A self-powered intracardiac pacemaker in swine model.

Harvesting biomechanical energy from cardiac motion is an attractive power source for implantable bioelectronic devices. Here, we report a battery-free, transcatheter, self-powered intracardiac pacemaker based on the coupled effect of triboelectrification and electrostatic induction for the treatment of arrhythmia in large animal models. We show that the capsule-shaped device (1.75 g, 1.52 cc) can be integrated with a delivery catheter for implanting in the right ventricle of a swine through the intravenous route, which effectively converts cardiac motion energy to electricity and maintains endocardial pacing function during the three-week follow-up period. We measure in vivo open circuit voltage and short circuit current of the self-powered intracardiac pacemaker of about 6.0 V and 0.2 μA, respectively. This approach exhibits up-to-date progress in self-powered medical devices and it may overcome the inherent energy shortcomings of implantable pacemakers and other bioelectronic devices for therapy and sensing.

Novel sizing role of 3D transesophageal echocardiography in a novel left atrial appendage clip device for patients undergoing video-assisted atrial fibrillation ablation: a cohort study.

Background:Three-dimensional (3D) transesophageal echocardiography (TEE) has been successfully used in the sizing of left atrial appendage (LAA) occlusion devices, but its use has not yet been studied in LAA clip devices. We sought to develop and validate the novel use of 3D-TEE sizing in a novel LAA clip device for atrial fibrillation (AF) patients undergoing video-assisted thoracic surgery (VATS) ablation.Methods:Consecutive patients with isolated AF undergoing LAA clipping or excision during VATS ablation were included in the study between June 2021 and September 2022 at Fuwai Hospital. The patients underwent 3D-TEE examinations preoperatively and postoperatively. The VATS length, LAA clip effective length, and LAA excision margin length were recorded. A correlation analysis, intraclass correlation coefficient (ICC) analysis, and Bland-Altman plot analysis were conducted to examine the TEE parameters, VATS length, LAA clip effective length, and LAA excision margin length.Results:In total, 26 AF patients undergoing LAA clipping and 15 undergoing LAA excision were included in the study. In the LAA clipping group, in which the Atriclip size served as the control, the 3D-TEE with volumetric measurement (the perimeter-derived maximum orifice diameter) (R=0.938; ICC =0.934; Bland-Altman plot variability, 3.85%) showed the best sizing efficacy for the LAA clip device among the 3D-TEE with multiplanar reformatting sizing (the perimeter-derived maximum orifice diameter) (R=0.808; ICC =0.772; Bland-Altman plot variability, 3.85%), VATS sizing (R=0.851; ICC =0.756; Bland-Altman plot variability, 11.54%), and VATS plus 0.5-cm sizing (R=0.851; ICC =0.775; Bland-Altman plot variability, 11.54%) measurements (all P<0.001). In addition, for the distribution of matched sizing in the LAA clip group, 3D-TEE with volumetric measurement sizing (20/26) had a higher proportion than 3D-TEE with multiplanar reformatting sizing (11/26, P=0.011), VATS sizing (9/26, P=0.002), and VATS plus 0.5-cm sizing (14/26, P=0.08). Using the LAA excision margin length as the control, the mean difference in the LAA diameter was 1.17 cm [95% confidence interval (CI): 0.71-1.62 cm , P<0.001] in the maximum orifice diameter of two-dimensional-TEE, 0.15 cm (95% CI: -0.32 to 0.61 cm , P=0.523) in the perimeter-derived 3D multiplanar reformatting (the maximum orifice diameter), and 0.03 cm (95% CI: -0.47 to 0.53, P=0.901) in the perimeter-derived 3D volumetric (3DV) measurement (the maximum orifice diameter), and the related Pearson correlation coefficients for these modalities were 0.760 (P=0.001), 0.843 (P<0.001), and 0.963 (P<0.001), respectively.Conclusions:Our study showed that 3D-TEE might be employed in the sizing of a novel LAA clip device using the VATS approach in patients with AF. The 3DV measurement (the perimeter-derived maximum orifice diameter) was superior to the VATS measurement. These findings might also apply to LAA VATS excision patients with AF.

