Search Results (24)

Cardiac resynchronization therapy (CRT) is a cornerstone intervention for patients with heart failure (HF) and electrical dyssynchrony, improving quality of life, functional capacity, and survival. Beyond mechanical synchrony, mounting evidence suggests CRT exerts systemic and myocardial cardiometabolic benefits. CRT acutely enhances mechanical efficiency and shifts substrate utilization toward greater oxidation of fatty acids and ketones, effects that correlate with long-term reverse remodeling on cardiac magnetic resonance imaging. Earlier metabolomic profiling demonstrated that CRT normalizes circulating energy metabolites, improving Krebs cycle intermediates and substrate balance between glucose and lipids, while baseline metabolite patterns may differentiate responders from non-responders. These metabolic adaptations accompany favorable changes in diastolic performance, right ventricular function, and ventriculo-arterial coupling. In parallel, improved splanchnic perfusion and reduced congestion may ameliorate gut dysbiosis and endotoxemia, mitigating systemic inflammation. Collectively, these findings position CRT as a therapy capable of both mechanical and metabolic restoration in advanced HF. In this review, we discuss the emerging data on how CRT reconditions myocardial energy metabolism, influences ventricular–arterial interactions, and modulates peripheral and gut-derived metabolic pathways. Full article

Background/Objective: Pacing-induced cardiomyopathy (PICM) is a common complication of right ventricular (RV) pacing, affecting 6–25% of patients with frequent RV pacing, due to electrical and mechanical dyssynchrony. Certain clinical and electrocardiographic risk factors have been identified, including high RV-pacing burden and longer paced QRS, but their ability to predict the development PICM remains limited. Additionally, other forms of PICM have been described, including heart failure with preserved ejection fraction and RV failure. The goal of this narrative review is to summarize the current evidence utilizing noninvasive imaging to identify patients predisposed to a high risk of PICM. Methods: Using a literature search in the PubMed, Scopus, Google Scholar, and the Cochrane databases from 2000 to 2025, which included but was not limited to the keywords right ventricular pacing, pacemaker-related cardiomyopathy, pacemaker-induced cardiomyopathy, biventricular pacing, conduction system pacing, His bundle pacing, left bundle pacing, echocardiography, computed tomography imaging, and cardiac magnetic resonance imaging, we reviewed randomized control trials, observational retrospective and prospective cohort studies, societal guidelines, and systematic review articles. Conclusions: Essential in the diagnosis of PICM, cardiac imaging can identify patients at risk, even before left ventricular (LV) dysfunction or symptoms develop. Pre- and early post-implantation 2- and 3-dimensional echocardiography with global longitudinal strain provides sensitive parameters for the potential development of PICM. Relative indices of contractile asymmetry have been described. Cardiac magnetic resonance imaging offers an accurate assessment of cardiac volumes and LV synchrony and can also quantify myocardial fibrosis, a significant predictor of PICM. Performing pre-device implantation imaging may help predict subsequent heart failure development and potentially can guide pacing modality selection that can mitigate this risk. Thus, an imaging-guided framework will advance the management of PICM. Full article

Cardiac pacing has undergone a significant transformation in the last decade. Leadless pacing (LP), once only a conceptual idea stemming from the early interest in eliminating lead-related complications of transvenous pacemakers, has now become a reality in clinical practice. Since the introduction of the first human single-chamber asynchronous leadless ventricular pacing in 2012, atrioventricular-synchronized single- or dual-chamber leadless pacing systems have been approved for clinical use since 2020. Leadless cardiac resynchronization therapy (CRT) has shown optimistic results in case series and awaits its full utility in real-world clinical practice. With the successful feasibility study of leadless conduction system pacing, we are eagerly awaiting long-term safety and efficacy data on a large scale. Another important frontier is the development of self-rechargeable LP, which may be an ideal pacemaker for the future and may reduce the burden of multiple device replacements as batteries near the end-of-service. Totally extravascular percutaneous leadless pericardial micro-pacemaker system implantation is under development. In this state-of-the-art review, we examine the evolution of cardiac pacing, emphasizing the development and utility of LP to meet maximum physiological pacing needs, optimize atrioventricular synchrony and cardiac resynchronization, and broaden its indications. Full article

