Sotirios Nedios
Universität Leipzig, Cardiology, Faculty Member
- Dr. Nedios is an academic cardiologist, trained in the biggest EP center in Europe, the Heart Center, University of L... moreDr. Nedios is an academic cardiologist, trained in the biggest EP center in Europe, the Heart Center, University of Leipzig in Germany and the Massachusetts General Hospital, Harvard University in Boston, MA, USA. His work has focused on improving methods of imaging in electrophysiology and elaborating the association of anatomy and clinical outcomes in patients with arrhythmias. He is a member of the European Society of Cardiology (ESC), of the European Heart Rhythm Association (EHRA), Fellow of the Heart Rhythm Society (FHRS), participant of the innovative arrhythmia leadership course Diploma of Advanced Studies in Cardiac Arrhythmia Management (DAS-CAM) and reviewer of several EP journals.edit
The association between anatomical left atrial (LA) remodelling and ventricular diastolic dysfunction (DD) in atrial fibrillation (AF) patients is not well studied. We aimed to examine the effect of DD on anatomic LA remodelling and their... more
The association between anatomical left atrial (LA) remodelling and ventricular diastolic dysfunction (DD) in atrial fibrillation (AF) patients is not well studied. We aimed to examine the effect of DD on anatomic LA remodelling and their relation with ablation outcomes. In 104 patients (58 ± 10 years, 69% male) referred for AF ablation, LA volume (LAV) was determined by computed tomography. A cutting plane, between the pulmonary vein (PV) ostia and the appendage and parallel to the posterior wall, divided LAV into anterior- (LA-A) and posterior-LA parts. The ratio of LA-A and LAV was defined as the LA asymmetry index (ASI). According to the current guidelines, the presence of DD was evaluated by echocardiography. Regression analysis was used to identify predictors of asymmetry changes and long-term success. Univariate linear regression revealed that ASI is associated with LAV, the presence of DD, and mitral regurgitation. Asymmetry index was higher in patients with DD (n = 35, 62 ±...
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Left atrial (LA) remodeling causing slower and asynchronous conduction is crucial for the maintenance of atrial fibrillation (AF). We propose a simple and quick method to evaluate the LA asynchrony. One hundred thirty patients with AF (AF... more
Left atrial (LA) remodeling causing slower and asynchronous conduction is crucial for the maintenance of atrial fibrillation (AF). We propose a simple and quick method to evaluate the LA asynchrony. One hundred thirty patients with AF (AF group) and 70 patients without a history of AF (controls) were examined prospectively using pulsed-wave tissue Doppler imaging. The time intervals from the onset of the P wave to the onset of the A' wave (P-A') were measured at 4 sites at the mitral annulus: septal, lateral, anterior, and inferior. To assess the LA asynchrony, the differences between the longest and the shortest P-A' as well as the standard deviation of all 4 P-A' intervals were calculated. Both groups were matched for the baseline characteristics. The AF group had longer differences between the longest and the shortest P-A' than did controls (37 ± 16 ms vs 28 ± 13 ms; P = .0001). The standard deviation of all 4 P-A' intervals was also higher in the AF group...