Dyssynchronous heart failure models in canines: New insights into electrocardiographic, echocardiographic and histological features.

BACKGROUND:We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines.METHODS:A total of eight dogs were included in the experiment, four were tachy-paced in right ventricle apex (RVAP) and 4 were paced in right atrium after the ablation of left bundle branch to achieve left bundle branch block (RAP+LBBB). Three weeks of follow-up were conducted to observe the changes in cardiac function and myocardial staining was performed at the end of the experiment.RESULTS:Both experimental approaches successfully established heart failure with reduced ejection fraction models, with similar trends in declining cardiac function. The RAP+LBBB group exhibited a prolonged overall ventricular activation time, delayed left ventricular activation, and lesser impact on the right ventricle. The RVAP approach led to a reduction in overall right ventricular compliance and right ventricular enlargement. The RAP+LBBB group exhibited significant reductions in left heart compliance (LVGLS, %: RAP+LBBB -12.60 ± 0.12 to -5.93 ± 1.25; RVAP -13.28 ± 0.62 to -8.05 ± 0.63, p = 0.023; LASct, %: RAP+LBBB -15.75 ± 6.85 to -1.50 ± 1.00; RVAP -15.75 ± 2.87 to -10.05 ± 6.16, p = 0.035). Histological examination revealed more pronounced fibrosis in the left ventricular wall and left atrium in the RAP+LBBB group while the RVAP group showed more prominent fibrosis in the right ventricular myocardium.CONCLUSION:Both approaches establish HFrEF models with comparable trends. The RVAP group shows impaired right ventricular function, while the RAP+LBBB group exhibits more severe decreased compliance and fibrosis in left ventricle.

Morphology of hypertrophied basal septum contributes to left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy: a retrospective case-control study.

Background:Detailed assessment of basal septal morphology is essential for understanding the morphological mechanism of left ventricular outflow tract (LVOT) obstruction. We aimed to analyze the morphological alterations of the basal septum (BS) and its surrounding structures and explore their role in LVOT obstruction (LVOTO) in patients with hypertrophic cardiomyopathy (HCM).Methods:During January 2019 and December 2019, 239 patients were diagnosed with HCM at Fuwai Hospital. We retrospectively reviewed echocardiographic data sets from 105 consecutive patients with HCM [64 with hypertrophic obstructive cardiomyopathy (HOCM) and 41 with hypertrophic non-obstructive cardiomyopathy (HNOCM)] and 28 healthy controls. For quantitatively assessing the basal septal morphology, a novel measurement method was used to obtain the IVSa (the area of the BS protruding into the LVOT), LA (the largest distance of the BS protruding into the LVOT), LB (IVSa length in the direction perpendicular to the LA), and S-IVSa (IVSa divided by LB). Echocardiographic parameters associated with LVOTO were analyzed using multivariable logistic regression analyses.Results:There was no significant difference in the maximal basal septal thickness between the HOCM and HNOCM patients (P>0.99). Among the three groups, there were significant differences in the length of the anterior and posterior mitral leaflets (AML and PML), the angle between the mitral valve orifice and ascending aorta (MV-AO) angle, IVSa, LA, LB, and S-IVSa (all P<0.001). Compared with HNOCM patients, HOCM patients had significantly longer AML and PML, as well as larger MV-AO angle, IVSa, LA, and S-IVSa (P<0.001, P<0.001, P<0.001, P=0.002, P<0.001, and P=0.03, respectively). In the multivariate analysis, AML, MV-AO angle, IVSa, and S-IVSa were associated with LVOTO {odds ratio (OR) [95% confidence interval (CI)]: 0.649 (0.462-0.911), P=0.01; 0.842 (0.768-0.923), P<0.001; 1.025 (1.001-1.049), P=0.04; and 0.276 (0.101-0.754), P=0.01, respectively}.Conclusions:Morphological alterations of the BS relative to the LVOT may provide additional value for estimating the extent of LVOTO. The length of AML, MV-AO angle, IVSa, and S-IVSa were associated with LVOTO.

