Circulating miR-451a Expression May Predict Recurrence in Atrial Fibrillation Patients after Catheter Pulmonary Vein Ablation

Atrial fibrillation is the most prevalent tachyarrhythmia in clinical practice, with very high cardiovascular morbidity and mortality with a high-cost impact in health systems. Currently, it is one of the main causes of stroke and subsequent heart failure and sudden death. miRNAs mediate in several processes involved in cardiovascular disease, including fibrosis and electrical and structural remodeling. Several studies suggest a key role of miRNAs in the course and maintenance of atrial fibrillation. In our study, we aimed to identify the differential expression of circulating miRNAs and their predictive value as biomarkers of recurrence in atrial fibrillation patients undergoing catheter pulmonary vein ablation. To this effect, 42 atrial fibrillation patients were recruited for catheter ablation. We measured the expression of 84 miRNAs in non-recurrent and recurrent groups (45.2%), both in plasma from peripheral and left atrium blood. Expression analysis showed that miRNA-451a is downregulated in recurrent patients. Receiver operating characteristic curve analysis showed that miR-451a in left atrium plasma could predict atrial fibrillation recurrence after pulmonary vein isolation. In addition, atrial fibrillation recurrence is positively associated with the increment of scar percentage. Our data suggest that miRNA-451a expression plays an important role in AF recurrence by controlling fibrosis and progression.

Circulating miR-499a and miR-125b as Potential Predictors of Left Ventricular Ejection Fraction Improvement after Cardiac Resynchronization Therapy

Cardiac resynchronization therapy represents a therapeutic option for heart failure drug-refractory patients. However, due to the lack of success in 30% of the cases, there is a demand for an in-depth analysis of individual heterogeneity. In this study, we aimed to evaluate the prognostic value of circulating miRNA differences. Responder patients were defined by a composite endpoint of the presence of left ventricular reverse remodelling (a reduction ≥15% in telesystolic volume and an increment ≥10% in left ventricular ejection fraction). Circulating miRNAs signature was analysed at the time of the procedure and at a 6-month follow-up. An expression analysis showed, both at baseline and at follow-up, differences between responders and non-responders. Responders presented lower baseline expressions of miR-499, and at follow-up, downregulation of miR-125b-5p, both associated with a significant improvement in left ventricular ejection fraction. The miRNA profile differences showed a marked sensitivity to distinguish between responders and non-responders. Our data suggest that miRNA differences might contribute to prognostic stratification of patients undergoing cardiac resynchronization therapy and suggest that preimplant cardiac context as well as remodelling response are key to therapeutic success.

Sex-related differences of fatty acid-binding protein 4 and leptin levels in atrial fibrillation

AIMS

Adiposity plays a key role in the pathogenesis of atrial fibrillation (AF). Our aim was to study the sex differences in adipokines levels according to AF burden.

METHODS AND RESULTS

Two independent cohorts of patients were studied: (i) consecutive patients with AF undergoing catheter ablation (n = 217) and (ii) a control group (n = 105). (i) Adipokines, oxidative stress, indirect autonomic markers, and leucocytes mRNA levels were analysed; (ii) correlation between biomarkers was explored with heatmaps and Kendall correlation coefficients; and (iii) logistic regression and random forest model were used to determine predictors of AF recurrence after ablation. Our results showed that: (i) fatty acid-binding protein 4 (FABP4) and leptin levels were higher in women than in men in both cohorts (P < 0.01). In women, FABP4 levels were higher on AF cohort (20 ± 14 control, 29 ± 18 paroxysmal AF and 31 ± 17 ng/mL persistent AF; P < 0.01). In men, leptin levels were lower on AF cohort (22 ± 15 control, 13 ± 16 paroxysmal AF and 13 ± 11 ng/mL persistent AF; P < 0.01). (ii) In female with paroxysmal AF, there was a lower acetylcholinesterase and higher carbonic anhydrase levels with respect to men (P < 0.05). (iii) Adipokines have an important role on discriminate AF recurrence after ablation. In persistent AF, FABP4 was the best predictor of recurrence after ablation (1.067, 95% confidence interval 1-1.14; P = 0.046).

CONCLUSION

The major finding of the present study is the sex-based differences of FABP4 and leptin levels according to AF burden. These adipokines are associated with oxidative stress, inflammatory and autonomic indirect markers, indicating that they may play a role in AF perpetuation.

Use of an angioplasty wire in transseptal puncture: A new application of an old technique

OBJECTIVE

We wondered if a modification of the conventional transseptal puncture technique performed with an angioplasty wire could be useful in patients with contrast hypersensitivity or allergy-like reactions.

