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Introduction Class IC antiarrhythmic drugs (AADs) currently represent a cornerstone in the therapy of atrial fibrillation (AF). They also play an important role in the treatment of idiopathic ventricular arrhythmias. Following the results of the CAST study flecainide and by extension the other class IC AADs were contraindicated in patients with ischemic and structural heart disease, because of their proarrhythmic effect and the consequent increase in mortality observed in the study. Recent studies, carried out on patients with chronic coronary heart disease, have shown a good safety profile for this class of drugs. Methods The aim of our study was to evaluate the mortality and the mortality rate in patients affected by ischaemic heart disease who take Class IC AADs. A systematic review and meta-analysis was conducted using Pubmed and Embase databases, following the PRISMA guidelines, to collect literature data reporting Class IC AADs safety in patients affected by coronary artery disease. Results The final analysis included four studies accounting for a total of 3643. In the Classe IC AADs group the events (all cause death) were observed in 104/1170 patients, while in the control group were observed in 338/2473 patients, showing an ODDS ratio of 1.431 (IC 0.748-2.740), p value 0.279 (TABLE 1A). The event rate per year was 5,5% in the CLASS IC AADs group and 5,1 in the control group, with an ODDS ratio of 1.524 (IC 0.807-2.879), p value 0.194 (TABLE 1B). Conclusion Class IC AADs doesn't increase the overall mortality and mortality rate in patient affected by icheamic heart disease. These observations await confirmation through randomised clinical trial.

Background: Antithrombotic/anticoagulation effects of direct oral anticoagulants (DOACs) are dose-dependent. However, recent observations suggest that administering lower dose DOACs may better protect against all-cause mortality. We investigated whether, in patients with established atherosclerosis, DOAC dose selection would affect the risk of all-cause mortality. Methods: We performed a structured literature research for controlled trials allowing random assignment to a lower dose DOAC, a higher dose DOAC, or control therapy in patients with established atherosclerosis. Pooled risk ratios (RRs) of all-cause mortality in lower and higher dose DOACs versus control therapy were estimated using a random-effect model. Results: Atherosclerosis manifested as acute coronary syndrome (n=17,220), stable coronary (CAD) and/or peripheral artery disease (PAD) (n=27,395) or CAD associated with atrial fibrillation (n=4,510). Antithrombotic doses of rivaroxaban (2.5 mg or 5.0 mg BID) or dabigatran (50 mg, 75 mg, 110 mg, or 150 mg, BID) were tested in three trials versus single or dual antiplatelet control therapy, whereas anticoagulation doses of edoxaban (30 mg or 60 OD) were tested versus warfarin in one trial. Compared to control, patients receiving lower dose (RR 0.80, 95% CI 0.73-0.89, pI²=0%), but not those receiving higher dose DOACs (RR 0.95, 95% CI 0.87-1.05, p=0.3074, I²=0%), had a significant reduction of all-cause mortality. Benefit from lower dose DOACs remained after sensitivity analysis or direct comparison with higher dose DOACs (RR 0.84, 95% CI 0.76-0.93, p=0.0009, I²=0%). Conclusions: Within antithrombotic/anticoagulation regimens of DOAC administration, selection of lower dose appears to protect from all-cause mortality in patients with established atherosclerosis.

Aims Air entrapment (AE) has been reported as a potential cause of early inappropriate shocks (ISs) following subcutaneous implantable cardioverter defibrillator (S-ICD) implantation, but a cause–effect relationship is not always evident. This systematic review aims to analyse this phenomenon concerning implantation techniques, electrogram (EGM) features, radiologic findings, and patient management. Methods and results A systematic search was conducted using PubMed, Embase, and Google Scholar databases following the PRISMA guidelines to obtain all available literature data since 2010 on S-ICD malfunctions possibly due to AE. The final analysis included 54 patients with AE as a potential cause of S-ICD malfunction. Overall, the aggregate incidence of this condition was 1.2%. Of ICD malfunctions possibly due to AE, 93% were ISs, and 95% were recorded within the first week following implantation. Radiologic diagnosis of AE was confirmed in 28% of the entire study cohort and in 68% of patients in whom this diagnostic examination was reported. At the time of device malfunction, EGMs showed artefacts, baseline drift, and QRS voltage reduction in 95, 76, and 67% of episodes, respectively. Management included ICD reprogramming or testing, no action (observation), and invasive implant revision in 57, 33, and 10% of patients, respectively. No recurrences occurred during follow-up, irrespective of management performed. Conclusions Device malfunction possibly due to AE may occur in ∼1% of S-ICD recipients. Diagnosis is strongly suggested by early occurrence, characteristic EGM features, and radiologic findings. Non-invasive management, principally device reprogramming, appears to be effective in most patients.

