Left Atrial Function Post Radiofrequency and Cryoballoon Ablation Assessed by Volume-Pressure Loops.

Background: Left atrial (LA) function is linked to atrial fibrillation (AF) pathogenesis. AF catheter ablation decreases disease burden with potentially favorable effects on cardiac function. Atrial volume-pressure loops can optimally assess the LA function. Objective: To investigate changes in LA function by volume-pressure loops after paroxysmal AF ablation and explored potential differences between the radiofrequency and cryoballoon ablation. Methods: We analyzed 44 patients undergoing paroxysmal AF ablation from 2 centers, 22 treated with radiofrequency and 22 with cryoablation. Pre- and post-procedure, all patients underwent a real-time three-dimensional transthoracic ECG to evaluate LA volume, while simultaneously recording LA pressure following transseptal puncture. Volume-pressure loops pre- and post-procedure were created by paired data. Areas of A-loop (LA booster pump function) and V-loop (LA reservoir function), and the stiffness constant determining the slope of the exponential curve during LA filling were calculated. Results: Average LA pressure, A-wave amplitude, and V-wave amplitude were increased post-procedurally (p < 0.001). Overall, A-loop area decreased (p = 0.001) and V-loop area tended to increase (p = 0.07). The change in both A-loop and V-loop areas was similar between radiofrequency- and cryoballoon-treated patients (p = 0.18 and p = 0.52, respectively). However, compared with cryoballoon-treated patients, radiofrequency-treated patients had higher increase in the stiffness constant (b = 0.059; 95% CI: 0.022-0.096; p = 0.006). Conclusion: AF catheter ablation by the radiofrequency or cryoballoon is associated with the decrease of the booster pump function and increase of the reservoir function. Moreover, there is a post-procedural increase of LA pressure which is associated with an acute increase in LA stiffness in radiofrequency ablation, but not in cryoablation.

Noninvasive risk factors for the prediction of inducibility on programmed ventricular stimulation in post-myocardial infarction patients with an ejection fraction ≥40% at risk for sudden cardiac arrest: Insights from the PRESERVE-EF study.

BACKGROUND: In the PRESERVE-EF study, a two-step sudden cardiac death (SCD) risk stratification approach to detect post-myocardial infarction (MI) patients with left ventricle ejection fraction (LVEF) ≥40% at risk for major arrhythmic events (MAEs) was used. Seven noninvasive risk factors (NIRFs) were extracted from a 24-h ambulatory electrocardiography (AECG) and a 45-min resting recording. Patients with at least one NIRF present were referred for invasive programmed ventricular stimulation (PVS) and inducible patients received an Implantable Cardioverter - Defibrillator (ICD). METHODS: In the present study, we evaluated the performance of the NIRFs, as they were described in the PRESERVE-EF study protocol, in predicting a positive PVS. In the PRESERVE-EF study, 152 out of 575 patients underwent PVS and 41 of them were inducible. For the present analysis, data from these 152 patients were analyzed. RESULTS: Among the NIRFs examined, the presence of signal averaged ECG-late potentials (SAECG-LPs) ≥ 2/3 and non-sustained ventricular tachycardia (NSVT) ≥1 eposode/24 h cutoff points were important predictors of a positive PVS study, demonstrating in the logistic regression analysis odds ratios 2.285 (p = .027) and 2.867 (p = .006), respectively. A simple risk score based on the above cutoff points in combination with LVEF < 50% presented high sensitivity but low specificity for a positive PVS. CONCLUSION: Cutoff points of NSVT ≥ 1 episode/24 h and SAECG-LPs ≥ 2/3 in combination with a LVEF < 50% were important predictors of inducibility. However, the final decision for an ICD implantation should be based on a positive PVS, which is irreplaceable in risk stratification.

Trends in ablation procedures in Greece over the 2008-2018 period: Results from the Hellenic Cardiology Society Ablation Registry.