Background: Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative to conventional pacing, offering improved ventricular synchrony and clinical outcomes. However, extraction of deeply implanted LBBAP leads remains challenging, particularly in the context of device-related infections. Case Summary: We report two cases of successful extraction of chronically implanted LBBAP leads using a novel technique based on femoral countertraction with pigtail catheters. In the first case, a deep septal implanted 3830 lead was extracted in a patient with persistent bacteremia and suspected device-related endocarditis. Continuous traction was applied to the mid-portion of the lead using a pigtail catheter introduced via femoral access, facilitating safe removal without the use of powered sheaths proximal to the distal tip of the lead. In the second case, three leads (RA, RV, LBBAP) from a cardiac resynchronization therapy with deffibrilation support (CRT-D) system were completely removed in a patient with device extrusion and pocket erosion, using a dual pigtail approach anchored to the atrial and septal leads. Results: In both cases, the technique enabled successful extraction without complications. Procedural times were approximately 70 and 65 min, respectively. In vitro testing suggested that the pigtail catheter applied a sustained moderate traction force (~0.06 kgf), translating to an estimated pressure of 0.85–1.91 kgf/cm² at the septal lead interface. Conclusions: This case series demonstrates that LBBAP lead extraction is feasible using a novel femoral countertraction technique with pigtail catheters. Steady, moderate traction over time may provide a safer alternative to forceful subclavicular extraction, especially in chronically implanted deep septal leads. Further studies are warranted to evaluate the reproducibility, safety, and clinical applicability of this approach. Full article

Objective: The association between right ventricular myocardial fiber deformation and nutrition in weightlifters has not been fully characterized. This study analyzed nutritional factors and right ventricle speckle tracking echocardiography parameters in weightlifters before and after bench press exercises. Methods: This interventional study examined the effects of bench press exercises on myocardial function. Nutritional parameters were assessed prior to exercise. Echocardiography with speckle tracking using vector velocity analysis was performed before and immediately after the bench press exercise. This study included a group of non-elite athlete weightlifters and a non-athlete control group to compare right myocardial function. In the athlete group, transthoracic echocardiograms (TTEs) were conducted before and after the exercise to assess changes in systolic and diastolic right heart function. A cohort of 30 weightlifters from 2014 who continued regular training was re-evaluated in 2024, and nutritional data were collected. Data analyses included ANOVA and Student’s T-tests, and correlation coefficients were calculated to explore associations with speckle tracking results. Results: This study involved 211 male weightlifters and a control group of 60 non-athletes. Measured values for the control group and athletes before and after bench press exercise were as follows: right longitudinal global strain (−27.31 ± 1.47, −23.55 ± 2.37, −30.98 ± 2.12); right global longitudinal strain rate (−1.79 ± 0.078, −1.48 ± 0.33, −2.88 ± 0.259 1/s), all p < 0.001; and isovolumic acceleration (2.38 ± 0.22, 3.52 ± 0.15, 6.66 ± 0.88 m/s², p < 0.001). Following exercise, right intraventricular synchrony increased, and longitudinal strain delay decreased (144.88 ± 22.52, 168.92 ± 29.35, 98.27 ± 12.11 ms, p < 0.001). The follow-up group demonstrated a similar response to exercise as the other weightlifters. Right ventricular longitudinal strain showed correlations with protein, vitamin E, and zinc levels (R² = 0.399, p = 0.021; R² = 0.378, p = 0.03; R² = 0.566, p < 0.01), and right ventricular radial velocities correlated with group B vitamins. Conclusions: Weightlifters show less right ventricular deformity before exercise compared to controls, but their strain increases significantly post-exercise. Speckle tracking values might correlate with nutrition. Full article

