Ablation of Paroxysmal Atrial Fibrillation: between Present and Future.

Pulmonary vein isolation (PVI) is the established cornerstone for atrial fibrillation (AF) ablation, indeed current guidelines recognize PVI as the gold standard for first-time AF ablation, regardless of if it is paroxysmal or persistent. Since 1998 when Haïssaguerre pioneered AF ablation demonstrating a burden reduction after segmental pulmonary vein (PV) ablation, our approach to PVI was superior in terms of methodology and technology. This review aims to describe how paroxysmal atrial fibrillation ablation has evolved over the last twenty years. We will focus on available techniques, a mechanistic understanding of paroxysmal AF genesis and the possibility of a tailored approach for the treatment of AF, before concluding with a future perspective.

Intermittent ventricular pre-excitation in symptomatic adults: Always a marker of low risk?

BACKGROUND: Intermittent ventricular pre-excitation was considered a low-risk marker for sudden death. However, to date, some studies do not exclude the existence of accessory pathways (APs) with high-risk intermittent antegrade conductive properties. According to current European Guidelines, high-risk features of APs are antegrade pathway conduction ≤250 ms in baseline or during the adrenergic stimulus, inducibility of atrioventricular reciprocating tachycardias (AVRT), inducibility of pre-excited atrial fibrillation (AF), and presence of multiple APs. For all of these transcatheter ablation is recommended. The aim of our study was to evaluate the existence of differences in risk characteristics between patients with intermittent pre-excitation (IPX) and those with persistent pre-excitation (PPX), from a sample of adults with ventricular pre-excitation and symptoms like palpitations. METHODS: 293 adults [IPX: 51 (17.4%); PPX: 242 (82.6%)] underwent electrophysiological study and then catheter ablation of their APs if arrhythmia inducibility (AVRT/AF) was noted, or, conversely, if it was appreciated a fast AP antegrade conduction, in baseline or during intravenous isoproterenol infusion, or if multiple APs were detected. RESULTS: There were no statistically significant differences in demographic characteristics (age and gender), AVRT/AF inducibility, antegrade conductive properties, the prevalence of multiple APs, and APs locations between IPX and PPX patients. CONCLUSIONS: In our study, patients with IPX did not show significant differences in clinical and electrophysiological features versus PPX patients.

Contact-force monitoring increases accuracy of right ventricular voltage mapping avoiding "false scar" detection in patients with no evidence of structural heart disease.

PURPOSE: Electroanatomical mapping (EAM) could increase cardiac magnetic resonance imaging (CMR) sensitivity in detecting ventricular scar. Possible bias may be scar over-estimation due to inadequate tissue contact. Aim of the study is to evaluate contact-force monitoring influence during EAM, in patients with idiopathic right ventricular arrhythmias. METHODS: 20 pts (13 M; 43 ± 12 y) with idiopathic right ventricular outflow tract (RVOT) arrhythmias and no structural abnormalities were submitted to Smarttouch catheter Carto3 EAM. Native maps included points collected without considering contact-force. EAM scar was defined as area ≥1 cm2 including at least 3 adjacent points with signal amplitude (bipolar <0.5 mV, unipolar 3,5 mV), surrounded by low-voltage border zone. EAM were re-evaluated offline, removing points collected with contact force <5 g. Finally, contact force-corrected maps were compared to the native ones. RESULTS: An EAM was created for each patient (345 ± 85 points). After removing poor contact points, a mean of 149 ± 60 points was collected. The percentage of false scar, collected during contact force blinded mapping compared to total volume, was 6.0 ± 5.2% for bipolar scar and 7.1 ± 5.9% for unipolar scar, respectively. No EAM scar was present after poor contact points removal. Right ventricular areas analysis revealed a greater number of points with contact force < 5 g acquired in free wall, where reduced mean bipolar and unipolar voltage were recorded. CONCLUSIONS: To date this is the first work conducted on structurally normal hearts in which contact-force significantly increases EAM accuracy, avoiding "false scar" related to non-adequate contact between catheter and tissue.

Patients with left bundle branch block and left axis deviation show a specific left ventricular asynchrony pattern: Implications for left ventricular lead placement during CRT implantation.

