Long-term effect of right ventricular pacing on myocardial perfusion and function

The effect of right ventricle septal pacing versus apical pacing in dual-chamber pacemakers on patients' anxiety and depression: a one-year follow-up study

BACKGROUND

Anxiety and depression are potentially harmful outcomes of permanent cardiac pacemakers. Dual-chamber P.P.M. is frequently used to treat life threatening bradycardia. The study aims to estimate the effect of the right ventricular PM lead position on recipients' anxiety and depression before, 6 months, and 1 year after implantation.

RESULTS

A statistically significant correlation was discovered between the studied groups regarding HADS depression score after 6 months (p 0.013) and 1 year (p 0.013). A statistically non-significant difference was found among the studied groups at any point of time regarding baseline (p 0.063), after 6 months (p 0.054), or after 1 year (p 0.099). Significance was found between HADS anxiety score (p 0.015) or depression score after 1 year and the incidence of complications (p 0.001).

CONCLUSIONS

A strong relationship was found between the level of depression and the R.V. site of implantation, as patients with the apical group had higher levels of depression post-implantation. The septal position has less stress and depression on the patient's well-being than the apical one.

Enhancing cardiac pacing strategies: a review of conduction system pacing compared with right and biventricular pacing and their influence on myocardial function

Traditional right ventricular pacing (RVP) has been linked to the deterioration of both left ventricular diastolic and systolic function. This worsening often culminates in elevated rates of hospitalization due to heart failure, an increased risk of atrial fibrillation, and increased morbidity. While biventricular pacing (BVP) has demonstrated clinical and echocardiographic improvements in patients afflicted with heart failure and left bundle branch block, it has also encountered significant challenges such as a notable portion of non-responders and procedural failures attributed to anatomical complexities. In recent times, the interest has shifted towards conduction system pacing, initially, His bundle pacing, and more recently, left bundle branch area pacing, which are seen as promising alternatives to established methods. In contrast to other approaches, conduction system pacing offers the advantage of fostering more physiological and harmonized ventricular activation by directly stimulating the His-Purkinje network. This direct pacing results in a more synchronized systolic and diastolic function of the left ventricle compared with RVP and BVP. Of particular note is the capacity of conduction system pacing to yield a shorter QRS, conserve left ventricular ejection fraction, and reduce rates of mitral and tricuspid regurgitation when compared with RVP. The efficacy of conduction system pacing has also been found to have better clinical and echocardiographic improvement than BVP in patients requiring cardiac resynchronization. This review will delve into myocardial function in conduction system pacing compared with that in RVP and BVP.

Cardiac implantable electronic device-induced tricuspid regurgitation: Implications and management

Tricuspid regurgitation (TR) secondary to cardiac implantable electronic devices (CIEDs) has been well documented and is associated with worse cardiovascular outcomes. A variety of mechanisms have been proposed including lead-induced mechanical disruption of the tricuspid valvular or subvalvular apparatus and pacing-induced electrical dyssynchrony. Patient characteristics such as age, sex, baseline atrial fibrillation, and pre-existing TR have not been consistent predictors of CIED-induced TR. While two-dimensional echocardiography is helpful in assessing the severity of TR, three-dimensional echocardiography has significantly improved accuracy in identifying the etiology of TR and whether lead position contributes to TR. Three-dimensional echocardiography may therefore play a future role in optimizing lead positioning during implant to reduce the risk of CIED-induced TR. Optimal lead management strategies in addition to percutaneous interventions and surgery in alleviating TR are very important.

Pacing-induced cardiomyopathy in patients with preserved ejection fraction undergoing permanent cardiac pacemaker placement

BACKGROUND

Chronic right-ventricular (RV) pacing can worsen heart failure in patients with a low ejection fraction (EF), but little is known about pacing-induced cardiomyopathy (PICM) in patients with preserved EF. We aimed to investigate risk factors of PICM in these patients during long-term follow-up.

METHODS

The prospective registry at Chosun University Hospital, South Korea, included de novo patients with preserved EF undergoing transvenous permanent pacemaker (PPM) implantation for atrioventricular blockage from 2017 to 2021. Patients with EF ≥ 50% and expected ventricular pacing ≥ 40% were included. Composite outcomes were cardiac death (pump failure), hospitalization because of heart failure, PICM, and biventricular pacing (BVP) upgrade.

RESULTS

A total of 168 patients (69 men, 76.3 ± 10.4 years) were included. During three years of follow-up, one patient died, 14 were hospitalized, 16 suffered PICM, and two underwent BVP upgrade. PICM were associated with reduced global longitudinal strain (GLS), prolonged paced QRS duration (pQRSd) and diastolic variables (E/e', LAVI). Cox regression analysis identified pQRSd (hazard ratio [HR], 1.111; 95% confidence interval [CI], 1.011-1.222; P = 0.03) and reduced GLS (HR, 1.569; 95% CI, 1.163-2.118; P = 0.003) as independent predictors of PICM. GLS showed high predictive accuracy for PICM, with an area under the curve of 0.84 (95% CI 0.779-0.894; P < 0.001) [GLS -12.0, 62.5% sensitivity, and 86.1% specificity].

CONCLUSION

RV pacing increased the risk of PICM in patients with preserved EF. Reduced GLS and prolonged pQRSd could help identify individuals at high risk of PICM even with preserved EF.

Left bundle branch area pacing improving the left atrial outcomes in pace-dependent patients compared with right ventricular outflow tract septal pacing

BACKGROUND

Recent studies suggested that the left bundle branch area pacing (LBBAP) has a better efficacy to reduce QRS duration and produce a lower pacing threshold than the conventional right ventricular outflow tract septal pacing (RVOP), which resulted in a better cardiac function and ventricular synchronization. However, whether the LBBAP has a better efficacy in improving left atrial structure, function in pace-dependent patients compared with RVOP has not been well studied.

OBJECTIVE

The purpose of this study was to compare the atrial outcomes of pace-dependent patients who received LBBAP or RVOP procedures.

