Efficacy of multi-electrode linear irreversible electroporation.

AIMS: We investigated the efficacy of linear multi-electrode irreversible electroporation (IRE) ablation in a porcine model. METHODS AND RESULTS: The study was performed in six pigs (weight 60-75 kg). After median sternotomy and opening of the pericardium, a pericardial cradle was formed and filled with blood. A linear seven polar 7-Fr electrode catheter with 2.5 mm electrodes and 2.5 mm inter-electrode spacing was placed in good contact with epicardial tissue. A single IRE application was delivered using 50 J at one site and 100 J at two other sites, in random sequence, using a standard monophasic defibrillator connected to all seven electrodes connected in parallel. The pericardium and thorax were closed and after 3 weeks survival animals were euthanized. A total of 82 histological sections from all 18 electroporation lesions were analysed. A total of seven 50 J and fourteen 100 J epicardial IRE applications were performed. Mean peak voltages at 50 and 100 J were 1079.2 V ± 81.1 and 1609.5 V ± 56.8, with a mean peak current of 15.4 A ± 2.3 and 20.2 A ± 1.7, respectively. Median depth of the 50 and 100 J lesions were 3.2 mm [interquartile range (IQR) 3.1-3.6] and 5.5 mm (IQR 4.6-6.6) (P < 0.001), respectively. Median lesion width of the 50 and 100 J lesions was 3.9 mm (IQR 3.7-4.8) and 5.4 mm (IQR 5.0-6.3), respectively (P < 0.001). Longitudinal sections showed continuous lesions for 100 J applications. CONCLUSION: Epicardial multi-electrode linear application of IRE pulses is effective in creating continuous deep lesions.

Feasibility of Linear Irreversible Electroporation Ablation in the Coronary Sinus.

INTRODUCTION: Previous studies demonstrated that the coronary sinus (CS) is an important target for ablation in persistent atrial fibrillation. However, radiofrequency ablation in the CS is associated with coronary vessel damage and tamponade. Animal data suggest irreversible electroporation (IRE) ablation can be a safe ablation modality in vicinity of coronary arteries. We investigated the feasibility of IRE in the CS in a porcine model. METHODS: Ablation and pacing was performed in the CS in six pigs (weight 60-75 kg) using a modified 9-French steerable linear hexapolar Tip-Versatile Ablation Catheter. Pacing maneuvers were performed from distal to proximal segments of the CS to assess atrial capture thresholds before and after IRE application. IRE ablations were performed with 100 J IRE pulses. After 3-week survival animals were euthanized and histological sections from the CS were analyzed. RESULTS: A total of 27 IRE applications in six animals were performed. Mean peak voltage was 1509 ± 36 V, with a mean peak current of 22.9 ± 1.0 A. No complications occurred during procedure and 3-week survival. At 30 min post ablation 100% isolation was achieved in all animals. At 3 weeks follow-up pacing thresholds were significant higher as compared to baseline. Histological analysis showed transmural ablation lesions in muscular sleeves surrounding the CS. CONCLUSION: IRE ablation of the musculature along the CS using a multi-electrode catheter is feasible in a porcine model.

Atrial fibrillation ablation strategies and technologies: past, present, and future.

Catheter ablation is an established treatment option for atrial fibrillation (AF), and pulmonary vein isolation (PVI) has become the gold standard in AF ablation. AF recurrence after PVI remains an important clinical problem. Recovery of conduction from the pulmonary veins (PVs) is considered the dominant mechanism for AF recurrence in paroxysmal AF. However, the underlying mechanism of AF recurrence after PVI is more complex in patients with persistent and longstanding persistent AF. Different ablation technologies and energy sources have been developed aimed at improving lesion quality and durability with an acceptable safety profile. Novel technologies are under evaluation which have a great potential to produce permanent PVI after a single ablation procedure. However, clinical value of these novel devices needs to be tested in adequately powered randomized controlled trials. In this article, we review the history of catheter ablation for AF and discuss the present and future ablation technologies.

Quality of life after catheter and minimally invasive surgical ablation of paroxysmal and early persistent atrial fibrillation: results from the SCALAF trial.

