Optical mapping and optogenetics in cardiac electrophysiology research and therapy: a state-of-the-art review.

State-of-the-art innovations in optical cardiac electrophysiology are significantly enhancing cardiac research. A potential leap into patient care is now on the horizon. Optical mapping, using fluorescent probes and high-speed cameras, offers detailed insights into cardiac activity and arrhythmias by analysing electrical signals, calcium dynamics, and metabolism. Optogenetics utilizes light-sensitive ion channels and pumps to realize contactless, cell-selective cardiac actuation for modelling arrhythmia, restoring sinus rhythm, and probing complex cell-cell interactions. The merging of optogenetics and optical mapping techniques for 'all-optical' electrophysiology marks a significant step forward. This combination allows for the contactless actuation and sensing of cardiac electrophysiology, offering unprecedented spatial-temporal resolution and control. Recent studies have performed all-optical imaging ex vivo and achieved reliable optogenetic pacing in vivo, narrowing the gap for clinical use. Progress in optical electrophysiology continues at pace. Advances in motion tracking methods are removing the necessity of motion uncoupling, a key limitation of optical mapping. Innovations in optoelectronics, including miniaturized, biocompatible illumination and circuitry, are enabling the creation of implantable cardiac pacemakers and defibrillators with optoelectrical closed-loop systems. Computational modelling and machine learning are emerging as pivotal tools in enhancing optical techniques, offering new avenues for analysing complex data and optimizing therapeutic strategies. However, key challenges remain including opsin delivery, real-time data processing, longevity, and chronic effects of optoelectronic devices. This review provides a comprehensive overview of recent advances in optical mapping and optogenetics and outlines the promising future of optics in reshaping cardiac electrophysiology and therapeutic strategies.

Electrocardiographic changes and changes in cardiac lactate and troponin I levels associated with search and rescue physical activity in military dogs / Alterações eletrocardiográficas e nos níveis de lactato e troponina I cardíaca associadas à atividade física de busca e salvamento em cães militares

Rescue and recovery dogs intercalate the activity intensity developed, which also triggers significant metabolic changes in cardiac physiology. Thus, we evaluated the changes that search simulation causes in glucose, lactate, and cardiac troponin I level (cTnI) and the electrocardiographic and heart rate during the activity and recovery phase to predict the physiological adaptation to the exercise. Five healthy adult dogs from the Rescue and Recovery Service of Military Firefighters Corps were submitted to 60 minutes search operation simulation in the woods. They covered a forest area of approximately 50,000 m2. The dogs were loose and accompanied by their driver, and they could perform any physical activity. Were evaluated serum biochemical analysis of glucose, lactate, cardiac troponin I, electrocardiographic, and heart rate (rest, exercise phase, and recovery time). No changes in glucose levels, heart rate, and cardiac rhythm were detected. In comparison to baseline values, there is an increase: in lactate at the end of the exercise phase [EXER] (60'EXER), and in the recovery phase [RCT] at 30'RCT and 60'RCT, and cTnI at 60'RCT, 120'RCT, and 4hRCT. P wave duration was significantly higher at 60'EXER, 15'RCT, and 30'RCT, with no alterations in wave amplitude. QRS interval duration significantly increased at 30'RCT, and the ST segment presented a significant difference at 60'EXER, 15'RCT, and 60'RCT compared to the rest moment. The moderate alterations in lactate and cTnI and few alterations in the electrocardiographic and heart rate maintenance suggest the adaptation of rescue and recovery dogs to the type, intensity, and duration of search operation simulation performed.(AU)