OBJECTIVE: In 2008, the radiofrequency ablation (RFA) procedures registry of the Hellenic Society of Cardiology was created. This online database allowed electrophysiologists around the country to input data for all performed ablation procedures. The aim of this study is to provide a thorough report and interpretation of the data submitted to the registry between 2008 and 2018. METHODS: In 2008, a total of 27 centers/medical teams in 24 hospitals were licensed to perform RFA in Greece. By 2018, the number had risen to 31. Each center was tasked with inserting their own data into the registry, which included patient demographics (anonymized), type of procedure and technique, complications, and outcomes. RESULTS: A total of 18587 procedures in 17900 patients were recorded in the period of 2008-2018. By 2018, slightly more than 70% of procedures were performed in 7 high-volume centers (>100 cases/year). The most common procedure since 2014 was atrial fibrillation ablation, followed by atrioventricular nodal reentry tachycardia ablation. Complication rates were low, and success rates remained high, whereas the 6-month relapse rates declined steadily. CONCLUSION: This online RFA registry has proved that ablation procedures in Greece have reached a very high standard, with results and complication rates comparable to European and American standards. Ablation procedures for atrial fibrillation are increasing constantly, with it being the most common intervention over the last 6-year period, although the absolute number of procedures still remains low, compared to other European countries.

Effect of cryoballoon and radiofrequency ablation for pulmonary vein isolation on left atrial function in patients with nonvalvular paroxysmal atrial fibrillation: A prospective randomized study (Cryo-LAEF study).

BACKGROUND: Isolation of the pulmonary veins (PVI) has become a mainstay in atrial fibrillation (AFib) therapy. Lesions in left atrial tissue lead to scar formation and this may affect left atrial function. METHODS: Patients with paroxysmal AFib were randomly assigned in a 1:2 allocation scheme to radiofrequency (RF) ablation or cryoballoon. Real-time three-dimensional echocardiography was performed (under sinus rhythm in all cases) before ablation and at 1 and 3 months to evaluate the left atrial functional indices. The primary outcome measure was change in left atrial ejection fraction (LAEF) at 1 month. RESULTS: 120 patients were randomized (80 to cryoballoon, 40 to RF). The absolute change in LAEF at 1 month was 4.0 (Q1-Q3, -0.1to 7.6)% in the cryoballoon group and -0.8 (Q1-Q3, -1.9 to 0.9)% in the RF group (P < 0.001 for the comparison between groups). At 3 months, the corresponding changes were 6.7 (Q1-Q3, 3.4-11.2)% and 0.7 (Q1-Q3, -0.7 to 3.5)%, respectively (P < 0.001). Overall, the rate of patients with lower LAEF at 3 months compared to baseline was 2.5% in the cryoballoon group and 32.5% in the RF group (P < 0.001). AFib recurrence rate at 6 months was higher in patients with decreased LAEF (odds ratio, 6.2; 95% confidence interval, 2.0-19.5; P = 0.002). CONCLUSION: The Cryo-LAEF study prospectively compared the effects of RF and cryoballoon ablation on left atrial function. Both at 1 and 3 months postablation, LAEF was either improved or stable in both ablation groups.

Regional differences in referral, procedures, and outcome after ablation for atrial fibrillation in Europe: a report from the Atrial Fibrillation Ablation Pilot Registry of the European Society of Cardiology.

AIMS: Ablation is an effective treatment of symptomatic and drug refractory atrial fibrillation (AF). Using data from the European AF Ablation Pilot Registry comprising 1410 patients from 10 European countries, we prospectively investigated regional differences in AF ablation regarding patient selection, ablation strategy, and outcome. METHODS AND RESULTS: Countries were divided into three regions: South (Greece, Italy, Spain), East (Czech Republic, Poland), and West/North (Belgium, Denmark, France, Germany, and the Netherlands). One-year success was defined as patient survival free from atrial arrhythmia, with or without antiarrhythmic drugs (AAD). In all regions, patients were symptomatic and treated extensively with beta-blockers and AAD pre-ablation. Patients in East had more co-morbidity, increased thromboembolic risk, were more likely to have paroxysmal AF, and they underwent more left atrial linear ablations. Adverse events remained within expected levels, albeit with a significantly higher reporting of adverse cardiovascular events in the West/North (4.7 vs. 1.4 and 1.5% in South and East, P = 0.0032). There was no significant difference in peripheral/vascular, neurological, pulmonary, gastrointestinal, or general adverse events. The 1-year success rate after ablation differed non-statistically between regions ranging from 69.1 to 74.7%. A second ablation was performed in 23.2% in West/North compared with 10.5 and 16.5% in South and East. The proportion of patients still on AADs was highest in the South region (51.6 vs. 42.3 and 38.8% in East and West/North). CONCLUSION: This study with all-comer patients shows that patient selection for ablation follows current guidelines but reveals significant differences regarding co-morbidity, medication, and ablation strategy. Despite this, 1-year outcomes are without significant differences and in line with previously published clinical trials.

Association Between rs2200733 Polymorphism on Chromosome 4q25 and Atrial Fibrillation in a Greek Population.