BACKGROUND: Left bundle branch block (LBBB) and left axis deviation (LAD) patients may have poor response to resynchronization therapy (CRT). We sought to assess if LBBB and LAD patients show a specific pattern of mechanical asynchrony. METHODS: CRT candidates with non-ischemic cardiomyopathy and LBBB were categorized as having normal QRS axis (within -30° and +90°) or LAD (within -30° and -90°). Patients underwent tissue Doppler imaging (TDI) to measure time interval between onset of QRS complex and peak systolic velocity in ejection period (Q-peak) at basal segments of septal, inferior, lateral and anterior walls, as expression of local timing of mechanical activation. RESULTS: Thirty patients (mean age 70.6years; 19 males) were included. Mean left ventricular ejection fraction was 0.28±0.06. Mean QRS duration was 172.5±13.9ms. Fifteen patients showed LBBB with LAD (QRS duration 173±14; EF 0.27±0.06). The other 15 patients had LBBB with a normal QRS axis (QRS duration 172±14; EF 0.29±0.05). Among patients with LAD, Q-peak interval was significantly longer at the anterior wall in comparison to each other walls (septal 201±46ms, inferior 242±58ms, lateral 267±45ms, anterior 302±50ms; p<0.0001). Conversely, in patients without LAD Q-peak interval was longer at lateral wall, when compared to each other (septal 228±65ms, inferior 250±64ms, lateral 328±98ms, anterior 291±86ms; p<0.0001). CONCLUSIONS: Patients with heart failure, presenting LBBB and LAD, show a specific pattern of ventricular asynchrony, with latest activation at anterior wall. This finding could affect target vessel selection during CRT procedures in these patients.

Safety and feasibility of atrial fibrillation ablation using Amigo® system versus manual approach: A pilot study.

BACKGROUND: The Amigo® Remote Catheter System is a relatively new robotic system for catheter navigation. This study compared feasibility and safety using Amigo (RCM) versus manual catheter manipulation (MCM) to treat paroxysmal atrial fibrillation (PAF). Contact force (CF) and force-time integral (FTI) values obtained during pulmonary vein isolation (PVI) ablation were compared. METHODS: Forty patients were randomly selected for either RCM (20) or MCM (20). All were studied with the Thermocool® SmartTouch® force-sensing catheter (STc). Contact Force (CF), Force Time Integral (FTI) and procedure-related data, were measured/stored in the CARTO®3. RESULTS: All cases achieved complete PVI without major complications. Mean CF was significantly higher in the RCM group (13.3 ± 7.7 g in RCM vs. 12.04 ± 7.42 g in MCM p < 0.001), as was overall mean FTI (425.6 gs ± 199.6 gs with RCM and 407.5 gs ± 288.0 gs in MCM (p = 0.007) and was more likely to fall into the optimal FTI range (400-1000) using RCM (66.1% versus 49.1%, p < 0.001). FTI was significantly more likely to fall within the optimal range in each PV, as was CF within its optimal range in the right PVs, but trended higher in the left PVs. Freedom from atrial tachyarrhythmia was 90.0% for the RCM and 70.0% for the MCM group (p = 0,12) at 540 days follow-up. CONCLUSIONS: This pilot study suggests that use of the Amigo RCM system, with STc catheter, seems to be safe and effective for PVI ablation in paroxysmal AF patients. A not statistically significant favorable trend was observed for RCM in term of AF-free survival.

Impact of the third generation cryoballoon on atrial fibrillation ablation: An useful tool?

