Georgios Kollias

• Doctor of Medicine (MD)
• Evangelismos Hospital

Heart failure (HF) is a major clinical challenge characterized by significant morbidity and mortality. Electrical conduction abnormalities play a critical role in HF pathophysiology and progression, often leading to suboptimal outcomes with conventional pacing techniques. Con-duction system pacing (CSP), encompassing His bundle pacing and left bund...

Background Temperature-controlled high-power short-duration (HPSD) radiofrequency catheter ablation for pulmonary vein isolation (PVI) utilizing a novel ablation catheter (QDOT Micro) with real-time assessment of catheter tip temperature aims for safer, more effective and faster procedures. Methods The peQasus study is a large European multicenter...

Background Advanced ablation strategies are needed to treat ventricular tachycardia (VT) and premature ventricular contractions (PVC) refractory to standard unipolar radiofrequency ablation (Uni-RFA). Bipolar radiofrequency catheter ablation (Bi-RFA) has emerged as a treatment option for refractory VT, PVC. Multicenter registry data on the use of B...

The current gold standard in device therapy for advanced heart failure (HF), which has been firmly established in HF management for more than 25 years, is classical biventricular pacing (BiV-CRT). In the last decade, a new pacing modality called conduction system pacing (CSP) has emerged as a variant for advanced cardiac device therapy. It provides...

Background: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is a standard-of-care treatment in the rhythm control strategy of symptomatic atrial fibrillation (AF). Ablation protocols, varying in the power and duration of energy delivery, have changed rapidly in recent years. Very high-power very short-duration ablation (vHPvSD) i...

Atrial fibrillation is associated with neurocognitive comorbidities such as stroke and dementia. Evidence suggests that rhythm control-especially if implemented early-may reduce the risk of cognitive decline. Catheter ablation is highly efficacious for restoring sinus rhythm in the setting of atrial fibrillation; however, ablation within the left a...

Introduction Cardiac device therapy has recently been extended by the option of Conduction System Pacing, CSP (HIS Bundle Pacing, HBP; Left Bundle Branch Area Pacing, LBBAP). Similar to cardiac resynchronization therapy (CRT), complex procedures can result in long fluoroscopy-duration and considerable radiation exposure for the patient and the impl...

Radiofrequency (RF) catheter ablation is an established method of treating patients with atrial fibrillation (AF). However, the optimal levels of power and duration required to achieve a successful ablation while avoiding complications are unknown. High-power short-duration (HPSD) ablation for the treatment of AF is already emerging as an alternati...

Background A 19-year-old woman with an established diagnosis of long QT syndrome (LQTS) 2 and underlying KCNH2-mutation was referred to our centre for recurrent polymorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) refractory to medical therapy and bilateral thoracic sympathectomy. Case summary Holter monitoring revealed a rel...

PurposeCerebral thromboembolic events are well-known complications of pulmonary vein isolation (PVI) and can manifest as stroke or silent cerebral embolic lesions. The aim of this study was to compare the incidence of cerebral embolic lesions (including silent cerebral embolism and stroke) after AF ablation in patients on vitamin K antagonists vers...

Aims Cerebral thromboembolic events are well-known complications of pulmonary vein isolation (PVI) and can manifest as stroke or silent cerebral embolic lesions. Over the last years, the preferred oral anticoagulation in atrial fibrillation (AF) shifted from vitamin K antagonists (VKA) to non-vitamin K-dependent oral anticoagulants (NOAC). The aim...

Reel syndrome occurs due to the rotation of the implantable device on its transverse axis with subsequent coiling of the leads around the pulse generator. Device interrogation and chest X‐ray should be performed in any case of device malfunction. Reel syndrome occurs due to the rotation of the implantable device on its transverse axis with subseque...

Renal denervation (RDN) has been proposed as a novel interventional antihypertensive technique. However, existing evidence was mainly from patients with severe resistant hypertension. The authors aimed to evaluate the efficacy of RDN in patients with resistant hypertension with mildly elevated blood pressure (BP). Studies of RDN in patients with mi...

Sufficient electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). We assessed the impact of direct catheter force measurement on acute procedural parameters and outcome of RFCA for paroxysmal and persistent atrial fibrillation (AF). Ninety-nine consecutive patients (70% men) with paroxysmal (63...

Aortic blood pressure (BP) and 24-h ambulatory BP are both better associated with target organ damage than office brachial BP. However, it remains unclear whether a combination of these two techniques would be the optimal methodology to evaluate patients' BP in terms of left ventricular diastolic dysfunction (LVDD) prevention. In 230 participants,...

Objective: To test the hypothesis that left-ventricular hypertrophy (LVH) is better associated with aortic, than brachial, 24-h average blood pressure (BP) in individuals with hypertension. Background: The office aortic BP is associated better with organ damage, such as LVH, than the office brachial BP; whether the 24-h average aortic BP associa...