Tricuspid regurgitation following pacemaker implantation for bradycardia: a two-year study comparing different pacing strategies.

A novel approach for developing left bundle branch pacing and left bundle branch block in a canine model.

BACKGROUND AND OBJECTIVE:Left bundle branch pacing (LBBP) has shown the benefits in the treatment of dyssynchronous heart failure (HF). The purpose of this study was to develop a novel approach for LBBP and left bundle branch block (LBBB) in a canine model.METHODS:A "triangle-center" method by tricuspid valve annulus angiography for LBBP implantation was performed in 6 canines. A catheter was then applied for retrograde His potential recording and left bundle branch (LBB) ablation simultaneously. The conduction system was stained to verify the "triangle-center" method for LBBP and assess the locations of the LBB ablation site in relation to the left septal fascicle (LSF).RESULTS:The mean LBB potential to ventricular interval and stimulus-peak left ventricular activation time were 11.8 ± 1.2 and 35.7 ± 3.1 ms, respectively. The average intrinsic QRS duration was 44.7 ± 4.7 ms. LBB ablation significantly prolonged the QRS duration (106.3 ± 8.3 ms, p < .001) while LBBP significantly shortened the LBBB-QRS duration to 62.5 ± 5.3 ms (p < .001). After 6 weeks of follow-up, both paced QRS duration (63.0 ± 5.4 ms; p = .203) and LBBB-QRS duration (107.3 ± 7.4 ms; p = .144) were unchanged when comparing to the acute phase, respectively. Anatomical analysis of 6 canine hearts showed that the LBBP lead-tip was all placed in LSF area.CONCLUSION:The new approach for LBBP and LBBB canine model was stable and feasible to simulate the clinical dyssynchrony and resynchronization. It provided a useful tool to investigate the basic mechanisms of underlying physiological pacing benefits.

Randomized Trial of Left Bundle Branch vs Biventricular Pacing for Cardiac Resynchronization Therapy.

BACKGROUND:Left bundle branch pacing (LBBP) is the most rapidly growing conduction system pacing technique that is capable of correcting intrinsic left bundle branch block (LBBB). As such, it is potentially an optimal alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BiVP).OBJECTIVES:The authors sought to compare the efficacy of LBBP-CRT with BiVP-CRT in patients with heart failure and reduced left ventricular ejection fraction (LVEF).METHODS:This is a prospective, randomized trial of patients with nonischemic cardiomyopathy and LBBB with 6-month preplanned follow-up. Crossovers were allowed if LBBP or BiVP were unsuccessful. The primary endpoint was the difference in LVEF improvement between 2 groups. The secondary endpoints included changes in echocardiographic measurements, N-terminal pro-B-type natriuretic peptide (NT-proBNP), New York Heart Association functional class, 6-minute walk distance, QRS duration, and CRT response.RESULTS:The study included 40 consecutive patients (20 males, mean age 63.7 years, LVEF 29.7% ± 5.6%). Crossovers occurred in 10% of LBBP-CRT and 20% of BiVP-CRT. All patients completed follow-up. Intention-to-treat analysis showed significantly higher LVEF improvement at 6 months after LBBP-CRT than BiVP-CRT (mean difference: 5.6%; 95% CI: 0.3-10.9; P = 0.039). LBBP-CRT also appeared to have greater reductions in left ventricular end-systolic volume (-24.97 mL; 95% CI: -49.58 to -0.36 mL) and NT-proBNP (-1,071.80 pg/mL; 95% CI: -2,099.40 to -44.20 pg/mL), and comparable changes in New York Heart Association functional class, 6-minute walk distance, QRS duration, and rates of CRT response compared with BiVP-CRT.CONCLUSIONS:LBBP-CRT demonstrated greater LVEF improvement than BiVP-CRT in heart failure patients with nonischemic cardiomyopathy and LBBB. (Left Bundle Branch Pacing Versus Biventricular Pacing for Cardiac Resynchronization Therapy [LBBP-RESYNC]; NCT04110431).

Tricuspid regurgitation outcomes in left bundle branch area pacing and comparison with right ventricular septal pacing.

