Christodoulos Stefanadis’s research while affiliated with National and Kapodistrian University of Athens and other places

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (872)


Correction: A wire to guide: a complementary method for facilitating access during device lead implantation using a guidewire inserted through a peripheral vein
  • Article
  • Publisher preview available

February 2024

·

1 Read

Journal of Interventional Cardiac Electrophysiology

Christodoulos Stefanadis

·

Christos-Konstantinos Antoniou

·

Panagiota Manolakou

·

View access options

Direct approach. In this most basic technique, the catheter sheath is used to apply pressure to the balloon, leading to vein occlusion. Care must be taken to avoid pushing the balloon inside the venous ostium, leading to suboptimal isolation. Flexion of the balloon sheath itself may also be required (see text for further details).
Hockey stick approach. This variation of the direct approach for the isolation of the inferior veins involves curving the catheter shaft more than in the direct approach, to take advantage of the more upward oriented inferior vein ostium orientation. Once proper alignment in the posterior/anterior plane is achieved (contralateral view is used—not shown) and the catheter, as well as the balloon, shafts are flexed, forward pressure leads to antral occlusion, with pressure mostly directed to the upper semicircle of the occlusion line. Consequently, after 60 s the pulldown maneuver is performed, with slight removal of flexion and gentle retraction of the catheter sheath to achieve greater contact force with the inferior part of the occlusion line circumference.
CB-only approach. In cases of unusually oriented veins, it is likely that pressure applied through the stiff catheter sheath will actually offset the balloon relative to the vein, preventing proper occlusion. Thus, the more flexible balloon shaft may be used as a more accommodating alternative. Balloon sheath flexion may or may not be helpful if this approach is chosen, depending on the particular anatomy of each case.
Delayed occlusion approach. This variation of the direct approach takes advantage of the slight increase in diameter of the balloon once it freezes. Thus, the operator will apply pressure when the temperature has started dropping below 20 °C, attempting to achieve better sealing. Otherwise, it is identical to the direct approach.
Trap-based approach. This is the most refined approach, mostly used for right inferior vein occlusion, although in principle, as shown, it can be used for all cases where achieving proper alignment of the catheter/balloon system with the pulmonary vein antrum is challenging. Thus, the operator attempts to use the pulmonary vein itself as a means to impart the proper alignment to the system by inflating the balloon slightly inside the vein. Then, as the balloon is ejected (care must be taken not to cause venous wall rupture by inflating too distally or by allowing for the fully pressurized balloon to dwell too long inside the vein—if not spontaneously ejected the balloon must be withdrawn). Then the closely positioned catheter sheath is promptly used to trap the balloon into place, which usually leads to adequate sealing of the vein. Again, it is emphasized that prior to inflation, proper orientation in the anterior/posterior plane must have been achieved, using the contralateral oblique projection.

+1

Best Practice Guide for Cryoballoon Ablation in Atrial Fibrillation: The Compilation Experience of More than 1000 Procedures

January 2023

·

237 Reads

·

5 Citations

·

Christos-Konstantinos Antoniou

·

·

[...]

·

Konstantinos Tsioufis

Nowadays, the cryoballoon (CB) constitutes an established alternative to radio frequency (RF) ablation for pulmonary vein isolation (PVI), which offers the possibility to isolate the PVs with a single application. Since the introduction of the second-generation CB, we prospectively collected our data to optimize the procedure on >1000 consecutive patients who underwent CB PVI performed in our center. It is expected that subsequent guidelines will suggest first-line PVI through CB in patients with paroxysmal AF with a class I indication. Indeed, in the long-term follow-up (36 months) of the EARLY-AF trial, CB had a lower incidence of persistent atrial fibrillation episodes compared to the anti-arrhythmic drugs group. We now review the current best practices in an effort to drive consistent outcomes and minimize complications. PV isolation through CB is the most studied single-shot technique for atrial fibrillation ablation, having shown the potential to alter the natural history of the arrhythmia. Several procedural tips and tricks can improve procedural flow and effectiveness. In the present article we provided not only technical details but measurable biophysical parameters that can reliably guide the operator into achieving the best outcome for his patients.


