Fethi Kilicaslan

Response of Atrial Fibrillation to Pulmonary Vein Antrum Isolation Is Directly Related to Resumption and Delay of Pulmonary Vein Conduction

Background—The role of pulmonary vein (PV) isolation in ablative treatment of atrial fibrillation (AF) has been debated in conflicting reports. We sought to compare PV conduction in patients who had no AF recurrence (group I), patients who could maintain sinus rhythm on antiarrhythmic medication (group II), and patients who had recurrent AF despite antiarrhythmic medication (group III) after PV antrum isolation (PVAI). Methods and Results—PV conduction was examined in consecutive patients undergoing second PVAI for AF recurrence. We also recruited some patients cured of AF to undergo a repeat, limited electrophysiological study at >3 months after PVAI. All patients underwent PVAI with an intracardiac echocardiography (ICE)–guided approach with complete isolation of all 4 PV antra (PVA). The number of PVs with recurrent conduction and the shortest atrial to PV (A-PV) conduction delay was measured with the use of consistent Lasso positions defined by ICE. Late AF recurrence was defined as AF >2 months after PVAI with the patient off medications. Patients in groups I (n=26), II (n=37), and III (n=44) did not differ at baseline (38% permanent AF; ejection fraction 53±6%). Recurrence of PV–left atrial (LA) conduction was seen in 1.7±0.8 and 2.2±0.8 PVAs for groups II and III but only in 0.2±0.4 for group I (P=0.02). In patients with recurrent PV-LA conduction, the A-PV delay increased from the first to second procedure by 69±47% for group III, 267±110% for group II, and 473±71% for group I (P<0.001). When pacing was at a faster rate, A-PV block developed in all 5 of the group I patients with recurrent PV-LA conduction. Conclusions—The majority of patients with drug-free cure show no PV-LA conduction recurrence. Substantial A-PV delay is seen in patients able to maintain sinus rhythm on antiarrhythmic medication or cured of AF compared with patients who fail PVAI.

Assessment of temperature, proximity, and course of the esophagus during radiofrequency ablation within the left atrium

Background—Left atrioesophageal fistula is a devastating complication of atrial fibrillation ablation. There is no standard approach for avoiding this complication, which is caused by thermal injury during ablation. The objectives of this study were to evaluate the course of the esophagus and the temperature within the esophagus during pulmonary vein antrum isolation (PVAI) and correlate these data with esophagus tissue damage. Methods and Results—Eight-one patients presenting for PVAI underwent esophagus evaluation that included temperature probe placement. Esophagus course was obtained with computed tomography, 3D imaging (NAVX), or intracardiac echocardiography. For each lesion, the power, catheter and esophagus temperature, location, and presence of microbubbles were recorded. Lesion location and esophagus course were defined with 6 predetermined left atrial anatomic segments. Endoscopy evaluated tissue changes during and after PVAI. Of 81 patients, the esophagus coursed near the right pulmonary veins in 23 (28.4%), left pulmonary veins in 31 (38.3%), and mid-posterior wall in 27 (33%). Esophagus temperature was significantly higher during left atrial lesions along its course than with lesions elsewhere (38.9±1.4°C, 36.8±0.5°C, P<0.01). Lesions that generated microbubbles had higher esophagus temperatures than those without (39.3±1.5°C, 38.5±0.9°C, P<0.01). Power was not predictive of esophagus temperatures. Distance between the esophagus and left atrium was 4.4±1.2 mm. Conclusions—Lesions near the course of the esophagus that generated microbubbles significantly increased esophagus temperature compared with lesions that did not. Power did not correlate with esophagus temperatures. Esophagus variability makes the avoidance of lesions along its course difficult. Rather than avoiding posterior lesions, emphasis could be placed on better esophagus monitoring for creation of safer lesions.

Relationship between successful ablation sites and the scar border zone defined by substrate mapping for ventricular tachycardia post-myocardial infarction

Introduction: It is unknown if identification of scar border zones by electroanatomical mapping correlates with successful ablation sites determined from mapping during ventricular tachycardia (VT) post‐myocardial infarction (MI). We sought to assess the relationship between successful ablation sites of hemodynamically stable post‐MI VTs determined by mapping during VT with the scar border zone defined in sinus rhythm.

Electrical isolation of the superior vena cava: An adjunctive strategy to pulmonary vein antrum isolation improving the outcome of AF ablation

PV isolation at the antrum (PVAI) has improved safety and efficacy of ablation procedures for atrial fibrillation (AF). AF triggers from the superior vena cava (SVC) may compromise the outcome of PVAI.