METHODS AND RESULTS

A total of 72 patients (including II° AVB, high AVB, and III° AVB, excluding atrial fibrillation patients with atrioventricular block) consecutively enrolled in this single-center prospective clinical study and randomly assigned to the RVOP group and the LBBP group with 36 patients. All patients were pace-dependent. The changes in echocardiogram, speckle-tracking echocardiography, brain natriuretic peptide (BNP), and 6-min walking distance were documented and compared between two groups at baseline, 7 days, 1, 3, and 6 months after the implantation. There were no significant differences in baseline characteristics between the two groups. The results of the study were as following: (1) left atrial structure index: Our study indicated that there are no significant differences in left atrial anteroposterior dimension (LAAPD), left atrial superoinferior dimension, and left atrial mediolateral dimension between two groups. While the LAAPD in the LBBAP group was significantly reduced at 6 months after implantation ([38.22 ± 2.17] mm vs. [34.13 ± 1.59] mm, p < .05). (2) Left atrial strain index: We observed that the S% was significantly improved in both groups at 3 and 6 months after implantation but more prominent in the LBBAP group at 6 months (36.94 ± 11.67 vs. 25.87 ± 8.93, p = .01). SRs, SRe were improved in the RVOP group at 6 months after implantation but was further significantly increased in the LBBAP group. Similarly, the SRa in the LBBAP group was significantly better than the RVOP group after 6 months (-2.11 ± 0.75 vs. -2.51 ± 0.70, p = .04). (3) Left atrial ejection index: LAEF% in the LBBAP group was significantly improved compared with the RVOP group (60.02 ± 1.88 vs. 53.65 ± 2.45, p = .047) and baseline (60.02 ± 1.88 vs. 49.68 ± 2.75, p < .05) at 6 months after the surgery. (4) Left ventricular ejection index: The LVEF% in the LBBAP group was significantly increased than the RVOP group after 6 months (69.14 ± 4.99 vs. 64.60 ± 4.84, p = .01) and the BNP level was significantly lower in the LBBAP group compared with the RVOP group at 7 days, 1, 3, and 6 months after implantation (p < .05). (5) 6-min walking distance: the 6-min walking distance was significantly increased at 3 and 6 months after implantation compared with that before (p < .05) in both groups, but was more prominent in LBBAP groups ([483.03 ± 11.02] m vs. [431.09 ± 10.69] m,p < .05).

CONCLUSION

Compared with the traditional RVOP, the LBBAP procedure increased left atrial myocardial stress as well as left atrial ejection in pace-dependent patients at follow-up to 6 months.

Safety and efficacy of left bundle branch area pacing compared with right ventricular pacing in patients with bradyarrhythmia and conduction system disorders: Systematic review and meta-analysis

BACKGROUND

Right Ventricular Pacing (RVP) may have detrimental effects in ventricular function. Left Bundle Branch Area Pacing (LBBAP) is a new pacing strategy that appears to have better results. The aim of this systematic review and meta-analysis is to compare the safety and efficacy of LBBAP vs RVP in patients with bradyarrhythmia and conduction system disorders.

METHODS

MEDLINE, EMBASE and Pubmed databases were searched for studies comparing LBBAP with RVP. Outcomes were all-cause mortality, atrial fibrillation (AF) occurrence, heart failure hospitalizations (HFH) and complications. QRS duration, mechanical synchrony and LVEF changes were also assessed. Pairwise meta-analysis was conducted using random and fixed effects models.

RESULTS

Twenty-five trials with 4250 patients (2127 LBBAP) were included in the analysis. LBBAP was associated with lower risk for HFH (RR:0.33, CI 95%:0.21 to 0.50; p < 0.001), all-cause mortality (RR:0.52 CI 95%:0.34 to 0.80; p = 0.003), and AF occurrence (RR:0.43 CI 95%:0.27 to 0.68; p < 0.001) than RVP. Lead related complications were not different between the two groups (p = 0.780). QRSd was shorter in the LBBAP group at follow-up (WMD: -32.20 msec, CI 95%: -40.70 to -23.71; p < 0.001) and LBBAP achieved better intraventricular mechanical synchrony than RVP (SMD: -1.77, CI 95%: -2.45 to -1.09; p < 0.001). LBBAP had similar pacing thresholds (p = 0.860) and higher R wave amplitudes (p = 0.009) than RVP.

CONCLUSIONS

LBBAP has better clinical outcomes, preserves ventricular electrical and mechanical synchrony and has excellent pacing parameters, with no difference in complications compared to RVP.

Actual conditions of atrial septal lead implantation and the factors related to successful implantation

BACKGROUND

Pacemaker leads were originally implanted into the right atrial appendage (RAA) and right ventricular apex, but septal pacing, which is more physiological, is becoming increasingly popular. The usefulness of atrial lead implantation in the RAA or atrial septum is inconclusive, and whether or not atrial septum implantation is accurate has not yet been verified.

METHODS

Patients who underwent pacemaker implantation between January 2016 and December 2020 were included. The success rate of atrial septal implantation was validated using thoracic computed tomography performed for any reason postoperatively. We examined factors related to the successful implantation of the atrial lead in the atrial septum.

RESULTS

Forty-eight people were included in this study. Lead placement was performed with a delivery catheter system (SelectSecure MRI SureScan; Medtronic Japan Co., Ltd., Tokyo, Japan) in 29 cases and a conventional stylet in 19 cases. The mean age was 74 ± 12 years old, and 28 (58%) were male. Successful atrial septal implantation was performed in 26 patients (54%), with only 4 (21%) successful implantations in the stylet group. There were no significant differences in the age, gender, body mass index (BMI), pacing P wave axis, duration, or amplitude between the atrial septal implantation group and non-septal groups. The only significant difference was for delivery catheter use [22 (85%) vs. 7 (32%), p < 0.001]. In multivariate logistic analysis, the use of a delivery catheter was independently associated with successful septal implantation [odds ratio (OR): 16.9, 95% confidence interval 3.0-90.9] after adjusting for the age, gender, and BMI.

CONCLUSION

The success rate of atrial septal implantation was very low at 54%, and only the use of a delivery catheter was associated with successful septal implantation. However, even with a delivery catheter, the success rate was 76%, so further investigations are warranted.

New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models

Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.

2023 HRS/EHRA/APHRS/LAHRS expert consensus statement on practical management of the remote device clinic

Remote monitoring is beneficial for the management of patients with cardiovascular implantable electronic devices by impacting morbidity and mortality. With increasing numbers of patients using remote monitoring, keeping up with higher volume of remote monitoring transmissions creates challenges for device clinic staff. This international multidisciplinary document is intended to guide cardiac electrophysiologists, allied professionals, and hospital administrators in managing remote monitoring clinics. This includes guidance for remote monitoring clinic staffing, appropriate clinic workflows, patient education, and alert management. This expert consensus statement also addresses other topics such as communication of transmission results, use of third-party resources, manufacturer responsibilities, and programming concerns. The goal is to provide evidence-based recommendations impacting all aspects of remote monitoring services. Gaps in current knowledge and guidance for future research directions are also identified.

Consecutive Experience with Left Bundle Branch Area Pacing in a High-Volume Australian Centre

INTRODUCTION

Left-bundle branch area pacing (LBBAP) is a relatively new technique for conduction system pacing. Australian safety and efficacy data is currently lacking. We aim to evaluate the learning curve, medium-term safety, and lead performance in a high-volume Australian setting.

METHODS

We performed a retrospective cohort study of 200 consecutive LBBAP procedures performed by a single operator at two centres between January 2019 and May 2020. Left bundle branch area pacing was performed predominantly via left subclavian access using a 69 cm Medtronic SelectSecure 3830 pacing lead and a preformed non-steerable C315-His sheath. Procedural success was defined as evidence of left septal or left bundle branch area capture as evidenced by a right bundle branch block-like paced morphology. Procedural characteristics, and follow-up (including lead performance) data were collected. Procedural efficiency over time, as well as safety data, were collected.