More than 2 decades ago, para-Hisian pacing was introduced to assess the pattern of retrograde conduction during electrophysiological studies. Although there is no ideal maneuver for every patient and condition, para-Hisian pacing is a valuable and handy strategy to differentiate between retrograde conduction over the atrioventricular node and the accessory pathways. The dynamic behavior of para-Hisian pacing, in a region with unique anatomical features, can produce various activation patterns and intriguing electrophysiological phenomena. Although the demonstration of a retrograde nodal activation pattern during para-Hisian pacing does not rule out the presence of an accessory pathway, evidence of retrograde conduction over an accessory pathway does not prove its active role in the culprit tachycardia. Multipolar His bundle recordings, detailed atrial mapping, and recognition of the truly captured structures and the impact of temporal changes of autonomic tone or pacing rates, are essential keys for accurate interpretation of this maneuver that may ultimately guide judicious catheter ablation of the arrhythmic substrate. This review aims to summarize the practical usefulness and potential pitfalls of the para-Hisian pacing maneuver, focusing on the interpretation of electrocardiograms and intracardiac recordings.

This case concerns a 24‐year‐old female who developed malignant ventricular tachyarrhythmia a few weeks after pacemaker implantation for complete heart block. Apparently, right ventricular pacing caused significant repolarization abnormalities in both native and paced rhythms with marked QT prolongation and substantial electrical instability. This case highlights other intriguing phenomena in the puzzle of cardiac repolarization and how pacing therapy may alter this complex process providing arrhythmic substrate in vulnerable subjects. Though such arrhythmic events are clinically rare, vulnerable patients or with suspected myocardial disease that may cause QT prolongation should be carefully followed in the course of pacing therapy.

More than 2 decades ago, para-Hisian pacing was introduced to assess the pattern of retrograde conduction during electrophysiological studies. Although there is no ideal maneuver for every patient and condition, para-Hisian pacing is a valuable and handy strategy to differentiate between retrograde conduction over the atrioventricular node and the accessory pathways. The dynamic behavior of para-Hisian pacing, in a region with unique anatomical features, can produce various activation patterns and intriguing electrophysiological phenomena. Although the demonstration of a retrograde nodal activation pattern during para-Hisian pacing does not rule out the presence of an accessory pathway, evidence of retrograde conduction over an accessory pathway does not prove its active role in the culprit tachycardia. Multipolar His bundle recordings, detailed atrial mapping, and recognition of the truly captured structures and the impact of temporal changes of autonomic tone or pacing rates, are essential keys for accurate interpretation of this maneuver that may ultimately guide judicious catheter ablation of the arrhythmic substrate. This review aims to summarize the practical usefulness and potential pitfalls of the para-Hisian pacing maneuver, focusing on the interpretation of electrocardiograms and intracardiac recordings.

Intravenous adenosine is a short-acting blocker of the atrioventricular node that has been used to unmask subtle or latent preexcitation, and also to enable catheter ablation in selected patients with absent or intermittent preexcitation. Depending on the accessory pathway characteristics, intravenous adenosine may produce specific electrocardiographic changes highly suggestive of the preexcitation variant. Herein, we view different ECG responses to this pharmacological test in various preexcitation patterns that were confirmed by electrophysiological studies. Careful analysis of electrocardiographic changes during adenosine test, with emphasis on P-delta interval, preexcitation degree, and atrioventricular block, can be helpful to diagnose the preexcitation variant/pattern.

Aim Ectopic atrial tachycardia (EAT) is a common arrhythmia in children, adolescents, and young adults. Radiofrequency (RF) ablation is often considered the treatment of choice in this population. We sought to evaluate the long‐term follow‐up after RF ablation. Methods and Results We retrospectively analyzed 36 young patients (age range 8‐29 years), with clinical signs and symptoms suspected for EAT who underwent an electrophysiological study in our center. We evaluated the safety and acute success rate of ablation and the long‐term follow‐up. Ectopic foci were more frequently localized in the right atrium along the crista terminalis (28%) and EAT was successfully terminated in 97% of patients. At median follow‐up (38 months), the recurrence rate was 20% with mostly recurrences expressed within 6 months. Conclusions The study confirmed the safety and high acute success rate of EAT ablation in a population of children, adolescents, and young adults. Therefore, catheter ablation of EAT can be considered early in the course of treatment of these patients. The evidence of most recurrences within 6 months could be useful for advising patients on likely outcomes.

