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Conduction disturbances requiring permanent pacemaker (PPM) implantation are common after tricuspid valve replacement (TVR). Conventional transvalvular right ventricular pacing carries a risk of prosthetic valve dysfunction, whereas epicardial pacing is limited by surgical complexity, high pacing thresholds, and reduced lead durability. Coronary sinus (CS) pacing represents a potential alternative; however, data following TVR remain limited. We retrospectively analyzed eight patients who underwent PPM implantation via the CS after TVR at our center. Demographic characteristics, procedural details, and pacing parameters were collected. Electrical performance (pacing threshold, lead impedance, and pacing percentage) was assessed during follow-up. PPM implantation via the CS was successfully performed in all patients (median age: 61 years; 87.5% female). Seven patients underwent bioprosthetic TVR and one underwent mechanical TVR. The median interval between surgery and PPM implantation was 7 days. Mean procedure and fluoroscopy times were 66.5 ± 25.2 min and 13.3 ± 6.8 min, respectively. No acute or periprocedural complications occurred. During a median follow-up of 20.5 months, pacing thresholds and lead impedance remained stable (median threshold: 1.5 V, IQR: 1.0-2.25; median impedance: 846 Ω, IQR: 470-979), with a median ventricular pacing percentage of 82%. No lead-related complications were observed. CS pacing is a feasible and safe strategy for patients requiring PPM implantation after TVR, providing stable electrical performance while avoiding the risks associated with transvalvular and epicardial leads. This approach may be particularly valuable in patients with mechanical prostheses and should also be considered in selected bioprosthetic valve recipients. Larger studies are required to confirm long-term outcomes.
Cardiac electrograms form the foundation of contemporary clinical electrophysiology and are essential for activation mapping, substrate characterization and catheter ablation of cardiac arrhythmias. Electrogram morphology, however, is not solely determined by myocardial electrophysiology, but also by multiple technological factors related to signal acquisition and processing. Electrode size, interelectrode spacing, electrode orientation, tissue coupling, filtering settings and annotation algorithms all influence electrogram morphology, voltage and activation timing. Consequently, identical myocardial activation patterns may generate markedly different electrograms depending on the recording configuration used. Recent advances in high-density mapping technologies, multi-electrode electrogram reconstruction and advanced signal-processing techniques have further expanded the possibilities and complexity of electrogram interpretation. This review discusses the biophysical principles underlying cardiac electrogram formation and examines the technological determinants that influence electrogram characteristics. In addition, the properties, advantages and limitations of different electrogram types, including unipolar, bipolar, multipolar, omnipolar and Laplacian electrograms, are reviewed together with their implications for voltage and activation mapping. A comprehensive understanding of both the physiological basis and technological limitations of electrogram acquisition remains essential for accurate electrogram interpretation and responsible advancement of cardiac arrhythmia mapping and ablation strategies.
The coronary sinus and its tributaries constitute the anatomical foundation for successful cardiac resynchronization therapy. Despite the emergence of conduction system pacing as a physiological alternative, conventional transvenous CRT retains its important role-not all clinical scenarios can be addressed by left bundle branch area or His bundle pacing alone. Understanding coronary venous anatomy therefore remains essential for every implanting physician. This review provides a clinically oriented analysis of coronary venous anatomy as it pertains to left ventricular lead implantation. We examine the embryological origins of the coronary sinus, explaining why variants such as persistent left superior vena cava and obstructive Thebesian and Vieussens valves occur. The gross anatomy section details coronary sinus dimensions, ostial localization, and tributary classification using attitudinally correct nomenclature. Microanatomical considerations include wall thickness gradients, subepicardial adipose tissue thickness, and myocardial sleeve distribution. We review imaging modalities-fluoroscopy, computed tomography, and magnetic resonance imaging-emphasizing their complementary roles in preprocedural planning and real-time guidance. Catheter and wire handling techniques are discussed, from cannulation strategies to lead delivery. Electrophysiological parameters including Q-LV and S-QRS intervals are examined in the context of anatomical lead positioning. Finally, we analyze how anatomy influences outcomes, complications, and non-response. Understanding the coronary venous system transforms cardiac resynchronization therapy from a technical procedure into an anatomically informed intervention where success depends on matching therapeutic goals with individual patient anatomy.