Clinical Outcomes in Patients With Left Bundle Branch Area Pacing vs. Right Ventricular Pacing for Atrioventricular Block.

Background: Left bundle branch area pacing (LBBAP) is a novel pacing modality with stable pacing parameters and a narrow-paced QRS duration. We compared heart failure (HF) hospitalization events and echocardiographic measures between LBBAP and right ventricular pacing (RVP) in patients with atrioventricular block (AVB). Methods and Results: This multicenter observational study prospectively recruited consecutive AVB patients requiring ventricular pacing in five centers if they received LBBAP or RVP and had left ventricular ejection fraction (LVEF) >50%. Data on electrocardiogram, pacing parameters, echocardiographic measurements, device complications, and clinical outcomes were collected at baseline and during follow-up. The primary outcome was first episode hospitalization for HF or upgrade to biventricular pacing. LBBAP was successful in 235 of 246 patients (95.5%), while 120 patients received RVP. During a mean of 11.4 ± 2.7 months of follow-up, the ventricular pacing burden was comparable (83.9 ± 35.1 vs. 85.7 ± 30.0%), while the mean LVEF differed significantly (62.6 ± 4.6 vs. 57.8 ± 11.4%) between the LBBAP and RVP groups. Patients with LBBAP had significantly lower occurrences of HF hospitalization and upgrading to biventricular pacing than patients with RVP (2.6 vs. 10.8%, P <0.001), and differences in primary outcome between LBBAP and RVP were mainly observed in patients with ventricular pacing >40% or with baseline LVEF <60%. The primary outcome was independently associated with LBBAP (adjusted HR 0.14, 95% CI: 0.04-0.55), previous myocardial infarction (adjusted HR 6.82, 95% CI: 1.23-37.5), and baseline LVEF (adjusted HR 0.91, 95% CI: 0.86-0.96). Conclusion: Permanent LBBAP might reduce the risk of HF hospitalization or upgrade to biventricular pacing compared with RVP in AVB patients requiring a high burden of ventricular pacing. Clinical Trial Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03851315; URL: http://www.chictr.org.cn; Unique Identifier: ChiCTR2100043296.

Incidence, risk factors and prognostic effect of imaging right ventricular involvement in patients with COVID-19: a dose-response analysis protocol for systematic review.

INTRODUCTION:Emerging evidence has shown that COVID-19 infection may result in right ventricular (RV) disturbance and be associated with adverse clinical outcomes. The aim of this meta-analysis is to summarise the incidence, risk factors and the prognostic effect of imaging RV involvement in adult patients with COVID-19.METHODS:A systematical search will be performed in PubMed, EMBase, ISI Knowledge via Web of Science and preprint databases (MedRxiv and BioRxiv) (until October 2021) to identify all cohort studies in adult patients with COVID-19. The primary outcome will be the incidence of RV involvement (dysfunction and/or dilation) assessed by echocardiography, CT or MRI. Secondary outcomes will include the risk factors for RV involvement and their association with all-cause mortality during hospitalisation. Additional outcomes will include the RV global or free wall longitudinal strain (RV-GLS or RV-FWLS), tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC) and RV diameter. Univariable or multivariable meta-regression and subgroup analyses will be performed for the study design and patient characteristics (especially acute or chronic pulmonary embolism and pulmonary hypertension). Sensitivity analyses will be used to assess the robustness of our results by removing each included study at one time to obtain and evaluate the remaining overall estimates of RV involvement incidence and related risk factors, association with all-cause mortality, and other RV parameters (RV-GLS or RV-FWLS, TAPSE, S', FAC and RV diameter). Both linear and cubic spline regression models will be used to explore the dose-response relationship between different categories (>2) of RV involvement and the risk of mortality (OR or HR).ETHICS AND DISSEMINATION:There was no need for ethics approval for the systematic review protocol according to the Institutional Review Board/Independent Ethics Committee of Fuwai Hospital. This meta-analysis will be disseminated through a peer-reviewed journal for publication.PROSPERO REGISTRATION NUMBER:CRD42021231689.

A self-powered intracardiac pacemaker in swine model.