Electroanatomical mapping of the triangle of Koch and annotation of His cloud and ablation points. A 4 mm tip ablation catheter with a standard curve was used for identification and tagging of His potentials (green tags) at the anterior‐inferior end of the interatrial septum (His cloud). Boundaries of the triangle of Koch, along with coronary sinus anatomy, were also marked as a field map. RF energy was applied at sites with an ideal slow pathway potential and if nodal beats or rhythms were induced, red tags were placed. If junctional beats were not evident after 15 s of RF, these sites were tagged gray. Black tags were used if any prolongation of the atrio‐ventricular interval or blocking of a P wave occurred and in areas of fast junctional rhythm.
Slow pathway potential and subsequent slow junctional rhythm during RF ablation.
Survival curves for the freedom from arrhythmia recurrence. Kaplan–Meier curves for survival free from arrhythmia recurrence. Note early curve separation, despite shorter follow‐up in the EAM (+) group (slow pathway recovered early).
Three‐dimensional electroanatomically guided slow pathway elimination is associated with procedural improvements and clinical benefit in atrioventricular node reentrant tachycardia patients

September 2022

·

125 Reads

·

1 Citation

Background Slow pathway (SP) ablation, in the context of atrioventricular node reentrant tachycardia (AVNRT) treatment could result in either complete elimination or only modification of the SP with ambiguity regarding associated benefits. Three-dimensional electroanatomical mapping (3D-EAM) may be used adjunctively aiming to complete SP elimination. Our purpose was to compare a 3D-EAM-based strategy targeting SP elimination to the conventional fluoroscopic approach with respect to clinical outcomes. Methods One hundred and two consecutive AVNRT patients (36 males, mean age 53.2 ± 13.7 years) underwent in two successive periods a conventional fluoroscopic ablation approach (n = 42) or a 3D-EAM-guided ablation focusing on complete SP elimination (n = 60). Results Several procedural parameters improved with 3D-EAM use, including fluoroscopy time (2.4 ± 4.7 min vs. 13 ± 4.5 min), dose-area product (1061 ± 3122 μGy × m² vs. 5002 ± 3032 μGy × m²) and slow pathway elimination frequency (95% vs. 50%, all p < .001). Procedural time was slightly prolonged in the 3D-EAM group (101 ± 31 min vs. 87 ± 24 min, p = .013). Two major complications occurred in the conventional group. Altogether, over a mean follow-up of approximately 2.7 years, recurrence occurred in 6 of 42 (14.3%) in the conventional group as compared to 1 of 62 (1.7%) in the EAM-based group (p = .019). In the Kaplan–Meier analysis, time-to-event was significantly longer for the EAM-based patients (p < .030). Moreover, the EAM-based strategy was associated with less redo procedures' rates (9.5% in the non-EAM group vs. 0% in the EAM group, p = .026). Conclusions The present study showed that an EAM-based SP elimination strategy is not only feasible and safe but it is also accompanied by improved clinical outcomes in the setting of AVNRT ablation.


Reappraising the role of class Ic antiarrhythmics in atrial fibrillation

June 2022

·

165 Reads

·

6 Citations

European Journal of Clinical Pharmacology

Purpose The objective of the present systematic review was to compare the effectiveness and safety of class Ic agents for cardioversion of paroxysmal atrial fibrillation (AF), in patients with and without structural heart disease (SHD). Methods We focused on RCTs enrolling at least 50 adult patients with electrocardiogram-documented paroxysmal AF that compared either two pharmacological class Ic cardioversion agents (flecainide, propafenone), regardless of study design (parallel or crossover). We searched MEDLINE and the Cochrane Central Register of Controlled Trials. Initial search was performed from inception to 15 July 2021 with no language restrictions. Results Intravenous flecainide is the most effective option for pharmacologic cardioversion of AF since only 2 patients need to be treated in order to cardiovert one more within 4 h. Most importantly, class Ic agents appear to be safe in the context of pharmacologic cardioversion of AF irrespective of the presence of SHD, pointing towards a possible reappraisal of the role in this setting. Conclusion We suggest that class Ic agents (with flecainide appearing to be more effective) should be used for pharmacologic cardioversion in stable AF patients presenting in emergency department with unknown medical history, after excluding severe cardiac disease through a bedside examination. Registration number (DOI) Available in https://osf.io/apwt7/, https://doi.org/10.17605/OSF.IO/APWT7