RESULTS

Median age was 78.26 years (interquartile range [IQR] 71-85), 37% were female. Atrial fibrillation was present in 22%. The left ventricular ejection fraction <50% in 24%, atrioventricular (AV) block was present in 43.5%, left bundle branch block in 22.5% and right bundle branch block in 24.5%. Acute procedural success was 91.5%. Implant threshold was 0.6V @ 0.5 ms, and 0.75V @ 0.5 ms at 11.9 months of follow-up. The QRS was significant reduced (baseline 134 ms vs implant 114 ms, p<0.001) There was a reduction in procedural time and X-ray dose over the course of the study. There were no complications specific to LBBAP.

CONCLUSION

LBBAP appears to be a safe and effective pacing strategy. The QRS duration was significantly reduced compared to baseline. There appears to be an early learning curve with LBBAP.

2023 HRS/EHRA/APHRS/LAHRS Expert Consensus Statement on Practical Management of the Remote Device Clinic

Remote monitoring is beneficial for the management of patients with cardiovascular implantable electronic devices by impacting morbidity and mortality. With increasing numbers of patients using remote monitoring, keeping up with higher volume of remote monitoring transmissions creates challenges for device clinic staff. This international multidisciplinary document is intended to guide cardiac electrophysiologists, allied professionals, and hospital administrators in managing remote monitoring clinics. This includes guidance for remote monitoring clinic staffing, appropriate clinic workflows, patient education, and alert management. This expert consensus statement also addresses other topics such as communication of transmission results, use of third-party resources, manufacturer responsibilities, and programming concerns. The goal is to provide evidence-based recommendations impacting all aspects of remote monitoring services. Gaps in current knowledge and guidance for future research directions are also identified.

miR Profile of Chronic Right Ventricular Pacing: a Pilot Study in Children with Congenital Complete Atrioventricular Block

Chronic ventricular pacing can lead to pacing-induced cardiomyopathy (PICM). Clinical data alone is insufficient to predict who will develop PICM. Our study aimed to evaluate the circulating miR profile associated with chronic right ventricular pacing in children with congenital complete AV block (CCAVB) and to identify candidate miRs for longitudinal monitoring. Clinical data and blood were collected from chronically paced children (N = 9) and compared with non-paced controls (N = 13). miR microarrays from the buffy coat revealed 488 differentially regulated miRs between groups. Pathway analysis predicted both adaptive and maladaptive miR signaling associated with chronic pacing despite preserved ventricular function. Greater profibrotic signaling (miRs-92a, 130, 27, 29) and sodium and calcium channel dysregulation (let-7) were seen in those paced > 10 years with the most dyregulation seen in a patient with sudden death vs. those paced < 10 years. These miRs may help to identify early adverse remodeling in this population.

Efficacy and Safety of Leadless Pacemakers for Atrioventricular Synchronous Pacing: A Systematic Review and Meta-Analysis

Leadless pacemakers with an atrioventricular synchrony algorithm represent a novel technology for patients qualified for VDD pacing. The current evidence of their performance is limited to several small-scale observational studies. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of this new technology. We systematically searched the PubMed, Embase, and Cochrane library databases from their inception to 12 September 2022. The primary efficacy outcome was atrioventricular synchrony after implantation, whereas the secondary efficacy outcome was the change in cardiac output represented by the left ventricular outflow tract velocity time integral (LVOT-VTI). The primary safety outcome was major complications related to the procedures and the algorithm. Means or mean differences with 95% confidence interval (95% CI) were combined using a random-effects model or a fixed-effects model. Finally, 8 published studies with 464 participants were included in the qualitative analysis. The pooled atrioventricular synchrony proportion was 78.9% (95% CI 71.9–86.0%), and a further meta-regression did not screen factors that contributed significantly to the heterogeneity. Additionally, a significant increase in atrioventricular synchrony of 11.3% (95% CI 7.0–15.7%, p < 0.01) was achieved in patients experiencing programming optimization. LVOT-VTI was significantly increased by 1.9 cm (95% CI 1.2–2.6, p < 0.01), compared with the VVI pacing mode. The overall incidence of complications was approximately 6.3%, with major complications related to the algorithm being extremely low. Overall, leadless pacemakers with atrioventricular synchronous pacing demonstrated favorable safety and efficacy. Future data on their long-term performance are required to facilitate their widespread adoption in clinical practice.

Adverse effects of right ventricular pacing on cardiac function: prevalence, prevention and treatment with physiologic pacing

Right ventricular (RV) pacing is the main treatment modality for patients with advanced atrioventricular (AV) block. Chronic RV pacing can cause cardiac systolic dysfunction and heart failure (HF). In this review, we discuss studies that have shown deleterious effects of chronic RV pacing on systolic cardiac function causing pacing-induced cardiomyopathy (PiCM), heart failure (HF), HF hospitalization, atrial fibrillation (AF) and cardiac mortality. RV apical pacing is the most widely used and studied. Adverse effects of RV pacing appear to be directly related to pacing burden and are worse in patients with pre-existing left ventricular (LV) dysfunction. Chronic RV pacing is also associated with heart failure with preserved ejection fraction (HFpEF). Mechanisms, risk factors, clinical and echocardiographic features, and strategies to minimize RV pacing-induced cardiac dysfunction are discussed in light of the latest data. Studies on biventricular (Bi-V) pacing upgrade in patients who develop RV PiCM, use of alternate RV pacing sites, de novo Bi-V pacing, and physiologic pacing using HIS bundle pacing (HBP) and left bundle area (LBBA) pacing in patients with an anticipated high RV pacing burden are discussed.

His bundle pacing versus right ventricular pacing: A comparative study

BACKGROUND

Pacing is the most effective and dependable method for treating complete atrioventricular block (AVB).

OBJECTIVE

The purpose of this study is to investigate the use of His bundle pacing (HBP) in patients with atrioventricular block.

METHODS

Patients who underwent HBP or right ventricular pacing (RVP) were enrolled and divided into two groups: the HBP group and the RVP group, respectively. We compared baseline clinical data, fluoroscopy duration, operation duration, pacing electrode parameters during the operation or follow-up, baseline QRS duration, and pacing QRS duration.

RESULTS

HBP was attempted in 48 patients and was successful in 34 patients who were included in the HBP group. In addition, 30 RVP patients were included in the RVP group. Fluoroscopy duration and operation duration were significantly longer in the HBP group compared to the RVP group. Compared to the RVP group, the HBP group had a higher pacing threshold, a lower R wave amplitude, and a shorter pacing QRS duration. At 6 months of follow-up, the pacing threshold remained higher, the R wave amplitude was significantly lower, and the end-diastolic diameter of the left ventricle was smaller in the HBP group.

CONCLUSION

HBP was safe and effective for atrioventricular block despite the longer fluoroscopy and operation duration in the HBP group when compared to the RVP group.

