic HV interval. In the latter group, abnormal response to ajmaline was observed in 3 patients. In this group only one patient was implanted with an ILR, 8 patients were implanted with a pacemaker. Among the seven patients without conduction disturbances (group ECG-), no one had a diagnostic basal HV interval. After drug administration, 4 patients had a non-diagnostic response and were implanted with an ILR, while 3 patient had a pathological response and were implanted with a pacemaker. No difference was found in the values of maximum HV interval prolongation after ajmaline between the two groups (P = 0.89). During a mean follow up of 13±3 months, no patient has developed a syncopal episode. One patient in group ECG- and negative drug test was implanted after 3 months with a permanent pacemaker because of a two to one asymptomatic AV block at ILR interrogation. Conclusions: Ajmaline challenge is a useful tool to unmask the presence of a infrahisian disease in patients with preserved EF, unexplained syncope and negative workup, even in the absence of conduction disturbances on 12-leads ECG. It is a simple and safe test that may disclose the detection of the disease. In these patients, an earlier pacemaker implantation of a pacemaker, may avoid the consequences of a syncopal recurrence. Values of HV interval > 70 msec in basal conditions and ≥ 100 msec after ajmaline administration seem appropriate to unmask infrahisian disease. Larger population is required to validate this hypothesis.

Vagomimetic effects of fingolimod: physiology and clinical implications

Fingolimod is a sphingosine 1-phosphate (S1P) receptor modulator approved to treat relapsing-remitting multiple sclerosis (MS). Initiation of treatment with fingolimod has been found to produce transient bradycardia and/or slowing of atrioventricular impulse conduction in a small proportion of patients. This effect is thought to be due to the interaction of fingolimod with S1P receptors on the surface membrane of atrial myocytes causing a vagomimetic effect, similar to the action of acetylcholine on muscarinic receptors. As a precaution, patients are under electrocardiogram (ECG) monitoring for 6 h after receiving their first dose. Fingolimod is contraindicated in patients with overt or concealed cardiac diseases. However, the Fingolimod Initiation and caRdiac Safety Trial (FIRST), which was designed specifically to investigate the cardiac profile of fingolimod, did not show an increased risk of clinically relevant cardiac events with fingolimod. This review examines the electrophysiology and pathophysiology of cardiac impulse formation in the context of fingolimod. It concludes that these vagomimetic effects should be considered benign and should not prevent the effective use of fingolimod in the treatment of patients with MS.

[New antiarrhythmic drugs for the treatment of atrial fibrillation]

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and a difficult-to-treat arrhythmia. Conventional antiarrhythmic drugs, including flecainide, propafenone, sotalol and amiodarone, have several limitations in terms of efficacy and tolerability, and have made new drug development crucial. In the last decade, intensive research was undertaken to find new pharmacological options for the treatment of AF, and two new drugs are now available. Vernakalant is an atrial-selective drug specifically designed to block sodium channels at the atrial level, and its intravenous formulation has recently been recommended for approval by the Food and Drug Administration for pharmacological conversion of AF. Dronedarone is a chemical derivative of amiodarone (though having a significantly different clinical profile) with effects on multiple ion channels that proved effective in reducing the rate of the combined endpoint of death from any cause and cardiovascular hospitalization in patients with non-permanent AF enrolled in the ATHENA study. The available evidence on the efficacy of dronedarone has led to approval for recommendation in many clinical situations in which rhythm control is desirable. The complexity of the mechanisms underlying AF and the large variability of associated comorbidities render the AF patient a unique entity, making the identification of patients who may benefit from these novel approaches challenging.

Peptides or small molecules? Different approaches to develop more effective CDK inhibitors

Cell cycle regulation involves processes crucial to the survival of a cell, including the detection and repair of genetic damage as well as the prevention of uncontrolled cell division. The molecular events that control cell cycle are ordered and directional. Cyclins and cyclin-dependent kinases (CDKs), determine cell progression through the cycle ensuring the orderly coordination of cellular events. Alterations of cell cycle controllers are among the main causes of cancer onset. In the past decades many efforts have been made to develop kinase inhibitors that are able to modulate cyclin and CDK complexes, either by mimicking the function of natural CDK inhibitors, such as p21, p16 and p27, or by modulating the cyclin-CDK complexes or their targets directly. The great debate is whether to use peptides or small molecules. Peptides are more selective being derived by the linear protein sequences, indeed they should mimic the catalytic or the regulatory subunits of the cell cycle controller complexes, but on the other side they usually present poorer pharmacokinetic characteristics. In contrast, small molecules have better pharmacokinetic features but lower specificity because many protein kinases show high sequence similarity within the active site. The purpose of this review article is to provide an overview of the main classes of CDK inhibitors focusing on structure-activity relationship (SAR) studies and discussing the pharmacological and therapeutic implications.