of evidence search and selection
Network plots for pharmacological cardioversion at different time settings. a Network plot for pharmacological cardioversion at 4 h. Treatments are represented by nodes with size proportional to the number of participants randomized to each intervention and edges with width proportional to the number of studies evaluating each direct comparison. b Network plot for pharmacological cardioversion at 12 h. Treatments are represented by nodes with size proportional to the number of participants randomized to each intervention and edges with width proportional to the number of studies evaluating each direct comparison. c Network plot for pharmacological cardioversion at 24 h. Treatments are represented by nodes with size proportional to the number of participants randomized to each intervention and edges with width proportional to the number of studies evaluating each direct comparison
Pharmacologic Cardioversion in Patients with Paroxysmal Atrial Fibrillation: A Network Meta-Analysis

April 2021

·

180 Reads

·

15 Citations

Cardiovascular Drugs and Therapy

PurposeWe sought to indirectly compare and rank antiarrhythmic agents focusing exclusively on adults with paroxysmal atrial fibrillation in order to identify the most effective for pharmacologic cardioversion over different time settings (4 h as primary, and 12, 24 h as secondary outcomes).Methods We searched several databases from inception to March 2020 without language restrictions, ClinicalTrials.gov, references of reviews, and meeting abstract material. We included randomized controlled trials of patients with AF lasting ≤7 days comparing either two or more intravenous (i.v.) or oral (p.o.) pharmacologic cardioversion agents or an agent against placebo. For each outcome, we performed network meta-analysis based on the frequentist approach.ResultsForty-one trials (6013 patients) were included in our systematic review. Moderate confidence evidence suggests that i.v. vernakalant and flecainide have the highest conversion rate within 4 h, possibly allowing discharge from the emergency department and reducing hospital admissions. Intravenous and p.o. formulations of class IC antiarrhythmics (flecainide more so than propafenone) are superior regarding conversion rates within 12 h, while amiodarone efficacy is exhibited in a delayed fashion (within 24 h), especially if ranolazine is added.Conclusion Our network meta-analysis identified with sufficient power and consistency the most effective antiarrhythmics for pharmacologic cardioversion over different time settings, with vernakalant and flecainide exhibiting a safer and more efficacious profile toward faster cardioversion.Graphical abstract





Figure 1. Differential association of LVMI with plasma TGs in men (blue dots and line) and women (green dots and line). Beta coefficients and p-values are derived from multiple regression analysis of (log) LVMI on TGs after controlling for age, SBP, fasting glucose and smoking.
Figure 2. Difference in plasma TGs between hypertensive males with and without LV hypertrophy (LVMI below or above 115 g/m 2 ). p-value was derived from logistic regression analysis after adjustment for age, SBP, plasma fasting glucose and smoking.
Baseline characteristics of study hypertensive patients.
Difference in plasma TGs between hypertensive females with and without LV hypertrophy (LVMI below or above 95 g/m²). p-value was derived from logistic regression analysis after adjustment for age, SBP, plasma fasting glucose and smoking.
Triglycerides are related to left ventricular mass in hypertensive patients independently of other cardiometabolic risk factors: the effect of gender

August 2020

·

92 Reads

·

15 Citations

Given the inconsistent results on the prognostic significance of triglycerides (TGs), the purpose of the present study was to investigate the association of plasma TGs with left ventricular mass (LVM) in hypertensive patients. We studied 760 never treated, non diabetic, hypertensive patients. Τransthoracic echocardiography was performed and LVMI was calculated according to the Devereux formula, adjusted to body surface area. Triglycerides were associated with LVMI after adjustment for age, gender, systolic blood pressure (SBP), smoking and fasting glucose (b = 0.08, p = 0.009). This relationship remained significant even after adjustment for BMI, LDL-C and ApoB/ApoA1 ratio (b = 0.07, p = 0.04). Gender-stratified analysis indicated that TGs were related to LVMI in men (p = 0.001) but not in women (p = NS). In addition, TGs were related with LV hypertrophy (LVH) in men, increasing the odds by 7% to present LVMI over 115 g/m² (OR = 1.07 per 10 mg/dl increase in TGs, p = 0.01). In conclusion, TGs are associated with LVMI in hypertensive patients, independently of other risk factors, including LDL-C. Given the prognostic significance of LVH, it might be suggested that TGs may serve as a useful marker for indentifying hypertensive patients at high risk. The gender discrepancy may suggest a possible gender-specific modulatory effect of TGs on LV structure.