Initial Experience with Left Bundle Branch Area Pacing in Patients with Atrioventricular Block and Impaired LV Function

Chronic right ventricular (RV) pacing can exacerbate heart failure in patients with a low left ventricular ejection fraction (LVEF). Left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing technique; however, information remains limited on its use among patients with a low EF. This study investigated the safety and short-term clinical outcomes of LBBAP among patients with impaired left ventricular (LV) function. This retrospective analysis of pacemakers at Chosun University Hospital, South Korea, included all patients with impaired LV function (EF<50%) who underwent pacemaker implantation for atrioventricular blockage from 2019-2022. Clinical characteristics, 12-lead electrocardiography findings, echocardiography findings, and laboratory parameters were evaluated. Composite outcomes were defined as all-cause mortality, cardiac death, and hospitalization due to heart failure during the 6-month follow-up. Altogether 57 patients (25 men; mean age, 77.4±10.8 y; LVEF, 41.5±3.8%) were divided into LBBAP (n=16), biventricular pacing (BVP; n=16), and conventional RV pacing (RVP; n=25) groups. In the LBBAP group, the mean paced QRS duration (pQRSd) was narrower (119.5±14.7 vs. 140.2±14.3 vs. 163.2±13.9; p<0.001) and cardiac troponin I level was elevated post-pacing (1.14±1.29 vs. 0.20±0.29 vs. 0.24±0.51, p=0.001). Lead parameters were stable. One patient was hospitalized, and four died (one patient each from heart failure admission, myocardial infarction, unexplained death, and pneumonia in RVP vs. one from intracerebral hemorrhage in BVP) during the follow-up period. In conclusion, LBBAP is feasible in patients with impaired LV function without acute or significant complications and provides a remarkably narrower pQRSd with a stable pacing threshold.

Impact of diastolic dysfunction in patients with preserved ejection fraction undergoing permanent cardiac pacemaker placement

Background

Chronic right-ventricular (RV) pacing can exacerbate heart failure in patients with a low ejection fraction (EF). There is little information on the effects of diastolic dysfunction (DD) in patients with preserved EF undergoing permanent pacemaker (PPM) placement. We aimed to investigate the clinical outcomes in these patients.

Methods

This multicenter, retrospective analysis of PPM use in Chonnam, South Korea, included all patients with preserved EF undergoing transvenous PPM implantation for atrioventricular blockage from 2017 to 2019. Patients were divided into two groups according to DD, which were assessed by including mitral flow velocities (E′ velocity, E/E′ ratio), peak velocity of the tricuspid regurgitant, and left atrial maximum volume index. Composite outcomes were defined as (1) cardiovascular death, and (2) hospitalization by heart failure during the follow-up period.

Results

One hundred sixty-seven patients (66 men; overall mean age, 75.3 ± 11.9 years) were divided into two groups: 125 normal versus 42 DD. Compared with normal subjects, the DD group included older patients (mean age, 79.1 ± 9.9 vs. 74.0 ± 12.3; p = 0.016), and had longer paced QTc interval (pQTc, 168.5 ± 20.1 vs. 159.1 ± 16.3 ms; p < 0.001). Fifteen patients were hospitalized and two died. In a Cox proportional regression analysis, DD (hazard ratio [HR], 7.343; 95% confidence interval [CI], 2.035–26.494; p = 0.002) and pQRSd (HR, 1.046; 95% CI, 1.004–1.091; p = 0.033) were independent predictors of composite outcomes.

Conclusion

In patients with DD, RV pacing raised the risk of pacing-induced heart failure despite preserved left-ventricular function. Thus, patients with DD should be monitored intensively.

Individualised left anterior oblique projection for lead implantation into interventricular septum

Objective

We sought to investigate whether it is possible to obtain individualised left anterior oblique (LAO) by preprocedural electrocardiographic parameters and, if so, whether these parameters can help to improve the success rate of right ventricular (RV) lead implantation into the interventricular septum.

Methods

In this observational study, we assessed the relationship between preoperative electrocardiographic parameters and the angle of the interventricular septum obtained using thoracic CT. The participants were divided into two groups: a retrospective derivation cohort to derive the optimal formula for the individual septum axis, and a prospective internal validation cohort to which we applied the optimal formula and implanted using the new method.

Results

In the retrospective derivation cohort (n=39), the mean angle of individualised LAO assessed by thoracic CT was 53.1°±8.9°, and the preoperative ECG QRS axis was strongly correlated with the interventricular septum axis (R²=0.490). LAO projection derived from the preoperative ECG QRS axis confirmed that the RV lead was placed in the interventricular septum during the pacemaker procedure in the prospective internal validation group (n=30). The success rate for placing the RV lead into the interventricular septum was significantly improved in the internal validation cohort (93% vs 64%, p<0.05). In addition, the N-terminal pro-brain natriuretic peptide level decreased significantly after surgery in the interventricular septal indwelling group.

Conclusions

Individualised LAO angle derived from the preoperative ECG QRS axis is a new useful and simple method for RV lead implantation into the interventricular septum.

Trial registration number

UMIN000045741.

Ventricular Dyssynchrony and Pacing-induced Cardiomyopathy in Patients with Pacemakers, the Utility of Ultra-high-frequency ECG and Other Dyssynchrony Assessment Tools

The majority of patients tolerate right ventricular pacing well; however, some patients manifest signs of heart failure after pacemaker implantation and develop pacing-induced cardiomyopathy. This is a consequence of non-physiological ventricular activation bypassing the conduction system. Ventricular dyssynchrony was identified as one of the main factors responsible for pacing-induced cardiomyopathy development. Currently, methods that would allow rapid and reliable ventricular dyssynchrony assessment, ideally during the implant procedure, are lacking. Paced QRS duration is an imperfect marker of dyssynchrony, and methods based on body surface mapping, electrocardiographic imaging or echocardiography are laborious and time-consuming, and can be difficult to use during the implantation procedure. However, the ventricular activation sequence can be readily displayed from the chest leads using an ultra-high-frequency ECG. It can be performed during the implantation procedure to visualise ventricular depolarisation and resultant ventricular dyssynchrony during pacing. This information can assist the electrophysiologist in selecting a pacing location that avoids dyssynchronous ventricular activation.

Mid- to Long-Term Clinical and Echocardiographic Effects of Post-procedural Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Aims

To date, the prognostic effects of permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) remain controversial. The purpose of this meta-analysis was to investigate the mid- (1 year) to long-term (> 1 year) clinical and echocardiographic effects of post-procedural PPI in patients after TAVR.

Methods

PubMed, Embase, Web of Science, and Cochrane Library databases were systematically searched from the establishment of databases up to 1 December 2021. Studies comparing clinical and echocardiographic outcomes between patients with and without post-TAVR PPI of ≥ 1-year follow-up were collected for further meta-analysis.