Junctional and AV nodal reentrant tachycardia share common electrocardiographic features, but they differ in their management and outcomes after catheter ablation. This case concerns a 60-year-old female who presented with recurrent episodes of a relatively slow, regular supraventricular arrhythmia. Electrocardiographic features of the arrhythmia were discordant regarding its underlying mechanism. However, careful analysis of 12-lead electrocardiograms, with focus on the effect of spontaneous premature beats, pointed out the arrhythmia etiology. Electrophysiological study and pacing maneuvers defined the arrhythmic substrate that was successfully treated by catheter ablation.

BACKGROUNDImplantable cardioverter-defibrillators (ICDs) prevent sudden death from cardiac causes in selected patients but require the use of transvenous lead systems. To eliminate the need for venous access, we designed and tested an entirely subcutaneous ICD system.METHODSFirst, we conducted two shortterm clinical trials to identify a suitable device configuration and assess energy requirements. We evaluated four subcutaneous ICD configurations in 78 patients who were candidates for ICD implantation and subsequently tested the best configuration in 49 additional patients to determine the subcutaneous defibrillation thresh old in comparison with that of the standard transvenous ICD. Then we evaluated the long-term use of subcutaneous ICDs in a pilot study, involving 6 patients, which was followed by a trial involving 55 patients.RESULTSThe best device configuration consisted of a parasternal electrode and a left lateral thoracic pulse generator. This configuration was as effective as a transvenous ICD for terminating induced ventricular fibrillation, albeit with a significantly higher mean (+/- SD) energy requirement (36.6 +/- 19.8 J vs. 11.1 +/- 8.5 J). Among patients who received a permanent subcutaneous ICD, ventricular fibrillation was successfully detected in 100% of 137 induced episodes. Induced ventricular fibrillation was converted twice in 58 of 59 patients (98%) with the delivery of 65-J shocks in two consecutive tests. Clinically significant adverse events included two pocket infections and four lead revisions. After a mean of 10 +/- 1 months, the device had successfully detected and treated all 12 episodes of spontaneous, sustained ventricular tachyarrhythmia.CONCLUSIONSIn small, nonrandomized studies, an entirely subcutaneous ICD consistently detected and converted ventricular fibrillation induced during electrophysiological testing. The device also successfully detected and treated all 12 episodes of spontaneous, sustained ventricular tachyarrhythmia. (ClinicalTrials.gov numbers, NCT00399217 and NCT00853645.)

A 68-year-old woman with permanent atrial fibrillation and a VVI pacemaker underwent catheter ablation of the atrioventricular junction. Before ablation, pacemaker interrogation confirmed correct functioning and it was programmed to VVI backup-pacing at 35 bpm. While positioning the ablation

Aim : The purpose of the study was to assess the incidence and survival rate of patients with complete atrio-ventricular block in the cardiac centre of St Elizabeth Catholic General Hospital, Kumbo, Cameroon. Methods : Between 2009 and 2011, 26 patients with complete atrio-ventricular block were diagnosed at our institution. Complete atrio-ventricular block was defined as complete heart block, diagnosed by echocardiographic or electrocardiographic documentation of the dissociation between electrical activity of the atria and ventricles. Hospital charts, electrocardiograms (ECG), echocardiography and chest radiography were reviewed. Results : The triad of symptoms that pointed to the diagnosis of complete atrio-ventricular block was mainly fatigue, shortness of breath on mild physical exertion, and dizziness. The median age at diagnosis was 65 ± 15 years. The escape rhythm showed a narrow QRS complex in 35.2% of patients, whereas wide QRS complexes were seen in 64.8%. In only 15 patients were pacemakers implanted: dual-chamber in 10 and single-chamber in five cases, depending on the availability of the pacemakers. During the observational period, five non-implanted patients died, giving a mortality rate of 45%. We recorded no deaths in patients with pacemakers. Conclusion : In developing countries, natural selection is observed in patients with complete atrio-ventricular block. Lack of infrastructure and early detection, and financial limitations are the main problems faced in the follow up of these patients. Re-organisation of the public health system, new programmes for the prevention of cardiovascular diseases, and government subsidisation are needed in our milieu.