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The modern era of cardiology has changed the population of implantable cardioverter-defibrillator (ICD) recipients. Identifying predictors of electrical storm (ES) in contemporary ICD patients could improve risk stratification,... more
The modern era of cardiology has changed the population of implantable cardioverter-defibrillator (ICD) recipients. Identifying predictors of electrical storm (ES) in contemporary ICD patients could improve risk stratification, therapeutic strategies, and mortality. The purpose of this study was to address these points in a real-world setting. In 330 consecutive patients (65 ± 11 years, 81% male, left ventricular ejection fraction 29% ± 9%) with ICD implanted because of ischemic (n, 204) or nonischemic dilated cardiomyopathy (n, 126), we analyzed the prevalence, predictors, and outcome of ES (≥3 separate VT/VF episodes within 24 hours) therapy. During a median of 21 months (range 17-36 months), 23 patients (7%) had ES. Secondary prevention (61% vs 24%, P <.01), single-chamber devices (57% vs 38%, P = .02), and prior appropriate (96% vs 24%, P < .001) and inappropriate (30% vs 9%, P = .004) therapies were more prevalent in these patients. In ES patients, first appropriate therapy occurred more often in the first year after implantation than in the rest of the cohort (85% vs 45%, P = .008), and mortality was significantly higher (22% vs 2%, P < .001). Multivariate Cox regression analysis showed that secondary prevention (hazard ratio [HR] 2.83, 95% confidence interval [CI] 1.21-6.61, P = .016) and prior appropriate (HR 88.99, 95% CI 11.73-675, P < .001) and inappropriate (HR 2.83, 95% CI 1.14-7.0, P = .04) therapies were independent predictors of ES. ES is not uncommon in ICD recipients. A secondary prevention indication and the occurrence of both appropriate and inappropriate ICD therapies increase the risk for ES. Prompt initiation of aggressive treatment, especially catheter ablation, should be considered for these patients.
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In patients with atrial fibrillation (AF), LAA morphology has been suggested to modify thromboembolic event (TE) risk. We tested the hypothesis that TE in low-risk patients is associated with LAA characteristics. Of 2069 patients who... more
In patients with atrial fibrillation (AF), LAA morphology has been suggested to modify thromboembolic event (TE) risk. We tested the hypothesis that TE in low-risk patients is associated with LAA characteristics. Of 2069 patients who underwent AF ablation, 25 (1.2%) had a prior TE and a low CHA2 DS2 -VASc score (≤1). Those patients were matched for the CHA2 DS2 -VASc criteria with 75 event-free patients and CT data were compared. LAA measurements, morphology (Cactus, Chicken-Wing, Windsock, Cauliflower) and takeoff of the superior and inferior edge in relation (higher or lower) to the respective takeoff of the adjacent pulmonary vein (PV) were determined. LAA flow in relation to heart rate was also compared. Univariate analysis showed that TE-patients had a higher incidence of superior LAA takeoff (i.e., higher than the left superior PV; 28% vs. 4%, p = 0.002) and a higher incidence of hyperlipidemia (40% vs. 17%, p = 0.028), while LAA morphologies, inferior takeoff and other LAA characteristics were similar between groups. Logistic regression revealed that a superior LAA takeoff (OR: 9.1, 95% CI: 2.1 to 38.6, p = 0.003) was the only independent predictor of TE. There was a negative correlation between heart rate and LAA flow (r = -0.2 cm/s pro bpm, p = 0.048), that was even more pronounced for the superior LAA takeoff (r = -0.67 cm/s pro bpm, p = 0.035). A higher LAA takeoff is associated with a tachycardia-mediated thrombogenic flow and an increased thromboembolic risk. These findings may have implications for anticoagulation management of AF patients with low CHA2 DS2 -VASc scores and higher LAA takeoff. This article is protected by copyright. All rights reserved.
Implantable cardioverter-defibrillators (ICDs) have been shown to reduce mortality in patients with both ischaemic and non-ischaemic cardiomyopathy by terminating life-threatening arrhythmias. However, such arrhythmic events are unequally... more
Implantable cardioverter-defibrillators (ICDs) have been shown to reduce mortality in patients with both ischaemic and non-ischaemic cardiomyopathy by terminating life-threatening arrhythmias. However, such arrhythmic events are unequally distributed among different patient subgroups. We aimed to evaluate predictors of appropriate ICD therapies as a step towards risk stratification in a real-world cohort. The prevalence and predictors of appropriate ICD therapies were analysed in 330 consecutive patients (mean age 65 ± 11, 81% male) with implanted ICDs due to ischaemic (n = 204) or dilated (n = 126) cardiomyopathy. During a mean follow-up of 19 ± 9 months, 1545 appropriate ICD therapies (antitachycardia pacing and shocks) were detected in 94 patients (29%). In multivariate analysis applied on the whole cohort, the presence of atrial fibrillation [AF: odds ratio (OR) = 1.906, confidence interval (CI) = 1.143-3.177, P = 0.013] and secondary prevention indication (OR = 1.963, CI = 1.12...