Cães de busca e resgate intercalam a intensidade da atividade desenvolvida que desencadeia alterações metabólicas significativas, bem como na fisiologia cardíaca. Assim, foram avaliadas as alterações que a simulação de busca produz nos níveis de glicose, lactato, troponina I cardíaca (cTnI), bem como na frequência cardíaca e atividade eletrocardiográfica durante a fase de atividade e recuperação, a fim de predizer a adaptação fisiológica ao exercício. Cinco cães adultos saudáveis do Serviço de Resgate e Salvamento do Corpo de Bombeiros Militares foram submetidos à simulação de operação de busca de 60 minutos na mata e cobriram uma área florestal de aproximadamente 50.000 m2. Os cães estavam soltos, acompanhados pelo condutor e estavam livres para realizar qualquer tipo de atividade física. Foram avaliados os níveis séricos de glicose, lactato e troponina I cardíaca, atividade eletrocardiográfica e frequência cardíaca em repouso, na fase de exercício e no tempo de recuperação. Não foram detectadas alterações nos níveis de glicose, frequência cardíaca e ritmo cardíaco. Em comparação com os valores basais houve aumento de lactato ao final da fase de exercício [EXER] (60'EXER) e na fase de recuperação [RCT] aos 30'RCT e 60'RCT; e cTnI aos 60'RCT, 120'RCT e 4hRCT. Duração da onda P foi significativamente maior em 60'EXER, 15'RCT e 30'RCT, sem alterações na amplitude da onda. Duração do intervalo QRS teve aumento significativo em 30'RCT e o segmento ST apresentou diferença significativa em 60'EXER, 15'RCT e 60'RCT quando comparado ao basal. As alterações moderadas nos níveis de lactato e cTnI, bem como a pouca alteração na atividade eletrocardiográfica e manutenção da frequência cardíaca sugerem boa adaptação dos cães de busca e resgate ao tipo, intensidade e duração da operação de busca simulada realizada.(AU)

Interatrial septal tachycardias following atrial fibrillation ablation or cardiac surgery: Electrophysiological features and ablation outcomes.

BACKGROUND: Interatrial septal tachycardias (IAS-ATs) following atrial fibrillation (AF) ablation or cardiac surgery are rare, and their management is challenging. OBJECTIVE: The purpose of this study was to investigate the electrophysiological features and outcomes associated with catheter ablation of IAS-AT. METHODS: We screened 338 patients undergoing catheter ablation of ATs following AF ablation or cardiac surgery. Diagnosis of IAS-AT was based on activation mapping and analysis of response to atrial overdrive pacing. RESULTS: Twenty-nine patients (9%) had IAS-AT (cycle length [CL] 311 ± 104 ms); 16 (55%) had prior AF ablation procedures (median 3; range 1-5), 3 (10%) had prior surgical maze, and 12 (41%) had prior cardiac surgery (including atrial septal defect surgical repair in 5 and left atrial myxoma resection in 1). IAS substrate abnormalities were documented in all patients. Activation mapping always demonstrated a diffuse early IAS breakout with centrifugal biatrial activation, and atrial overdrive pacing showed a good postpacing interval (equal or within 25 ms of the AT CL) only at 1 or 2 anatomically opposite IAS sites in all cases. Ablation was acutely successful in 27 patients (93%) (from only the right IAS in 2, only the left IAS in 9, both IAS sides with sequential ablation in 13, and both IAS sides with bipolar ablation in 3). After median follow-up of 15 (6-52) months, 17 patients (59%) remained free from recurrent arrhythmias. CONCLUSION: IAS-ATs are rare and typically occur in patients with evidence of IAS substrate abnormalities and prior cardiac surgery. Catheter ablation can be challenging and may require sequential unipolar ablation or bipolar ablation.

Organization and procedures in contemporary catheter ablation centres: data from the 2018 Italian Catheter Ablation Registry.

AIMS: This report describes the findings of the 2018 Italian Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC). METHODS: The Italian Catheter Ablation Registry systematically collects data on the ablation procedures performed in Italy. Data collection was retrospective. A standardized questionnaire was completed by participating centres. RESULTS: We collected data on 15 714 catheter ablation procedures performed in Italy during 2018 in 94 electrophysiology centres. In most centres (75/94, 80%), a single electrophysiology laboratory was available, and a hybrid electrophysiology laboratory was available in 15% (14/94) of centres. In most (93%) centres, at least two electrophysiologists were involved in the catheter ablation procedures. In only 13 out of 94 (14%) electrophysiology laboratories, an anaesthesiologist assists every electrophysiology procedure; in most cases (74/94, 79%), an on-demand anaesthesiology service was available. On-site cardiothoracic surgery was reported in 43 out of 94 (46%) centres.Nonfluoroscopic navigation systems were available in most centres (88/94, 93%). Intracardiac echocardiography was used in 59 out of 94 (63%) electrophysiology laboratories. Atrial fibrillation (31%) was the most frequently treated ablation target, followed by atrioventricular nodal re-entrant tachycardia (20%) and cavo-tricuspid isthmus (15%). In 61.7% of all procedures, a 3D mapping system was used. In about one-third of procedures, a near-zero approach was performed. CONCLUSION: In most Italian electrophysiology centres, a single electrophysiology laboratory was available and at least two electrophysiologists were involved in the ablation procedures. An increasing number of procedures were performed by means of a nonfluoroscopic mapping system with a near-zero approach.