When water hurts

Deglutition syncope refers to an uncommon cause of neurally mediated syncope induced by swallowing. We briefly review a case of a 66-year-old man who experienced recurrent syncope episodes during ingestion of beverages, mainly water. Our investigations documented several short asymptomatic episodes of asystole and one prolonged complete atrioventricular block of around 15 seconds associated with the syncopal events, during swallowing. Barium x-ray and manometry evaluations revealed only a nonspecific esophageal dysmotility. An underlying sick-sinus syndrome was found on electrophysiologic study. A DDD pacemaker implantation was performed leading to total disappearance of patient's symptoms.

Involvement of H4(D10S170) protein in ATM-dependent response to DNA damage

H4(D10S170) gene has been identified upon its frequent rearrangement with RET in papillary thyroid tumours (RET/PTC1). The kinase ataxia telangectasia mutated (ATM) phosphorylates a limited number of downstream protein targets in response to DNA damage. We investigated the potential role of H4(D10S170) in DNA damage signaling pathways. We found that in cells treated with etoposide or ionizing radiation (IR), H4(D10S170) underwent ATM-mediated phosphorylation at Thr 434, stabilizing nuclear H4. In ataxia telangectasia cells (A-T), endogenous H4(D10S170) was localized to cytoplasm and was excluded from the nucleus. Moreover, H4(D10S170) was not phosphorylated in ATM-deficient lymphoblasts after ionizing irradiation. Inhibition of ATM kinase interfered with H4(D10S170) apoptotic activity, and expression of H4 with threonine 434 mutated in Alanine, H4(T434A), protected the cells from genotoxic stress-induced apoptosis. Most importantly, after exposure to IR we found that silencing of H4(D10S170) in mammalian cells increased cell survival, as shown by clonogenic assay, allows for DNA synthesis as evaluated by bromodeoxyuridine incorporation and permits cells to progress into mitosis as demonstrated by phosphorylation on Histone H3. Our results suggest that H4(D10S170) is involved in cellular response to DNA damage ATM-mediated, and that the impairment of H4(D10S170) gene function might have a role in thyroid carcinogenesis.

A 3.4-kbp transcript of ZNF331 is solely expressed in follicular thyroid adenomas

Translocations involving chromosomal region 19q13 are a frequent finding in follicular adenomas of the thyroid and might represent the most frequent type of structural aberration in human epithelial tumors. By positional cloning, a putative candidate gene, ZNF331 (formerly RITA) located close to the breakpoint was identified. Recently, aberrant expression of ZNF331 has been described in two cell lines of follicular thyroid adenomas with aberrations in 19q13 indicating an involvement of ZNF331 in tumorigenesis. Nevertheless, knowledge about structure and expression of ZNF331 is limited. We performed RACE-PCR and genomic sequence analyses to gain a deeper insight into its molecular structure. To elucidate ZNF331 expression patterns we performed Northern blot analyses on various normal tissues as well as on thyroid carcinoma and adenoma cell lines. Herein, unique expression of a 3.4-kbp transcript is described in thyroid adenoma cell lines with 19q13 aberrations, which was not detected either in normal tissues or in thyroid carcinoma cell lines.

RET expression in papillary thyroid cancer from patients irradiated in childhood for benign conditions

Both external and internal exposure to radiation have been linked to the development of papillary thyroid cancer. Rearrangement of the gene for RET tyrosine kinase and subsequent expression of this protein has also been found to occur in many papillary thyroid cancers, and with increased frequency in radiation-related cancers following the Chernobyl accident. However, little has been reported on the frequency of RET rearrangements in cancers after exposure to external radiation. We here report on RET protein immunoreactivity in paraffin-embedded thyroid samples from 30 patients with papillary thyroid cancer who received radiation treatment during childhood for benign conditions at Michael Reese Hospital in Chicago, and in 34 patients identified from the tumor registry as having papillary thyroid cancer with no history of therapeutic radiation. The subjects were characterized by sex, age at surgery, and the following attributes of tumor pathology: size, number of lobes involved, number of foci, lymph node metastases, and soft tissue invasion. Representative tissue samples were reacted with an antibody against the RET tyrosine kinase domain whose expression has been shown to correlate highly with RET/PTC rearrangements. A greater percentage of cancers positive for RET immunoreactivity was found in the radiation-exposed group (86.7% vs. 52.9%, P = 0.006). Although the mean age at surgery of the exposed group was lower than the control group, there was no correlation of positive RET immunoreactivity with the age at surgery. No characteristics of the tumors were associated with positive RET immunoreactivity. In summary, the greater incidence of RET-immunopositives in the irradiated group indicates that the expression of RET immunoreactivity is strongly associated with radiation exposure, but the prognostic significance of this is not yet clear.

