Ruken Özge Akbulak

Loss of Pace Capture on the Ablation Line During Pulmonary Vein Isolation Versus “Dormant Conduction”: Is Adenosine Expendable?

Permanent pulmonary vein isolation (PVI) remains an essential goal of ablation therapy in patients with atrial fibrillation. Aim of this study was the intraindividual comparison of unexcitability to pacing along the ablation line versus dormant conduction (DC) as additional procedural endpoints.

Characterization, Mapping, and Ablation of Complex Atrial Tachycardia: Initial Experience With a Novel Method of Ultra High‐Density 3D Mapping

Conventional mapping of complex atrial tachycardias (ATs) can be challenging. Thus, we evaluated feasibility and utility of a novel, ultra high‐density 3D mapping approach to characterize and map AT in these cases.

Substrate characterization and catheter ablation in patients with scar-related ventricular tachycardia using ultra high-density 3-D mapping

Ablation of scar‐related ventricular tachycardia (VT), especially in noninducible VT or hemodynamically unstable patients, can be challenging. Thus, we evaluated feasibility of an ultra high‐density 3‐D mapping approach to characterize the ventricular substrate and, if possible, to map VT.

Reduction of Radiation Exposure in Atrial Fibrillation Ablation Using a New Image Integration Module: A Prospective Randomized Trial in Patients Undergoing Pulmonary Vein Isolation

Recently, a new image integration module (IIM, CartoUnivu™ Module) has been introduced to combine and merge fluoroscopy images with 3‐dimensional‐(3D)‐electroanatomical maps (Carto® 3 System) into an accurate 3D view. The aim of the study was to investigate the influence of IIM on the fluoroscopy exposure during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) in a prospective randomized trial.

Risk stratification of patients with left atrial appendage thrombus prior to catheter ablation of atrial fibrillation: An approach towards an individualized use of transesophageal echocardiography

The need for transesophageal echocardiography (TEE) before catheter ablation of atrial fibrillation (CA‐AF) is still being questioned. The aim of this study is to analyze patients’ (patients) risk factors of left atrial appendage thrombus (LAAT) prior to CA‐AF in daily clinical practice, according to oral anticoagulation (OAC) strategies recommended by current guidelines.

Acute and long-term effects of fingolimod on heart rhythm and heart rate variability in patients with multiple sclerosis

BACKGROUND Fingolimod can lead to increased risk of cardiac events such as bradycardia or atrioventricular (AV) block. OBJECTIVE Evaluate acute and long-term effects of fingolimod on heart rhythm (HR), heart rate variability (HRV) and development of AV-blocks. METHODS In 64 patients with relapsing-remitting multiple sclerosis Holter ECG monitoring (HEM) and HRV analysis were performed 24h before, six h during and 72h after initiation of fingolimod. We additionally analyzed a 24h HEM after a follow up of ≥ three months. RESULTS Heart rate (HR) decreased significantly (p < 0.001) under fingolimod treatment with nadir at five hours after starting and maintained decreased for 72h. Five (7.8%) patients suffered from new-onset AV-block requiring cessation of treatment. In four of five patients (80%), the AV-block could only be documented in the 72h-HEM with a median time of occurrence at 14h. The mean heart rate was still significant lower after a mean follow up time of 14.1 ± 9.6 months (85.0 ± 9.8 vs. 75.3 ± 16.2 bpm; p = 0.002) in comparison to baseline. CONCLUSION The treatment with fingolimod leads to an increase of vagal activation which persists even after 14 months of treatment. These changes did not return to baseline levels on treatment with fingolimod. Based on our data an additional at least 24h hour-HEM after the initiation of fingolimod therapy should be considered.

