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Purpose: Syncope remains a common medical problem. Recently, the role of dedicated syncope units and implantable loop recorders has emerged in the investigation of unexplained syncope. This study aims to investigate the possibilities for a more rational and targeted use of various diagnostic tools. Methods: In this retrospective single-center study, 196 patients with unexplained syncope were included between March 2019 and February 2023. Various diagnostic tools were utilized during the investigation, according to clinical judgement. Patients were retrospectively allocated into Group A (including those who, among other tests, underwent loop recorder insertion) and Group B (including patients investigated without loop recorder implantation). Data were compared with Group C, including patients assessed prior to syncope unit establishment. Results: There was no difference between Group A (n = 133) and Group B (n = 63) in the diagnostic yield (74% vs. 76%, p = 0.22). There were significant differences between Groups A and B regarding age (67.3 ± 16.9 years vs. 48.3 ± 19.1 years, p < 0.001) and cause of syncope (cardiogenic in 69% of Group A, reflex syncope in 77% of Group B, p < 0.001). Electrocardiography-based diagnosis occurred in 55% and 19% of Groups A and B, respectively (p < 0.001). The time to diagnosis was 4.2 ± 2.7 months in Group A and 7.5 ± 5.6 months in Group B (p < 0.001). In Group C, the diagnostic yield was 57.9% and the electrocardiography-based diagnostic yield was 18.3%. Conclusions: A selective use of loop recorders according to clinical and electrocardiographic characteristics increases the effectiveness of the structured syncope unit approach and further preserves financial resources.

Background The aim of this study was to develop a structured 2‐step approach, based on noninvasive diagnostic criteria, that led to an electrophysiology study in patients with unexplained syncope. Methods and Results Two independent cohorts were used: the derivation cohort with 665 patients based on electronic health record data to develop our 2‐step diagnostic approach, and the validation cohort based on 160 prospectively screened patients, presenting with unexplained syncope episodes. Noninvasive electrocardiographic and imaging markers and an electrophysiology study–based invasive assessment were combined. A positive diagnostic approach according to our study's prespecified criteria resulted in a decision to proceed with a permanent pacemaker/implantable cardioverter‐defibrillator. The primary end point was the time until the event of recurrent syncope (syncope‐free survival). Number needed to treat was calculated for patients with a positive diagnostic approach. The number of patients with unexplained syncope and borderline sinus bradycardia needed to treat was 5, and the number of patients with unexplained syncope and bundle branch block needed to treat was 3 over a mean follow‐up of ≈4 years. After the structured 2‐step approach, the primary outcome occurred in 14 of 82 (17.1%) with a pacemaker/implantable cardioverter‐defibrillator and 19 of 57 (33%) with a negative approach, with a mean follow‐up of ≈2.5 years (29.29±12.58 months, P=0.03). Conclusions The low number needed to treat in the derivation cohort and the low percentage of syncope recurrence in the validation cohort supports the proposed 2‐step electrophysiology‐inclusive algorithm as a potentially low‐cost, 1‐day, structured tool for these patients.

Abstract Background Risk stratification for sudden cardiac death in post‐myocardial infarction (post‐MI) patients remains a challenging task. Several electrocardiographic noninvasive risk factors (NIRFs) have been associated with adverse outcomes and were used to refine risk assessment. This study aimed to evaluate the performance of NIRFs extracted from 45‐min short resting Holter ECG recordings (SHR), in predicting ventricular tachycardia inducibility with programmed ventricular stimulation (PVS) in post‐MI patients with preserved left ventricular ejection fraction (LVEF). Methods We studied 99 post‐MI ischemia‐free patients (mean age: 60.5 ± 9.5 years, 86.9% men) with LVEF ≥40%, at least 40 days after revascularization. All the patients underwent PVS and a high‐resolution SHR. The following parameters were evaluated: mean heart rate, ventricular arrhythmias (premature ventricular complexes, couplets, tachycardias), QTc duration, heart rate variability (HRV), deceleration capacity, heart rate turbulence, late potentials, and T‐wave alternans. Results PVS was positive in 24 patients (24.2%). HRV, assessed by the standard deviation of normal‐to‐normal R–R intervals (SDNN), was significantly decreased in the positive PVS group (42 ms vs. 51 ms, p = .039). SDNN values