Research Interests: Multivariate Analysis, Humans, Female, Male, Atrial Fibrillation, and 15 moreRisk factors, Registries, Clinical Sciences, Aged, Middle Aged, Odds ratio, Protective factors, Chi Square Distribution, Risk Factors, Cardiomyopathies, SECONDARY PREVENTION, Logistic Models, Myocardial Ischemia, cardiac resynchronization therapy, and Disease Free Survival
Left atrium (LA) size is a common predictor of ablation outcomes in atrial fibrillation (AF), but different LA diameters have not been adequately studied yet. We aimed to find the best predictor of ablation outcomes using single-linear LA... more
Left atrium (LA) size is a common predictor of ablation outcomes in atrial fibrillation (AF), but different LA diameters have not been adequately studied yet. We aimed to find the best predictor of ablation outcomes using single-linear LA dimensions by computed tomography (CT) or echocardiography. Patients (n = 103, 72 males, 59 ± 9 years) undergoing AF ablation were analyzed. LA diameter (LA-D) was measured by transthoracic echocardiography (parasternal long axis). After 3D reconstruction of CT data (EnSite Verismo, SJM, MN), maximal LA dimensions were measured on a coronal plane (superior-inferior, SI, and transversal, TV) and a sagittal plane (anterior-posterior, AP). Volume (LAV) was rendered after LA appendage and pulmonary vein exclusion. Patients with persistent AF (n = 40) had significantly larger LA size than those with paroxysmal AF (n = 63). After 26 ± 14 months, 31 (30 %) patients had AF recurrence. Univariate Cox regression analysis revealed that LA-D, LA-SI, LA-TV, LAV, and LAV-index (LAV/body surface area) were associated with AF recurrence. Multivariate Cox regression analysis revealed that LAV was the strongest independent predictor of AF recurrence (HR = 1.011 per ml, 95 % CI 1.003-1.020, p = 0.002). LA-TV had the best correlation with LAV (r = 0.69, p < 0.01) and was the strongest single-linear predictor (HR = 1.07 per mm, 95 % CI 1.022-1.121, p = 0.004). Independent of LA-D, an LA-TV>74.5 mm predicted AF recurrence similarly to LAV>126 ml. LA dilatation, especially on the coronal plane, is associated with reduced long-term success after catheter ablation. LA-TV is the best linear predictor of AF recurrence, stronger than the commonly used LA-D.
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Atrial fibrillation (AF) has been defined as the new cardiovascular "epidemic". Its prevalence is rising in developed countries, and the associated social and economic costs are high. In the last few years, there has been an... more
Atrial fibrillation (AF) has been defined as the new cardiovascular "epidemic". Its prevalence is rising in developed countries, and the associated social and economic costs are high. In the last few years, there has been an increasing interest in understanding the mechanisms of AF and its management. New pharmacotherapies together with novel techniques for surgical and catheter treatment of AF have been developed, allowing the maintenance of sinus rhythm and the alleviation of symptoms in a large number of patients with AF. However, there are still some challenges that need to be addressed. This article gives an overview of the current state of the art on novel techniques for diagnosis and management of AF.