INTRODUCTION: Atrial fibrillation (AF) is a common arrhythmia with evidence of genetic susceptibility. The rs2200733 single-nucleotide polymorphism (SNP) in a non-coding region on chromosome 4q25 has been associated with AF. The purpose of this case-control study was to examine the possible association of the rs2200733 polymorphism with AF in the Greek population. METHODS: A total of 295 individuals, 167 AF patients and 128 controls, were genotyped for the presence of the rs2200733 polymorphism using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLPs) method. RESULTS: The T/T genotype and the T allele were detected more frequently in patients with AF compared to controls (13.2% vs. 2.3%, p=0.001, and 29.6% vs. 17.9%, p=0.001), suggesting that the rs2200733 polymorphism increases susceptibility to AF in the Greek population. In a multivariate stepwise analysis that included many conventional precipitating factors for AF, T/T genotype and left atrium (LA) diameter were the only independent predictors of AF (OR 1.74, 95% CI: 1.40-2.98, p=0.005, and OR 2.88, 95% CI: 1.835.62, p<0.001, respectively). A trend of association was observed between the T/T genotype and lone AF (p=0.08). CONCLUSIONS: Our results suggest that SNP rs2200733 confers a significant risk of AF in the Greek population, providing further support to the previously reported association between AF and rs2200733 polymorphism on chromosome 4q25.

Endocardial late potentials during sinus rhythm define the re-entry circuit of ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited cardiomyopathy characterized by progressive fibro-fatty replacement of the right ventricular myocardium. We report a case where mapping of endocardial potentials during sinus rhythm identified the re-entry circuit of a recurrent ventricular tachycardia in a patient with ARVC. The tachycardia was subsequently ablated successfully.

Drug-induced Brugada syndrome by noncardiac agents.

Drug-induced Brugada syndrome (BrS) represents a great challenge for the prescribing clinicians as well as for those involved in the development of novel pharmaceuticals and in the regulatory bodies responsible with monitoring drug safety. Apart from well-known cardiac agents (mainly Class I antiarrhythmics), an increasing number of noncardiac agents, including psychotropic and anesthetic drugs, have been shown to induce the characteristic Brugada electrocardiogram pattern predisposing to fatal ventricular arrhythmias. Up to now, both repolarization and depolarization abnormalities are thought to be related to the development of ventricular fibrillation in BrS patients. This review highlights the mechanisms and the noncardiac medical agents that unmask a genetic predisposition to BrS.

Association of post-cardioversion transcardiac concentration gradient of soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) and inflammatory biomarkers to atrial fibrillation recurrence.

OBJECTIVES: Soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) has been shown to have both pro- and anti-apoptotic activities and is associated to better prognosis in heart failure. The aim of this study was to determine the transcardiac concentration gradient of sTRAIL and inflammatory biomarkers after AF cardioversion and assess their relation to AF recurrence. DESIGN AND METHODS: We measured transcardiac gradients (coronary sinus concentration minus aortic root concentration) of sTRAIL, C-reactive protein (hsCRP) and interleukin-6 (IL-6) in patients with non-valvular AF after electrical cardioversion. Six-month AF recurrence was the study endpoint. RESULTS: There were no differences in sTRAIL and hsCRP concentrations in peripheral venous blood between patients with and without AF recurrence (p=0.066 and 0.149, respectively), while IL-6 was higher in patients with recurrence (p=0.032). Only sTRAIL showed a significant transcardiac gradient [3 pg/mL (IQR 1-4 pg/mL); p=0.01]. sTRAIL gradient was 4 pg/mL (IQR 3-5 pg/mL) in patients without recurrence versus -1 pg/mL (IQR -2-1 pg/mL) in those with recurrence (p<0.001). IL-6 (p=0.281) and hsCRP (p=0.979) aortic concentrations were not significantly different from coronary sinus concentrations. In multivariate analysis, sTRAIL transcardiac gradient (beta -0.81, p=0.004) remained a negative predictor of AF recurrence. CONCLUSION: This study demonstrates the existence of a significant transcardiac sTRAIL concentration gradient in patients with non-valvular AF, inversely associated to AF recurrence. These results suggest production of sTRAIL by the heart and a protective role against substrate-altering processes in AF-prone atria. This could have implications for TRAIL-targeting therapies currently under development.

Pacing-facilitated proarrhythmia.