Objective: The objective of this study was to provide data on implantable loop recorder (ILR)-based atrial fibrillation (AF) rates, recurrent stroke rates, and predictors of AF in patients with cryptogenic stroke (CS) after 1, 6, 12, 24, and 36 months of follow-up. Methods: We searched MEDLINE/PubMed, Cochrane Central Register of Controlled Trials, EMBASE, Web of Science, and reference lists of retrieved reports, which were published by April 30, 2023, which was the date of our last search. We utilized random-effects meta-analysis for detection rates, and meta-regression analysis, t-test (for normally distributed variables), and Mann-Whitney (for skewed variables) for predictor factors. Results: Thirteen studies were analyzed, which included data from 3,377 patients with CS or embolic stroke of undetermined source. The ILR-based AF rates in patients with CS were 4.73% (95% confidence interval [CI] 3.91–5.71) at 1 month, 13.45% (95% CI 12.19–14.81) at 6 months, 17.5% (95% CI 16.25–18.82) at 12 months, 20.69% (95% CI 19–22.49) at 24 months, and 25.98% (95% CI 23.21–28.58) at 36 months. Age and CHA2DS2-VASc score were positively associated with AF detection. Specifically, the mean difference of age and CHA2DS2-VASc score in the group with AF versus the group without AF was 7.47 (95% CI 4.58–10.36, P < 0.001) and 0.75 (95% CI 0.22–1.28, P = 0.01), respectively. Finally, AF detection was positively associated with recurrent strokes with an estimated risk ratio of 1.27 (95% CI 0.69–2.31). Conclusions: There is a correlation between AF detection rate and ILR monitoring duration. One out of eight patients was diagnosed with AF after 6 months of follow-up and about one quarter after 3 years. Our results demonstrate the critical use of ILRs, especially in older patients, and in patients with high CHA2DS2-VASc scores.

Cardiac rehabilitation (CR) is a complex intervention that improves functional capacity and quality of life in patients with heart failure (HF). Besides exercise training (ET), CR includes aggressive risk factor management, education about medication adherence, stress management, and psychological support. Current guidelines strongly recommend CR as an integral part of chronic and stable HF patient care. However, CR programs are underused for multiple reasons, namely, low physician referral and patient adherence, high cost, and lack of awareness. In this review, we present existing evidence of the beneficial effects of ET and CR in HF with reduced and preserved ejection fraction, the underlying pathophysiologic mechanisms by which exercise might alleviate symptoms, and the different types of exercise that can be used in HF. Current guidelines supporting the use of CR, reasons for its underutilization, and home-based CR as an alternative or adjunct to traditional center-based programs are also described.

His bundle pacing (HBP) is proven to be a safe and effective alternative pacing modality that, in addition, avoids pacemaker-induced cardiomyopathy (PICM) by achieving a “physiological” ventricular stimulation, via the native conduction system. Indications include various causes of bradycardia requiring anti-bradycardic pacing, inadequately controlled atrial fibrillation requiring AV node ablation and established PICM. In addition, HBP may also be used as an alternative therapy for patients with heart failure (HF) and an indication for cardiac resynchronization therapy (CRT). Available data show several advantages of HBP with regard to preservation or restoration of intra- and inter-ventricular synchronization; improvement in left ventricular ejection fraction, functional status and quality of life; decrease in atrial fibrillation incidence and improvement in HF hospitalization rates, compared with conventional pacing. Nevertheless, superiority in terms of mortality rates has not been consistently demonstrated, and the long-term efficacy and safety of HBP remain to be proven. In the present manuscript, we review the status of HBP and present our current experience with this novel pacing modality.

Objective: Syncope, whose cause is unknown after an initial assessment, has an uncertain prognosis. It is critical to identify patients at the highest risk who may require a pacemaker and to identify the cause of recurrent syncope to prescribe proper therapy. The aim of this study was to evaluate the effect of permanent pacing on the incidence of syncope in patients with unexplained syncope and electrophysiology study (EPS)-proven atrioventricular (AV) node disease. Methods: This was an observational study based on a prospective registry of 236 consecutive patients (60.20 ± 18.66 years, 63.1% male, 60.04 ± 9.50 bpm) presenting with recurrent unexplained syncope attacks admitted to our hospital for invasive EPS. The decision to implant a permanent pacemaker was made in all cases by the attending physicians according to the results of the EPS. A total of 135 patients received the antibradycardia pacemaker (ABP), while 101 patients were declined. Results: The mean of reported syncope episodes was 1.97 ± 1.10 (or presyncope 2.17 ± 1.50) before they were referred for a combined EP-guided diagnostic and therapeutic approach. Over a mean follow-up of approximately 4 years (49.19 ± 29.58 months), the primary outcome event (syncope) occurred in 31 of 236 patients (13.1%), and 6 of 135 (4.4%) patients in the ABP group as compared to 25 of 101 (24.8%) in the no pacemaker group (p