An 18-year-old woman with Down syndrome and ventricular preexcitation was referred to our center for electrophysiological evaluation. She had no structural heart disease, and her 12-lead ECG showed minimal preexcitation. After obtaining an informed consent, an electrophysiology study was performed under conscious sedation. Via bilateral femoral veins, multipolar diagnostic catheters were introduced and positioned at the His bundle region and coronary sinus. A roving quadripolar catheter was positioned alternatively in the right ventricle, the right atrium appendage, and successively was used for mapping. At the beginning of the procedure, nonpreexcited junctional beats were recorded, a phenomenon compatible with a typical atrioventricular accessory pathway (AP). However, a comprehensive electrophysiology study confirmed the presence of an innocent fasciculoventricular pathway (FVP), showing minimal and fixed preexcitation (ie, the His–ventricular interval) during multisite atrial pacing and at different pacing rates. The effective refractory period …

AIM To describe the long-term follow-up of patients with complex congenital heart disease who underwent subcutaneous implantable cardiac defibrillator (S-ICD), focusing on local complications, appropriate and inappropriate shocks. METHODS Patients with complex congenital heart disease underwent S-ICD implant in two centers with the conventional technique. Data at follow-up were retrieved from clinical notes and institutional database. RESULTS Eight patients were implanted in two centres between 2010 and 2016. Median age at implant was 37.5 years (range 13-57). All patients who were deemed suitable for S-ICD implant passed the pre-procedural screening. Three patients were previously implanted with a anti-bradycardia device, one of whom with CRT. In one patient the device was explanted due to local infection. During the total median follow-up of 874 d, one patient had an appropriate and one inappropriate shock triggered by fast atrial tachycardia. None of the patients had inappropriate shocks secondary to T wave oversensing or electrical interference with anti- bradycardia devices. CONCLUSION S-ICD appears to be effective and safe in patients with complex congenital heart disease.

Regular narrow QRS tachycardia, particularly if well‐tolerated, is usually considered a “benign” arrhythmia of a supraventricular origin. This case concerns an 82‐year‐old male with ischemic heart disease who presented with recurrent episodes of a narrow QRS tachycardia that was initially diagnosed and treated as atrial tachyarrhythmia. However, careful physical examination and ECG analysis established the correct diagnosis, and the patient was managed appropriately. Remarkably, the observation of irregular cannon A waves, and Lewis lead recording, confirmed atrioventricular dissociation during tachycardia and indicated its underlying mechanism.

Clear advantages of nanopatterned Pd/Co films over continuous Pd/Co films are demonstrated as candidates for future hydrogen gas sensing devices based upon hydrogen-absorption-modified ferromagnetic resonance. Nanopatterning results in a higher sensitivity to hydrogen gas and a much faster hydrogen desorption rate. It also avoids the need for an external biasing magnetic field which may be important for practical sensor implementation. A wide range of hydrogen gas concentrations has been detected with the nanopatterned material: from 0.1% to 50%, across the threshold of hydrogen flammability in air (4%).

There are no parameters predicting the individual probability of "full response" to cardiac resynchronization therapy (CRT). The aim of this work was to find prognostic factors of full clinical and echocardiographic responses (i.e., ≥50\% left ventricular ejection fraction [LVEF] and New York Heart Association class I) after 1 year of CRT. This was a prospective follow-up study that involved 2 hospitals. Patients (n = 75) with advanced heart failure (64 ± 9 years of age, 87\% men, LVEF 24 ± 7\%) who received CRT were followed for 17 ± 9 months. Univariate and multivariate regression analyses were used to identify predictors of full CRT response. A nomogram predicting the individual probability of full CRT response during follow-up was calculated. There were 13 patients with restoration of normal LVEF versus 62 without (mean LVEF 56\% ± 5\% vs 31\% ± 8\%, respectively, p 75\% probability of restoration of normal LVEF. In conclusion, our nomogram using a combination of cause, baseline QRS width, and degree of QRS shortening in response to CRT allows assessment of individual probability of full response. This observation awaits further confirmation from larger series.