Background/Objectives: Patients with normal sinus rhythms undergoing cardiac resynchronization therapy defibrillator (CRT-D) implantation may benefit from a novel two-lead CRT-D system (CRT-DX), which features an atrial sensing dipole integrated into the right ventricular lead. This single-arm, international, non-controlled investigation focused on the safety and clinical efficacy of CRT-DX devices in CRT-D candidates who do not require atrial pacing. Methods: Patients indicated for CRT-D implantation (resting heart rates > 40 bpm and ≥100 bpm during exercise, no second or higher-degree AV block, and no history of persistent or permanent atrial fibrillation) were enrolled across 21 sites in four European countries. The primary endpoint was the need for an additional RA lead implantation within 12 months. Secondary endpoints comprised any invasive re-intervention to the CRT-DX system or infection. Results: Among the 110 patients (mean age 62 years, 70% male), 60% had an underlying non-ischemic cardiac disease. During 12 months of follow-up, RA lead implantation was required in two patients for atrial undersensing or chronotropic incompetence (RA lead implantation-free rate: 98.2% (95% CI: 92.7–99.5%)). Atrial sensing amplitudes were stable (mean: 4.7 ± 1.7 mV), AV-synchrony was maintained at >99%, and the median percentage of biventricular pacing exceeded 98%. The left ventricular ejection fraction improved by an absolute 14.7%. Conclusions: Using simple, clinically applicable inclusion criteria, the two-lead CRT-DX system demonstrated a low rate of subsequent RA lead implantations (1.8%) and maintained adequate RA sensing amplitudes throughout the observation period. The two-lead CRT-DX concept appears to be a feasible alternative for patients with preserved chronotropic competence. Full article

Background and Objectives: The role of biventricular pacing (BVP) is less well-established in patients with heart failure with reduced ejection fraction (HFrEF) without left bundle branch block (LBBB). Conduction system pacing (CSP) has gained significant traction and may provide a safe and more physiological alternative to BVP in these patients. A few small studies studying this question have reported conflicting results. This meta-analysis aims to compare procedural and clinical outcomes between CSP and BVP in this group. Materials and Methods: An online literature search was systematically conducted to retrieve studies comparing CSP and BVP in HFrEF patients with non-LBBB. Four studies with 461 patients were included. Results: Implant-derived paced QRS duration was significantly shorter (mean difference [MD] −19.7 ms, 95% confidence interval [CI] −36.2 to −3.3, p = 0.0355) with CSP. Echocardiographic response with significantly greater improvement in left ventricular ejection fraction (MD 5.6%, 95% CI 3.1 to 8.0, p = 0.0106) was also observed with CSP. There were no statistically significant differences in clinical outcomes such as all-cause mortality (relative risk [RR] 0.53, 95% CI 0.18 to 1.60, p = 0.133) and heart failure hospitalization (RR 0.54, 95% CI 0.19 to 1.56, p = 0.129). Conclusions: This meta-analysis suggests that CSP may have better electrical synchrony and echocardiographic response compared to BVP in HFrEF patients with non-LBBB. Further randomized studies with longer follow-up may be required to elucidate potential benefits in clinical outcomes. Full article