Background and Aim: The association of atrial fibrillation (AF) with the ischemic stroke has emerged as an area of clinical research. The purpose of the present study is to investigate possible correlations between the severity, progress, and outcome of ischemic stroke and the presence of AF. Materials and Methods and Results: The clinical assessment of patients was based on the neurological status at the time of diagnosis utilizing the National Institutes of Health Stroke Scale (NIHSS), the neurological semiology during hospitalization (improvement, deterioration, and without differentiation), and the final outcome at the end of the treatment optimizing the modified Rankin scale (mRS). A total of 344 patients diagnosed with an ischemic stroke were enrolled in the study. The presence of AF was found to be associated with higher severity, poorer progress, and more adverse clinical outcomes of the ischemic stroke. Furthermore, a lower frequency of transient ischemic attacks was observed in patients with AF. Finally, patients with AF presented higher incidence of middle cerebral artery occlusion and were more frequently found with a lesion on the left brain hemisphere. Conclusion: AF was found to be highly associated with higher severity and poorer prognosis of ischemic strokes, independently from the presence of other cardiovascular risk factors.

Syncope of cardiac origin may be associated with an increased risk of sudden cardiac death if not treated in a timely and appropriate manner. The diagnostic approach of syncope imposes a significant economic burden on society. The investigation and elucidation of the pathogenetic mechanism of syncope are of great clinical importance, as both prognosis and appropriate therapeutic approaches depend on these factors. The responsible mechanism of presyncope or syncope can only be revealed through the patient history, baseline clinical examination and electrocardiogram. The percentage of patients who are diagnosed with these tests alone exceeds 50%. In patients with a history of organic or acquired heart disease or/and the presence of abnormal findings on the electrocardiogram, a further diagnostic electrophysiology inclusive approach should be followed to exclude life threatening arrhythmiological mechanism. However, if the patient does not suffer from underlying heart disease and does not show abnormal electrocardiographic findings in the electrocardiogram, then the probability in the electrophysiology study to find a responsible cause is small but not absent. The role of a two-step electrophysiology study inclusive risk stratification approach for the effective management of the former is thoroughly discussed in this review.

Abstract Background Electrocardiographic non‐invasive risk factors (NIRFs) have an important role in the arrhythmic risk stratification of post‐myocardial infarction (post‐MI) patients with preserved or mildly reduced left ventricular ejection fraction (LVEF). However, their specific relation to left ventricular systolic function remains unclear. We aimed to evaluate the association between NIRFs and LVEF in the patients included in the PRESERVE‐EF trial. Methods We studied 575 post‐MI ischemia‐free patients with LVEF≥40% (mean age: 57.0 ± 10.4 years, 86.2% men). The following NIRFs were evaluated: premature ventricular complexes, non‐sustained ventricular tachycardia (NSVT), late potentials (LPs), prolonged QTc, increased T‐wave alternans, reduced heart rate variability, and abnormal deceleration capacity with abnormal turbulence. Results There was a statistically significant relationship between LPs (Chi‐squared = 4.975; p

Abstract Background Significant sinus bradycardia (SB) in the context of sinus node dysfunction (SND) has been associated with neurological symptoms. The objective was to evaluate the effect of permanent pacing on the incidence of syncope in patients with rather mild degrees of SB, unexplained syncope, and “positive” invasive electrophysiologic testing. Methods This was an observational study based on a prospective registry of 122 consecutive mild SB patients (61.90 ± 18.28 years, 61.5% male, 57.88 ± 7.73 bpm) presenting with recurrent unexplained pre and syncope attacks admitted to our hospital for invasive electrophysiology study (EPS). Τhe implantation of a permanent antibradycardia pacemaker (ABP) was offered to all patients according to the results of the EPS. Eighty patients received the ABP, while 42 denied. Results The mean of reported syncope episodes was 2.23 ± 1.29 (or presyncope 2.36 ± 1.20) in the last 12 months before they were referred for a combined EP guided diagnostic and therapeutic approach. Over a mean follow‐up of approximately 4 years (50.39 ± 32.40 months), the primary outcome event (syncope) occurred in 18 of 122 patients (14.8%), 6 of 80 (7.5%) in the ABP group as compared to 12 of 42 (28.6%) in the no pacemaker group (P = .002). Conclusions Among patients with mild degree of SB and a history of unexplained syncope, a set of positivity criteria for the presence of EPS defined SND after differentiating reflex syncope, identifies a subset of patients who will benefit from permanent pacing.