BACKGROUND: Third-generation cryoballoon (CB3) is characterized by a 40% shorter distal tip designed to increase the rate of pulmonary veins real-time signal recording in order to measure time necessary to isolate veins, the "Time to effect" (TTE). Few data are currently available on clinical follow up of CB3 treated patients. METHODS: Sixtyeight consecutive patients (mean age 57.8 ±â€¯9.6 years, 48 male) with paroxysmal or persistent atrial fibrillation (AF) were enrolled. Thirthyfour (25 paroxysmal AF) underwent to a 28 mmCB3 pulmonary veins isolation and were compared to 34 treated (21 paroxysmal AF) with 28 mmCB2. RESULTS: CB3 use was correlated to significant increase of the possibility to measure TTE in every treated veins (left superior 82,35% vs 23,53%, left inferior 70,59% vs 38,24%, right superior 58,82% vs 14,71%, right inferior 52,94% vs 17,65%). When it is measured, TTE wasn't different between two groups. Higher nadir temperature was observed in CB3 patients (-39.4 ±â€¯5.2 °C vs -43.0 ±â€¯7.2 °C, p = 0.03). CB3 procedures were shorter (91.4 ±â€¯21.7 vs 110.9 ±â€¯31.8 min, p = 0.018), with a significant reduction in cryoenergy delivery time (24.2 ±â€¯8.5 vs 20.3 ±â€¯6.7 min, p < 0.05), and a significant reduction in left atrium dwell time (59.3 ±â€¯9.8 vs 69.3 ±â€¯10.8 min, p = 0.02, p < 0.05). At one year follow up period the Kaplan-Meier curve didn't show any significant difference in AF-free survival (Log p = 0,49). CONCLUSIONS: Novel CB3 is a useful tool in order to simplify AF cryoballoon ablation when compared to second generation cryoballoon, as observed in our experience. Follow up data seem confirm a clinical CB3 efficacy at least comparable CB2.

Prognostic significance of electrophysiological study in drug-induced type-1 Brugada syndrome: a brief systematic review.

BACKGROUND: Risk stratification in drug-induced type-1 Brugada syndrome (BrS) patients is challenging. The role of electrophysiological study (EPS) is debated as the majority of drug-induced type-1 BrS patients would not be studied according to the latest recommendations. METHODS: A complete systematic literature search was performed to gauge the EPS role in this population. Three subgroups were defined: positive-EPS group, negative-EPS group, no-EPS group. RESULTS: Among 1318 drug-induced type-1 BrS patients, no significant difference in the incidence rate of arrhythmic events was observed between groups (I2 = 45%, P for subgroup difference = 0.10) during a mean follow-up of 5.1 years, also considering symptomatic status. CONCLUSION: In long-term follow-up of drug-induced type-1 BrS patients, EPS does not seem to aid prognostic stratification.

Non-Pharmacological Treatment of Heart Failure-From Physical Activity to Electrical Therapies: A Literature Review.

Heart failure (HF) represents a significant global health challenge that is still responsible for increasing morbidity and mortality despite advancements in pharmacological treatments. This review investigates the effectiveness of non-pharmacological interventions in the management of HF, examining lifestyle measures, physical activity, and the role of some electrical therapies such as catheter ablation, cardiac resynchronization therapy (CRT), and cardiac contractility modulation (CCM). Structured exercise training is a cornerstone in this field, demonstrating terrific improvements in functional status, quality of life, and mortality risk reduction, particularly in patients with HF with reduced ejection fraction (HFrEF). Catheter ablation for atrial fibrillation, premature ventricular beats, and ventricular tachycardia aids in improving left ventricular function by reducing arrhythmic burden. CRT remains a key intervention for selected HF patients, helping achieve left ventricular reverse remodeling and improving symptoms. Additionally, the emerging therapy of CCM provides a novel opportunity for patients who do not meet CRT criteria or are non-responders. Integrating non-pharmacological interventions such as digital health alongside specific medications is key for optimizing outcomes in HF management. It is imperative to tailor approaches to individual patients in this diverse patient population to maximize benefits. Further research is warranted to improve treatment strategies and enhance patient outcomes in HF management.

Management of cerebral amyloid angiopathy and atrial fibrillation: We are still far from precision medicine.

The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy (CAA) and atrial fibrillation (AF). In fact, CAA is an age-related cerebral vasculopathy that predisposes patients to intracerebral hemorrhage. Nevertheless, many AF patients require oral systemic dose-adjusted warfarin, direct oral anticoagulants (such as factor Xa inhibitors) or direct thrombin inhibitors to control often associated with cardioembolic stroke risk. The prevalence of both CAA and AF is expected to rise, due to the aging of the population. This clinical dilemma is becoming increasingly common. In patients with coexisting AF and CAA, the risks/benefits profile of anticoagulant therapy must be assessed for each patient individually due to the lack of a clear-cut consensus with regard to its risks in scientific literature. This review aims to provide an overview of the management of patients with concomitant AF and CAA and proposes the implementation of a risk-based decision-making algorithm.

Thromboembolic prevention in athletes: management of anticoagulation in sports players affected by atrial fibrillation.