Background/Objectives: Although cardiac resynchronization therapy (CRT) plays an established role in the management of heart failure, a significant proportion of patients do not respond despite appropriate candidate selection. The optimization of CRT pacing is one strategy to enhance response. Fusion pacing algorithms aim to synchronize intrinsic right ventricular (RV) conduction with paced left ventricular (LV) activation, resulting in a more physiological ventricular depolarization pattern. This approach may improve electrical synchrony and enhance left ventricular contraction compared to conventional simultaneous biventricular pacing. The aim of this study was to compare the acute, beat-to-beat effects of standard biventricular pacing versus fusion pacing on myocardial function, using both conventional and speckle-tracking echocardiography in heart failure patients with left bundle branch block (LBBB). Methods: In total, 27 heart failure patients (21 men and 6 women) with reduced ejection fraction (EF < 35%), left bundle branch block (QRS > 150 ms), and newly implanted CRT-D systems (Abbott) underwent echocardiographic assessment immediately after device implantation. Echocardiographic parameters—including left atrial strain, left ventricular strain, TAPSE, mitral and tricuspid valve function, and cardiac output—were measured at 5 min intervals under three different pacing conditions: pacing off, simultaneous biventricular pacing, and fusion pacing using Abbott’s SyncAV^® algorithm. Results: In our study, CRT led to a significant shortening of the QRS duration from 169 ± 19 ms at baseline to 131 ± 17 ms with standard biventricular pacing, and further to 118 ± 16 ms with fusion pacing (p < 0.05). Despite the electrical improvement, no significant changes were observed in global longitudinal strain (GLS: −9.15 vs. −9.39 vs. −9.13; p = NS), left ventricular stroke volume (67.5 mL vs. 68.4 mL vs. 68.5 mL; p = NS), or left atrial parameters including strain, area, and ejection fraction. However, fusion pacing was associated with more homogeneous segmental strain patterns, improved aortic valve closure time, and enhanced right ventricular function as reflected by tissue Doppler-derived S’. Conclusions: Immediate QRS narrowing observed in CRT patients—particularly with fusion pacing optimization—is associated with a more homogeneous pattern of left ventricular contractility and improvements in selected measures of mechanical synchrony. However, these acute electrical changes do not translate into immediate improvements in stroke volume, global LV strain, or left atrial function. Longer-term follow-up is needed to determine whether the electrical benefits of CRT, especially with fusion pacing, lead to meaningful hemodynamic improvements. Full article

Background and Clinical Significance: Scimitar Syndrome is a rare congenital cardiopulmonary anomaly characterized by partial anomalous pulmonary venous return, often requiring early surgical correction. It may coexist with other congenital or acquired cardiovascular anomalies, including valvular diseases such as mitral regurgitation. When surgical correction of Scimitar Syndrome is combined with mitral valve annuloplasty, the proximity to the atrioventricular node may potentially predispose patients to late-onset conduction disturbances, although causality remains speculative. Case Presentation: We describe the case of a 53-year-old male who developed paroxysmal atrial fibrillation, atrial flutter, and intermittent second-degree AV block decades after undergoing surgical correction of Scimitar Syndrome with concomitant mitral annuloplasty. Multimodal echocardiographic evaluation revealed preserved left atrial volume, normal intra-atrial conduction time, mildly reduced strain, and maintained atrial synchrony. The patient was treated with direct oral anticoagulants and beta-blockers and underwent the implantation of a ventricular leadless pacemaker. Conclusions: This case highlights the supportive role of atrial function imaging in assessing atrial health and informing rhythm management and procedural choices in surgically corrected congenital heart disease. Full article

Cardiac resynchronization therapy (CRT) using biventricular (BiV) pacing is the standard treatment for heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) and electrical dyssynchrony. However, one in three patients remains a non-responder. Left bundle branch area pacing (LBBAP) could represent a more physiological alternative, but its effectiveness is limited in cases of atypical left bundle branch block (LBBB) or intraventricular conduction delay (IVCD). Left Bundle Branch Pacing Optimized cardiac resynchronization therapy (LOT-CRT) integrates LBBAP with coronary sinus (CS) lead pacing to improve electrical synchrony and clinical outcomes. This review evaluates the feasibility, advantages, disadvantages, and clinical outcomes of LOT-CRT. Additionally, we describe our center’s experience and propose an evidence-based implantation algorithm. A review of published studies investigating LOT-CRT was conducted, comparing its effectiveness with BiV-CRT and LBBAP alone using QRS narrowing, LVEF improvement, left ventricular remodeling, New York Heart Association (NYHA) class changes and NT-proBNP levels. It was found that LOT-CRT outperforms BiV-CRT or LBBAP alone in selected populations, at the cost of higher clinical skills, longer procedural times, and specific device setups. Randomized trials are underway to further define its role in clinical practice. Full article