Artificial intelligence (AI) is the use of computational models to learn from electrical, anatomical and imaging data to assist or automate interpretation, prediction and decision making in arrhythmia diagnosis and treatment. This includes interpretation of signals, integration of multimodal data to support procedural decisions and to predict outcomes. When personalized to individual patients, these mechanistic approaches give rise to cardiac digital twins capable to procedural planning and hypothesis testing. In the electrophysiology (EP) lab, AI aims to reduce inter-observer variability, improve identification of the arrhythmogenic substrate by combining information from multimodality imaging and promises to streamline mapping and ablation workflows. Integration of AI with cardiac CT and cardiac MRI allows for automated segmentation, wall thickness and scar characterization and identification of conducting channels for ventricular tachycardia. Similarly, AI guided approaches for spatiotemporal dispersion and focal drivers in atrial fibrillation have demonstrated improved procedural consistency and promising clinical outcomes. This review synthesizes the current evidence on use of AI in the EP lab particularly preprocedural planning, intra procedural imaging and use of digital twins. We highlight practical workflows, representative clinical use cases and key limitations of AI.
Cardiogenic shock complicating inferior acute myocardial infarction is usually attributed to pump failure, but rhythm-mediated mechanisms may predominate when ischemia involving the sinoatrial nodal artery produces sinus node dysfunction, chronotropic incompetence, and junctional rhythm-induced atrioventricular dyssynchrony. We report a 79-year-old man who developed recurrent cardiogenic shock several hours after successful revascularization for inferior ST-elevation myocardial infarction despite only mildly reduced left ventricular systolic function. Invasive hemodynamic assessment demonstrated that increasing the temporary right ventricular pacing rate failed to improve left ventricular systolic pressure, whereas right atrial appendage pacing immediately restored hemodynamics, establishing chronotropic incompetence and loss of atrioventricular synchrony as the dominant contributors. Because durable atrial pacing was required and prolonged temporary atrial pacing was impractical, a helix-fixation atrial leadless pacemaker was implanted despite markedly adverse acute ischemic atrial electrical parameters, including blunted local electrograms, minimal current of injury, and a high initial pacing threshold. Pacing thresholds improved progressively after implantation, and hemodynamic stability was maintained without escalation to advanced mechanical circulatory support. To our knowledge, this is the first reported use of atrial leadless pacing in the acute phase of myocardial infarction.
Out-of-hospital cardiac arrest (OHCA) is a major public health challenge in India. Cardiopulmonary resuscitation (CPR) awareness, training, and bystander response rates remain critically low across the country. This Indian Society of Electrocardiology position statement aims to promote nationwide CPR awareness, strengthen community response to sudden cardiac arrest (SCA) and improve survival in OHCA, with measures adapted to India-specific systems of care and bystander training. The statement highlights the SCA burden, early recognition, rapid response, barriers to community CPR training in India, dispatcher-assisted CPR, and public access defibrillation (PAD). It emphasizes school-based CPR education, corporate social responsibility partnerships, legislative support, and development of a national CPR ecosystem. Role of digital innovations, mobile applications, virtual reality, mobile CPR training units, psychological barriers and the bystander effect are emphasized. The position statement advocates transforming CPR from a medical skill into a societal responsibility and improve OHCA survival in India.