Abstract Background Although some post myocardial infarction (post‐MI) and dilated cardiomyopathy (DCM) patients with mid‐range ejection fraction heart failure (HFmrEF/40%‐49%) face an increased risk for arrhythmic sudden cardiac death (SCD), current guidelines do not recommend an implantable cardiac defibrilator (ICD). We risk stratified hospitalized HFmrEF patients for SCD with a combined non‐invasive risk factors (NIRFs) guiding to programmed ventricular stimulation (PVS) two‐step approach. Methods Forty‐eight patients (male = 83%, age = 64 ± 14 years, LVEF = 45 ± 5%, CAD = 69%, DCM = 31%) underwent a NIRFs screening first‐step with electrocardiogram (ECG), SAECG, Echocardiography and 24‐hour ambulatory ECG (AECG). Thirty‐two patients with presence of one of three NIRFs (SAECG ≥ 2 positive criteria for late potentials, ventricular premature beats ≥ 240/24 hours, and non‐sustained ventricular tachycardia [VT] episode ≥ 1/24 hours) were further investigated with PVS. Patients were classified as either low risk (Group 1, n = 16, NIRFs−), moderate risk (Group 2, n = 18, NIRFs+/PVS−), and high risk (Group 3, n = 14, NIRFs+/PVS+). All in Group 3 received an ICD. Results After 41 ± 18 months, 9 of 48 patients, experienced the major arrhythmic event (MAE) endpoint (clinical VT/fibrillation = 3, appropriate ICD activation = 6). The endpoint occurred more frequently in Group 3 (7/14, 50%) than in Groups 1 and 2 (2/34, 5.8%). Logistic regression model adjusted for PVS, age, and LVEF revealed that PVS was an independent MAE predictor (OR: 21.152, 95% CI: 2.618‐170.887, P = .004). Kaplan‐Meier curves diverged significantly (log rank, P

Psychiatric patients often present with symptoms similar to those indicating the need for a cardiac rhythm management device or even cardiac arrhythmia ablation. However, due to the unreliability of symptom self-reporting, the ability of the underlying neuropsychiatric condition to elicit similar phenomena, and the perceived reduced compliance and increased complication rates among this population, both of the above approaches remain underutilized with often detrimental effects. In the present case series, it is attempted to describe an alternative, electrophysiology study-guided approach to these patients, aiming to both firmly establish the need for invasive intervention (including implantation of pacemakers – three cases, implantable cardioverter-defibrillators – three cases, and electrophysiological ablations – two cases), as well as dispel preconceptions, bordering on stigma, regarding their outcomes.

Background: Supraventricular and ventricular tachyarrhythmias represent a common complication in grown-up patients with congenital heart defects (CHD) associated with worsening of functional capacity and increased morbidity. The aim of this study was to present the experience of our department on catheter ablation (CA) addressing safety and efficacy concerns. Methods: Consecutive patients with CHD treated with CA between 2002 and 2021 in our hospital were included in this study. The established ablation techniques modified according to the patient's special anatomic characteristics were applied. NYHA functional status along with the underlying cardiac rhythm were recorded during the follow-up. Results: In total, 35 patients (44.9 ​± ​2.7 years, 22 males) underwent CA for the management of either supraventricular or ventricular (n ​= ​2) arrhythmia during the study period. The most common anatomical diagnoses were atrial septal defect (13), Tetralogy of Fallot (5) and transposition of great arteries (3). Atrial fibrillation or atrial flutter was the most frequent baseline diagnosis, observed in 15 (42.8%) patients, followed by intra-atrial reentrant tachycardia in 9 (25.7%) patients and atrioventricular nodal reentry tachycardia (AVNRT) in 5 (14.2%). No significant complication occurred during CA. Patients were followed for a median period of 9 years after the index procedure. At this time, arrhythmia recurrence was observed in 13 patients (37,1%) of whom 6 underwent a redo procedure. Furthermore, 4 patients underwent a permanent pacemaker implantation, while 6 were offered an ICD treatment. Conclusion: CA is a safe method offering significant benefits regarding the management of tachyarrhythmias and preserving functional capacity in adult patients with CHD.