High mobility group I (Y) proteins bind HIPK2, a serine-threonine kinase protein which inhibits cell growth

The HMGI proteins (HMGI, HMGY and HMGI-C) have an important role in the chromatin organization and interact with different transcriptional factors. The HMGI genes are expressed at very low levels in normal adult tissues, whereas they are very abundant during embryonic development and in several experimental and human tumours. In order to isolate proteins interacting with the HMGI(Y) proteins, a yeast two-hybrid screening was performed using the HMGI(Y) protein as bait. This analysis led to the isolation of homeodomain-interacting protein kinase-2 (HIPK2), a serine/threonine nuclear kinase. HIPK2 co-immunoprecipitates with the HMGI(Y) protein in 293T cells. The interaction between HIPK2 and HMGI(Y) occurs through the PEST domain of HIPK2 and it is direct because in vitro translated HIPK2 binds HMGI(Y). We also show that HIPK2 is able to phosphorylate the HMGI(Y) protein by an in vitro kinase assay. In order to understand a possible role of HIPK2 gene in cell growth we performed a colony assay which showed an impressive HIPK2 inhibitory effect on normal thyroid cells. Flow cytometric analysis would indicate the block of cell growth at the G2/M phase of the cell cycle. Since normal thyroid cells do not express detectable HMGI(Y) protein levels, we assume that the HIPK2 inhibitory effect is independent from the interaction with the HMGI(Y) protein.

High mobility group HMGI(Y) protein expression in human colorectal hyperplastic and neoplastic diseases

HMGI(Y) proteins are overexpressed in experimental and human malignancies, including colon, prostate and thyroid carcinomas. To determine at which step of the carcinogenic process HMGI(Y) induction occurs, we analysed the expression of the HMGI(Y) proteins in hyperplastic, preneoplastic and neoplastic tissues of colorectal origin by immunohistochemistry. All the colorectal carcinomas were HMGI(Y)-positive, whereas no expression was detected in normal colon mucosa tissue. HMGI(Y) expression in adenomas was closely correlated with the degree of cellular atypia. Only 2 of the 18 non-neoplastic polyps tested were HMGI(Y)-positive. These data indicate that HMGI(Y) protein induction is associated with the early stages of neoplastic transformation of colon cells and only rarely with colon cell hyperproliferation.

FRA-1 expression in hyperplastic and neoplastic thyroid diseases

fra-1 gene overexpression has been shown to represent a general event in thyroid cell transformation in vitro and in vivo. Moreover, inhibition of FRA-1 protein synthesis by stable transfection with a fra-1 antisense construct significantly reduces the malignant phenotype of the transformed thyroid cells, indicating a pivotal role of the fra-1 gene product in the process of cellular transformation. In the attempt to define the potential use of FRA-1 protein detection in the diagnosis of thyroid diseases, we analyzed Fra-1 expression by a combination of immunohistochemistry and reverse transcription-PCR (RT-PCR) assay in 174 samples of thyroid nodules (22 nodular hyperplasias, 102 follicular adenomas, 34 papillary carcinomas, 12 follicular carcinomas, and 4 anaplastic carcinomas) representative of the spectrum of thyroid tumor pathology. FRA-1 protein was abundant in all of the carcinoma samples (50/50, 100%), with an intense staining in the nucleus and the cytoplasm. Positive staining was also found in most of the adenomas (90 of 102; 88%), but in this case, the staining was restricted to the nucleus. Similar results were obtained from the analysis of thyroid goiters; however, the number of positive cases is lower than adenomas (8 of 22; 36%); moreover, the staining was not observed in all of the cells. Conversely, no FRA-1 protein was detectable in 12 normal thyroid tissue samples used as controls. RT-PCR analysis confirmed a higher fra-1 expression in papillary and follicular carcinomas compared with goiters and adenomas. fra-1 expression was also analyzed on 10 fine needle aspiration biopsy (FNAB) samples by RT-PCR. fra-1-specific mRNA was detected in seven of the eight FNABs corresponding to thyroid nodules that were eventually diagnosed as adenomas (three of four) and carcinomas (four of four) after surgery. Conversely, no fra-1 gene expression was observed in two FNABs derived from normal thyroid. Further studies are required before suggesting FRA-1 protein detection as a useful tool for the diagnosis of hyperplastic and neoplastic disorders of the thyroid gland.

