Indications For Pacing Research Articles

Left bundle branch pacing preserves ventricular mechanical synchrony better than right ventricular pacing-a two-center study

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch pacing (LBBP) has emerged as a novel pacing method. We sought to evaluate left ventricular (LV) mechanical synchrony under permanent LBBP and compare it with conventional and leadless right ventricular pacing (CRVP, LRVP). Methods Sixty-four patients with pacing indication for bradycardia were prospectively enrolled. Twenty-two patients received LBBP in the basal ventricular septum. Twenty-three patients received CRVP and 19 LRVP. All patients underwent echocardiography before and after device implantation. Myocardial work was estimated by pressure-strain analysis. Regional work in the septum (SEP) and lateral wall (LW) was calculated as the average from the respective basal and mid-ventricular segments in the apical four-chamber and three-chamber view. The absolute difference between work in LW and SEP (LW-S-work difference) was used as a measure of asymmetry in workload. Results Baseline characteristics were similar among the three groups. The electrocardiogram during LBBP showed a right bundle branch block pattern; during CRVP and LRVP a left bundle branch block pattern. The paced QRS duration was 114.27±9.9 ms in the LBBP group, significantly shorter than that in the CRVP and LRVP groups (153.9±25.26 ms and 159.1±13.99ms, respectively, both p<0.001). The SEP work decreased in all groups during ventricular pacing (all P<0.05), while the LW work remained similar. The paced LW-S work difference and work difference change between pacing on and off were more significant in the CRVP (1012.9±566.0mmHg*%) and LRVP group (1066.1±472.6mmHg*%) than the LBBP group (260.5±239.8mmHg*%, both P<0.001). In addition, LW-S work difference during ventricular pacing and work difference change between pacing and baseline were comparable in CRVP and LRVP group. Conclusion LBBP causes less LV dyssynchrony than CRVP and LRVP as it preserves a more physiologic conduction pattern. CRVP and LRVP did not differ in this respect. Further studies need to prove that LBBP has advantages over RVP with regards to preservation of LV synchrony and contractility.

Left bundle branch area pacing in patients with heart failure and right bundle branch block: Results from International LBBAP Collaborative-Study Group.

BackgroundCardiac resynchronization therapy (CRT) using biventricular pacing has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) is a novel physiologic pacing option.ObjectiveThe aim of the study was to assess the feasibility and outcomes of LBBAP in HF patients with RBBB and reduced left ventricular systolic function, and indication for CRT or ventricular pacing.MethodsLBBAP was attempted in patients with left ventricular ejection fraction (LVEF) <50%, RBBB, HF, and indications for CRT or ventricular pacing. Procedural, pacing, and electrocardiographic parameters; clinical response (no HF hospitalization and improvement in NYHA class); and echocardiographic response (≥5% increase in ejection fraction) to LBBAP were assessed.ResultsLBBAP was attempted in 121 patients and successful in 107 (88%). Patient characteristics included age 74 ± 12 years, female 25%, ischemic cardiomyopathy 49%, and ejection fraction 35% ± 9%. QRS axis at baseline was normal in 24%, left axis 63%, right axis 13%. LBBAP threshold and R-wave amplitudes were 0.8 ± 0.3 V @ 0.5 ms and 10 ± 9 mV at implant and remained stable during mean follow-up of 13 ± 8 months. LBBAP resulted in narrowing of QRS duration (156 ± 20 ms to 150 ± 24 ms (P = .01) with R-wave peak times in V6 of 85 ± 16 ms. LVEF improved from 35% ± 9% to 43% ± 12% (P < .01). Clinical and echocardiographic response was observed in 60% and 61% of patients, respectively. Female sex and reduction in QRS duration with LBBAP were predictive of echocardiographic response and super-response.ConclusionLBBAP is a feasible alternative to deliver CRT or physiologic ventricular pacing in patients with RBBB, HF, and LV dysfunction.

Atrioventricular Block Necessitating Chronic Ventricular Pacing After Tricuspid Valve Surgery in Patients With a Systemic Right Ventricle: Long-Term Follow-Up.