Background/Objectives: Right ventricular pacing (RVP), leadless pacing (LL), and conduction system pacing (CSP) are treatment options for atrioventricular block (AVB), each with distinct characteristics. However, the long-term outcomes of these pacing strategies remain insufficiently compared. This study evaluates clinical and echocardiographic outcomes of patients with AVB treated with dual chamber RVP, His bundle pacing (HBP), or LL. Methods: This single-center observational registry study included 22 consecutive patients receiving LL with atrioventricular resynchronization functionality (October 2020 to October 2022), matched with 66 control patients receiving either RVP (33 patients) or HBP (33 patients) using propensity score matching (2:3:3 ratio). Primary and secondary endpoints included all-cause mortality, cardiovascular mortality, heart failure, and echocardiographic outcomes. Atrioventricular synchrony in the LL group was assessed. Results: At two years, all-cause mortality was significantly higher in the LL group compared to RVP (36.4% vs. 6.1%, p = 0.002) and HBP (36.4% vs. 12.1%, p = 0.03), but LL had a more severe clinical profile. Cardiovascular mortality and heart failure incidence showed no significant differences. Patients receiving RVP showed a significant decrease in left ventricular ejection fraction and an increase in ventricular volumes. In contrast, HBP patients exhibited favorable cardiac remodeling. Stratification based on atrial sensing showed that LL patients with >66% AV synchrony had a lower mortality (p = 0.02). Conclusions: CSP offers superior results compared to other pacing methods in terms of ventricular function owing to a physiological ventricular activation and maintenance of AV synchrony. However, LL may be a viable alternative for frail and high-risk patients, as the suboptimal AV synchrony is traded off with lesser ventricular dyssynchrony. Full article

Background: Restoring electrical synchrony with cardiac resynchronization therapy (CRT) reverses the heart failure phenotype developed by left-ventricular (LV) dyssynchrony. This study aimed to identify new predictors of response to LV-only fusion pacing CRT. Methods: A select group of patients with CRT-P indications received a right atrium (RA)/LV DDD pacing system. LV dyssynchrony was assessed via offline TDI timing focusing on the temporal difference between peak septal (E″T) and lateral wall (A“T) motion. CRT effectiveness was evaluated at each follow-up, involving the heart rate recovery index (HRRI) parameter (acceleration/deceleration time) derived from exercise testing along with the echocardiographic parameters. Patients were classified into super-responders (SR), responders (R), and non-responders (NR). Results: Baseline initial characteristics: 62 patients (35 male) aged 62 ± 11 y.o. with non-ischemic dilated cardiomyopathy (DCM). Ejection fraction (EF) 27 ± 5.2%; QRS 164 ± 18 ms; 29% had type III diastolic dysfunction (DD), 63% type II DD, and 8% type I DD. Average follow-up was 45 ± 19 months: 34% of patients were SR, 61% R, and 5% NR. The E″T decreased from 90 ± 20 ms to 25 ± 10 ms in SR, with a shorter deceleration time (DT) during exercise test compared to NR (109 ± 68 ms vs. 330 ± 30 ms; p < 0.0001). The responders present a higher HRRI (2.87 ± 1.47 vs. 0.98 ± 0.08; p = 0.03) compared to NR and a significantly decrease in E“T and A“T from 76 ± 13 ms to 51 ± 11 ms (p < 0.0001). Prolonged DT was associated with an accentuated LV dyssynchrony and nonoptimal response to CRT. Conclusions: The study identified new parameters for assessing responsiveness to LV-only fusion pacing CRT, which could improve candidate selection and CRT implementation. Full article