Background— QRS-ST changes in the inferior and lateral ECG leads are frequently observed in athletes. Recent studies have suggested a potential arrhythmogenic significance of these findings in the general population. The aim of our study was to investigate whether QRS-ST changes are markers of cardiac arrest (CA) of unexplained cause or sudden death in athletes. Methods and Results— In 21 athletes (mean age, 27 years; 5 women) with cardiac arrest or sudden death, the ECG recorded before or immediately after the clinical event was compared with the ECG of 365 healthy athletes eligible for competitive sport activity. We measured the height of the J wave and ST elevation and searched for the presence of QRS slurring in the terminal portion of QRS. QRS slurring in any lead was present in 28.6% of cases and in 7.6% of control athletes ( P =0.006). A J wave and/or QRS slurring without ST elevation in the inferior (II, III, and aVF) and lateral leads (V 4 to V 6 ) were more frequently recorded in cases than in control athletes (28.6% versus 7.9%, P =0.007). Among those with cardiac arrest, arrhythmia recurrences did not differ between the subgroups with and without J wave or QRS slurring during a median 36-month follow-up of sport discontinuation. Conclusions— J wave and/or QRS slurring was found more frequently among athletes with cardiac arrest/sudden death than in control athletes. Nevertheless, the presence of this ECG pattern appears not to confer a higher risk for recurrent malignant ventricular arrhythmias.

Introduction: Atrial fibrillation (AF) may occasionally affect athletes by impairing their ability to compete, and leading to noneligibility at prequalification screening. The impact of catheter ablation (CA) in restoring full competitive activity of athletes affected by AF is not known. The aim of our study was to investigate the effectiveness of CA of idiopathic AF in athletes with palpitations impairing physical performance and compromising eligibility for competitive activities. Methods and Results: Twenty consecutive competitive athletes (all males; 44.4 ± 13.0 years) with disabling palpitations on the basis of idiopathic drug-refractory AF underwent 46 procedures (2.3 ± 0.4 per patient) according to a prospectively designed multiprocedural CA approach that consolidates pulmonary veins (PV) isolation through subsequent steps. Preablation, effort-induced AF could be documented in 13 patients (65%) during stress ECG and significantly reduced maximal effort capacity (176 ± 21 W), as compared with patients with no AF during effort (207 ± 43 W, P < 0.05). At the end of CA protocol, which also included ablation of atrial flutter (AFL) in 7 patients, 18 (90.0%) patients were free of AF and two (10.0%) reported short-lasting (minutes) episodes of palpitations during 36.1 ± 12.7 months follow-up. Compared with preablation, postablation maximal exercise capacity significantly improved (from 183 ± 32 to 218 ± 20 W, P < 0.02). All baseline quality of life (QoL) parameters pertinent to physical activity significantly improved (P < 0.05) at the end of CA protocol. All athletes obtained reeligibility and could effectively reinitiate sport activity. Conclusions: AF, alone or in combination with AFL, may significantly impair maximal effort capacity thereby limiting competitive performance. Multiple PV isolation proved very effective in these patients to restore full competitive activity and allow reeligibility.

A 24-year-old female underwent an electrophysiological study because of recurrent episodes of drug-refractory, paroxysmal supraventricular tachycardia. During adrenergic stress, a narrow QRS tachycardia with eccentric atrial activation was reproducibly inducible. The response to premature ventricular extrastimulation during tachycardia suggested the presence of a slowly conducting accessory pathway. However, a comprehensive appraisal of the electrophysiological study delineated the tachycardia substrate as an atypical atrioventricular nodal reentrant tachycardia in the presence of a bystander nodofascicular pathway. Careful analysing of the basal pacing manoeuvers during sinus rhythm (para-Hisian and differential ventricular pacing) was crucial to establish the correct diagnosis and to avoid unnecessary left-side access to ablate this tachycardia.

Although conventional implantable cardioverter-defibrillators (ICDs) have proved effective in the prevention of sudden cardiac death (SCD), they still appear to be limited by non-trivial acute and long-term complications. The recent advent of an entirely subcutaneous ICD (S-ICD) represents a further step in the evolution of defibrillation technology towards a less-invasive approach. This review highlights some historical and current issues concerning the S-ICD that may offer a viable therapeutic option in selected patients at high risk of SCD and in whom pacing is not required. After the CE Mark and US Food and Drug Administration (FDA) approvals, the S-ICD is being implanted worldwide with growing clinical data regarding its safety and efficacy (the EFFORTLESS Registry). The recently developed new generation of S-ICD (EMBLEM, Boston Scientific) demonstrates favourable features including a smaller device, longer longevity and remote-monitoring compatibility. Further innovations in the S-ICD system and potential integration with leadless pacing may play an important role in defibrillation therapy and prevention of SCD in the near future.