Harvesting biomechanical energy from cardiac motion is an attractive power source for implantable bioelectronic devices. Here, we report a battery-free, transcatheter, self-powered intracardiac pacemaker based on the coupled effect of triboelectrification and electrostatic induction for the treatment of arrhythmia in large animal models. We show that the capsule-shaped device (1.75 g, 1.52 cc) can be integrated with a delivery catheter for implanting in the right ventricle of a swine through the intravenous route, which effectively converts cardiac motion energy to electricity and maintains endocardial pacing function during the three-week follow-up period. We measure in vivo open circuit voltage and short circuit current of the self-powered intracardiac pacemaker of about 6.0 V and 0.2 μA, respectively. This approach exhibits up-to-date progress in self-powered medical devices and it may overcome the inherent energy shortcomings of implantable pacemakers and other bioelectronic devices for therapy and sensing.

Novel sizing role of 3D transesophageal echocardiography in a novel left atrial appendage clip device for patients undergoing video-assisted atrial fibrillation ablation: a cohort study.

Background:Three-dimensional (3D) transesophageal echocardiography (TEE) has been successfully used in the sizing of left atrial appendage (LAA) occlusion devices, but its use has not yet been studied in LAA clip devices. We sought to develop and validate the novel use of 3D-TEE sizing in a novel LAA clip device for atrial fibrillation (AF) patients undergoing video-assisted thoracic surgery (VATS) ablation.Methods:Consecutive patients with isolated AF undergoing LAA clipping or excision during VATS ablation were included in the study between June 2021 and September 2022 at Fuwai Hospital. The patients underwent 3D-TEE examinations preoperatively and postoperatively. The VATS length, LAA clip effective length, and LAA excision margin length were recorded. A correlation analysis, intraclass correlation coefficient (ICC) analysis, and Bland-Altman plot analysis were conducted to examine the TEE parameters, VATS length, LAA clip effective length, and LAA excision margin length.Results:In total, 26 AF patients undergoing LAA clipping and 15 undergoing LAA excision were included in the study. In the LAA clipping group, in which the Atriclip size served as the control, the 3D-TEE with volumetric measurement (the perimeter-derived maximum orifice diameter) (R=0.938; ICC =0.934; Bland-Altman plot variability, 3.85%) showed the best sizing efficacy for the LAA clip device among the 3D-TEE with multiplanar reformatting sizing (the perimeter-derived maximum orifice diameter) (R=0.808; ICC =0.772; Bland-Altman plot variability, 3.85%), VATS sizing (R=0.851; ICC =0.756; Bland-Altman plot variability, 11.54%), and VATS plus 0.5-cm sizing (R=0.851; ICC =0.775; Bland-Altman plot variability, 11.54%) measurements (all P<0.001). In addition, for the distribution of matched sizing in the LAA clip group, 3D-TEE with volumetric measurement sizing (20/26) had a higher proportion than 3D-TEE with multiplanar reformatting sizing (11/26, P=0.011), VATS sizing (9/26, P=0.002), and VATS plus 0.5-cm sizing (14/26, P=0.08). Using the LAA excision margin length as the control, the mean difference in the LAA diameter was 1.17 cm [95% confidence interval (CI): 0.71-1.62 cm , P<0.001] in the maximum orifice diameter of two-dimensional-TEE, 0.15 cm (95% CI: -0.32 to 0.61 cm , P=0.523) in the perimeter-derived 3D multiplanar reformatting (the maximum orifice diameter), and 0.03 cm (95% CI: -0.47 to 0.53, P=0.901) in the perimeter-derived 3D volumetric (3DV) measurement (the maximum orifice diameter), and the related Pearson correlation coefficients for these modalities were 0.760 (P=0.001), 0.843 (P<0.001), and 0.963 (P<0.001), respectively.Conclusions:Our study showed that 3D-TEE might be employed in the sizing of a novel LAA clip device using the VATS approach in patients with AF. The 3DV measurement (the perimeter-derived maximum orifice diameter) was superior to the VATS measurement. These findings might also apply to LAA VATS excision patients with AF.