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Research Interests: Biomedical Engineering, Magnetic Resonance Imaging, MRI, HR, Electrocardiography, and 15 moreHumans, Female, Male, Ct, Atrial Fibrillation, Aged, Middle Aged, Analysis of Variance, Catheter ablation, Predictive value of tests, Confidence Interval, Case Control Studies, Postoperative Complications, IQR, and Multidetector Computed Tomography
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Background:The incidence of postoperative complications following pacemaker or implantable cardioverter-defibrillator implantations in patients treated with new oral anticoagulation agents has not been studied. Here we present a first... more
Background:The incidence of postoperative complications following pacemaker or implantable cardioverter-defibrillator implantations in patients treated with new oral anticoagulation agents has not been studied. Here we present a first comparison of complications after cardiac rhythm device (CRD) implantations in patients with atrial fibrillation (AF) treated with dabigatran or uninterrupted warfarin.Methods and Results:Using a case-control study design, we compared complications within 30 days after 236 CRD procedures performed under uninterrupted warfarin (n=118) or interrupted dabigatran (n=118).There were no significant differences in the baseline characteristics of both groups. In the warfarin group, 9 (8%) pocket hematomas were observed vs. 3 (3%) in the dabigatran group (P=0.075). Two complications in the warfarin group necessitated surgical intervention as opposed to none in the dabigatran group (P=0.156). The postprocedural blood loss expressed as a drop in hemoglobin was significantly greater in the warfarin group (-0.9±0.7 vs. -0.5±0.4 mmol/L, P=0.023). In the dabigatran group, 1 case of transient ischemic attack occurred. The mean time to hospital discharge was shorter in patients treated with dabigatran (2.5±2.3 vs. 3.8±4.1 days, P=0.02).Conclusions:The incidence and severity of bleeding complications may be lower in patients treated with periprocedurally discontinued dabigatran when compared with uninterrupted warfarin therapy. Further evaluation of peri-interventional complications and establishment of an optimal anticoagulation management protocol are needed.
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Recurrence of atrial fibrillation (AF) after ablative treatment is common. We hypothesized that AF recurrence is heralded by fast ectopic atrial activity occurring after electrical reconnection of previously isolated pulmonary veins.... more
Recurrence of atrial fibrillation (AF) after ablative treatment is common. We hypothesized that AF recurrence is heralded by fast ectopic atrial activity occurring after electrical reconnection of previously isolated pulmonary veins. Patients with paroxysmal or persistent AF undergoing pulmonary vein isolation (PVI) were followed up by 24-h Holter monitoring every 3 months for the first year and every 6 months thereafter. Antiarrhythmic drugs were withdrawn after a blanking period of 4 weeks for paroxysmal and 3 months for persistent AF. Ectopic atrial activity was defined as a burden of atrial extrasystoles >5 % of the total QRS number. Fast atrial activity was present if mean cycle length of ectopic atrial activity was shorter than 50 % of the mean cycle length of sinus rhythm in the last ten heartbeats. Patients with symptomatic fast atrial activity but without AF recurrence were randomized to undergo a second PVI procedure or resume antiarrhythmic medication. During follow-up...
Research Interests: Treatment Outcome, Risk assessment, Electrocardiography, Prospective studies, Humans, and 13 moreFemale, Male, Atrial Fibrillation, Follow-up studies, Recurrence, Aged, Middle Aged, Survival Rate, Risk Assessment, Catheter ablation, Proportional Hazards Models, Predictive value of tests, and Reoperation
Electrical reconnection of the pulmonary veins (PVs) plays a key role in the recurrence of atrial fibrillation (AF) after ablative treatment. This randomized controlled study tested the hypothesis that prolonged ablations, on areas that... more
Electrical reconnection of the pulmonary veins (PVs) plays a key role in the recurrence of atrial fibrillation (AF) after ablative treatment. This randomized controlled study tested the hypothesis that prolonged ablations, on areas that may be critical for left atrial (LA)-PV conduction, can significantly reduce the rate of acute PV reconnection and AF recurrence. Patients with paroxysmal AF were randomly assigned to either a control or an add-on group.Ostial PV isolation (PVI) was performed by point-to-point RF ablation (irrigated tip, 30 Watts, 30 seconds).An ostial segment was assumed to be critical for LA-PV connection if any of the following reactions occurred during RF application: (1) sudden delay of LA-PV conduction, (2) change of activation sequence,and (3) PVI. In this case, RF application was prolonged from 30 seconds to 90 seconds in the add-on group only. A total of 131 patients (58 ± 11 years, 47 female) were assigned to a control (n = 64) and an add-on (n = 67) group. Ablation time was longer in the add-on (48 ± 16 minutes vs 37 ± 15 minutes, P = 0.03). Acute PV reconnection was observed in 20 of 64 controls and in eight of 66 add-on patients (31% vs 12%, P < 0.001). During a follow-up of 26 months, AF recurred in 33 of 64 controls and in 16 of 66 add-on patients (52% vs 24%, P = 0.001) after a single ablation procedure. Prolonged radiofrequency application on critical segments of LA-PV connection is a safe and effective ablative strategy that significantly reduces acute PV reconnection and AF recurrence rates after a single ablation procedure for paroxysmal AF.