METHODS

This study comprised our initial experience in 22 patients with atrial fibrillation who were scheduled for an electrophysiology study (EPS) and pulmonary vein ablation and who had a contraindication for iodinated contrast administration.

RESULTS

Of the 22 patients, 16 were men and ages ranged from 27 to 74 years (mean 56 years). Overall successful transseptal access was achieved in all 22. A control echocardiogram was performed in all patients. There were no complications in any case and no significant differences were found from the conventional transseptal puncture technique regarding procedure or fluoroscopy time.

CONCLUSIONS

A modification of the conventional transseptal puncture technique performed with fluoroscopy and EPS catheters for anatomical reference and an angioplasty wire is an option in cases with severe contrast hypersensitivity.

Comparison and Validation of Recommended QT Interval Correction Formulas for Predicting Cardiac Arrhythmias in Patients With Advanced Heart Failure and Cardiac Resynchronization Devices

QT interval prolongation is an important marker for the development of cardiac arrhythmias (CAs). Optimal methods to estimate QT/QTc intervals in patients with ventricular pacing (VP) and its correlation with CA have not been widely investigated. We aimed to validate the currently available formulas for QT determination during VP and to compare their abilities in predicting the occurrence of CA (atrial fibrillation [AF] and malignant ventricular arrhythmias [VAs] in patients with advanced heart failure and cardiac resynchronization therapy). Consecutive patients with advanced heart failure who underwent cardiac resynchronization therapy implantation between August 2001 and April 2015 were included in a retrospective study. Four proposed formulas for QT correction in VP rhythms were evaluated. One hundred eighty patients were enrolled. During 44 months of follow-up, 43 patients (37.7%) developed AF and 16 patients (8.9%) developed VA. There was no correlation between corrected QT increments and AF risk with any of the formulas for paced rhythms. Regarding VA, higher corrected QT values measured with Massachusetts' formula (QTcM) were found to have a higher risk of event (p = 0.036) (Beta = 1.012 [1.001 to 1.023]). Each 1 ms increase in QTc increased the probability of experiencing VA by 12‰. QTcM >444 was found to be a strong predictor of VA. In conclusion, there are significant differences in mean QTc interval measured by the currently advised formulas. QTc interval was not associated with AF in any of the formulas. Only the QTcM formula showed a significant stepwise increase in the risk of experiencing malignant VA.

The Micra Leadless Transcatheter Pacemaker. Implantation and Mid-term Follow-up Results in a Single Center

INTRODUCTION AND OBJECTIVES

Currently, studies on the leadless pacemaker (Micra) have mostly been limited to clinical trials with less than 6 months' follow-up and they often fail to reflect real population outcomes. We sought to evaluate electrical parameters at implantation and chronologically during follow-up, as well as the safety of this new technique.

METHODS

This prospective, observational study included 30 consecutive patients, all ≥ 65 years, with an indication for single-chamber pacemaker implantation.

RESULTS

Successful implantation was accomplished in all patients referred for leadless implantation. The mean age was 79.4±6.4 years (range, 66-89 years); 20 (66.6%) were men and 28 had permanent atrial fibrillation (93.3%); 1 had atrial tachycardia and 1 had sinus rhythm. Concomitant atrioventricular node ablation was performed immediately after implantation in 5 patients (16.6%), and implantation was performed after transcatheter aortic valve implantation in 2. The procedure was performed under an uninterrupted anticoagulation regimen (maximum INR 2.4) in 23 patients (76.6%). With the exception of 1 moderate pericardial effusion without tamponade, there were no severe complications. The mean follow-up was 5.3±3.3 months and 4 patients had more than 1 year of follow-up. Sensing and pacing parameters were stable both at implantation and during the short- to mid-term follow-up.

CONCLUSIONS

Implantation of leadless pacemakers is feasible, safe and provides advantages over the conventional system. Further studies with longer follow-up periods will be needed before these devices become widely used in routine clinical practice.

Ablation of Inappropriate Sinus Tachycardia: A Systematic Review of the Literature

OBJECTIVES

The goal of this study was to describe short- and long-term outcomes in all patients referred for inappropriate sinus tachycardia ablation, along with the potential complications of the intervention.

BACKGROUND

Sinus node (SN) ablation/modification has been proposed for patients refractory to pharmacological therapy. However, available data derive from limited series.

METHODS

The electronic databases MEDLINE, Embase, CINAHL, Cochrane, and Scopus were systematically searched (January 1, 1995-December 31, 2015). Studies were screened according to predefined inclusion and exclusion criteria.