Atrial fibrillation (AF) is a common cardiac arrhythmia that poses a significant risk of stroke and thromboembolic events. Anticoagulation therapy is essential for preventing stroke in patients with AF. An increasing number of people of all ages, including cardiac patients, approach physical activity as both a leisure-time exercise and a competitive sport. Therefore, patients at risk of AF are increasingly allowed to practice sports activities. Management of oral anticoagulant therapy (OAT) in these patients is extremely challenging because of the need to balance the risks and benefits of medications, considering both hemorrhagic (in case of trauma) and ischemic complications when the drugs are avoided. Official recommendations are limited for these patients and forbid sports that increase the risk of trauma and consequent bleeding in most cases. These recommendations are strongly influenced by the "traditional" management of OAT, which mainly involves coumarin derivatives. Non-vitamin K antagonist direct oral anticoagulants (DOACs), with their more favorable pharmacokinetic-pharmacodynamic profile than that of coumarin derivatives, may represent an opportunity to modify the approach to sports activity in patients with AF and indications for OAT. This study aimed to review the use of anticoagulants in athletes with AF, highlight their efficacy and safety, and provide practical considerations regarding their management.

Electrocardiographic predictors of left ventricular scar in athletes with right bundle branch block premature ventricular beats.

AIMS: Right bundle branch block (RBBB) morphology non-sustained ventricular arrhythmias (VAs) have been associated with the presence of non-ischaemic left ventricular scar (NLVS) in athletes. The aim of this cross-sectional study was to identify clinical and electrocardiogram (ECG) predictors of the presence of NLVS in athletes with RBBB VAs. METHODS AND RESULTS: Sixty-four athletes [median age 39 (24-53) years, 79% males] with non-sustained RBBB VAs underwent cardiac magnetic resonance (CMR) with late gadolinium enhancement in order to exclude the presence of a concealed structural heart disease. Thirty-six athletes (56%) showed NLVS at CMR and were assigned to the NLVS positive group, whereas 28 athletes (44%) to the NLVS negative group. Family history of cardiomyopathy and seven different ECG variables were statistically more prevalent in the NLVS positive group. At univariate analysis, seven ECG variables (low QRS voltages in limb leads, negative T waves in inferior leads, negative T waves in limb leads I-aVL, negative T waves in precordial leads V4-V6, presence of left posterior fascicular block, presence of pathologic Q waves, and poor R-wave progression in right precordial leads) proved to be statistically associated with the finding of NLVS; these were grouped together in a score. A score ≥2 was proved to be the optimal cut-off point, identifying NLVS athletes in 92% of cases and showing the best accuracy (86% sensitivity and 100% specificity, respectively). However, a cut-off ≥1 correctly identified all patients with NLVS (absence of false negatives). CONCLUSION: In athletes with RBBB morphology non-sustained VAs, specific ECG abnormalities at 12-lead ECG can help in detecting subjects with NLVS at CMR.

In athletes with right bundle branch block (RBBB) morphology non-sustained ventricular arrhythmias (VAs), the presence of a non-ischaemic left ventricular scar (NLVS) may be highly suspected if one or more of the following electrocardiogram (ECG) characteristics are present at the 12-lead resting ECG: low QRS voltages in limb leads, negative T waves in inferior leads, negative T waves in limb leads I­aVL, negative T waves in precordial leads V4­V6, presence of left posterior fascicular block, presence of pathologic Q waves, and poor R-wave progression in right precordial leads. This score should be externally validated in a larger population of athletes with VAs. In athletes with RBBB morphology non-sustained Vas, attention should be placed on the 12-lead resting ECG to suspect the presence of an NLVS. In athletes with RBBB VAs and the presence of one or more of the identified ECG characteristics, a cardiac magnetic resonance with late gadolinium enhancement is useful to rule out an NLVS.

CPVT and Complete Atrio-Ventricular Block: The Flipside of the Same Coin.

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a rare electrical genetic disease characterized by ventricular polymorphic tachycardia and/or bidirectional ventricular tachycardia induced by the release of catecholamines caused by intense physical or emotional stress in structurally normal hearts. Mostly, it is caused by mutations in genes that are involved in calcium homeostasis, in particular in the gene encoding for cardiac ryanodine receptor (RyR2). Our observation is the first description of familial CPVT caused by mutation of the RyR2 gene, linked to the complete AV block.