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Research Interests: Biomedical Engineering, Imaging, Treatment Outcome, Comparative Study, Computer assisted orthopaedic surgery, and 12 moreHumans, Female, Male, Atrial Fibrillation, Heart, Clinical Sciences, Angiography, Middle Aged, Reproducibility of Results, Rotation, Sensitivity and Specificity, and X ray Computed Tomography
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Atrial fibrillation (AF) is associated with electroanatomical remodelling of the left atrium (LA), especially with LA dilatation. However, little is known about the changes of the three-dimensional structure of the LA, regarding the type... more
Atrial fibrillation (AF) is associated with electroanatomical remodelling of the left atrium (LA), especially with LA dilatation. However, little is known about the changes of the three-dimensional structure of the LA, regarding the type of atrial fibrillation and their prognostic value after an ablative treatment. One hundred fifteen patients (72 males, 59 ± 11 years) with an indication for AF ablation were prospectively included. Preoperatively, all patients underwent cardiac computed tomography (CCT). A reconstruction of the LA and the pulmonary veins (PV) was made from CCT data using specialized software (EP PreNavigator, Philips, The Netherlands). Left atrial volume (LAV) after exclusion of the atrial appendage (LAA) and the PV was determined. The LA was then arbitrarily divided by a cutting plane, between the anterior segment of the PV ostia and the atrial appendage and parallel to the posterior wall, to anterior-(LA-Ant.) and posterior-LA (LA-Post.). The ratio LA-Ant./LAV was defined as asymmetry index (ASI). The cardiac CT data, of 25 patients (11 women, 47 ± 11 years) without organic heart disease, were similarly studied for the same parameters, as a control group. Patients with paroxysmal AF (n = 63) had significantly higher LAV (131 ± 31 vs. 95 ± 18 ml, p < 0.001) and higher ASI (61 ± 6 % vs. 57 ± 4, p = 0.002) than the control group. Patients with persistent AF (n = 34) in comparison with paroxysmal AF showed significantly larger volumes (154 ± 44 vs. 131 ± 31 ml, p = 0.007) but no difference in the ASI (60 ± 8% vs. 61 ± 6%, p = 0.63). Finally, patients with long-term persistent AF (n = 18) showed a bigger asymmetry index than the patients with persistent AF (64 ± 5% vs. 60 ± 8%, p = 0.06) but no significant difference in volumes (161 ± 21 vs. 154 ± 44 ml, p = 0.49). LAA and partial LA volumes had a dilatation pattern similar to LAV. During a follow-up of over 25 ± 7 months, AF recurred in 31 (27%) patients. Multivariate analysis showed that ASI and LAV were the only two significant predictors of AF recurrence after ablative treatment. Independent of LAV, an ASI over 60% predicted AF recurrence with 74% sensitivity and 73% specificity. Characteristic differences of both left atrial volume and geometry exist between the different forms of atrial fibrillation (paroxysmal, persistent and long-term persistent). The asymmetry index is a simple parameter derived by cardiac CT data that reflects these changes of LA geometry and predicts the outcome after the pulmonary vein isolation.