RESULTS

A total of 153 patients were included. Their mean age was 35.18 ± 10.02 years, and 139 (90.8%) were female. All patients had failed to respond to maximum tolerated doses of pharmacological therapy (3.5 ± 2.4 drugs). Mean baseline heart rates averaged 101.3 ± 16.4 beats/min according to electrocardiography and 104.5 ± 13.5 beats/min according to 24-h Holter monitoring. Two electrophysiological strategies were used, SN ablation and SN modification, with the latter being used more. Procedural acute success (using variably defined pre-determined endpoints) was 88.9%. Consistently, all groups reported high-output pacing from the ablation catheter to confirm absence of phrenic nerve stimulation before radiofrequency delivery. Need of pericardial access varied between 0% and 76.9%. Thirteen patients (8.5%) experienced severe procedural complications, and 15 patients (9.8%) required implantation of a pacemaker. At a mean follow-up interval of 28.1 ± 12.6 months, 86.4% of patients demonstrated successful outcomes. The symptomatic recurrence rate was 19.6%, and 29.8% of patients continued to receive antiarrhythmic drug therapy after procedural intervention.

CONCLUSIONS

Inappropriate sinus tachycardia ablation/modification achieves acute success in the vast majority of patients. Complications are fairly common and diverse. However, symptomatic relief decreases substantially over longer follow-up periods, with a corresponding high recurrence rate.

Initial experience and treatment of atrial fibrillation using a novel irrigated multielectrode catheter: Results from a prospective two-center study

BACKGROUND

PV electrical isolation has become the cornerstone of catheter ablation for the treatment of atrial fibrillation (AF). Several strategies have been proposed to achieve this goal. The aim of this study was to assess the efficacy and safety of AF ablation using a new circular irrigated multielectrode ablation catheter designed to achieve single-delivery pulmonary vein (PV) isolation.

METHODS

Thirty-five patients with drug refractory paroxysmal AF and normal ejection fraction from two centers were prospectively enrolled in this study. All patients underwent PV isolation with an nMARQ circular irrigated multielectrode ablation catheter guided by an electroanatomic mapping system. Magnetic resonance imaging was performed to exclude PV stenosis.

RESULTS

PV isolation was achieved in 138 of 140 (98.57%) targeted veins. The mean procedure time was 79.5 min (SD 39.3 min). During a mean follow up of 16.8±2.8 months, 27 of 35 (77.2%) patients were free of AF. No PV narrowing was observed. One case of pericardial effusion due to perforation of the left atrial free wall during catheter manipulation did occur.

CONCLUSIONS

PV isolation with a circular irrigated multielectrode ablation catheter is a feasible technique with a high acute success rate. The majority of patients remained asymptomatic during the midterm follow-up period. PV stenosis was not detected. While only a single serious adverse event occurred, this technique׳s safety profile should be tested in larger studies.

Assessment of long-term quality of life after cavotricuspid isthmus ablation for typical atrial flutter

BACKGROUND

Cavotricuspid isthmus (CTI) ablation is the treatment of choice in preventing recurrences of typical atrial flutter (AFl). However, little is known about long-term quality of life (QoL) after CTI ablation.

METHODS AND RESULTS

From 01/2003 to 05/2005, 94 patients who consecutively underwent typical AFl ablation were included in the study. An SF-36 health questionnaire was self-administered before ablation and at follow-up. Transformed scores were calculated, adjusted for age and sex and then normalized and standardized for the Spanish population. Additionally, the minimal important differences (MID) were calculated to assess the smallest change in QoL that patients perceived as positive. A linear regression model was constructed to assess long-term QoL predictors. All SF-36 scales were lower than Spanish population scores. After a mean (SD) follow-up of 6.25 (0.5) years, all scales, except Bodily Pain, were higher than baseline. There was a significant difference for Physical Role (46.4 vs. 38.6, p < 0.001), Vitality (44.4 vs. 41.9, p = 0.038) and Mental Health (46.1 vs. 42.0, p = 0.001). However, only Physical Role achieved the criteria for MID. Recurrence of AFl, basal QoL, history of diabetes mellitus, atrial fibrillation and oral anticoagulation were predictors of long-term QoL.

CONCLUSION

CTI ablation provides a significant improvement in long-term QoL for the dimensions of Physical Role, Vitality and Mental Health, although the smallest positive change that patients perceive as positive was only observed for Physical Role. Previous diabetes mellitus, atrial fibrillation, oral anticoagulation, basal QoL and AFl recurrence were determinants of a worse long-term QoL.