Circumstances around ablation catheters placed in the ventricular cavity and pericardial space are not identical, and therefore bipolar (BIP) ablation targeting the interventricular septum (IVS) or left ventricular free wall (LVFW) may induce lesions with different characteristics on either side of the wall. Porcine hearts prepared for IVS or LVFW were placed between two inner containers which were set in an outer experimental container. For IVS ablation, each inner container was filled with Tyrode's solution circulated by a pump to mimic the right- and left-ventricular cavities. For LVFW ablation, a plastic board was inserted into one of the inner containers to mimic the pericardial space, thereby minimizing the circulating solution. Thereafter, BIP ablation (30W, 120-s) was attempted 30 applications each in IVS and LVFW. All 60 applications were successfully accomplished without steam-pop. Total impedance decline (TID) and %-TID were larger in LVFW than IVS ablation (-19.4 ± 5.3 vs. -15.8 ± 4.6 Ω, and -16.2 ± 4.0 vs. -13.2 ± 3.6%), and total lesion depth was deeper in LVFW than in IVS (14.4 ± 2.6 vs. 12.7 ± 3.3 mm) due to deeper lesions in the epicardial wall. Surface lesions were also larger in epicardial than in endocardial wall in LVFW ablation, whereas there were no differences between right- and left-side septal wall. Transmural lesion was created in 13/30 in LVFW and 9/30 in IVS ablation. As compared to IVS, BIP ablation targeting LVFW demonstrated larger TID and induced deeper lesions in the epicardial wall in this study, probably due to less current leakage into the small space.
Patients with persistent atrial fibrillation (AF) associated with scarred/low voltage left atrial myocardium have suboptimal outcomes following pulmonary vein isolation (PVI). In the LAUDABLE study, we showed that PVI durability in these patients is poor. Here, we report follow-up outcomes from LAUDABLE, including relevance of posterior wall isolation (PWI), quality of life (QOL) and cardiac dysfunction as measured by N-terminal pro-B-type natriuretic peptide (NT-proBNP). LAUDABLE was a single-centre, pilot randomised controlled study. Patients with persistent AF were randomised to cryoballoon (CB) PVI or contact force and local impedance guided radiofrequency (RF) PVI. Patients underwent a protocol mandated 2-month redo procedure to isolate reconnected PVs. The index RF group additionally underwent PWI during the redo procedure. Arrhythmia follow-up included daily handheld ECGs, clinical review, QOL questionnaires and NT-proBNP analysis at 12 months. 38 patients underwent both procedures (17 CB/PVI-only, 21 RF/PVI + PWI). Over median 303 day follow-up, arrhythmia-free survival was observed in 23 (61%) patients, similar between arms (Kaplan-Meier estimate: CB/PVI-only 58.8% [95% CI 38.8-87.5%] vs RF/PVI + PWI 61.9% [95% CI 44.3-86.6%]; p = 0.788). Significant improvements in QOL (AFEQT baseline: 61 vs follow-up: 96; p < 0.001) and NT-proBNP (baseline: 535 pg/mL vs follow-up: 151 pg/mL; p = 0.004) were observed. The majority of patients with significant left atrial scar at index ablation, who may be considered unsuitable for redo, derived significant benefit following durable PVI in terms of arrhythmia burden, QOL and NT-proBNP. Accepting low patient numbers, PWI offered no additive benefits.
Contact force (CF)-sensing catheters may improve lesion quality and procedural efficiency during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF), but data on their clinical and economic implications in developing countries remain limited. This pilot study evaluated the technical, clinical, and economic outcomes of CF catheters compared with non-CF catheters in symptomatic paroxysmal AF. In this pilot study conducted in Vietnam, 45 patients underwent PVI. Technical outcomes included first-pass isolation (FPI), fluoroscopy time, and lesion-related procedural measures. Clinical outcomes included acute pulmonary vein reconnection and AF recurrence at 3 months. An economic analysis was performed from the payer perspective. CF-guided PVI was associated with lower fluoroscopy time than non-CF ablation (12.19 ± 2.46 vs 14.04 ± 2.93 min, p = 0.026) and higher bilateral FPI (81.0% vs 37.5%, p = 0.003). The acute reconnection rate was 2.38% with CF and 8.33% with non-CF (p = 0.170). No procedural complications occurred in either group. At 3 months, 85.7% of patients in the CF group and 58.3% in the non-CF group were free from AF recurrence (p = 0.055). Total procedural cost was higher with CF catheters (201.08 ± 23.56 vs 191.03 ± 9.71 million VND), with an ICER of 36.7 million VND per additional patient free from AF recurrence at 3 months. CF-guided PVI was associated with better technical performance and a possible favorable short-term clinical trend, despite higher upfront costs. Exploratory economic analysis suggested a possible short-term economic benefit, pending confirmation in larger long-term studies.