Background & aims: Meal patterns and their relationship with cardiovascular disease are insufficiently examined with important clinical implications. Our aim was to investigate associations between eating frequency (EF) and early markers of atherosclerosis. Methods: In this cross-sectional study, we consecutively recruited 164 healthy subjects (...

Context: Although adrenal incidentalomas (AIs) are associated with a high prevalence of cardiovascular risk (CVR) factors, it is not clear whether patients with nonfunctioning AI (NFAI) have increased CVR. Objective: Our objective was to investigate CVR in patients with NFAI. Design and setting: This case-control study was performed in a terti...

Background and Aims Meal patterns and their relationship with cardiovascular disease are insufficiently examined with important clinical implications. Our aim was to investigate associations between eating frequency (EF) and early markers of atherosclerosis. Methods In this cross - sectional study, we consecutively recruited 164 healthy subjects (...

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 agen...

Background: Electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). Objective: We assessed the impact of direct catheter force measurement on acute procedural parameters of RFCA for atrial fibrillation (AF). Methods: 99 consecutive patients (pts; 72% male) with paroxysmal (63%) or persistent (37...

Accumulating data have shown that the autonomic nervous system is strongly implicated in the genesis of atrial fibrillation (AF). The aim of this study was to assess the efficacy of a single ablation procedure in patients with vagotonic, adrenergic and random type of paroxysmal AF. The clinical records of consecutive patients with symptomatic, drug...

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)...

The presence of early repolarization (ER) in inferior or inferolateral leads has been associated with malignant arrhythmias and increased mortality. Transmural dispersion of repolarization (TDR) has been proposed to underlie arrhythmogenesis in J-wave syndromes. The present study investigated specific electrocardiographic (ECG) markers including Tp...

It is ambiguous whether one should use this ap-proach only after an endocardial VT ablation failure or when the ECG of clinical VT suggests an epicar-dial origin. Consequently, multiple published ECG criteria may be used to predict epicardial VT origin. A maximal deflection index (MDI, the longest pre-cordial lead onset-peak time divided by total Q...

Although long-term weight gain has been associated with cardiovascular risk and intima-media thickening (IMT), no sufficient data exist on possible associations of such weight changes with more advanced stages of subclinical atherosclerosis. Moreover, the value of self-reported weight changes, a more practical approach to assess long-term history i...

Hyperprolactinemia has been recently associated with hypertension and endothelial dysfunction in humans, confirming animal studies performed in the 1970s that showed high prolactin levels to exert positive chronotropic and vasoconstrictive effects. Whether prolactin affects endothelial function, in the absence of hyperprolactinemia, remains unknown...

Left ventricular outflow tract arrhythmias originating from the aortomitral continuity, the left coronary cusp, the superior basal septum, and the epicardial left ventricular summit display common electrocardiographic and electrophysiological features, probably due to the close proximity of those locations. Catheter ablation of these arrhythmias ca...

The extent of target organ damage has been associated with both central hemodynamics and arterial stiffening, and the time rate of blood pressure (BP) changes in essential hypertension. However, the relative significance of these parameters has not been examined. We recruited 232 consecutive uncomplicated newly diagnosed hypertensive patients and 2...

The Brugada syndrome is an inherited channelopathy associated with a high propensity of ventricular tachyarrhythmias and sudden cardiac death in individuals with structurally normal hearts. Recent data are indicative of mild structural changes, mainly involving the right ventricle, in patients with Brugada syndrome. We present the case of a patient...

The onset of cardiovascular events presents a circadian variation that may be mediated by similar temporal patterns of vascular function. Blood pressure also follows circadian variation. We investigated the possible diurnal variation of endothelial function and arterial stiffness in patients with hypertension. Thirty-five individuals with recently...

The aim of this study was to examine the association between glycemia and markers of early atherosclerosis in healthy nondiabetic individuals. In 309 individuals without diabetes or symptomatic cardiovascular disease, we assessed long-term glycemia by glycosylated hemoglobin (HbA1c) and endothelial function by flow-mediated dilatation (FMD) in the...

Heartscore is not well validated for individuals less than 40 years of age. In the latest guidelines a relative risk chart is provided with the proposal to be used for young adults aged less than 60 years instead of projecting risk at the age of 60 years. Moreover, coronary artery disease is insidiously manifested in younger patients. Cross-section...

The aim of this study was to examine the impact of renal dysfunction on both coronary and peripheral atherosclerosis in patients with coronary artery disease (CAD) without severe renal impairment. One hundred and eighty-seven consecutive patients referred for elective coronary angiography were enrolled. Mean IMT and the presence of plaques were mea...