Dyssynchronous heart failure models in canines: New insights into electrocardiographic, echocardiographic and histological features.

BACKGROUND:We investigated the similarities and differences between two experimental approaches using tachy-pacing technology to induce desynchronized heart failure in canines.METHODS:A total of eight dogs were included in the experiment, four were tachy-paced in right ventricle apex (RVAP) and 4 were paced in right atrium after the ablation of left bundle branch to achieve left bundle branch block (RAP+LBBB). Three weeks of follow-up were conducted to observe the changes in cardiac function and myocardial staining was performed at the end of the experiment.RESULTS:Both experimental approaches successfully established heart failure with reduced ejection fraction models, with similar trends in declining cardiac function. The RAP+LBBB group exhibited a prolonged overall ventricular activation time, delayed left ventricular activation, and lesser impact on the right ventricle. The RVAP approach led to a reduction in overall right ventricular compliance and right ventricular enlargement. The RAP+LBBB group exhibited significant reductions in left heart compliance (LVGLS, %: RAP+LBBB -12.60 ± 0.12 to -5.93 ± 1.25; RVAP -13.28 ± 0.62 to -8.05 ± 0.63, p = 0.023; LASct, %: RAP+LBBB -15.75 ± 6.85 to -1.50 ± 1.00; RVAP -15.75 ± 2.87 to -10.05 ± 6.16, p = 0.035). Histological examination revealed more pronounced fibrosis in the left ventricular wall and left atrium in the RAP+LBBB group while the RVAP group showed more prominent fibrosis in the right ventricular myocardium.CONCLUSION:Both approaches establish HFrEF models with comparable trends. The RVAP group shows impaired right ventricular function, while the RAP+LBBB group exhibits more severe decreased compliance and fibrosis in left ventricle.

Morphology of hypertrophied basal septum contributes to left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy: a retrospective case-control study.

Background:Detailed assessment of basal septal morphology is essential for understanding the morphological mechanism of left ventricular outflow tract (LVOT) obstruction. We aimed to analyze the morphological alterations of the basal septum (BS) and its surrounding structures and explore their role in LVOT obstruction (LVOTO) in patients with hypertrophic cardiomyopathy (HCM).Methods:During January 2019 and December 2019, 239 patients were diagnosed with HCM at Fuwai Hospital. We retrospectively reviewed echocardiographic data sets from 105 consecutive patients with HCM [64 with hypertrophic obstructive cardiomyopathy (HOCM) and 41 with hypertrophic non-obstructive cardiomyopathy (HNOCM)] and 28 healthy controls. For quantitatively assessing the basal septal morphology, a novel measurement method was used to obtain the IVSa (the area of the BS protruding into the LVOT), LA (the largest distance of the BS protruding into the LVOT), LB (IVSa length in the direction perpendicular to the LA), and S-IVSa (IVSa divided by LB). Echocardiographic parameters associated with LVOTO were analyzed using multivariable logistic regression analyses.Results:There was no significant difference in the maximal basal septal thickness between the HOCM and HNOCM patients (P>0.99). Among the three groups, there were significant differences in the length of the anterior and posterior mitral leaflets (AML and PML), the angle between the mitral valve orifice and ascending aorta (MV-AO) angle, IVSa, LA, LB, and S-IVSa (all P<0.001). Compared with HNOCM patients, HOCM patients had significantly longer AML and PML, as well as larger MV-AO angle, IVSa, LA, and S-IVSa (P<0.001, P<0.001, P<0.001, P=0.002, P<0.001, and P=0.03, respectively). In the multivariate analysis, AML, MV-AO angle, IVSa, and S-IVSa were associated with LVOTO {odds ratio (OR) [95% confidence interval (CI)]: 0.649 (0.462-0.911), P=0.01; 0.842 (0.768-0.923), P<0.001; 1.025 (1.001-1.049), P=0.04; and 0.276 (0.101-0.754), P=0.01, respectively}.Conclusions:Morphological alterations of the BS relative to the LVOT may provide additional value for estimating the extent of LVOTO. The length of AML, MV-AO angle, IVSa, and S-IVSa were associated with LVOTO.

