Edina Nagy-Baló

Transcranial Measurement of Cerebral Microembolic Signals During Pulmonary Vein Isolation A Comparison of Two Ablation Techniques

Background—Pulmonary vein isolation has increasingly been used to cure atrial fibrillation, but concerns have recently been raised that subclinical brain damage may occur because of microembolization during these procedures. We compared the occurrence of bubble formation seen on intracardiac echocardiography and the microembolic signals (MESs) detected by transcranial Doppler on the use of different ablation techniques and anticoagulation strategies. Methods and Results—This prospective study included 35 procedures in 34 consecutive patients (age, 52; SD, 12.8 years; female:male 9:25). Pulmonary vein isolation was performed with a cryoballoon and the conventional anticoagulation protocol (activated clotting time >250 s) in 10 procedures (group 1), with a multipolar duty-cycled radiofrequency pulmonary group 2), and with regime a pulmonary vein ablation catheter with an aggressive anticoagulation (activated clotting time >320 s) in 13 procedures (group 3). The mean total numbers of MESs detected during the procedures were 833.7 (SD, 727.4) in group 1, 3142.6 (SD, 1736.4) in group 2, and 2204.6 (SD, 1078.1) in group 3 (P=0.0005). MESs were detected mostly during energy delivery in the pulmonary vein ablation catheter groups, whereas a relatively even distribution of emboli formation was seen during cryoballoon ablations. A significant correlation was found in all groups between the degree of bubble formation on intracardiac echocardiography and the number of MESs (P=0.0000). Conclusions—Duty-cycled radiofrequency ablation is associated with significantly more MESs, even when more aggressive anticoagulation is applied. With both techniques most of these microemboli are gaseous in nature.

Cerebral microembolization during atrial fibrillation ablation: Comparison of different single-shot ablation techniques

BACKGROUND Clinically silent cerebral ischemia (SCI) detected by diffusion-weighted MRI has been reported in 5-40% of patients undergoing pulmonary vein isolation (PVI). Although initial reports suggested a high rate of SCI with phased radiofrequency (RF) ablation on use of the pulmonary vein ablation catheter (PVAC), the incidence was subsequently markedly reduced in consequence of procedural modifications in recent studies. We analyzed cerebral microembolization as assessed with transcranial Doppler during phased RF ablation and with two other single-shot AF ablation technologies: the cryoballoon (CB) and the nMARQ™ multipolar irrigated RF ablation system. METHODS AND RESULTS A total of 89 patients (mean age: 57, SD: 12years; 62 males) with paroxysmal or persistent AF underwent PVI. Phased RF was used according to the initial protocol in 7 patients (PVAC Group I), with procedural modifications and a newer (14.4) version of the RF generator in 37 patients (PVAC Group II) and with the most recent (version 15.1) generator in 18 patients (PVAC Group III). Ablation was performed with the CB in 13 and with the nMARQ system in 14 patients. The number of microemboli (mean+(SD)) detected in the middle cerebral arteries was 2703 (918) in PVAC Group I, 1087 (542) in PVAC Group II, 719 (469) in PVAC Group III, 1057 (784) with CB and 2166 (1047) with nMARQ (p<0.01). CONCLUSION Significant decreases in MES counts were observed thanks to the procedural modifications and newer RF generator with phased RF. High MES counts comparable to those with the initial phased RF resulted from the use of nMARQ.

Predictors of cerebral microembolization during phased radiofrequency ablation of atrial fibrillation: Analysis of biophysical parameters from the ablation generator

BACKGROUND Pulmonary vein isolation with phased radiofrequency current and use of a pulmonary vein ablation catheter (PVAC) has recently been associated with a high incidence of clinically silent brain infarcts on diffusion-weighted magnetic resonance imaging and a high microembolic signal (MES) count detected by transcranial Doppler. OBJECTIVE The purpose of this study was to investigate the potential correlation between different biophysical parameters of energy delivery (ED) and MES generation during PVAC ablation. METHODS MES counts during consecutive PVAC ablations were recorded for each ED and time stamped for correlation with temperature, power, and impedance data from the GENius 14.4 generator. Additionally, catheter-tissue contact was characterized by the template deviation score, calculated by comparing the temperature curve with an ideal template representing good contact, and by the respiratory contact failure score, to quantify temperature variations indicative of intermittent contact due to respiration. RESULTS A total of 834 EDs during 48 PVAC ablations were analyzed. A significant increase in MES count was associated with a lower average temperature, a temperature integral over 62°C, a higher average power, the total energy delivered, higher respiration and template deviation scores (P <.0001), and simultaneous ED to the most proximal and distal poles of the PVAC (P <.0001). CONCLUSION MES generation during ablation is related to different indicators of poor electrode-tissue contact, the total power delivered, and the interaction between the most distal and the most proximal electrodes.

Predictors of Cerebral Microembolization during Phased Radiofrequency Ablation of Atrial Fibrillation: Role of the Ongoing Rhythm and the Site of Energy Delivery

Pulmonary vein isolation with phased radiofrequency current and use of a pulmonary vein ablation catheter (PVAC) has recently been associated with a high incidence of clinically silent brain infarcts on diffusion‐weighted magnetic resonance imaging, and a high microembolic signal (MES) count detected by transcranial Doppler. We investigated the potential effects of the ongoing rhythm and the target vein during energy delivery (ED) on MES generation during PVAC ablations.