Remote monitoring (RM) is recommended as the standard of care in cardiac implantable electronic devices (CIED) management. RM allows the reduction of physical in-clinic visits during CIED follow-up, continuous monitoring and earlier detection of actionable events. Earlier studies have shown RM to be safe and effective in reducing all-cause mortality, unscheduled hospitalisations, Emergency Department and clinic visits, and inappropriate implantable cardioverter defibrillator (ICD) therapies. Apart from pacemakers and ICDs, RM is also helpful in the earlier identification of bradyarrhythmias in unexplained syncope. Across the United States and Europe, RM has been shown to be cost-effective with increased cost-savings due to reduced hospitalisation costs. Patients on RM reported increased quality of life, convenience and satisfaction, with many preferring the use of RM in their follow-up care. However, the lack of healthcare system reimbursements and the need for adequate staffing may impede RM adoption. Despite its benefits, the uptake of RM is heterogenous and remains low in Asia. Challenges to the adoption of RM in Asia include access to healthcare, geographical location, socioeconomic status and the lack of RM infrastructure. This review discusses the benefits and challenges of RM, and describes the implementation of RM at the National University Heart Centre Singapore, an academic centre with 6 CIED clinics across 2 tertiary hospitals providing care to 1.5 million people in Western Singapore.
Pulsed field ablation (PFA) is an emerging nonthermal ablation modality for the treatment of atrial fibrillation. Unlike conventional thermal energy sources such as radiofrequency and cryoablation, PFA delivers high-voltage pulsed electric fields that induce irreversible electroporation, resulting in selective cardiomyocyte death while largely preserving surrounding extracellular structures. The biological response to pulsed electric fields depends on parameters such as field strength, pulse duration, waveform configuration, and number of pulses. Variations in electroporation thresholds among different cell types contribute to the relative myocardial selectivity observed with PFA. Lesion formation is also influenced by electrode configuration, catheter-tissue contact, and electric field distribution. Early clinical experience and large registries suggest that PFA enables efficient pulmonary vein isolation with a favorable safety profile and reduced risk of collateral injury compared with thermal ablation technologies. This review summarizes the fundamental biophysical mechanisms underlying pulsed electric field ablation and discusses practical considerations for its clinical application in atrial fibrillation ablation.
Reports on catheter ablation for atrial fibrillation (AF) in patients with intracardiac tumors are scarce. We report a case of persistent AF in which the procedure was completed simply, and safely, using the FARAVIEW system, which is a 3D-integrated pulsed field ablation (PFA) system incorporating the FARAPULSE PFA system, alongside intracardiac echocardiography (ICE). The simplicity was evident in the relatively short procedure time, despite careful navigation around the cardiac tumor using FARAVIEW and ICE. Safety was paramount; we successfully performed pulmonary vein isolation, posterior wall isolation, and post-ablation mapping without causing symptomatic cerebral embolism. The FIELDTAG feature on the 3D-CT fusion image allowed for precise prediction of the isolation area and visualization of the tumor's location. This integrated approach led to the efficient termination of AF and subsequent improvement in heart failure status. This case demonstrates that the combination of ICE, and the 3D-integrated PFA system ensures safe left atrial ablation in the presence of a cardiac mass. Specifically, FIELDTAG on 3D-CT provided crucial visualization of the spatial relationship between the tumor and ablation lesions, enhancing procedural safety.