Results

A total of 39 studies comprising of 83,082 patients were included in this meta-analysis. At mid-term follow-up (1 year), the pooled results demonstrated a higher risk of all-cause mortality in patients with post-procedural PPI than those without following TAVR (relative risk (RR), 1.17; 95% CI, 1.10–1.24; P < 0.00001). No significant differences were observed in cardiovascular mortality (RR, 0.86; 95% CI, 0.71–1.03; P = 0.10) or heart failure rehospitalization (RR, 0.91; 95% CI, 0.58–1.44; P = 0.69) at 1-year follow-up. At long-term follow-up (> 1 year), post-TAVR PPI had negative effects on all-cause mortality (RR, 1.18; 95% CI, 1.09–1.28; P < 0.0001) and heart failure rehospitalization (RR, 1.42; 95% CI, 1.18–1.71; P = 0.0002). There was no difference in long-term cardiovascular mortality between the two groups (RR, 1.15; 95% CI, 0.97–1.36; P = 0.11). Left ventricular ejection fraction (LVEF) was not significantly different at baseline (mean difference, 1.40; 95% CI, –0.13–2.93; P = 0.07), but was significantly lower in the PPI group at 1-year follow-up (mean difference, –3.57; 95% CI, –4.88 to –2.26; P < 0.00001).

Conclusion

Our meta-analysis provides evidence that post-TAVR PPI has negative clinical and echocardiographic effects on patients at mid- to long-term follow-up. Further studies are urgently needed to explore the cause of these complications and optimize the treatment and management of patients requiring permanent pacing after TAVR.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021289935], identifier [CRD42021289935].

Animal Models to Study Cardiac Arrhythmias

Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.

Left ventricular systolic motion pattern differs among patients with left bundle branch block patterns

The study aimed to investigate left ventricular (LV) motion pattern in patients with LBBB patterns including patients with pacemaker rhythm (PM), type B Wolff-Parkinson-White syndrome (B-WPW), premature ventricular complexes originating from the right ventricular outflow tract (RVOT-PVC), and complete left bundle branch block (CLBBB). Two-dimensional speckle tracking was used to evaluate peak value and time to peak value of the LV twist, LV apex rotation, and LV base rotation in patients with PM, B-WPW, RVOT-PVC, and CLBBB with normal LV ejection fraction, and in age-matched control subjects. The LV motion patterns were altered in all patients compared to the control groups. Patients with PM and CLBBB had a similar LV motion pattern with a reduced peak value of LV apex rotation and LV twist. Patients with B-WPW demonstrated the opposite trend in the reduction of LV rotation peak value, which was more dominant in the basal layer. The most impairment in the LV twist/rotation peak value was identified in patients with RVOT-PVC. Compared to the control group, the apical-basal rotation delay was prolonged in patients with CLBBB, followed by those with B-WPW, PM, and RVOT-PVC. The LV motion patterns were different among patients with different patterns of LBBB. CLBBB and PM demonstrated a reduction in LV twist/rotation that was pronounced in the apical layer, B-WPW showed a reduction in the basal layer, and RVOT-PVC in both layers. CLBBB had the most pronounced LV apical-basal rotation dyssynchrony.

Clinical outcomes in patients with atrioventricular block undergoing pacemaker: 3-year follow-up

PURPOSE

Left ventricular function can be affected by chronic ventricular pacing. Different right ventricular (RV) pacing sites have shown heterogeneous clinical outcomes. We investigated these factors in patients receiving permanent pacemaker (PPM) implants.

METHODS

This multicenter, retrospective analysis of PPM use in South Korea, included all patients undergoing de novo transvenous PPM implantation for atrioventricular block from 2017 to 2019. Clinical characteristics, 12-lead electrocardiograms, echocardiography, and laboratory parameters were evaluated. Composite outcomes are defined by two coprimary endpoints: (1) hospitalizations and (2) cardiac death by heart failure during follow-up period.

RESULTS

There were 167 patients (66 males; overall mean age 75.3 ± 11.9 years), divided into two groups according to the pacing site: 83 apical RV (RVA) vs. 84 septal RV (RVS). There were no significant baseline differences. Paced QRS duration (pQRSd) increased with RVA (168.5 ± 20.1 vs. 159.1 ± 16.3 ms; p < 0.001). Over a median 31-month follow-up, there were 15 hospitalizations and 2 deaths. More patients with RVA were hospitalized or died (16% vs. 5%, respectively; p = 0.049). In Cox proportional regression analysis, pQRSd (hazard ratio [HR] 1.046; 95% confidence interval [CI] 1.004-1.091; p = 0.033), and diastolic dysfunction (HR 7.343; 95% CI 2.035-26.494; p = 0.002) were independent predictors of composite clinical outcomes.

CONCLUSIONS

RVS placement shortened the pQRSd and improved clinical outcomes. However, the determinants of these were pQRSd and diastolic dysfunction. Therefore, clinicians should try to shorten the pQRSd when implanting a PPM, and patients with diastolic dysfunction should be monitored intensively.

Left bundle branch area pacing versus right ventricular pacing in patients with persistent atrial fibrillation requiring ventricular pacing

PURPOSE

This study aims to assess whether left bundle branch area pacing (LBBAP) can result in favorable clinical and echocardiographic outcomes among patients with persistent atrial fibrillation (PeAF).

METHODS

We prospectively enrolled consecutive patients with PeAF if they required ventricular pacing and had left ventricular ejection fraction (LVEF) > 35%. During the same period, two experienced operators performed LBBAP and right ventricular pacing (RVP). All-cause death and heart failure hospitalization (HFH) were routinely followed after procedure. The primary outcome was the composite endpoints of all-cause death or HFH.

RESULTS

LBBAP was successful in 49 of 52 patients (94.2%), whereas 44 patients received RVP. During a mean follow-up of 13.9 ± 7.0 months, LBBAP group presented with higher ventricular pacing percentage (80% vs. 50.9%, p = .04) and narrower paced QRS duration (117.2 ± 18.8 ms vs. 151.8 ± 13.7 ms, p < .001) than RVP group. The primary endpoint was slightly reduced in LBBAP group than RVP without reaching statistical significance (7.7% vs. 11.4%, p = .48). Compared with baseline, we observed significant changes in LVEF (+0.7% vs. -2.2%, p = .007) and left atrial diameter (-1.63 mm vs. +1.23 mm, p = .011) between LBBAP and RVP.

CONCLUSION

Our results indicate possible effect of LBBAP on reverse remodeling of left atrium and a trend towards favorable clinical outcomes in patients with PeAF requiring high burden of ventricular pacing when compared with RVP.

His-Purkinje conduction system pacing: A systematic review and network meta-analysis in bradycardia and conduction disorders

BACKGROUND

His-Purkinje conduction system pacing (HPCSP) has emerged as an effective alternative to overcome the limitations of right ventricular pacing (RVP) via physiological left ventricular activation, but there remains a paucity of comparative information for His bundle pacing (HBP) and left bundle branch pacing (LBBP).

METHODS

A Bayesian random-effects network analysis was conducted to compare the relative effects of HBP, LBBP, and RVP in patients with bradycardia and conduction disorders. PubMed, Embase, Cochrane Library, and Web of Science were systematically searched from database inception until September 21, 2021.

RESULTS

Twenty-eight studies involving 4160 patients were included in this meta-analysis. LBBP significantly improved success rate, pacing threshold, pacing impedance, and R-wave amplitude compared with HBP. LBBP also demonstrated a nonsignificant trend towards superior outcomes of lead complications, heart failure hospitalization, atrial fibrillation, and all-cause death. However, HBP was associated with significantly shorter paced QRS duration relative to LBBP. Despite higher success rates, shorter procedure/fluoroscopy duration, and fewer lead complications, patients receiving RVP were more likely to experience reduced left ventricular ejection fraction, longer paced QRS duration, and higher rates of heart failure hospitalization than those receiving HPCSP. No statistical differences were observed in the remaining outcome measures.