AIMS: In the SCALAF trial, catheter-based pulmonary vein isolation (PVI) was as effective in long-term prevention of atrial fibrillation (AF) as minimally invasive thoracoscopic PVI and left atrial appendage ligation (MIPI). Catheter ablation (CA) resulted in significantly less major complications as compare to MIPI. We report quality of life (QOL) outcome in these patients. METHODS: In this study, 52 patients with symptomatic paroxysmal or early persistent AF were randomized to either MIPI or CA. QOL was assessed at baseline, 3, 6, and 12 months follow-up using the SF-36 Health Survey Questionnaire. AF-related symptoms were quantified at each follow-up visit using the European Heart Rhythm Association (EHRA) score. RESULTS: Median age was 57 years and 78% was male. Paroxysmal AF was present in 74%. At 3 months follow-up, physical role limitations (88.2 ± 29.5; versus 40.9 ± 44.0; P = 0.001, respectively) and bodily pain scores (95.5 ± 8.7; versus 76.0 ± 27.8; P = 0.021, respectively) were significantly higher after CA compared to MIPI, indicating less limitation in daily activity caused by physical problems and less pain after CA than after MIPI. AF symptoms assessed by the EHRA scores improved significantly at 3, 6, 12, and 24 months compared to baseline in both treatment groups (P < 0.001), with no significant differences between treatment groups. CONCLUSIONS: CA and MIPI ablation of AF both resulted in an improvement in several QOL measurements, although CA resulted in significantly less physical problems and bodily pain 3 months after treatment compared to MIPI. CLINICAL TRIAL NUMBER: ClinicalTrials.gov identifier: NCT00703157.

Arrhythmia-free survival and pulmonary vein reconnection patterns after second-generation cryoballoon and contact-force radiofrequency pulmonary vein isolation.

INTRODUCTION: The aim of this study was to compare second-generation cryoballoon and contact-force radiofrequency point-by-point pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients with regard to pulmonary vein reconnection and arrhythmia-free survival. METHODS AND RESULTS: Altogether, 269 consecutive patients with drug-refractory AF undergoing PVI were included and randomly allocated to second-generation cryoballoon or contact-force point-by-point radiofrequency ablation. Median follow-up duration was 389 days (interquartile range 219-599). Mean age was 59 years (71% male); 136 patients underwent cryoballoon and 133 patients underwent radiofrequency ablation. Acute electrical PVI was 100% for both techniques. Procedure duration was significantly shorter in cryoballoon vs radiofrequency (166.5 vs 184.13 min P = 0.016). Complication rates were similar (6.0 vs 6.7%, P = 1.00). Single procedure freedom of atrial arrhythmias was significantly higher in cryoballoon as compared to radiofrequency (75.2 vs 57.4%, P = 0.013). In multivariate analysis, persistent AF, AF duration, and cryoballoon ablation were associated with freedom of atrial tachyarrhythmias. The number of repeat ablation procedures was significantly lower in the cryoballoon compared to radiofrequency (15.0 vs 24.3%, P = 0.045). At repeat ablation, pulmonary vein reconnection rate was significantly lower after cryoballoon as compared to radiofrequency ablation (36.8 vs 58.1%, P = 0.003). CONCLUSIONS: Improved arrhythmia-free survival and more durable pulmonary vein isolation is seen after PVI using second-generation cryoballoon as compared to contact-force radiofrequency, in patients with drug-refractory paroxysmal AF. Complication rates for both ablation techniques are low.

Correction to: Arrhythmia-free survival and pulmonary vein reconnection patterns after second-generation cryoballoon and contact-force radiofrequency pulmonary vein isolation.

The name of the author Jaap Jan J. Smit was rendered wrongly in the original publication. The original article has been corrected.

Randomized Controlled Trial of Surgical Versus Catheter Ablation for Paroxysmal and Early Persistent Atrial Fibrillation.

BACKGROUND: Current guidelines recommend both percutaneous catheter ablation (CA) and surgical ablation in the treatment of atrial fibrillation, with different levels of evidence. No direct comparison has been made between minimally invasive thoracoscopic pulmonary vein isolation with left atrial appendage ligation (surgical MIPI) versus percutaneous CA comprising of pulmonary vein isolation as primary treatment of atrial fibrillation. We, therefore, conducted a randomized controlled trial comparing the safety and efficacy of these 2 treatment modalities. METHODS: Eighty patients were enrolled in the study and underwent implantable loop recorder implantation. Twenty-eight patients did not reach randomization criteria. A total of 52 patients with symptomatic paroxysmal or early persistent atrial fibrillation were randomized, 26 to CA and 26 to surgical MIPI. The primary end point was defined as freedom of atrial tachyarrhythmias, without the use of antiarrhythmic drugs. The safety end point was freedom of complications. RESULTS: Median age was 57 years (range, 37-75), and 78% were men. Paroxysmal atrial fibrillation was present in 74%. Follow-up duration was ≥2 years in all patients. CA was noninferior to MIPI in terms of single-procedure arrhythmia-free survival after 2 years of follow-up (56.0% versus 29.2%; HR, 0.56; 95% CI, 0.26-1.20; log-rank P=0.059). Procedure-related major adverse events occurred significantly more often in MIPI than CA (20.8% versus 0%; P=0.029). CONCLUSIONS: Percutaneous pulmonary vein isolation was noninferior to MIPI in terms of efficacy and resulted in less complications. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00703157.