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Ventricular arrhythmias arising from the left ventricular (LV) summit are technically challenging to ablate because of limited accessibility and proximity to the coronary arteries. Dual energy lattice-tip catheter (DLTC) could provide both very high-power temperature-controlled radiofrequency (RF) ablation and pulse field (PF) ablation. To describe the use of combined radiofrequency (RF) and pulsed field (PF) ablation using a dual-energy large lattice-tip catheter for treatment of ventricular tachycardia originating from the LV summit region. We report a 66-year-old man with atrial fibrillation, heart failure with reduced ejection fraction, and recurrent VT despite prior endocardial and epicardial radiofrequency ablation. Mapping localized the PVC/VT to a LV summit-adjacent region, with an endocardial target along the superior septum/LVOT consistent with an intramural or epicardial summit substrate. Given prior failed RF ablations compassionate-use ablation with the dual-energy lattice-tip catheter and Affera™ mapping system (Medtronic, Minneapolis, MN) was performed under intracardiac echocardiogram guidance. Interventional cardiology was directly involved, providing coronary angiography and intravascular imaging before and after ablation to ensure the absence of vasospasm or ischemia. At 6 week follow up, following dual-energy ablation with DLTC, there was significant suppression of ventricular arrhythmia off antiarrhythmic amiodarone. There was no evidence of coronary injury post ablation confirmed by coronary angiogram and intravascular ultrasound. This case highlights the feasibility of high-power temperature controlled-RFA and focal PFA for VT in anatomically regions where success with conventional energy sources is limited. Combined RF and PF ablation using the DLTC achieved safe and effective ablation of LV summit ventricular tachycardia without coronary injury.
Pulsed-field ablation (PFA) has rapidly emerged as a non-thermal modality for pulmonary vein isolation (PVI) in the treatment of atrial fibrillation. By delivering high-voltage, microsecond-scale electrical pulses, PFA produces irreversible electroporation of cardiomyocytes while preserving the extracellular matrix of adjacent structures. Compared with conventional thermal modalities, namely radiofrequency (RF) and cryoablation, PFA offers shorter procedural times, comparable or superior efficacy for paroxysmal atrial fibrillation, and a markedly reduced risk of esophageal injury, persistent phrenic nerve palsy, and pulmonary vein stenosis, as demonstrated in numerous randomized controlled trials and large registries. However, PFA introduces unique limitations: hemolysis with potential renal injury, acute and delayed coronary vasospasm when ablating near the coronaries, the need for deep sedation or general anesthesia in most current systems, and uncertain durability of non-pulmonary vein lesions including the mitral and cavotricuspid isthmuses. Thermal ablation retains advantages for lesions beyond the pulmonary veins matter most particularly along the cavotricuspid and mitral isthmuses. Dual-energy catheters that combine RF and PFA, and sequential colocalized RF + PFA strategies, are now in clinical evaluation and may allow operators to create stacked lesions which may offer benefits for lesion durability. PFA is poised to become the dominant energy source for PVI, but in current clinical practice it is best viewed as complementary to, rather than fully replacing, thermal ablation.
Leadless pacemakers offer an attractive alternative to transvenous systems in children but are limited by vascular size, cardiac chamber dimensions, and device-specific characteristics. We describe the first implantation of an atrial Aveir AR leadless pacemaker in the right ventricle of a pediatric patient using a superior venous approach. A 7-year-old, 23.7-kg girl presented with recurrent syncope and was found to have an 8.7-s sinus pause on ambulatory monitoring consistent with sinus node dysfunction. Pre-procedural echocardiography and ultrasound assessment demonstrated relatively small atrial dimensions and identified the right internal jugular vein (1 cm) as the largest available central vessel compared with the femoral and left internal jugular veins. To optimize catheter maneuverability and accommodate the 27-Fr delivery sheath, a right internal jugular approach was selected. The Aveir AR device was advanced across the tricuspid valve and fixed to the mid-right ventricular septum on the first attempt, with stable sensing and capture parameters and no periprocedural complications (threshold 0.5 V at 0.2 ms, impedance 400 Ω, R-wave 5.9 mV). The patient was discharged within 24 hours and remained asymptomatic with preserved device function on one month follow-up, with threshold 0.75 V at 0.2 ms, impedance 410 Ω, R-wave 8.3 mV, and with <1% pacing, predicted longevity at 15.9 years. This case illustrates that superior venous access can facilitate safe ventricular deployment of an Aveir AR leadless pacemaker in select pediatric patients with sinus pauses.