Frequent inappropriate implantable cardioverter defibrillator therapy was determined to be dual atrioventricular nodal non-reentrant tachycardia: A case report.

RATIONALE: Dual atrioventricular node non-reentrant tachycardia (DAVNNRT) is a rare arrhythmia. We present a case of inappropriate implantable cardioverter defibrillator (ICD) therapy caused by DAVNNRT. DAVNNRT is easily misdiagnosed as atrial fibrillation and is often identified as ventricular tachycardia (VT) by the supraventricular tachycardia-ventricular tachycardia (SVT-VT) discriminator of the ICD. PATIENT CONCERNS: A 73-year-old man with ischemic heart disease (IHD) presented with palpitations accompanied by dyspnea and syncope. Frequent multifocal premature ventricular beats and non-sustained ventricular tachycardia were observed on ambulatory electrocardiography. The left ventricular ejection fraction decreased to 32%. DIAGNOSIS: He was diagnosed with IHD, heart failure with reduced ejection fraction (HFrEF), and VT. INTERVENTIONS: : Initially, the patient received a single-chamber ICD implantation for secondary prevention of sudden death. He then suffered from inappropriate anti-tachycardia pacing (ATP)/shock therapy many times after the procedure. DAVNNRT was confirmed in an electrophysiology study (EPS), and radiofrequency ablation of the slow pathway successfully terminated this tachycardia. OUTCOMES: No episode of inappropriate ICD therapy or tachycardia occurred during the follow-up. LESSONS: In conclusion, it is essential to have a full understanding of DAVNNRT and eliminate slow pathways for patients with DAVNNRT and be prepared to implant an ICD.

Artificial neural network model for predicting changes in ion channel conductance based on cardiac action potential shapes generated via simulation.

Many studies have revealed changes in specific protein channels due to physiological causes such as mutation and their effects on action potential duration changes. However, no studies have been conducted to predict the type of protein channel abnormalities that occur through an action potential (AP) shape. Therefore, in this study, we aim to predict the ion channel conductance that is altered from various AP shapes using a machine learning algorithm. We perform electrophysiological simulations using a single-cell model to obtain AP shapes based on variations in the ion channel conductance. In the AP simulation, we increase and decrease the conductance of each ion channel at a constant rate, resulting in 1,980 AP shapes and one standard AP shape without any changes in the ion channel conductance. Subsequently, we calculate the AP difference shapes between them and use them as the input of the machine learning model to predict the changed ion channel conductance. In this study, we demonstrate that the changed ion channel conductance can be predicted with high prediction accuracy, as reflected by an F1 score of 0.985, using only AP shapes and simple machine learning.

Electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias originating from the vicinity of tricuspid annulus.

Electrocardiographic and electrophysiological characteristics of VAs originating from the vicinity of the TA are not fully understood. Hence, 104 patients (mean age 52.6 ± 17.9 years; 62 male) with VAs originating from the vicinity of the TA were enrolled. After electrophysiological evaluation and ablation, data were compared among those patients. The ECGs and the correction of the ECGs based on the long axis of the heart calculated from the chest X-Ray were also analyzed. VAs originating from the vicinity of TA had distinctive ECG characteristics that were useful for identifying the precise origin. Our localization algorithm adjusted by the angle between the cardiac long axis and the horizon was found to be accurate in predicting the exact ablation site in 92.3% (n = 96) cases. Logistic regression analysis showed fractionated electrograms, the magnitudes of the local atrial electrograms and a/V ratio were critical factors for successful ablation. Among the 104 patients with VAs, complete elimination could be achieved by RFCA in 96 patients (success rate 92.3%) during a follow-up period of 35.2 ± 19.6 months. This study suggests that the ablation site could be localized by ECG analysis adjusted by the angle between the cardiac long axis and the horizon. Fractionated electrograms, the magnitudes of the local atrial electrograms and a/V ratio were demonstrated to be critical factors for successful ablation.

Shining light on cardiac electrophysiology: From detection to intervention, from basic research to translational applications.