BackgroundPatients with transposition of the great arteries (TGA) after an atrial switch or congenitally corrected TGA (ccTGA) are prone to systemic right ventricular (sRV) failure. Tricuspid valve (TV) regurgitation aggravates sRV dysfunction. Timely TV surgery stabilizes sRV function, yet the development of atrioventricular (AV)-conduction disturbances in the course of sRV failure can contribute to sRV dysfunction through pacing-induced dyssynchrony. This study aims to explore the incidence, timing, and functional consequences of AV-block requiring ventricular pacing after TV surgery in patients with sRV.MethodsConsecutive adolescent and adult patients with an sRV who underwent TV surgery between 1989 and 2020 and followed-up at our center were included in this observational cohort study.ResultsThe data of 28 patients (53% female, 57% ccTGA, and a mean age at surgery 38 ± 13 years) were analyzed. The mean follow-up was 9.7 ± 6.8 years. Of the remaining 22 patients at the risk of developing high degree AV-block after TV surgery, 9 (41%) developed an indication for chronic ventricular pacing during follow-up, of which 5 (56%) within 24 months postoperatively (3 prior to hospital discharge). The QRS duration, a surrogate marker for dyssynchrony, was significantly higher in patients with chronic left ventricular pacing than in patients with native AV-conduction (217 ± 24 vs. 116 ± 23 ms, p = 0.000), as was the heart failure biomarker NT-pro-BNP [2,746 (1,242–6,879) vs. 495 (355–690) ng/L, p = 0.004] and the percentage of patients with ≥1 echocardiographic class of deterioration of systolic sRV function (27 vs. 83%, p = 0.001). Of the patients receiving chronic subpulmonary ventricular pacing (n = 12), 9 (75%) reached the composite endpoint of progressive heart failure [death, ventricular assist device implantation, or upgrade to cardiac resynchronization therapy (CRT)]. Only 4 (31%) patients with native AV-conduction (n = 13) reached this composite endpoint (p = 0.027).ConclusionPatients with a failing sRV who undergo TV surgery are prone to develop AV-conduction abnormalities, with 41% developing an indication for chronic ventricular pacing during 10 years of follow-up. Patients with chronic subpulmonary ventricular pacing have a significantly longer QRS complex duration, have higher levels of the heart failure biomarker NT-pro-BNP, and are at a higher risk of deterioration of systolic sRV function and progressive heart failure.

PO-687-02 THE EXTRAVASCULAR IMPLANTABLE CARDIOVERTER - DEFIBRILLATOR: A CASE FOR CONCERN

The investigational Extravascular Implantable Cardioverter Defibrillator (Medtronic EV-ICD) system with its substernal lead placement may offer an alternative to transvenous ICD while reducing the risks associated with transvenous system such as infection requiring extraction, vascular injury, and venous obstruction. The EV-ICD lead is placed just beneath the sternum in the retrosternal space. Patients with prior or planned sternotomy and prior chest radiotherapy are excluded from the EV-ICD trials due to increased surgical risk. We describe a patient with cardiac sarcoidosis in whom we decided not to implant the EV-ICD due to pericardial adhesions noted on preoperative imaging. N/A A 55-year-old man with history of chronic systolic heart failure due to cardiac sarcoidosis and family history of sudden cardiac death was noted to have non sustained ventricular tachycardia on an event monitor. He underwent an electrophysiologic study which showed inducible monomorphic ventricular tachycardia. ICD implantation was recommended. Due to an active lifestyle and no pacing indication, he opted for an EV-ICD. As part of the pre-operative protocol, a chest X ray is obtained but is not used to determine device eligibility. However, in this case it was noted that the right ventricle was closely approximated to the sternum. Due to history of inflammatory cardiomyopathy, a gated cardiac CT was obtained to evaluate the retrosternal space. Cardiac CT showed adhesion of the right ventricular pericardium to the midline sternum. The right ventricle was tethered but not adherent to the sternum. The EV-ICD procedure was cancelled due to increased surgical risk associated with tunneling with an adherent pericardium. He later underwent a transvenous ICD placement. Pericardial adhesions may be associated with inflammatory cardiomyopathies such as cardiac sarcoidosis. Thorough preoperative evaluation of the retrosternal space is recommended in such patients prior to considering substernal lead tunneling.