Local Electrical Dyssynchrony during Atrial Fibrillation: Theoretical Considerations and Initial Catheter Ablation Results

Background Electrogram-based identification of the regions maintaining persistent Atrial Fibrillation (AF) is a subject of ongoing debate. Here, we explore the concept of local electrical dyssynchrony to identify AF drivers. Methods and Results Local electrical dyssynchrony was calculated using mean phase coherence. High-density epicardial mapping along with mathematical model were used to explore the link between local dyssynchrony and properties of wave conduction. High-density mapping showed a positive correlation between the dyssynchrony and number of fibrillatory waves (R2 = 0.68, p<0.001). In the mathematical model, virtual ablation at high dyssynchrony regions resulted in conduction regularization. The clinical study consisted of eighteen patients undergoing catheter ablation of persistent AF. High-density maps of left atrial (LA) were constructed using a circular mapping catheter. After pulmonary vein isolation, regions with the top 10% of the highest dyssynchrony in LA were targeted during ablation and followed with ablation of complex atrial electrograms. Catheter ablation resulted in termination during ablation at high dyssynchrony regions in 7 (41%) patients. In another 4 (24%) patients, transient organization was observed. In 6 (35%) there was no clear effect. Long-term follow-up showed 65% AF freedom at 1 year and 22% at 2 years. Conclusions Local electrical dyssynchrony provides a reasonable estimator of regional AF complexity defined as the number of fibrillatory waves. Additionally, it points to regions of dynamical instability related with action potential alternans. However, despite those characteristics, its utility in guiding catheter ablation of AF is limited suggesting other factors are responsible for AF persistence.

Incidence of intracardiac thrombus formation prior to electrical cardioversion in respect to the mode of oral anticoagulation

To evaluate the incidence of newly diagnosed intracardiac thrombi (ICT) in respect to the mode of OAC in patients undergoing cardioversion (CV).

Image integration into 3-dimensional-electro-anatomical mapping system facilitates safe ablation of ventricular arrhythmias originating from the aortic root and its vicinity

Aims During ablation in the vicinity of the coronary arteries establishing a safe distance from the catheter tip to the relevant vessels is mandatory and usually assessed by fluoroscopy alone. The aim of the study was to investigate the feasibility of an image integration module (IIM) for continuous monitoring of the distance of the ablation catheter tip to the main coronary arteries during ablation of ventricular arrhythmias (VA) originating in the sinus of valsalva (SOV) and the left ventricular summit part of which can be reached via the great cardiac vein (GCV). Methods and results Of 129 patients undergoing mapping for outflow tract arrhythmias from June 2014 till October 2015, a total of 39 patients (52.4 ± 18.1 years, 17 female) had a source of origin in the SOV or the left ventricular summit. Radiofrequency (RF) ablation was performed when a distance of at least 5 mm could be demonstrated with IIM. A safe distance in at least one angiographic plane could be demonstrated in all patients with a source of origin in the SOV, whereas this was not possible in 50% of patients with earliest activation in the summit area. However, using the IIM a safe position at an adjacent site within the GCV could be obtained in three of these cases and successful RF ablation performed safely without any complications. Ablation was successful in 100% of patients with an origin in the SOV, whereas VAs originating from the left ventricular summit could be abolished completely in only 60% of cases. Conclusion Image integration combining electroanatomical mapping and fluoroscopy allows assessment of the safety of a potential ablation site by continuous real-time monitoring of the spatial relations of the catheter tip to the coronary vessels prior to RF application. It aids ablation in anatomically complex regions like the SOV or the ventricular summit providing biplane angiograms merged into the three-dimensional electroanatomical map.

Catheter ablation of hemodynamically unstable ventricular tachycardia in ischemic cardiomyopathy using high-resolution mapping

Catheter ablation is a recommended therapy option for ventricular tachycardia (VT). The antegrade transseptal approach for targeting VT with left ventricular origin is feasible with the high‐resolution basket catheter. High‐resolution mapping offers the potential to quickly acquire detailed voltage and activation maps. This may help to identify the crucial VT‐substrate even in patients with huge scar areas and hemodynamically unstable VT.