Left Atrial Flutter Following Pulmonary Vein Antrum Isolation with Radiofrequency Energy: Linear Lesions or Repeat Isolation

Introduction: Left atrial flutter (LAFL) is a known complication of pulmonary vein isolation. Treatment of this arrhythmia currently involves both linear lesions as well as re‐isolation. However, it is unknown if re‐isolation alone is sufficient to prevent recurrence. This study reviews the incidence of LAFL following segmental PV antrum isolation (PVAI) in a large patient population and evaluates if re‐isolation alone is sufficient to prevent recurrence.

Preimplantation B-type natriuretic peptide concentration is an independent predictor of future appropriate implantable defibrillator therapies

Objective: To assess prospectively whether preimplantation B-type natriuretic peptide (BNP) and C reactive protein (CRP) concentrations predict future appropriate therapies from an implantable cardioverter-defibrillator (ICD). Design and setting: Prospective cohort study conducted in a tertiary cardiac care centre. Methods: 345 consecutive patients undergoing first time ICD implantation were prospectively studied. Serum BNP and CRP concentrations were obtained the day before ICD implantation. Patients were followed up with device interrogation to assess for appropriate shocks or antitachycardia pacing. Inappropriate therapies were excluded. Mean (SD) follow up was 13 (5) months. Results: Patients had ischaemic (71%), primary dilated (17%), and valvar or other cardiomyopathies (12%). About half (52%) had ICDs implanted for primary prevention. Sixty three (18%) received appropriate ICD therapies. Serum creatinine, β blocker, statin, and angiotensin converting enzyme inhibitor usage did not differ between therapy and no therapy groups. By univariate comparison, ejection fraction (p  =  0.048), not taking amiodarone (p  =  0.033), and BNP concentration (p  =  0.0003) were risk factors for ICD therapy. However, by Cox regression multivariate analysis, only BNP above the 50th centile was a significant predictor (hazard ratio 2.19, 95% confidence interval 1.07 to 4.71, p  =  0.040). Median BNP was 573 ng/l versus 243 ng/l in therapy and no therapy patients, respectively (p  =  0.0003). More patients with BNP above the 50th centile (27% v 10%, p  =  0.006) received ICD therapies. Conclusions: A single preimplantation BNP concentration determination is independently predictive of ICD therapies in patients with cardiomyopathies undergoing first time ICD implantation. CRP was not independently predictive of ICD therapies when compared with BNP.

Transcranial Doppler Detection of Microembolic Signals During Pulmonary Vein Antrum Isolation: Implications for Titration of Radiofrequency Energy

Background: Cerebrovascular events are an important complication during pulmonary vein antrum isolation (PVAI). Microembolic signals (MES) have been associated with stroke and neurological impairment. However, the incidence of MES during PVAI, and their relationship to microbubble formation and radiofrequency (RF) parameters are unknown.

Alternative Energy Sources for the Ablation of Arrhythmias

As catheter-based ablative therapies of cardiac arrhythmias become standard of care, establishing and refining the tools used for these procedures has become critical. With a wide variety of energy sources now available for use in arrhythmia ablation, understanding advantages, disadvantages, and specific uses of each modality can help physicians choose the best modality to achieve a successful result. This article reviews many of the energy sources currently available and discusses each modality’s potential advantages, disadvantages, and uses in a wide variety of electrophysiologic procedures.

Avoiding Microbubbles Formation During Radiofrequency Left Atrial Ablation Versus Continuous Microbubbles Formation and Standard Radiofrequency Ablation Protocols: Comparison of Energy Profiles and Chronic Lesion Characteristics

Background: Radiofrequency (RF) energy parameters and chronic lesion characteristics associated with the microbubbles formation have not been yet fully elucidated.

Left anterior descending coronary artery occlusion after left lateral free wall accessory pathway ablation: what is the possible mechanism?

We describe a complication after radiofrequency (RF) ablation of a left free wall accessory pathway that resulted in acute occlusion of proximal left anterior descending (LAD) coronary artery in a 32-year-old male non-cocaine abuser. An interesting feature is the site of coronary artery occlusion which is remote from the RF application site. The RF energy applications were performed in the left lateral annulus remote from the LAD. The occlusion was successfully treated with placement of an intracoronary stent.