Research Interests: Electrocardiography, Multivariate Analysis, Cardiac Computed Tomography, Prospective studies, Humans, and 15 moreFemale, Male, Atrial Fibrillation, Heart Disease, Aged, Middle Aged, Observer Variation, Analysis of Variance, Chi Square Distribution, Catheter ablation, Indexation, Predictive value of tests, Control Group, Pulmonary vein isolation, and Left Atrium
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Atrial fibrillation (AF) ablation is increasingly used in patients with reduced left ventricular ejection fraction (LVEF), but long-term outcomes are still unknown. To assess the long-term effects of AF ablation in patients with systolic... more
Atrial fibrillation (AF) ablation is increasingly used in patients with reduced left ventricular ejection fraction (LVEF), but long-term outcomes are still unknown. To assess the long-term effects of AF ablation in patients with systolic heart failure according to rhythm outcome. We included 69 patients with LVEF ≤40%, referred for circumferential pulmonary vein isolation with or without additional substrate modification to our institution in 2006-2010. Follow-up included 7-day Holter electrocardiography and echocardiography at baseline and at 6, 12, and 24 months after ablation. A matched control group (n = 69) after AF ablation without heart failure was used for comparison. After 28 ± 11 months and 1.6 ± 0.7 ablation procedures, 45 (65%) patients were still in the stable sinus rhythm (SSR) group. LVEF increased from 33 ± 6% to 53 ± 11% (P < .001) in the SSR group and from 33 ± 5% to 38 ± 12% (P = .03) in patients with recurrences (atrial tachycardia/fibrillation group). While LVEF increase was similar in the 2 groups at 6 months (15 ± 12% vs 8 ± 11%; P = .2), further LVEF improvements were observed in the SSR group only. Adjustments for baseline characteristics revealed that the increase in LVEF at 6 months was associated with higher baseline heart rate and not with rhythm outcome. Heart rate did not change in either group after 6 months of follow-up. Complications and procedural data of the study group were similar to the control group. In patients with heart failure undergoing AF ablation, there is an initial short-term LVEF improvement related to baseline heart rate. However, long-term LVEF improvement is associated with rhythm outcome.
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Pulmonary vein (PV) isolation is a technically challenging intervention. For this reason, integration of three-dimensional imaging with computed tomography (CT) or magnetic resonance imaging (MRI) in order to enhance effectiveness and... more
Pulmonary vein (PV) isolation is a technically challenging intervention. For this reason, integration of three-dimensional imaging with computed tomography (CT) or magnetic resonance imaging (MRI) in order to enhance effectiveness and safety has been widely adopted. A novel imaging approach--intraprocedural rotational angiography and reconstruction of the left atrium and PVs--is feasible and provides high anatomic accuracy. The purpose of this study was to prove the feasibility, safety, and efficacy of this imaging approach as a single navigation tool for PV isolation. Forty-four patients (25 men and 19 women; age 57 +/- 11 years) with atrial fibrillation (AF) who presented for PV isolation were studied. Rotational angiography during adenosine-induced ventricular asystole was performed under sedation with propofol. The left atrium and PVs were reconstructed by three-dimensional atriography using specialized software (EP navigator prototype, Philips Medical Systems). Three-dimensional atriography was used as a single navigation tool for guiding PV isolation. Of 176 PVs, 174 (99%) were isolated. Total procedural and fluoroscopy times were 192 +/- 46 minutes and 44 +/- 12 minutes, respectively. During follow-up of 6 +/- 3 months, 31 (70%) patients were free of symptoms and had no evidence of AF without any antiarrhythmic medication. MRI examination of 41 patients at 3-month follow-up excluded PV stenosis. No major complications occurred. Three-dimensional atriography is a novel intraprocedural three-dimensional imaging technique that is based on rotational angiography. It can be safely and effectively used as a single navigation tool for performing PV isolation.
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Abstracts16-01ArcticLine: A New Cryo Ablation Catheter for the creation of Linear Lesions16-02Plasma transforming growth factor β1-mediated atrial fibrosis to predict the recurrence of atrial fibrillation after surgical maze procedure16-03Prognostic significance of cytokine concentrations in the ...more