Abstract 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

Background: Left ventricular ejection fraction (LVEF) is the gold standard for evaluating heart failure (HF) in coronary artery disease (CAD) patients. It is an essential metric in categorizing HF patients as preserved (HFpEF), mid-range (HFmEF), and reduced (HFrEF) ejection fraction but differs, depending on whether the ASE/EACVI or ESC guidelines are used to classify HF.Objectives: We sought to investigate the effectiveness of using deep learning as an automated tool to predict LVEF from patient clinical profiles using regression and classification trained models. We further investigate the effect of utilizing other LVEF-based thresholds to examine the discrimination ability of deep learning between HF categories grouped with narrower ranges.Methods: Data from 303 CAD patients were obtained from American and Greek patient databases and categorized based on the American Society of Echocardiography and the European Association of Cardiovascular Imaging (ASE/EACVI) guidelines into HFpEF (EF > 55%), HFmEF (50% ≤ EF ≤ 55%), and HFrEF (EF < 50%). Clinical profiles included 13 demographical and clinical markers grouped as cardiovascular risk factors, medication, and history. The most significant and important markers were determined using linear regression fitting and Chi-squared test combined with a novel dimensionality reduction algorithm based on arc radial visualization (ArcViz). Two deep learning-based models were then developed and trained using convolutional neural networks (CNN) to estimate LVEF levels from the clinical information and for classification into one of three LVEF-based HF categories.Results: A total of seven clinical markers were found important for discriminating between the three HF categories. Using statistical analysis, diabetes, diuretics medication, and prior myocardial infarction were found statistically significant (p < 0.001). Furthermore, age, body mass index (BMI), anti-arrhythmics medication, and previous ventricular tachycardia were found important after projections on the ArcViz convex hull with an average nearest centroid (NC) accuracy of 94%. The regression model estimated LVEF levels successfully with an overall accuracy of 90%, average root mean square error (RMSE) of 4.13, and correlation coefficient of 0.85. A significant improvement was then obtained with the classification model, which predicted HF categories with an accuracy ≥93%, sensitivity ≥89%, 1-specificity

Abstract Syncope represents a relatively uncommon symptom of supraventricular tachycardia (SVT). It is likely that an impaired autonomic vasomotor response to the hemodynamic stress of tachycardia is the determinant of hemodynamic changes leading to cerebral hypoperfusion and syncope. In this regard, tilt‐table test may detect abnormalities in the autonomic nervous function and predict the occurrence of syncope during SVT. Electrophysiology studies may reproduce the SVT, distinguish it from other life‐threatening ventricular tachyarrhythmias, and exclude other causes of syncope. Not infrequently mixed syncope mechanisms are revealed during the above diagnostic workup raising doubts about the operating mechanism in the clinical setting. In such cases of uncertainty, an implantable loop recorder, providing long‐term cardiac monitoring, may play a pivotal role in the establishment of the diagnosis, confirming the association of an arrhythmic event with the symptom. Herein, we present four such cases with recurrent unexplained syncope finally attributed to paroxysmal SVT guiding them to a potentially radical treatment through radiofrequency catheter ablation.

Dilated cardiomyopathy (DCM) is a heart disorder of diverse etiologies that affects millions of people worldwide, associated with increased mortality rate and high risk of sudden cardiac death. Patients with DCM are characterized by a wide range of clinical and pre-clinical phenotypes which are related with different outcomes. Dominant studies have failed to demonstrate the value of the left ventricular ejection fraction as the only indicator for patients’ assessment and arrhythmic events prediction, thus making sudden cardiac death (SCD) risk stratification strategy improvement, more crucial than ever. The multifactorial two-step approach, examining non-invasive and invasive risk factors, represents an alternative process that enhances the accurate diagnosis and the individualization of patients’ management. The role of genetic testing, regarding diagnosis and decision making, is of great importance, as pathogenic variants have been detected in several patients either they had a disease relative family history or not. At the same time there are specific genes mutations that have been associated with the prognosis of the disease. The aim of this review is to summarize the latest data regarding the genetic substrate of DCM and the value of genetic testing in patients’ assessment and arrhythmic risk evaluation. Undoubtedly, the appropriate application of genetic testing and the thoughtful analysis of the results will contribute to the identification of patients who will receive major benefit from an implantable defibrillator as preventive treatment of SCD.