Cerebrovascular Complications Related to Atrial Fibrillation Ablation and Strategies for Periprocedural Stroke Prevention

Transcatheter treatment of atrial fibrillation (AF) is a complex intervention performed in patients who are at inherently increased risk of a thromboembolic complication, including stroke. It is therefore not surprising that cerebrovascular accidents have been among the most feared complications since the inception of AF ablation. While improvements have been made to limit the incidence of thromboembolic events during catheter ablation of AF, the optimal strategy to minimize such complications has yet to be determined. It is hoped that larger trials using periprocedural anticoagulation strategies can be undertaken to definitively address these important concerns.

Intracardiac Hemostasis and Fibrinolysis Parameters in Patients with Atrial Fibrillation

Aims To identify intracardiac hemostasis or fibrinolysis abnormalities, which are associated with atrial fibrillation (AF) and increase the risk of thromboembolism. Patients and Methods Patient group consisted of 24 patients with AF and control group included 14 individuals with other supraventricular tachycardia undergoing transcatheter radiofrequency ablation. Blood samples were drawn from the femoral vein (FV), left atrium (LA), and left atrial appendage (LAA) before the ablation procedure. Fibrinogen, factor VIII (FVIII) and factor XIII activity, von Willebrand factor (VWF) antigen, thrombin-antithrombin (TAT) complex, quantitative fibrin monomer (FM), plasminogen, α2-plasmin inhibitor, plasmin-α2-antiplasmin (PAP) complex, PAI-1 activity, and D-dimer were measured from all samples. Results Levels of FVIII and VWF were significantly elevated in the FV and LA of AF patients as compared to controls. TAT complex, FM, PAP complex, and D-dimer levels were significantly elevated in the LA as compared to FV samples in case of both groups, indicating a temporary thrombotic risk associated with the catheterization procedure. Conclusions None of the investigated hemostasis or fibrinolysis parameters showed significant intracardiac alterations in AF patients as compared to non-AF controls. AF patients have elevated FVIII and VWF levels, most likely due to endothelial damage, presenting at both intracardiac and systemic level.

Relationship between cardiovascular diseases and circulating cell-free nucleic acids in human plasma

Cardiovascular diseases (CVDs) are the main cause of human morbidity and mortality worldwide. Early diagnosis could improve the efficiency of treatments. New biomarkers are needed for the identification of high-risk populations in order to make accurate diagnosis and therapy monitoring. Circulating cell-free nucleic acids (cf-NAs) offer a promising new noninvasive tool. These have a role in the regulation of normal physiological functions and in the development of pathological alterations. There is extended research on the clinical application and utilization of cell-free genomic DNA, mtDNA, mRNA, miRNA and long noncoding RNA in CVDs. These molecules could serve as components of new generation therapeutics. Our review focuses on the role of cf-NAs in the pathogenesis of CVDs and we are discussing also possible diagnostic applications and therapeutic implications.

Cerebral micro-embolization during pulmonary vein isolation: Relation to post-ablation silent cerebral ischemia

BACKGROUND High incidences of silent cerebral ischemia (SCI) have been revealed by diffusion-weighted magnetic resonance imaging (DW MRI) after pulmonary vein isolation (PVI) for atrial fibrillation. A high number of mostly gaseous micro-embolic signals (MESs) was detected by transcranial Doppler (TCD) during PVI. In this investigation the possible relationship between MESs detected intraoperatively by TCD and new SCI on DW MRI post-ablation is reported. METHODS 27 consecutive atrial fibrillation patients (6 female, age median: 64 interquartile range: 13.23) undergoing PVI with the pulmonary vein ablation catheter, pre- and post-ablation DW MRI and intra-operative MES detection by TCD were included in the study. Procedures were performed on a therapeutic international normalized ratio (2-3) and with a target activated clotting time ≥ 350 s in all patients. DW MRI scans performed pre- and post-ablation revealed new SCI in 6 out of 27 (22%) patients. RESULTS The median (interquartile range) MES count recorded during the whole procedure was 1642 (912) in patients with and 1019 (529) in those without SCI (p = 0.129). The number of MESs recorded during pulmonary vein angiography was significantly higher in patients as compared to those without a new lesion on the post-ablation DW MRI: 257 (249) vs. 110 (71), respectively (p = 0.0009). On mul-tivariate logistic regression, the total MES count was predictive of SCI in patients older than 68 years. CONCLUSIONS Micro-embolus generation detected by TCD during pulmonary vein angiography significantly correlates with new SCI on DW MRI post-ablation.

Long-term arrhythmia variability after monomorphic ventricular tachycardia in patients with an implantable cardioverter defibrillator.

Background:  Arrhythmia burden in patients receiving an implantable cardioverter defibrillator (ICD) after monomorphic ventricular tachycardia (mVT) is higher than in patients with other indications. We investigated the long‐term arrhythmia profile in this subset of patients.

Correlation of body mass index and responder status in heart failure patients after cardiac resynchronization therapy: Does the obesity paradox exist?

Abstract Aims: We investigated the influence of body mass index (BMI) on the prevalence of responder status in chronic heart failure patients after cardiac resynchronization therapy (CRT). Methods: Data on 169 patients with resynchronization therapy were analyzed. Patients were categorized on the basis of the BMI measured at device implantation according to the WHO classification, as normal (BMI: 18.5–24.9 kg/m2), overweight (BMI: 25–29.9 kg/m2) or obese (BMI:≥30 kg/m2). Patients were considered responders if left ventricular ejection fraction was increased by at least 5% at 6-month follow-up. Results: The mean age in the study population was 60.9±10.86 years (females 29%). The BMI subgroups did not exhibit any significant differences in baseline characteristics (age, gender, left ventricular ejection fraction or NYHA class). Elevated BMIs were associated with higher prevalence of responder status (overweight: 71.4%, obese: 63.0%) relative to subjects with a normal BMI (44.7%) (p=0.015). Conclusions: In t...