Background/Objectives: Hemodialysis-induced myocardial stunning (HIMS) is a frequent complication in patients undergoing maintenance hemodialysis, characterized by transient left ventricular dysfunction due to ischemic episodes. Mitochondrial dysfunction and fluctuations in key ions such as potassium (K⁺) and calcium (Ca²⁺) are implicated in the pathogenesis of HIMS. This study aims to investigate the role of mitochondrial dysfunction and the protective potential of mitochondrial ATP-sensitive potassium channels (mitoK_ATP) in mitigating HIMS. Methods: A 5/6 nephrectomy rat model was established to mimic chronic kidney disease and the subsequent HIMS. The effects of mitoK_ATP channel modulators were evaluated by administering diazoxide (DZX), a mitoK_ATP opener, and 5-hydroxydecanoate (5-HD), a mitoK_ATP blocker, before hemodialysis. Mitochondrial function was assessed by measuring membrane potential, ATP synthase activity, and intramitochondrial Ca²⁺ levels. Myocardial function was evaluated using speckle tracking echocardiography. Results: Rats undergoing hemodialysis exhibited significant reductions in left ventricular strain and synchrony. DZX administration significantly improved mitochondrial function and reduced myocardial strain compared to controls. Conversely, 5-HD worsened mitochondrial swelling and disrupted myocardial function. Higher K⁺ and Ca²⁺ concentrations in the dialysate were associated with improved mitochondrial energy metabolism and myocardial strain. Conclusions: Mitochondrial dysfunction and ion imbalances during hemodialysis are key contributors to HIMS. The activation of mitoK_ATP channels provides mitochondrial protection and may serve as a potential therapeutic strategy to mitigate HIMS. Full article

Introduction: The problem can be stated as over three billion choices to improve 14 disease states with nine optimization goals (some of the optimization goals are diametrically opposed) to improve dyspnea, shortness of breath, fatigability, exercise intolerance, edema, swelling, fluid retention, and arrhythmias. The goal is to increase the Left Ventricular Outflow Integral, reduce mitral regurgitation, increase longitudinal conduction velocities, and restore synchrony of the septum to the ventricle that needs it the most. The paper is organized in the following sections: (I) Spectrum of Cardiac Disease and Desired Pacing Outcomes; (II) Echo Evaluation of Disease Processes; (III) Pacing Goals in the Spectrum of Disease; (IV) Remodeling—Mathematical Model; (V) Method of Optimization of the Pacing Devices. Conclusions: Pacing trials provided the basic justification for an additional pacing lead but fell short in optimizing individual patients. The physician needs to recognize the spectrum of disease and use the protocol to improve the quality of life of the individual patient. A method to accomplish this task for the spectrum of cardiac disease is presented. Full article

Background and Objectives: Atrioventricular (AV) dyssynchrony as well as atrial and ventricular pacing affect left atrial (LA) function. We conducted a study evaluating the effect of atrial and ventricular pacing on LA morphological and functional changes after dual-chamber pacemaker implantation. Materials and Methods: The study prospectively enrolled 121 subjects who had a dual-chamber pacemaker implanted due to sinus node disease (SND) or atrioventricular block (AVB). Subjects were divided into three groups based on indication and pacemaker programming: (1) SND DDDR 60; (2) AVB DDD 60 and (3) AVB DDD 40. Subjects were invited to one- and three-month follow-up visits. Three subsets based on pacing burden were analyzed: (1) high atrial (A) low ventricular (V); (2) high A, high V and (3) low A, high V. LA function was assessed from volumetric parameters and measured strains from echocardiography. Results: The high A, low V group consisted of 38 subjects; while high A, high V had 26 and low A, high V had 23. A significant decrease in reservoir and contractile LA strain parameters were only observed in the high A, low V pacing group after three months (reservoir 25.9 ± 10.3% vs. 21.1 ± 9.9%, p = 0.003, contractile −14.0 ± 9.0% vs. −11.1 ± 7.8, p = 0.018). While the re-established atrioventricular synchrony in the low A, high V group maintained reservoir LA strain at the baseline level after three months (21.4 ± 10.4% vs. 22.5 ± 10.4%, p = 0.975); in the high A, high V group, a further trend to decrease was noted (20.3 ± 8.9% vs. 18.7 ± 8.3%, p = 0.231). Conclusions: High atrial pacing burden independently of atrioventricular dyssynchrony and ventricular pacing impairs LA functional and morphological parameters. Changes appear soon after pacemaker implantation and are maintained. Full article