Cardiac arrhythmias are an important group of cardiovascular diseases, which can occur alone or in association with other cardiovascular diseases. The development of cardiac arrhythmias cannot be separated from changes in cardiac electrophysiology, and the investigation and clarification of cardiac electrophysiological changes are beneficial for the treatment of cardiac arrhythmias. However, electrical energy-based pacemakers and defibrillators, which are widely used to treat arrhythmias, still have certain disadvantages. Thereby, optics promises to be used for optical manipulation and its use in biomedicine is increasing. Since visible light is readily absorbed and scattered in living tissues and tissue penetration is shallow, optical modulation for cells and tissues requires conversion media that convert light energy into bioelectrical activity. In this regard, fluorescent dyes, light-sensitive ion channels, and optical nanomaterials can assume this role, the corresponding optical mapping technology, optogenetics technology, and optical systems based on luminescent nanomaterials have been introduced into the research in cardiovascular field and are expected to be new tools for the study and treatment of cardiac arrhythmias. In addition, infrared and near-infrared light has strong tissue penetration, which is one of the excellent options of external trigger for achieving optical modulation, and is also widely used in the study of optical modulation of biological activities. Here, the advantages of optical applications are summarized, the research progresses and emerging applications of optical-based technologies as detection and intervention tools for cardiac electrophysiological are highlighted. Moreover, the prospects for future applications of optics in clinical diagnosis and treatment are discussed.

Optogenetic current in myofibroblasts acutely alters electrophysiology and conduction of co-cultured cardiomyocytes.

Interactions between cardiac myofibroblasts and myocytes may slow conduction and generate spontaneous beating in fibrosis, increasing the chance of life-threatening arrhythmia. While co-culture studies have shown that myofibroblasts can affect cardiomyocyte electrophysiology in vitro, the extent of myofibroblast-myocyte electrical conductance in a syncytium is unknown. In this neonatal rat study, cardiac myofibroblasts were transduced with Channelrhodopsin-2, which allowed acute and selective increase of myofibroblast current, and plated on top of cardiomyocytes. Optical mapping revealed significantly decreased conduction velocity (- 27 ± 6%, p < 10-3), upstroke rate (- 13 ± 4%, p = 0.002), and action potential duration (- 14 ± 7%, p = 0.004) in co-cultures when 0.017 mW/mm2 light was applied, as well as focal spontaneous beating in 6/7 samples and a decreased cycle length (- 36 ± 18%, p = 0.002) at 0.057 mW/mm2 light. In silico modeling of the experiments reproduced the experimental findings and suggested the light levels used in experiments produced excess current similar in magnitude to endogenous myofibroblast current. Fitting the model to experimental data predicted a tissue-level electrical conductance across the 3-D interface between myofibroblasts and cardiomyocytes of ~ 5 nS/cardiomyocyte, and showed how increased myofibroblast-myocyte conductance, increased myofibroblast/myocyte capacitance ratio, and increased myofibroblast current, which occur in fibrosis, can work in tandem to produce pro-arrhythmic increases in conduction and spontaneous beating.

Predictors of AVNRT Recurrence After Slow Pathway Modification.

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common regular supraventricular tachycardia (SVT). Slow pathway modification (SPM) is the accepted first line treatment with reported success rates around 95%. Information regarding possible predictors of AVNRT recurrence is scarce.Out of 4170 consecutive patients with SPM in our department from 1993-2018, we identified 78 patients (1.9%) receiving > 1 SPM (69% female, median age 50 years) with a recurrence of AVNRT after a successful SPM. We matched these patients for age, gender and number of radiofrequency applications during first SPM with 78 patients who received one successful SPM in our center without AVNRT recurrence. Both groups were analyzed for possible predictors of a recurrence of AVNRT during long-term follow-up. The recurrence group contained a significantly lower proportion of patients with an occurrence of junctional beats during SPM (69% versus 89%, P = 0.006). Moreover, significantly more cases of previously diagnosed atrial fibrillation/tachycardia (AF/AT; 21% versus 5%, P = 0.007) and inducible AF/AT during electrophysiology study (23% versus 6%, P = 0.006) were present in the recurrence group. While more than half of patients had a recurrence within the first year, in 20% symptoms reappeared ≥ 4 years after ablation.In a small percentage of patients, AVNRT recurs after an initially successful ablation. Interestingly, these patients had significantly fewer junctional beats during ablation and a higher rate of other (inducible) arrhythmias. AVNRT recurrence spanned a considerable timeframe and should remain a differential diagnosis, even years after ablation.