CONCLUSIONS

This network meta-analysis demonstrates the efficacy and safety of HPCSP for the treatment of bradycardia and conduction disorders, with differences in pacing parameters, electrophysiology characteristics, and clinical outcomes between HBP and LBBP. Larger-scale, long-term comparative studies are warranted for further verification.

Do the predictors of right ventricular pacing-induced cardiomyopathy add up?

Objective

Knowledge of factors causing pacing-induced cardiomyopathy (PICM) is incomplete. We sought to estimate the incidence and predisposing factors for PICM and evaluate if the risk they portend adds up.

Methods

Single centre retrospective study where consecutive patients with preserved LVEF undergoing pacemaker (PM) implantation between 2012 and 2018 were analysed.

Results

A total of 749 patients (68.4 % male; mean age 59.2 ± 14.08 years) were included in the analysis. PICM developed in 74 (9.9%) patients over a median follow up of 2.2 years (IQR 1.1–3.2). Pre-implant LVEF, paced QRS duration and RV pacing burden were independent predictors of PICM. Using 90 % specificity cut-off values for LVEF and paced QRS, and the value separating lowest tertile of RV pacing from the higher tertiles, three risk factors were identified: (i) baseline LVEF < 55 %, (ii) paced QRS duration > 160 msec, and (iii) RV pacing burden > 33 %. Patients with two or more risk factors were at the highest risk (OR 11.62, 95 % CI 4.62–29.21, p-value < 0.001) for developing PICM while those with one risk factor had an intermediate risk (OR 3.89, 95 % CI 1.62–9.34, p-value 0.002) when compared to those without any risk factors.

Conclusion

Low-normal baseline LVEF, wider paced QRS and higher RV pacing burden independently predicted the development of PICM. The presence of ≥2 factors increased the odds of PICM, twelve-fold. A narrower paced QRS, the only modifiable risk factor may help mitigate development of PICM.

Impact of conduction disturbances on left ventricular mass regression and geometry change following transcatheter aortic valve replacement

Our study aimed to compare the difference of LV mass regression and remodeling in regard of conduction disturbances (CD) following transcatheter aortic valve replacement (TAVR). A prospective analysis of 152 consecutive TAVR patients was performed. 53 patients (34.9%) had CD following TAVR, including 30 (19.7%) permanent pacemaker implantation and 23 (15.2%) new left bundle branch block. In 123 patients with 1-year follow-up, significant improvement of LV ejection fraction (LVEF) (baseline vs 12-month: 65.1 ± 13.2 vs 68.7 ± 9.1, P = 0.017) and reduced LV end-systolic volume (LVESV) (39.8 ± 25.8 vs 34.3 ± 17.1, P = 0.011) was found in non-CD group (N = 85), but not in CD group (N = 38). Both groups had significant decrease in LV mass index (baseline vs 12-month: 148.6 ± 36.9 vs. 136.4 ± 34.7 in CD group, p = 0.023; 153.0 ± 50.5 vs. 125.6 ± 35.1 in non-CD group, p < 0.0001). In 46 patients with 3-year follow-up, only non-CD patients (N = 28) had statistically significant decrease in LV mass index (Baseline vs 36-month: 180.8 ± 58.8 vs 129.8 ± 39.1, p = 0.0001). Our study showed the improvement of LV systolic function, reduced LVESV and LV mass regression at 1 year could be observed in patients without CD after TAVR. Sustained LV mass regression within 3-year was found only in patients without CD.

His-Purkinje Conduction System Pacing in Atrioventricular Block: New Insights into Site of Conduction Block

OBJECTIVES

This study aims to assess the safety and feasibility of achieving His-Purkinje conduction system pacing (HPCSP) in consecutive patients with atrioventricular block (AVB) and to describe the site of conduction block in patients with infranodal AVB.

BACKGROUND

HPCSP has evolved as the preferred form of physiologic pacing. Left bundle branch area pacing (LBBAP) has emerged as an effective alternative to His bundle pacing (HBP).

METHODS

Consecutive patients with AVB referred for pacemaker implantation were included in the study. HBP or LBBAP was attempted in all patients. Site of conduction block was identified as nodal or infranodal (intra-Hisian or infra-Hisian) AVB.

RESULTS

HPCSP was attempted in 333 consecutive patients with AVB and was successful in 322 (97%) patients. HBP was achieved in 140 patients, LBBAP in 179 patients, and both in 3 patients. Site of conduction block was nodal in 55% and infranodal in 45% (intra-Hisian 89%; infra-Hisian 4%; indeterminate 7%). QRS duration at baseline was 111±27 versus 129±31 (P < 0.001) compared to 126 ± 24 vs 125 ± 21 milliseconds (P = 0.75) during HBP and LBBAP, respectively. HBP thresholds at implant were higher compared to LBBAP (1.2 ± 0.7 V at 0.9 milliseconds vs 0.6 ± 0.3 V at 0.5 milliseconds; P < 0.001) but remained stable during follow-up. Lead revision was required in 3% and 2% of patients with HBP and LBBAP, respectively.

CONCLUSIONS

HPCSP pacing was successfully performed in 97% of unselected patients with AVB irrespective of the site of conduction block. True infra-Hisian block (distal His-Purkinje conduction disease) is rare. HBP and LBBAP were complementary in achieving stable and low capture thresholds.

Is the right ventricular function affected by permanent pacemaker?

AIMS

The effect of right ventricular (RV) pacing on left ventricular (LV) function has been extensively evaluated, but the effect on RV function per se has not been evaluated systematically. We aimed to assess the effect of dual chamber pacemaker on RV function.

METHODS AND RESULTS

All consecutive patients undergoing dual chamber pacemaker from January 2018 to March 2019 for AV block with a structurally normal heart were included. They underwent pre-procedure detailed echocardiography (including three-dimensional [3D] RV ejection fraction [RVEF]), a screening echocardiogram 2 days after pacemaker implantation and again a detailed echocardiogram at 6-month follow-up. We compared the baseline echocardiographic RV parameters with those 6 months after the pacemaker implantation. A total of 60 patients underwent successful pacemaker implantation. At 6 months, most of the patients were pacemaker dependent with pacing percentage of 98.9% ± 2.4%; there was a significant increase in TR and a mean drop in RVEF by 2.8 ± 5%, with 23 (38.3%) having at least a 5% decrease in RVEF. The drop in RVEF positively correlated with TR vena contracta at 6 months but did not correlate with pulmonary artery systolic pressure at 6 months.

CONCLUSION

Our study shows the presence of demonstrable RV dysfunction as early as 6 months in a majority of patients who have undergone pacemaker implantation.