Tricuspid regurgitation following pacemaker implantation for bradycardia: a two-year study comparing different pacing strategies.

A novel approach for developing left bundle branch pacing and left bundle branch block in a canine model.

BACKGROUND AND OBJECTIVE:Left bundle branch pacing (LBBP) has shown the benefits in the treatment of dyssynchronous heart failure (HF). The purpose of this study was to develop a novel approach for LBBP and left bundle branch block (LBBB) in a canine model.METHODS:A "triangle-center" method by tricuspid valve annulus angiography for LBBP implantation was performed in 6 canines. A catheter was then applied for retrograde His potential recording and left bundle branch (LBB) ablation simultaneously. The conduction system was stained to verify the "triangle-center" method for LBBP and assess the locations of the LBB ablation site in relation to the left septal fascicle (LSF).RESULTS:The mean LBB potential to ventricular interval and stimulus-peak left ventricular activation time were 11.8 ± 1.2 and 35.7 ± 3.1 ms, respectively. The average intrinsic QRS duration was 44.7 ± 4.7 ms. LBB ablation significantly prolonged the QRS duration (106.3 ± 8.3 ms, p < .001) while LBBP significantly shortened the LBBB-QRS duration to 62.5 ± 5.3 ms (p < .001). After 6 weeks of follow-up, both paced QRS duration (63.0 ± 5.4 ms; p = .203) and LBBB-QRS duration (107.3 ± 7.4 ms; p = .144) were unchanged when comparing to the acute phase, respectively. Anatomical analysis of 6 canine hearts showed that the LBBP lead-tip was all placed in LSF area.CONCLUSION:The new approach for LBBP and LBBB canine model was stable and feasible to simulate the clinical dyssynchrony and resynchronization. It provided a useful tool to investigate the basic mechanisms of underlying physiological pacing benefits.

Randomized Trial of Left Bundle Branch vs Biventricular Pacing for Cardiac Resynchronization Therapy.

BACKGROUND:Left bundle branch pacing (LBBP) is the most rapidly growing conduction system pacing technique that is capable of correcting intrinsic left bundle branch block (LBBB). As such, it is potentially an optimal alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BiVP).OBJECTIVES:The authors sought to compare the efficacy of LBBP-CRT with BiVP-CRT in patients with heart failure and reduced left ventricular ejection fraction (LVEF).METHODS:This is a prospective, randomized trial of patients with nonischemic cardiomyopathy and LBBB with 6-month preplanned follow-up. Crossovers were allowed if LBBP or BiVP were unsuccessful. The primary endpoint was the difference in LVEF improvement between 2 groups. The secondary endpoints included changes in echocardiographic measurements, N-terminal pro-B-type natriuretic peptide (NT-proBNP), New York Heart Association functional class, 6-minute walk distance, QRS duration, and CRT response.RESULTS:The study included 40 consecutive patients (20 males, mean age 63.7 years, LVEF 29.7% ± 5.6%). Crossovers occurred in 10% of LBBP-CRT and 20% of BiVP-CRT. All patients completed follow-up. Intention-to-treat analysis showed significantly higher LVEF improvement at 6 months after LBBP-CRT than BiVP-CRT (mean difference: 5.6%; 95% CI: 0.3-10.9; P = 0.039). LBBP-CRT also appeared to have greater reductions in left ventricular end-systolic volume (-24.97 mL; 95% CI: -49.58 to -0.36 mL) and NT-proBNP (-1,071.80 pg/mL; 95% CI: -2,099.40 to -44.20 pg/mL), and comparable changes in New York Heart Association functional class, 6-minute walk distance, QRS duration, and rates of CRT response compared with BiVP-CRT.CONCLUSIONS:LBBP-CRT demonstrated greater LVEF improvement than BiVP-CRT in heart failure patients with nonischemic cardiomyopathy and LBBB. (Left Bundle Branch Pacing Versus Biventricular Pacing for Cardiac Resynchronization Therapy [LBBP-RESYNC]; NCT04110431).

Tricuspid regurgitation outcomes in left bundle branch area pacing and comparison with right ventricular septal pacing.