Electrophysiological Insights into Three Modalities of Left Bundle Branch Area Pacing in Patients Indicated for Pacing Therapy.

Left bundle branch pacing (LBBP) has been adopted as a new pacing therapy whether in routine pacing or patients with heart failure, but the criteria for a completely captured LBBP are too complicated and have a low success rate in routine clinical practice.Consecutive patients with pacing therapy indications were enrolled. Left bundle branch area pacing (LBBAP) was conducted, and the presence of LBB potential, paced QRS duration, stimulus to left ventricular activation time (Stim-LVAT), and LBB potential to left ventricular activation time (LBB po-LVAT) were determined and utilized to characterize LBBAP modalities. Pacing parameters and safety were assessed at 6-month follow-up. LBBAP succeeded in 95.6% of patients (103/106) who completed the 6-month follow-up. Complete LBBP was achieved in 21 (20%) patients, characterized with a short Stim-LVAT equal to LBB po-LVAT. Incomplete LBBP was achieved in 58 (56%) patients with a short Stim-LVAT equal to LBB po-LVAT at a high pacing output and a relatively longer Stim-LVAT at a low pacing output. Deep septal pacing (DSP) characterized with no LBB potential and a longer Stim-LVAT (83.3 ± 7.7 ms) than that in LBBP (71.37 ± 7.1 ms, P < 0.01 versus DSP) was observed in 24 (23%) patients. Complete LBBP had a longer total procedure time and longer fluoroscopic time than the other two groups.This study describes the similarities and differences in electrophysiological characteristics and the possible mechanisms of the different types of LBBAP, classified into 3 modalities in routine clinical practice, each with narrow paced QRS duration and stable parameters, indicating LBBAP can be a near-physiological pacing modality.

The Wenckebach Phenomenon.

Medicine has many great pioneers, and in 1899, one such pioneer - Karel Frederik Wenckebach made a discovery which, even to this day, remains one of the fundamental concepts within electrophysiology. Since the Wenckebach Phenomenon was first described, the field of electrophysiology has developed at a rapid pace, allowing us to observe this behaviour, and its complexities, in many new ways. In a similar way, this chapter will illustrate Wenckebach behaviour across a spectrum of modalities from the 12 lead ECG, through to the intra-cardiac recordings from both electrophysiological studies and implantable cardiac devices. In doing so, we continue to shed light on the phenomenon first identified through Wenckebach's meticulous attention to detail some 120 years ago.

Cardiac optogenetics: a decade of enlightenment.

The electromechanical function of the heart involves complex, coordinated activity over time and space. Life-threatening cardiac arrhythmias arise from asynchrony in these space-time events; therefore, therapies for prevention and treatment require fundamental understanding and the ability to visualize, perturb and control cardiac activity. Optogenetics combines optical and molecular biology (genetic) approaches for light-enabled sensing and actuation of electrical activity with unprecedented spatiotemporal resolution and parallelism. The year 2020 marks a decade of developments in cardiac optogenetics since this technology was adopted from neuroscience and applied to the heart. In this Review, we appraise a decade of advances that define near-term (immediate) translation based on all-optical electrophysiology, including high-throughput screening, cardiotoxicity testing and personalized medicine assays, and long-term (aspirational) prospects for clinical translation of cardiac optogenetics, including new optical therapies for rhythm control. The main translational opportunities and challenges for optogenetics to be fully embraced in cardiology are also discussed.

Case Report: Myocardial Bypass in Left Descending Artery - A Rare Congenital Anomaly

Abstract Myocardial bypass (MB) is known to have scientific relevance and is present in several studies with great statistical significance regarding its clinical manifestations and complications. There are still questions about MB in its relationship with heart disease and repercussion in life-threatening conditions. We present a case report of a MB in the left anterior descending coronary artery, whose objective is to identify this rare congenital anomaly and to highlight the patient's clinical outcome in order to elicit greater contributions about the presence of this variant in the emergency room, its diagnosis by angiography and therapeutic management.

Decreases in cardiac catheter laboratory workload during the COVID-19 level 4 lockdown in New Zealand.