Citations (91)


... The duration of cryoapplication was the time to isolation (TTI; 180 to 240 s per operator discretion) and the temperature nadir guided. If no TTI and no temperature of −40 • C was reached for one minute, another lesion was applied [26]. The endpoint was the achievement of a bidirectional conduction block between LA and PVs and the disappearance of PV potential, which was confirmed with a circumferential mapping catheter. ...

Reference:

The Detection of Early Changes in Inflammatory Response After Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation Can Predict Late Atrial Fibrillation Recurrence
Best Practice Guide for Cryoballoon Ablation in Atrial Fibrillation: The Compilation Experience of More than 1000 Procedures

... (Note that it would be 5% if no closure was performed.) With a mean efficacy of 66% (21,32,33) , we hypothesized that flecainide would reduce this rate to 8.5% at 3 months (still higher than the expected rate of 5% in patients without PFO closure). Considering the design, the ratio of flecainide vs SOC (control group) treated patients would be 2:1 before 3 months; thus, 56 patients per group would allow 80% power to detect the anticipated difference at 3 months using a chi-square test at a two-sided alpha level of 5%. ...

Reappraising the role of class Ic antiarrhythmics in atrial fibrillation

European Journal of Clinical Pharmacology

... There is a growing body of evidence suggesting that AF or AHREs are phenotypic expressions of atrial cardiomyopathy [29,30]. According to Doundoulakis et al. [31], AHRE and AF may act as a marker of atrial cardiomyopathy which may increases the risk of stroke in comparison to general population. ...

Atrial high rate episodes as a marker of atrial cardiomyopathy: In the quest of the Holy Grail
  • Citing Article
  • August 2021

European Journal of Internal Medicine

... Atherogenic hyperlipidemia (defined as increased levels of triglycerides, low levels of HDL cholesterol and normal levels of LDL cholesterol, which is composed of small, dense particles), prevalent in obese and overweight patients with abnormal glucose metabolism, is also associated with increased CV risk and may explain part of the residual CV risk, beyond LDL cholesterol [22]. Interestingly, researchers have found that the remnant cholesterol, not LDL cholesterol, is associated with incident cardiovascular disease in patients at high cardiovascular risk, including diabetic patients [23,24]. ...

The Prognostic Role of Triglycerides Should Be Revisited
  • Citing Article
  • April 2021

Journal of the American College of Cardiology

... Recientemente se han publicado varios metaanálisis en los que el uso de colchicina en pacientes con COVID-19 se ha asociado a una menor mortalidad de manera estadísiticamente significativa (46)(47)(48). ...

Impact of colchicine on mortality in patients with COVID-19: A meta-analysis

Hellenic Journal of Cardiology

... Table 2. Characteristics of reported studies which investigated role of ranolazine in AF. AF: atrial Several studies have explored the potential role of ranolazine in the pharmacological cardioversion of paroxysmal AF [24][25][26]. The results across these studies are consistent, demonstrating a higher rate of sinus rhythm restoration and a shorter conversion time in patients treated with ranolazine across all ejection fraction spectra. ...

Pharmacologic Cardioversion in Patients with Paroxysmal Atrial Fibrillation: A Network Meta-Analysis