A Decreased Preload Due to a Loaded Stomach: A Rare Presentation of a Paraesophageal Hernia.

A hiatal hernia is a condition in which intraabdominal content herniates into the intrathoracic cavity. On rare occasions, a hiatal hernia can lead to cardiorespiratory compromise. We report a case of chest pain followed by cardiac arrest in a patient not known to have hiatal hernia, and without preliminary symptoms. The patient was suspected of having cardiac ischemia; however, angiography did not reveal any abnormalities. Chest tomography revealed a large paraesophageal hernia with compression of the right ventricle causing decreased preload and cardiac output. Gastric decompression was performed, and definitive surgical treatment took place the subsequent day. The postoperative course was uncomplicated.

Association between pulmonary vein orientation and ablation outcome in patients undergoing multi-electrode ablation for atrial fibrillation.

BACKGROUND: Previous studies reported on the impact of pulmonary vein orientation on pulmonary vein isolation (PVI) outcome in atrial fibrillation patients undergoing laser balloon PVI and point-by-point radiofrequency ablation. OBJECTIVE: Demonstrate the association between pulmonary vein orientation and PVI outcome after multi-electrode radiofrequency ablation. METHODS: 120 patients undergoing PVI with a circular MER catheter were included. A left atrial ECG-triggered CT was performed in all patients prior to PVI. The orientation of all pulmonary veins at the insertion into the left atrium was measured in the axial and coronal planes. pulmonary veins were classified as having a ventral/dorsal and caudal/cranial orientation depending on the pulmonary vein trunk angle as compared to the median angle. RESULTS: Mean age was 56 years, arrhythmia-free survival after a median follow-up of 20 months was 54.2%. Left upper pulmonary vein orientation within the coronal plane was associated with arrhythmia-free survival, ranging from 58% with a cranial pulmonary vein orientation to 21% with a caudal orientation (p = 0.003). Similarly, arrhythmia-free survival was 50% in patients with a caudal orientation and 33% in patients with a cranial orientation of the left lower pulmonary vein in the coronal plane (p = 0.036). Pulmonary vein orientation in the axial plane and orientation of the right-sided pulmonary veins were not associated with arrhythmia-free survival. Multivariable analysis showed an independent association between both left upper (hazard ratio 2.8, p = 0.001) and left lower (hazard ratio 0.490, p = 0.034) pulmonary vein orientation and arrhythmia-free survival. CONCLUSION: In MER ablation, orientation of the left upper and caudalpulmonary veins in the coronal plane were independently associated with arrhythmia-free survival after multi-electrode PVI.

Identification of novel androgen-regulated pathways and mRNA isoforms through genome-wide exon-specific profiling of the LNCaP transcriptome.

Androgens drive the onset and progression of prostate cancer (PCa) by modulating androgen receptor (AR) transcriptional activity. Although several microarray-based studies have identified androgen-regulated genes, here we identify in-parallel global androgen-dependent changes in both gene and alternative mRNA isoform expression by exon-level analyses of the LNCaP transcriptome. While genome-wide gene expression changes correlated well with previously-published studies, we additionally uncovered a subset of 226 novel androgen-regulated genes. Gene expression pathway analysis of this subset revealed gene clusters associated with, and including the tyrosine kinase LYN, as well as components of the mTOR (mammalian target of rapamycin) pathway, which is commonly dysregulated in cancer. We also identified 1279 putative androgen-regulated alternative events, of which 325 (∼25%) mapped to known alternative splicing events or alternative first/last exons. We selected 30 androgen-dependent alternative events for RT-PCR validation, including mRNAs derived from genes encoding tumour suppressors and cell cycle regulators. Of seven positively-validating events (∼23%), five events involved transcripts derived from alternative promoters of known AR gene targets. In particular, we found a novel androgen-dependent mRNA isoform derived from an alternative internal promoter within the TSC2 tumour suppressor gene, which is predicted to encode a protein lacking an interaction domain required for mTOR inhibition. We confirmed that expression of this alternative TSC2 mRNA isoform was directly regulated by androgens, and chromatin immunoprecipitation indicated recruitment of AR to the alternative promoter region at early timepoints following androgen stimulation, which correlated with expression of alternative transcripts. Together, our data suggest that alternative mRNA isoform expression might mediate the cellular response to androgens, and may have roles in clinical PCa.