Since the first transvenous pacemaker implantation, which took place 50 years ago, important progress has been achieved in pacing technology. Consequently, at present, more than 700,000 pacemakers are implanted annually worldwide. However, conventional pacemakers' implantation has a non-negligible risk of periprocedural and long-term complications associated with the transvenous leads and pacemaker pocket. Recently, leadless pacing systems have emerged as a therapeutic alternative to conventional pacing systems that provide therapy for patients with bradyarrhythmias, while eliminating potential transvenous lead- and pacemaker pocket-related complications. Initial studies have demonstrated favorable efficacy and safety of currently developed leadless pacing systems, compared to transvenous pacemakers. In the present paper, we review the current evidence and highlight the advantages and disadvantages of this novel technology. New technological advances may allow the next generation of leadless pacemakers to further expand, thereby offering a wireless cardiac pacing in future. Keywords: cardiac pacing, pacemaker, leadless pacemaker, bradycardia

The introduction of an implantable cardioverter defibrillator (ICD) in clinical practice has revolutionized our therapeutic approach for both primary and secondary prevention of sudden cardiac death (SCD), as it has proven to be superior to medical therapy in treating potentially life-threatening ventricular arrhythmias and has resulted in reduced mortality rates. However, implantation of a conventional ICD carries a non-negligible risk of periprocedural and long-term complications associated with the transvenous ICD leads. The entirely subcutaneous implantable cardioverter defibrillator (S-ICD) has recently emerged as a therapeutic alternative to the conventional ICD for patients with various cardiopathies and who are at high risk of SCD. The main advantage is the avoidance of vascular access and thus avoidance of complications associated with transvenous leads. Patients without pacing indications, such as bradycardia, a need for antitachycardia pacing or cardiac resynchronization, as well as those at higher risk of complications from transvenous lead implantation are perfect candidates for this novel technology. The subcutaneous ICD has proven to be equally safe and effective compared to transvenous ICD systems in early clinical trials. Further technical improvements of the system will likely lead to the expansion of indications and widespread use of this technology. In the present review, we discuss the indications for this system, summarize early clinical experiences and highlight the advantages and disadvantages of this novel technology. In addition, we present the first two cases of subcutaneous cardioverter defibrillator system implantation in Greece. Keywords: Sudden cardiac death, Ventricular tachyarrhythmias, Brugada syndrome

Background: Non-documented palpitations, or phantom tachycardias, are palpitations deemed to be of unknown origin after evaluation with conventional diagnostic tools, such as 12-lead electrocardiogram and Holter recordings. Our aim was to determine the diagnostic value of an electrophysiologic study (EPS) and its role in the management of patients presenting with non-documented palpitations. Methods: We performed EPS in 78 consecutive patients with repeatable, poorly tolerated symptoms of paroxysmal, non-documented tachycardia, the absence of structural heart disease and at least one 24-h Holter recording. The duration and frequency of palpitations was registered in each patient. Results: Long-lasting palpitations (>1 hour) were present in 15.4% of patients. Half of patients reported symptoms less often than once per week. Only 13/78 patients (16.6%) had normal EPS findings, while dual pathways at the AV node ± echo beats were identified in another 13 patients without inducible tachycardia. At least one tachycardia event was induced in 52 patients (66.6%). AVNRT was provoked in 32 patients (41.2%). Ablation was performed in 14/52 patients with inducible tachycardia (26.9%). Slow pathway ablation was also performed in three patients with dual AV pathways and atrial echo-beats but without provoked tachycardia. Follow-up data were available in 52 patients, and 84.6% had fewer or no clinical recurrences. Conclusions: EPS is safe and of enhanced diagnostic value in patients with unexplained palpitations because only 1/6 had negative results. EPS also provided an explanation about the mechanism of arrhythmia and successfully guided the management of these patients, as well as enhanced improvement in the quality of life.

Sudden cardiac death threats ischaemic and dilated cardiomyopathy patients. Anti- arrhythmic protection may be provided to these patients with implanted cardiac defibrillators (ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity meaning that a significant number of victims will remain undetectable by this risk stratification approach because they have a preserved left ventricular systolic function. Current risk stratification strategies focus on combinations of non invasive methods like T wave alternans, late potentials, heart rate turbulence, deceleration capacity and others, with invasive methods like the electrophysiologic study. In the presence of an electrically impaired substrate with formed post myocardial infarction fibrotic zones, programmed ventricular stimulation provides important prognostic information for the selection of the patients expected to benefit from an ICD implantation, while due to its high negative predictive value, patients at low risk level may also be detected. Clustering evidence from different research groups and electrophysiologic labs support an electrophysiologic testing guided risk stratification approach for sudden cardiac death.