Cardiovascular Drugs and Therapy

... The device combines three certain methods of physiological studies into an integrated hardware complex, which makes it possible to achieve a fundamentally new quality of measurements, that is, simultaneous recording of HRV and ВPV at different stages of the respiratory act . ECG recording in 1 lead allowed to determine the indicators of heart rate variability (HRV) according to the spectral analysis of the sequence of RR intervals is total power (ТР, ms 2 ), power in the very low frequency range (VLF, ms 2 ), power in the low frequency range (LF, ms 2 ) and power in the high frequency range (HF, ms 2 ) and their derivatives (LFn, n.u., HFn, n.u., LF/HF) ; according to the math analysis of the sequence of RR intervals is ABI (autonomic balance index, c.u.), SRAI (subcortical regulation adequacy indicator, c.u.), ARI (autonomic regulation index, c.u.), SI (stress index, c.u.), SDANN (standard deviation of the values of cardio intervals, ms), RMSSD (square root of the sum of squares of the differences in the values of consecutive pairs of normal intervals, ms), pNN50 (the percentage of NN50 from the total number of consecutive pairs of intervals that differ by more than 50 milliseconds, obtained over the entire time recording, %) (Heart rate variability:.., 1996); according to cardiointervalometry -to define the heart rate (HR, min -1 ), durations and intervals of PQRST-complex -P (s), PQ (s), QRS (s), QT (s), QTC (s), ST (n.u.); indicators of systemic hemodynamics (Kim et al., 2005;Romanchuk & Pisaruk, 2013) -end-diastolic volume (EDV, cm 3 ), end-systolic volume (ESV, cm 3 ), stroke volume (SV, cm 3 ), cardiac output (CO, dm 3 ), stroke index (SI, cm 3 /m 2 ), cardiac index (CI, dm 3 / m 2 ), general peripheral vascular resistance (GPVR, dyn/s/cm −5 ); according to the pulse wave recording with the help of a photoplethysmographic sensor on the finger by the Penaz method (Penáz, 1992), blood pressure (SBP, mmHg; DBP, mmHg) and its variability (SBPV and DBPV) in ranges similarly to HRV were determined a total power of SBPV and DBPV (ТР SBP , mmHg 2 and ТР DBP , mmHg 2 ), power in the very low-frequency range (VLF SBP , mmHg 2 and VLF DBP , mmHg 2 ), power in the low-frequency range (LF SBP , mmHg 2 and LF DBP , mmHg 2 ) and power in the high-frequency range (HF SBP , mmHg 2 and HF DBP , mmHg 2 ) and their derivatives -LF SBP n, n.u., HF SBP n, n.u., LF/HF SBP , LF DBP n, n.u., HF DBP n, n.u., LF/ HF DBP (Pinna, 1996;Wesseling et al., 2017;Papaioannou, et al., 2020). Additionally by using the spectral method we determined the index of arterial baroreflex sensitivity (BRS, ms/mmHg)α-coefficient, that was calculated in high (BRS HF ) and low (BRS LF ) frequencies ranges (Karemaker et Papaioannou, et al., 2020). ...

Very-short-term blood pressure variability: Complexities and challenges
  • Citing Article
  • October 2020

Blood Pressure Monitoring

... C-reactive protein, Interleukin-6 and adhesion molecules, such as Intercellular Adhesion Molecule 1 (ICAM-1), Vascular Cell Adhesion Molecule 1 (VCAM-1) and Selectins, have been observed to be related to adverse cardiovascular prognosis [43][44][45]. Recently, the role of small (18-22 nucleotides) non-coding microRNAs has been studied in several disease states and pathophysiologic conditions and several patterns of circulating or tissue microRNAS have been recognized in patients with extensive atherosclerosis, CAD and acute coronary syndromes [46][47][48][49][50]. Similarly, the role of cell-free highly fragmented doublestranded DNA, circulating in the serum, is found in high levels in patients with myocardial infarction. ...

Exploration analysis of microRNAs -146a, -19b and -21 in patients with acute coronary syndrome

Hellenic Journal of Cardiology

... Previous studies have documented the association between several cardiovascular (CV) risk factors separately and left ventricular structure in both children (8,9) and adults (10,11). Indeed, abdominal obesity (12,13), elevated blood pressure (9,14), triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C) (15,16) are independently associated with cardiac structural remodeling in youth. ...

Triglycerides are related to left ventricular mass in hypertensive patients independently of other cardiometabolic risk factors: the effect of gender

... The life-threatening characteristics of severe coronavirus disease-19 are a cytokine storm and hyper-inflammatory state which often lead to multiorgan dysfunction and lung injury [9] . Considering the common inflammatory pathways, colchicine may demonstrate the same favorable effects on the course of COVID-19 [25] . Although small randomized studies and retrospective studies have demonstrated the significant benefits of colchicine, the same benefit has not been observed in some large-scale randomized controlled studies [10,[26][27][28] . ...

Colchicine as a potent anti-inflammatory treatment in COVID-19: can we teach an old dog new tricks?

European Heart Journal - Cardiovascular Pharmacotherapy