Degenerative complete heart block is a relatively common condition and is usually treated with endocardial pacing. Iatrogenic conduction disturbance is often seen after some cardiac surgical procedures. In a significant number of cases, it is irreversible and needs implantation of a pacemaker device. In this case report, we present a case of a young, severely sick patient who presented with tricuspid valve endocarditis with large vegetation. The patient was managed with surgical removal of the vegetation and replacement of the tricuspid valve with a metallic valve. Postoperatively, the patient developed complete heart block. In view of the presence of a metallic tricuspid valve, the patient was successfully managed with the implantation of a dual-chamber pacemaker using a CRT-P generator with a quadripolar lead in the posterior cardiac vein and an atrial lead in the right atrial appendage.
Sotalol is a class III anti-arrhythmic medication commonly used in maintaining sinus rhythm in patients with arrhythmias, most notably atrial fibrillation. Sotalol is conventionally initiated in an inpatient setting (typically three days) to allow close monitoring of its effects, particularly corrected QT interval (QTc) prolongation, which may predispose patients to fatal arrhythmias such as torsades de pointes. In this meta-analysis, we aimed to assess the safety of initiating sotalol in an outpatient setting. We searched PubMed, Scopus, Embase, Cochrane Library, Web of Science, Virtual Health Library, and Google Scholar for observational studies and randomized controlled trials assessing the safety of outpatient initiation of sotalol until July 2025. Our endpoints were the change from baseline in QTc interval at the longest follow-up and the rate of sotalol discontinuation due to adverse events. Standardized mean differences from baseline in QTc interval with 95% confidence intervals were pooled with a random-effects model using CMA V3 software. We included three observational studies with a total cohort of 1248 patients. At the longest follow-up post-sotalol initiation in an outpatient setting, there was no statistically significant change in QTc interval from baseline (SMD = +0.15, 95% CI: -0.357 to 0.658, p = 0.56). Across 1140 patients, the rate of drug discontinuation due to adverse events at one-month post-sotalol initiation ranged from 4.7% (41/880 patients; 95% CI 3.4%-6.3%) in one study to 8.1% (21/260 patients; 95% CI 5.3%-12.1%) in another. In carefully selected patients, the initiation of sotalol in an outpatient setting appears to be safe and associated with no significant adverse events. However, the current evidence is limited to a small number of observational cohorts, and large randomized controlled trials are warranted to establish the safety and efficacy of outpatient sotalol initiation.
Takotsubo cardiomyopathy is a transient form of stress-induced cardiomyopathy triggered by emotional or physical stressors. Although cardiac complications occur in nearly half of patients, atrioventricular conduction disturbances are rare, and the optimal management strategy, including the decision regarding pacemaker implantation and its timing, remains uncertain. We report the case of an 80-year-old woman who presented with Takotsubo cardiomyopathy and persistent complete heart block requiring pacemaker implantation with conduction system pacing despite recovery of the left ventricular systolic function.
Fetal echocardiography plays a pivotal role in the diagnosis and management of fetal arrhythmias, allowing evaluation of the electrophysiological mechanism and guiding appropriate medical therapy. Herein, we describe our ten-year experience as a tertiary referral center in Southern Italy in the diagnosis and management of fetal sustained supraventricular tachycardia. Thirty-two consecutive fetuses were included: 16 fetuses with atrioventricular reentrant tachycardia, 7 fetuses with ectopic atrial tachycardia, 8 fetuses with atrial flutter, and 1 fetus with permanent junctional reciprocating tachycardia. Transplacental therapy guided by echocardiographic diagnosis was highly effective in achieving complete rhythm control (74%) or partial rhythm control (24%), even in presence of heart failure or hydrops fetalis. Postnatal antiarrhythmic therapy was not required in over one third of cases due to spontaneous resolution. Earlier gestational age at diagnosis was associated with arrhythmia resolution at birth. The presence of fetal heart failure or hydrops did not predict postnatal persistence of arrhythmia.