Relationship between paced QRS duration and myocardial relaxation of the left ventricle in patients with chronic right ventricular apical pacing

BACKGROUND

Right ventricular (RV) apical pacing is associated with systolic dysfunction and heart failure. Paced QRS duration has been suggested as a predictor of heart failure and left ventricular (LV) systolic dysfunction. However, the effect of paced QRS duration on LV diastolic function is not well known.

OBJECTIVE

This study was designed to evaluate the relationship between paced QRS duration and LV diastolic function.

METHODS

This retrospective study included 88 patients who had chronic RV apical pacing. Myocardial relaxation was assessed with tissue Doppler imaging. Patients with severe valvular dysfunction or significant structural heart disease were excluded. Paced QRS duration was measured with standard 12‑lead ECG at follow-up.

RESULTS

Median age of the patients was 65.9 years (interquartile ranges (IQR), 56.5, 72.7) with 64.8% of female patients. Median duration of RV pacing was 8.6 years (IQR, 5.3, 11.1). Major indication of RV pacing was complete atrioventricular block (89.8%), and dual chamber pacemakers were predominantly implanted (89.8%). Mean of paced QRS duration was 160.5 ± 18.2 msec. Median LV ejection fraction (EF) was 63% (IQR, 55.5, 67.5), and negatively correlated with paced QRS duration (R = -0.478, p < 0.001). LV end diastolic dimension was positively correlated with paced QRS duration (R = 0.531, p < 0.001). Mean E' velocity at the septal mitral annulus was 5.2 ± 1.5 and negatively related to paced QRS duration (R = -0.521, p < 0.001). After adjusting covariables, paced QRS duration was independently related to E' velocity (beta = -0.038, p = 0.005). Paced QRS duration was also associated with worsening functional capacity or elevated LV filling pressure in patients with preserved EF (odd ratio = 1.10; 95% confidence interval, 1.02-1.20, p = 0.015).

CONCLUSION

Paced QRS duration was associated with LV relaxation which might be another possible mechanism of worsening heart failure in patients with long paced QRS duration.

Characteristics of Cardiac Memory in Patients with Implanted Cardioverter-defibrillators: The Cardiac Memory with Implantable Cardioverter-defibrillator (CAMI) Study

This study sought to determine factors associated with cardiac memory (CM) in patients with implantable cardioverter-defibrillators (ICDs). Patients with structural heart disease [n = 20; mean age: 72.6 ± 11.6 years; 80% male; mean left ventricular ejection fraction (LVEF): 31.7 ± 7.6%; history of myocardial infarction in 75% and nonsustained ventricular tachycardia (NSVT) in 85%] and preserved atrioventricular conduction received dual-chamber ICDs for primary (80%) or secondary (20%) prevention. Standard 12-lead electrocardiograms were recorded in AAI and DDD modes before and after seven days of right ventricular (RV) pacing in DDD mode with a short atrioventricular delay. The direction (azimuth and elevation) and magnitude of spatial QRS, T, and spatial ventricular gradient vectors were measured before and after seven days of RV pacing. CM was quantified as the degree of alignment between QRS_DDD-7 and T_AAI-7 vectors (QRS_DDD-7 –T_AAI-7 angle). Circular statistics and mixed models with a random slope and intercept were adjusted for changes in cardiac activation, LVEF, known risk factors, and the use of medications known to affect CM occurring on days 1 through 7. The QRS_DDD-7–T_AAI-7 angle strongly correlated (circular r = −0.972; p < 0.0001) with a T_AAI-7–T_DDD-7 angle. In the mixed models, CM-T azimuth changes [+132° (95% confidence interval (CI): 80°–184°); p < 0.0001] were counteracted by the history of MI [−180° (95% CI: −320° to −40°); p = 0.011] and female sex [−162° (95% CI: −268° to −55°); p = 0.003]. A CM-T area increase [+15 (95% CI: 6–24) mV*ms; p < 0.0001] was amplified by NSVT history [+27 (95% CI: 4–46) mV*ms; p = 0.007]. These findings suggest that preexistent electrical remodeling affects CM in response to RV pacing, that CM exhibits saturation behavior, and that women reach CM saturation more easily than men.

Predictors of pacing induced left ventricular dysfunction and cardiomyopathy assessed by three-dimensional echocardiography and speckle tracking strain

Background

Long-term RV pacing leads to ventricular dyssynchrony, in the form of LBBB-like morphology, with subsequent detrimental effects on LV structure and function. Three-dimensional echocardiography allowed early detection of volumetric changes associated with PICMP and provided more accurate assessment of mechanical dyssynchrony. Speckle tracking strain is able to identify LV dysfunction even before any reduction in LVEF. Our aim was to study pacing effects on LV function and hemodynamics using 3D echo and speckle tracking strain.

Results

This was a prospective study of 175 consecutive patients without structural heart disease (LVEF > 50%) presented for permanent pacing. Full-volume 3D echocardiography done before implantation, 1 week, and 6 months together with GLS. Patients were followed for 6 months to detect incidence of PIVD (defined as reduction in LVEF > 10% but still above 50%) and PICMP (defined as decrease in LVEF by 10% from baseline in absence of other known causes of cardiomyopathy resulting in EF< 50%). PIVD and PICMP predictors and risk factors were analyzed. Only 50 patients met study criteria. Twenty-five (50%) patients developed LV systolic dysfunction; of these, 19 (38%) developed PIVD and 6 (12%) developed PICMP. Pre-implantation GLS was significantly lower in the 6 patients who subsequently developed PICMP, compared to those who developed PIVD and the preserved EF group (mean GLS − 15.50 vs. − 21.0, − 20.0 respectively; p = 0.005, 0.033, respectively). At 1 week, GLS was significantly lower in the 25 patients who subsequently developed PIVD, compared to those who did not (GLS − 13.0 vs. − 18.0, respectively; p = 0.002). A reduction of baseline GLS by 15% or more at 1 week was associated with the development of PIVD and PICMP (p = < 0.001). A wider native QRS complex was associated with PIVD and PICMP (p = 0.008, 0.018, respectively). The other predictors were found non-significant.

Conclusion

PICMP may be more common than previously reported and it may occur shortly after implantation. Pre-implantation GLS is a sensitive parameter for PICMP. One-week GLS, pre-implantation QRS complex width are early predictors for PICMP and PIVD before any reduction in EF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43044-021-00136-x.

Assessing safety of leadless pacemaker (MICRA) at various implantation sites and its impact on paced QRS in Indian population

Background

In this study we report our experience in implanting MICRA TPS (transcatheter pacing system) at various RV sites; observing its safety, and impact on paced QRS in Indian population.

Material & methods

35 patients with MICRA TPS deployed from March 2017 to December 2019 at Army Hospital Research and Referral, New Delhi, at RVOT, apical septum and mid septum of RV were enrolled in the study. These patents were followed up and impact of implantation site, procedure related complications, change in pacing parameters, left ventricular ejection fraction and duration of paced QRS were monitored.