An increase in coronavirus disease (COVID-19) infections prompted Level 4 lockdown throughout New Zealand from 25 March 2020. We have investigated trends in coronary and electrophysiology (EP) procedures before and during this lockdown. The number of acute procedures for ST elevation myocardial infarction remained stable. In contrast, the number of in-patient angiograms and percutaneous intervention procedures fell by 53% compared with the previous 4 weeks in 2020 and by 56% compared with the corresponding period in 2019. Further study is required to determine the reasons for these trends.

Minimalistic strategy for coronary sinus lead implant: A single tool capable of electrophysiological mapping, pressure measurement, and angiography.

BACKGROUND: Left ventricular (LV) lead implantation for cardiac resynchronization therapy (CRT) may be confounded by contrast load during attempted cannulation and lead dislodgement during guiding catheter splitting. An LV lead implant system with a steerable single catheter that completely avoids the use of guiding catheters when needed, acquires atrioventricular electrograms, measures intracardiac pressures, permits CS angiography, and has the ability to direct a coronary angioplasty wire that will lead the final delivery of LV lead into a CS tributary, may help limit contrast use and avoid lead dislodgement at CS guide sheath removal. METHODS AND RESULTS: In this article as a proof of concept, we describe the use of this minimalist technique as a first line approach in six patients who had standard indications for CRT. The LV lead was successfully implanted in a target vein in all patients without acute complications. Contrast was not used in half the group and the LV lead was successfully implanted without guiding catheter in four patients. The implantation technique evolved through the series and in the final patient, no guiding sheath or contrast was used. Postimplant lead positions on chest X-ray and lead parameters were stable in all patients at follow-up. CONCLUSION: In proof of concept paper, we describe a technique of LV lead implantation potentially without the use of contrast and standard CS guiding catheters. Once familiar, this approach may provide a less complicated strategy.

Biomimetic Model of Contractile Cardiac Tissue with Endothelial Networks Stabilized by Adipose-Derived Stromal/Stem Cells.

Cardiac tissue engineering strategies have the potential to regenerate functional myocardium following myocardial infarction. In this study, we utilized novel electrospun fibrin microfiber sheets of different stiffnesses (50.0 ± 11.2 kPa and 90.0 ± 16.4 kPa) to engineer biomimetic models of vascularized cardiac tissues. We characterized tissue assembly, electrophysiology, and contractility of neonatal rat ventricular cardiomyocytes (NRVCMs) cultured on these sheets. NRVCMs cultured on the softer substrates displayed higher conduction velocities (CVs) and improved electrophysiological properties. Human umbilical vein endothelial cells (HUVECs) formed dense networks on the sheets when co-cultured with human adipose-derived stem/stromal cells (hASCs). To achieve vascularized cardiac tissues, we tested various tri-culture protocols of NRVCM:hASC:HUVEC and found that a ratio of 1,500,000:37,500:150,000 cells/cm2 enabled the formation of robust endothelial networks while retaining statistically identical electrophysiological characteristics to NRVCM-only cultures. Tri-cultures at this ratio on 90 kPa substrates exhibited average CVs of 14 ± 0.6 cm/s, Action Potential Duration (APD)80 and APD30 of 152 ± 11 ms and 71 ± 6 ms, respectively, and maximum capture rate (MCR) of 3.9 ± 0.7 Hz. These data indicate the significant potential of generating densely packed endothelial networks together with electrically integrated cardiac cells in vitro as a physiologic 3D cardiac model.

Coronovirus Disease-2019 (COVID-19) Pandemic and Cardiac Electrophysiology: Guidance Protocol From a UK Tertiary Cardiac Center.

Since December 2019, the coronovirus disease-2019 (COVID-19) pandemic has resulted in more than 2,160,000 positive cases and more than 145,000 deaths until April 18, 2020. The pressure to the health services worldwide has been unprecedented. The redeployment of staff and resources to treat more efficiently COVID-19 cases along with the need to reduce disease transmission has affected the field of electrophysiology among many others. Amendments to clinical pathways are obligatory in this perspective to continue to provide the necessary health services to the people who need them, although at the same time, infection control and prevention are not compromised by inadvertent disease transmission or unnecessary use of resources. We aim to provide a guide of the logistic aspects of electrophysiology procedures derived from our tertiary cardiac center during the current COVID-19 pandemic.