High prevalence of RET/PTC rearrangements in Ukrainian and Belarussian post-Chernobyl thyroid papillary carcinomas: a strong correlation between RET/PTC3 and the solid-follicular variant

A sharp increase in the incidence of pediatric thyroid papillary cancer was documented after the Chernobyl power plant explosion. An increased prevalence of rearrangements of the RET protooncogene (RET/PTC rearrangements) has been reported in Belarussian post-Chernobyl papillary carcinomas arising between 1990 and 1995. We analyzed 67 post-Chernobyl pediatric papillary carcinomas arising in 1995-1997 for RET/PTC activation: 28 were from Ukraine and 39 were from Belarus. The study, conducted by a combined immunohistochemistry and RT-PCR approach, demonstrated a high frequency (60.7% of the Ukrainian and 51.3% of the Belarussian cases) of RET/PTC activation. A strong correlation was observed between the solid-follicular subtype of papillary carcinoma and the RET/PTC3 isoform: 19 of the 24 RET/PTC-positive solid-follicular carcinomas harbored a RET/PTC3 rearrangement, whereas only 5 had a RET/PTC1 rearrangement. Taken together these results support the concept that RET/PTC activation plays a central role in the pathogenesis of thyroid papillary carcinomas in both Ukraine and Belarus after the Chernobyl accident.

Overexpressed cyclin D3 contributes to retaining the growth inhibitor p27 in the cytoplasm of thyroid tumor cells

The majority of thyroid carcinomas maintain the expression of the cell growth suppressor p27, an inhibitor of cyclin-dependent kinase-2 (Cdk2). However, we find that 80% of p27-expressing tumors show an uncommon cytoplasmic localization of p27 protein, associated with high Cdk2 activity. To reproduce such a situation, a mutant p27 devoid of its COOH-terminal nuclear-localization signal was generated (p27-NLS). p27-NLS accumulates in the cytoplasm and fails to induce growth arrest in 2 different cell lines, indicating that cytoplasm-residing p27 is inactive as a growth inhibitor, presumably because it does not interact with nuclear Cdk2. Overexpression of cyclin D3 may account in part for p27 cytoplasmic localization. In thyroid tumors and cell lines, cyclin D3 expression was associated with cytoplasmic localization of p27. Moreover, expression of cyclin D3 in thyroid carcinoma cells induced cytoplasmic retention of cotransfected p27 and rescued p27-imposed growth arrest. Endogenous p27 also localized prevalently to the cytoplasm in normal thyrocytes engineered to stably overexpress cyclin D3 (PC-D3 cells). In these cells, cyclin D3 induced the formation of cytoplasmic p27-cyclin D3-Cdk complexes, which titrated p27 away from intranuclear complexes that contain cyclins A-E and Cdk2. Our results demonstrate a novel mechanism that may contribute to overcoming the p27 inhibitory threshold in transformed thyroid cells.

Detection of high mobility group I HMGI(Y) protein in the diagnosis of thyroid tumors: HMGI(Y) expression represents a potential diagnostic indicator of carcinoma

Hyperplastic or neoplastic proliferative lesions of thyroid follicular epithelium consist of a spectrum, ranging from nodular hyperplasia to undifferentiated (anaplastic) carcinoma, and usually present as palpable thyroid nodules. Thyroid nodules are a common occurrence in the general population, but only a small proportion of them are eventually diagnosed as carcinoma. The difficulty in objectively identifying those thyroid nodules that are malignant to avoid unnecessary surgery, combined with the range and effectiveness of the available therapeutic options in those patients who do, indeed, have thyroid carcinoma, has prompted the search for tumor markers and prognostic indicators. The high mobility group I (HMGI) proteins represent a class of nuclear proteins involved in the regulation of chromatin structure and function. HMGI(Y), one of the members of this class, is expressed at high levels during embryogenesis and in malignant tumors but at generally low levels in normal adult human tissues. Previous work on a limited number of thyroid samples suggested that the detection of the HMGI(Y) proteins may provide a clinically useful diagnostic tool. To verify this assumption, we analyzed HMGI(Y) expression by a combination of immunohistochemistry and reverse transcription-PCR in 358 thyroid tissue samples that were representative of the spectrum of thyroid tumor pathology. HMGI(Y) was detectable in 18 of 19 follicular carcinomas, 92 of 96 papillary carcinomas, and 11 of 11 undifferentiated (anaplastic) carcinomas but in only 1 of 20 hyperplastic nodules, 44 of 200 follicular adenomas, and 0 of 12 normal tissue samples. The correlation between HMGI(Y) expression and a diagnosis of carcinoma was highly significant (P < 0.0001). We also prospectively collected and analyzed for HMGI(Y) expression by immunohistochemistry and reverse transcription-PCR in 12 fine needle aspiration biopsies from 10 patients who subsequently underwent surgical removal of a solitary thyroid nodule. HMGI(Y) was detectable only in the four fine needle aspiration biopsies, corresponding to the thyroid nodules that were definitively diagnosed as carcinomas after surgery (two follicular carcinomas and two papillary carcinomas). The remaining eight samples (six follicular adenomas and two samples consisting of normal follicular cells) were negative. The findings of this study confirm the differential expression of HMGI(Y) in thyroid neoplasia and indicate the HMGI(Y) protein as a potential marker for thyroid carcinoma.