Long-Term Sports Practice and Atrial Fibrillation: An Updated Review of a Complex Relationship.

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice, and it is an enormous burden worldwide because of its high morbidity, disability and mortality. It is generally acknowledged that physical activity (PA) is strongly associated with a significant reduction in the risk of cardiovascular (CV) disease and all-cause mortality. Moreover, it has been observed that moderate and regular physical activity has the potential to reduce the risk of AF, in addition to improving overall well-being. Nevertheless, some studies have associated intense physical activity with an increased risk of AF. This paper aims to review the main related literature to investigate the association between PA and AF incidence and draw pathophysiological and epidemiological conclusions.

Low fluoroscopy permanent His bundle pacing using a new electroanatomic mapping system (KODEX EPD). A multicenter experience.

Background: His bundle pacing (HBP) may be a challenging procedure, often involving a long fluoroscopic time (FT) and a long procedural time (PT). We sought to evaluate whether the use of a new nonfluroscopic mapping (NFM) system, the KODEX-EPD, is able to reduce FT and PT when mapping is performed by the pacing catheter rather than an electrophysiological mapping catheter. Methods and Results: We included 46 consecutive patients (77 ± 8 years; 63% male) who underwent HBP; in 22 a NFM-guided procedure with the KODEX-EPD system was performed (group 1), whereas in 24 a conventional fluoroscopy-guided approach was used (group 2). Pacing indications were sick sinus syndrome in 13, atrioventricular block in 21, and cardiac resynchronization therapy in 12 cases. Both a lumen-less fixed helix lead and a stylet-driven extendable helix lead were used, respectively, in 24% and 76% of patients. HBP was successful in 22 patients (100%) in group 1 and 23 patients (96%) in group 2. The FT was significantly reduced in group 1 (183 ± 117 s vs 464.1 ± 352 s in group 2, p = .012). There were no significant differences between groups in PT and other procedural outcomes. Conclusions: The KODEX-EPD system may be safely used in HBP procedures. It is effective in reducing ionizing radiation exposure, as evidenced by the significant drop in FT, without increasing PT.

Long-Term Follow-Up In Paroxysmal Atrial Fibrillation Patients With Documented Isolated Trigger.

Aims: Supraventricular tachycardias may trigger atrial fibrillation (AF). The aim of the study was to evaluate the prevalence of supraventricular tachycardia (SVT) inducibility in patients referred for AF ablation and to evaluate the effects of SVT ablation on AF recurrences. Methods and results: 249 patients (mean age: 54 ± 14 years) referred for paroxysmal AF ablation were studied. In all patients, only AF relapses had been documented in the clinical history. 47 patients (19%; mean age: 42 ± 11 years) had inducible SVT during the electrophysiological study and underwent an ablation targeted only at SVT suppression. Ablation was successful in all 47 patients. The ablative procedures were: 11 slow-pathway ablations for atrioventricular nodal re-entrant tachycardia; 6 concealed accessory pathway ablations for atrioventricular re-entrant tachycardia; 17 focal ectopic atrial tachycardia ablations; 13 with only one arrhythmogenic pulmonary vein. No recurrences of SVT were observed during the follow-up (32 ± 18 months). 4 patients (8.5%) showed recurrence of at least one episode of AF. Patients with inducible SVT had less structural heart disease and were younger than those without inducible SVT. Conclusion: A significant proportion of candidates for AF ablation are inducible for an SVT. SVT ablation showed a preventive effect on AF recurrences. Those patients should be selected for simpler ablation procedures tailored only to the triggering arrhythmia suppression.

Tailoring the Ablative Strategy for Atrial Fibrillation: A State-of-the-Art Review.