Results

Sick sinus syndrome was the commonest indication of pacing in this study (51.5%), followed by high degree AV block (34.2%). Mean follow up of 1.4 years showed no change in left ventricular ejection fraction, electrical parameters or change in pacing thresholds after implantation. Mean pQRS was broadest (166.60 ms) in apically implanted MICRA TPS and narrowest in mid septum group 139.33 ms. Among 35 cases, in our study one patient developed pericardial effusion, and other had intermittent diaphragmatic pacing.

Conclusion

Among these three implantation sites mid septum deployment is associated with narrowest paced QRS in Indian population.

Single-chamber leadless pacemaker for atrial synchronous or ventricular pacing

Leadless pacing is a major breakthrough in the management of bradyarrhythmia. Results of initial clinical trials that have demonstrated a significant reduction in acute and long-term pacing-related complications have been confirmed by real-world experience in a broader spectrum of patients. Nonetheless current use of a leadless pacemaker is hampered by its limited atrial sensing and pacing capability, as well as battery life-span and retrievability. We review the current clinical outcome data, indications and contraindications, implantation and retrieval techniques, synchronous ventricular pacing, and other clinical considerations. We also provide an overview of the latest advancements in leadless pacing technology including device-to-device communication and energy harvesting technology.

Comparison between his-bundle pacing and left bundle branch pacing in patients with atrioventricular block

BACKGROUND

Pacing the cardiac conduction system has been explored in patients with conduction system disease, but comprehensive comparisons between different pacing modalities are not well investigated.

OBJECTIVE

To compare pacing characteristics and ventricular synchrony between His-bundle pacing (HBP) and left bundle branch pacing (LBBP) in patients with atrioventricular block (AVB).

METHODS

Fifty pacemaker-indicated patients with AVB were enrolled. Twenty-five patients underwent HBP, and another 25 patients underwent LBBP. Success rate, procedural and fluoroscopy duration, pacing parameters, and echocardiographic data were perioperatively assessed and at 3-month follow-up.

RESULTS

HBP was successful in 19 of 25 (76.0%) patients, whereas LBBP was successful in 22 of 25 (88.0%) patients. Compared with HBP, LBBP capture threshold was significantly lower (0.76 ± 0.25 V/0.4 ms vs. 1.27 ± 0.61 V/1.0 ms, P = 0.003) and R-wave amplitude was significantly higher with LBBP (11.7 ± 6.6 vs. 4.9 ± 2.4 mV, P < 0.001) at implant. The mean procedural time (74.3 ± 17.8 vs. 63.2 ± 12.3 min, P = 0.029) and fluoroscopy duration (10.3 ± 4.5 vs. 6.8 ± 2.2 min, P = 0.005) were significantly longer in the HBP group compared to LBBP. At 3-month follow-up, pacing capture threshold remained more stable in LBBP than in HBP group while left ventricular synchrony was similar between both groups.

CONCLUSION

Despite similar impact on ventricular synchrony compared with HBP, LBBP featured a significantly lower pacing capture threshold, higher R-wave amplitude, and less time to achieve similar success rate in patients with AVB. These findings indicate LBBP as a physiological pacing strategy for AVB patients.

Can QRS morphology be used to differentiate between true septal vs. apparently septal lead placement? An analysis of ECG of real mid-septal, apparent mid-septal, and apical pacing

The location of the pacemaker lead is based on the shape of the lead on fluoroscopy only, typically in the left and right anterior oblique positions. However, these fluoroscopy criteria are insufficient and many leads apparently considered to be in septum are in fact anchored in anterior wall. Periprocedural ECG could determine the correct lead location. The aim of the current analysis is to characterize ECG criteria associated with a correct position of the right ventricular (RV) lead in the mid-septum. Patients with indications for a pacemaker had the RV lead implanted in the apex (Group A) or mid-septum using the standard fluoroscopic criteria. The exact position of the RV lead was verified using computed tomography. Based on the findings, the mid-septal group was divided into two subgroups: (i) true septum, i.e. lead was found in the mid-septum, and (ii) false septum, i.e. lead was in the adjacent areas (anterior wall, anteroseptal groove). Paced ECGs were acquired from all patients and multiple criteria were analysed. Paced ECGs from 106 patients were analysed (27 in A, 36 in true septum, and 43 in false septum group). Group A had a significantly wider QRS, more left-deviated axis and later transition zone compared with the true septum and false septum groups. There were no differences in presence of q in lead I, or notching in inferior or lateral leads between the three groups. QRS patterns of true septum and false septum groups were similar with only one exception of the transition zone. In the multivariate model, the only ECG parameters associated with correct lead placement in the septum was an earlier transition zone (odds ratio (OR) 2.53, P = 0.001). ECGs can be easily used to differentiate apical pacing from septal or septum-close pacing. The only ECG characteristic that could help to identify true septum lead position was the transition zone in the precordial leads. ClinicalTrials.gov identifier: NCT02412176.

His bundle pacing using a simple stylet and a standard active fixation electrode

Conventionally, His bundle pacing (HBP) is achieved using specially designed pacing leads and delivery sheaths. This paper describes the feasibility of permanent HBP with a pre-shaped simple stylet and a standard active-fixation electrode, through axillary vein access, without using dedicated delivery tools. This method may be a feasible and safe alternative to the only commercially available system.

Prevalence of left ventricular systolic dysfunction in a typical outpatient pacemaker cohort

Background

Right ventricular (RV) pacing is the standard treatment for symptomatic bradycardia. RV pacing is known to cause dyssyncrony. New treatment options like His bundle pacing enhance the focus on left ventricular dysfunction in patients with pacemakers.

Objectives

The aim of this cross-sectional study was to obtain a real-life picture of the patients in a representative cohort of outpatients with permanent pacemakers. The prevalence and causes of left ventricular dysfunction (LVD) were explored.

Methods

In total, 1869 patients of a pacemaker outpatient clinic were screened for left ventricular systolic dysfunction by transthoracic echocardiography. All patients were interviewed for symptoms and cardiologist care. Percentages of RV pacing and underlying cardiac disease were recorded.

Results

A left ventricular ejection fraction (LVEF) under 45% was found in 207 (11.1%) of all patients. Predictive factors for a reduced LVEF were a high pacing rate and long-term pacing. LVD due to RV pacing was diagnosed in 3.4% of all patients. Only 845 patients (45%) reported that they regularly visited a cardiologist.

Conclusion

There is a high prevalence of unknown LVD in a typical pacemaker cohort. Therefore, regular echocardiographic examinations should be performed in outpatients of pacemaker clinics.

How His bundle pacing prevents and reverses heart failure induced by right ventricular pacing

Ideal heart performance demands vigorous systolic contractions and rapid diastolic relaxation. These sequential events are precisely timed and interdependent and require the rapid synchronous electrical stimulation provided by the His-Purkinje system. Right ventricular (RV) pacing creates slow asynchronous electrical stimulation that disrupts the timing of the cardiac cycle and results in left ventricular (LV) mechanical asynchrony. Long-term mechanical asynchrony produces LV dysfunction, remodeling, and clinical heart failure. His bundle pacing preserves synchronous electrical and mechanical LV function, prevents or reverses RV pacemaker-induced remodeling, and reduces heart failure.