Clinical Outcomes in Patients With Left Bundle Branch Area Pacing vs. Right Ventricular Pacing for Atrioventricular Block.

Background: Left bundle branch area pacing (LBBAP) is a novel pacing modality with stable pacing parameters and a narrow-paced QRS duration. We compared heart failure (HF) hospitalization events and echocardiographic measures between LBBAP and right ventricular pacing (RVP) in patients with atrioventricular block (AVB). Methods and Results: This multicenter observational study prospectively recruited consecutive AVB patients requiring ventricular pacing in five centers if they received LBBAP or RVP and had left ventricular ejection fraction (LVEF) >50%. Data on electrocardiogram, pacing parameters, echocardiographic measurements, device complications, and clinical outcomes were collected at baseline and during follow-up. The primary outcome was first episode hospitalization for HF or upgrade to biventricular pacing. LBBAP was successful in 235 of 246 patients (95.5%), while 120 patients received RVP. During a mean of 11.4 ± 2.7 months of follow-up, the ventricular pacing burden was comparable (83.9 ± 35.1 vs. 85.7 ± 30.0%), while the mean LVEF differed significantly (62.6 ± 4.6 vs. 57.8 ± 11.4%) between the LBBAP and RVP groups. Patients with LBBAP had significantly lower occurrences of HF hospitalization and upgrading to biventricular pacing than patients with RVP (2.6 vs. 10.8%, P <0.001), and differences in primary outcome between LBBAP and RVP were mainly observed in patients with ventricular pacing >40% or with baseline LVEF <60%. The primary outcome was independently associated with LBBAP (adjusted HR 0.14, 95% CI: 0.04-0.55), previous myocardial infarction (adjusted HR 6.82, 95% CI: 1.23-37.5), and baseline LVEF (adjusted HR 0.91, 95% CI: 0.86-0.96). Conclusion: Permanent LBBAP might reduce the risk of HF hospitalization or upgrade to biventricular pacing compared with RVP in AVB patients requiring a high burden of ventricular pacing. Clinical Trial Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03851315; URL: http://www.chictr.org.cn; Unique Identifier: ChiCTR2100043296.

Incidence, risk factors and prognostic effect of imaging right ventricular involvement in patients with COVID-19: a dose-response analysis protocol for systematic review.

INTRODUCTION:Emerging evidence has shown that COVID-19 infection may result in right ventricular (RV) disturbance and be associated with adverse clinical outcomes. The aim of this meta-analysis is to summarise the incidence, risk factors and the prognostic effect of imaging RV involvement in adult patients with COVID-19.METHODS:A systematical search will be performed in PubMed, EMBase, ISI Knowledge via Web of Science and preprint databases (MedRxiv and BioRxiv) (until October 2021) to identify all cohort studies in adult patients with COVID-19. The primary outcome will be the incidence of RV involvement (dysfunction and/or dilation) assessed by echocardiography, CT or MRI. Secondary outcomes will include the risk factors for RV involvement and their association with all-cause mortality during hospitalisation. Additional outcomes will include the RV global or free wall longitudinal strain (RV-GLS or RV-FWLS), tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC) and RV diameter. Univariable or multivariable meta-regression and subgroup analyses will be performed for the study design and patient characteristics (especially acute or chronic pulmonary embolism and pulmonary hypertension). Sensitivity analyses will be used to assess the robustness of our results by removing each included study at one time to obtain and evaluate the remaining overall estimates of RV involvement incidence and related risk factors, association with all-cause mortality, and other RV parameters (RV-GLS or RV-FWLS, TAPSE, S', FAC and RV diameter). Both linear and cubic spline regression models will be used to explore the dose-response relationship between different categories (>2) of RV involvement and the risk of mortality (OR or HR).ETHICS AND DISSEMINATION:There was no need for ethics approval for the systematic review protocol according to the Institutional Review Board/Independent Ethics Committee of Fuwai Hospital. This meta-analysis will be disseminated through a peer-reviewed journal for publication.PROSPERO REGISTRATION NUMBER:CRD42021231689.