In spite of technological progress and the improving skills of operators, atrial fibrillation (AF) ablation results appear to date to be at a plateau. In any case, the superiority of ablation over pharmacological therapy in terms of effectiveness, reduction of hospitalizations, and improvement has been well demonstrated in recent randomized trials. Triggers, substrate, and modulating factors (elements of Coumel's triangle) play different roles in paroxysmal and persistent AF, so induction and perpetuation mechanisms of arrhythmia may be different in each patient. Although effective ablative strategies are available for the treatment of paroxysmal AF triggers and persistent AF substrates, an adequate clinical evaluation of the patient is crucial in order to increase the chances of success. Recognizing triggers allows not only performing an effective ablation but also to avoid unnecessary lesions and at the same time reducing the risk of complications. AF beginning and triggers could be recorded by 12-lead ECG, continuous Holter monitoring, or implantable devices. In case of an unsuccessful noninvasive evaluation, nonpulmonary vein triggers should be investigated with an electrophysiological study. Persistent AF needs more effort to perform an accurate substrate characterization. Among the many methods proposed, recently the use of high-density mapping and multipolar catheters seems of particular benefit in order to clarify the arrhythmia mechanisms. Surgical and hybrid techniques allow to treat regions such as the posterior wall or Bachmann's bundle, which is fundamental for an ablative strategy that goes beyond just pulmonary vein isolation. Too often, patients are referred to electrophysiology laboratories without adequate preprocedural screening and planning in order to submit them to a standard "ready-made" procedure. The accurate search for triggers in paroxysmal AF and the correct recognition of the link between a possible underlying heart disease and the substrate in persistent AF could allow us to tailor the interventional approach in order to overcome the current plateau, increasing ablative procedure success and minimizing complications.

Managing athletes with palpitations of unknown origin with an external loop recorder: a cohort study.

BACKGROUND: Palpitations in athletes are usually benign, but the presence of major cardiac arrhythmias should be ruled out despite the infrequent appraisal of symptoms. External loop recorders (ELR) are promising to identify arrhythmias in these circumstances, but experiences in athletes are lacking. We aimed to investigate the feasibility and diagnostic yield of an ELR in athletes with unexplained palpitations in a cohort study. METHODS: One hundred twenty-two consecutive subjects (61 athletes and 61 sedentary controls) with sporadic palpitations and inconclusive diagnosis were enrolled and equipped with an ELR. Findings were categorized as major and minor arrhythmic findings, non-arrhythmic findings or negative monitoring. RESULTS: Long-term ELR monitoring was feasible in all subjects, with median duration of 12 (11; 15) days. Major arrhythmic events during palpitations were found in 9 (14.8%) athletes: 7 experienced sustained paroxysmal supraventricular tachycardia, and 2 had non sustained ventricular tachycardia. Minor arrhythmic events (premature supraventricular or ventricular beats) were observed in 13 athletes (21.3%). Non-arrhythmic findings (i.e., sinus rhythm or sinus tachycardia) were recorded in 28 athletes (45.9%), whereas 11 (18%) had negative monitoring. In the sedentary group, arrhythmic events were similar for types and frequency to athletes. The diagnostic yield of loop monitoring was 82.8% in the overall population and 82.0% in the athlete's group. CONCLUSIONS: In the management of an athlete symptomatic with unexplained palpitations after 24-hour ECG monitoring and stress test, ELR is an efficient tool to identify major arrhythmic events, which can be present in up to 10% of symptomatic athletes during practice and competition.

Abnormal venous return: Still a challenge for electrophysiology procedures? A case report.

Catheter ablation of cardiac arrhythmias is usually performed through the femoral venous approach. Systemic venous return anomalies such as interruption of the inferior vena cava may represent a challenge during electrophysiological procedures. A 55-year-old patient with previous surgical correction of abnormal pulmonary venous return was admitted for poorly tolerated atrial flutter recurrences. He also had an interrupted inferior vena cava continuing as azygos vein and left superior vena cava draining via coronary sinus into the right atrium. Cavotricuspid isthmus radiofrequency ablation was successfully performed through the persistent left superior vena cava using a three-dimensional (3D) electroanatomical mapping system. Despite systemic venous abnormalities may potentially have important implications during electrophysiological procedures, arrhythmias can be successfully ablated with the aid of 3D electroanatomical mapping systems. .

Cardiac resynchronization therapy guided by the new KODEX-EPD imaging system.

Nowadays, fluoroscopy is the standard tool used to help physicians during pacing lead implantation. However, its use entails significant radiation exposure for physicians and especially for patients. For the first time, the present case report describes the use of the electro-anatomical mapping (EAM) navigation system KODEX-EPD for cardiac resynchronization therapy (CRT) implantation. These findings suggest that CRT implantation guided by the KODEX-EPD system is feasible and safe with the minimization of X-ray and dye exposure.