The implantable cardioverter-defibrillator (ICD) has been proven to reduce the mortality of patients with life-threatening ventricular arrhythmias, and has become the therapy of choice for patients with aborted sudden cardiac death or poorly tolerated ventricular tachycardias. Abrupt changes in ventricular cycle lengths or short-long-short (S-L-S) sequences might precede the initiation of ventricular tachycardia and ventricular fibrillation. The S-L-S sequences might be passively permitted or actively facilitated by pacing. We present a case of ICD-facilitated ventricular tachycardia.

Radiofrequency ablation procedures in Greece: initial experience and results from the national registry 2008-2010.

INTRODUCTION: In 2008 the radiofrequency ablation procedures (RFA) registry of the Hellenic Cardiological Society (HCS) was created. This is a dynamic, web-based application, which acts as the interface for storing and retrieving patients' demographic data and ablation procedures. Access to the site is permitted only to registered users. The purpose of this study is to report the results of RFA procedures performed in Greece over the 2008-2010 period. METHODS: There are 27 centers in 24 hospitals that are licensed to perform RFA in Greece. During the period 2008-2010, 3541 RFA procedures were performed in 3344 patients in 23 centers. Four centers did not contribute data at all for various reasons. It is interesting that nearly 50% of the total number of procedures were performed at 3 high volume centers (>100 cases/year). RESULTS: The most common procedure was slow pathway ablation for atrioventricular reentrant tachycardia, the second was ablation of accessory pathway related tachycardias, and the third was ablation of atrial fibrillation. Success rates were high (92.1%), the complication rate was 3% (serious complications <1%) and total relapse rate was 8.7% at six months' follow up. CONCLUSIONS: The electronic RFA registry in Greece confirmed that all RFA procedures are performed in Greece with high success and low complication rates, comparable to the European and US standards. The experience and results from the first three-year period using the registry are very interesting and encouraging, thus indicating the need for development of similar databases at the national level.

Low back pain following intravenous administration of amiodarone.

Amiodarone is a widely used antiarrhythmic drug whose use is significantly limited by numerous undesirable effects following long-term administration. In the literature so far, it has been reported that the most common acute adverse effect of the intravenous administration of amiodarone requiring intervention is hypotension. We present the case of a female patient who experienced low back pain after an intravenous loading dose of amiodarone.

Uric acid elevation in atrial fibrillation.

INTRODUCTION: Uric acid is a cardiovascular risk marker associated with oxidative stress and inflammation. Recently, atrial fibrillation (AF) has been associated with inflammation and oxidative stress. We therefore investigated the association between AF and uric acid levels. METHODS: Consecutive patients with AF and healthy control subjects were screened. Demographic, clinical, and echocardiographic characteristics were carefully recorded. In each participant, uric acid levels and conventional inflammatory markers were determined. The final study population consisted of 45 patients with paroxysmal AF, 41 patients with permanent AF, and 48 control subjects. RESULTS: A significant variance in uric acid levels was evident between patients with paroxysmal AF (5.7 +/- 1.1 mg/dl), permanent AF (6.7 +/- 1.4 mg/dl), and control subjects (5.1 +/- 1.3 mg/dl) (p<0.001). After univariate analysis considering 2 groups (control, AF patients), the following variables were significantly associated with the presence of AF: age, hypertension, -blocker use, low left ventricular ejection fraction (LVEF), increased left atrial diameter, uric acid levels, and C-reactive protein (CRP) levels. After multivariate logistic regression analysis, only CRP was an independent predictor for AF (odds ratio, OR: 2.172). In a subgroup analysis, CRP (OR: 1.434) and LVEF (OR: 0.361) were independent predictors of paroxysmal AF, while CRP (OR: 3.048), uric acid (OR: 2.172), and LVEF (OR: 0.34) were predictors of permanent AF. CONCLUSIONS: There is an association between increased levels of uric acid and permanent AF. Also, uric acid elevation may be related to the burden of AF. Undoubtedly, larger studies should further examine this potential association.

Sensitivity and specificity of sodium channel blocking test in the diagnosis of Brugada syndrome.

The ECG features of Brugada syndrome are dynamic and frequently concealed. Sodium channels blockers are widely used to unmask the Brugada electrocardiographic (ECG) pattern. The sensitivity and specificity of I(Na) channel blocking test varies significantly. A negative I(Na) blocking test does not exclude the presence of a SCN5A mutation, which is responsible for the phenotype of Brugada syndrome. Herein, we describe the case of a 65-years-old asymptomatic male who underwent a I(Na) channel blocking test, seven years ago due to a type 2 ECG pattern (saddleback configuration) which failed to induce the diagnostic type 1 ECG pattern. Diagnostic considerations at a molecular level and their clinical relevance are being discussed.