PO-673-03 ANODAL CAPTURE DURING LEFT BUNDLE AREA PACING OVERCOMES DELAYED RIGHT VENTRICULAR ACTIVATION BUT DOES NOT OFFER ANY HAEMODYNAMIC ADVANTAGE

The use of Left bundle area pacing is rapidly growing for both bradycardia and CRT indications. It offers physiological activation of the left ventricle, but right ventricular activation may be delayed. It is often possible to shorten QRS duration and eliminate the R wave in V1 by adjusting pacing output and/or configuration. It is not clear whether the reduction in QRS occurs as a result of bi-bundle capture or due to RV septal capture and it is not known whether programming this configuration offers an advantage in cardiac function. To assess the mechanism of QRS reduction and R prime elimination during left bundle area pacing (ECGi mapping) and whether this confers any haemodynamic benefit. Patients implanted with a LBAP lead were recruited if they exhibited R prime in lead V1 response to pacing and R prime could be eliminated by changing pacing output or configuration (e.g. switch from unipolar to bipolar pacing). We used ECGi mapping to determine ventricular activation (septal myocardial capture or bibundle capture) and a high precision haemodynamic protocol to measure systolic blood pressure change for each capture type. 15 patients were recruited (11 male), mean age 68 ± 11 years. Bradycardia was the pacing indication in 4 (27%) patients, heart failure in 11 (73%).ECGi mapping suggested that the mechanism of shortening of QRS duration was due to RV septal myocardial capture, rather than bi-bundle capture in all of our patients.Left bundle plus right septal capture was associated with significantly narrower QRS duration compared to left bundle only capture (-11.7ms, 95% CI: -15.7 to -7.6 ms, P<0.0001). However, this response required higher pacing outputs (mean threshold 3.28 V ± 2.16 at 0.4ms vs 0.69 V ± 0.25 at 0.4ms, p=0.0004) (Figure 1).Despite the narrower QRS duration, there was no significant difference in systolic blood pressure between the two capture types (-0.96 mm Hg; 95% CI: -3.3 to 1.4 mm Hg; P>0.05). (Figure 1). During left bundle branch pacing it is often possible to deliver earlier right ventricular activation achieved by right septal capture. However, this requires significantly higher pacing outputs without any haemodynamic advantage. When programming these devices, the lowest threshold that achieves left bundle capture is acceptable.

COVID-19 pandemic and elderly: is the curtain dropped for urgent pacemaker implantations?

Permanent cardiac pacing is the therapy of choice for treating severe and/or symptomatic bradyarrhythmia. During the COVID-19 outbreak, it has been reported a decrease in the incidence of acute coronary syndrome, but few data are available about pacemaker implantation rates. This study aimed to analyze patients referred to our center with permanent cardiac pacing indication during the COVID-19 outbreak. We compared the number, the characteristics and the outcomes of patients who underwent urgent pacemaker implantation between March and April 2019 (Group I) with those performed in the corresponding 2020 period (Group II). A total of 27 patients (Group I) were implanted in March-April 2019 and 34 patients (Group II) in the corresponding 2020 period. In both groups, about half of the patients received a dual-chamber pacemaker. No significant differences in baseline patients' characteristics were observed. The most frequent indication was advanced atrio-ventricular block with a prevalence of 78% and 62% in Group I and II, respectively. The rate of procedural complications, the in-hospital and 1-month mortality were also similar between the two groups. In our regional referral center, we observed a routine activity in terms of urgent pacemaker implantations for the treatment of symptomatic bradyarrhythmia during the COVID-19 outbreak.

CI-525-01 EARLY EXPERIENCE WITH A LEADLESS VENTRICULAR PACEMAKER PROVIDING ATRIOVENTRICULAR SYNCHRONOUS PACING IN THE REAL-WORLD SETTING: RESULTS FROM THE MICRA AV POST-APPROVAL REGISTRY

Advances in leadless pacemaker technology have enabled accelerometer based atrioventricular synchronous (AVS) pacing by sensing atrial mechanical contraction. However, performance of these devices in real-world clinical practice has not been assessed. To report the acute performance of the Micra AV leadless pacemaker from the global Micra AV post-approval registry (PAR). The Micra AV PAR is an ongoing prospective single-arm observational study designed to assess the safety and effectiveness of Micra AV in the real-world setting. The registry will enroll approximately 750 patients and follow them for 3-years. For this analysis, baseline characteristics, device performance, and pericardial effusion events were summarized. The device was successfully implanted in 400 of 402 patients (99.5%) at 77 centers (mean age 75.4±14.1 years, 43.8% female). The most common pacing indication was AV block (49.0%), followed by sinus node dysfunction (17.9%), and bradyarrhythmia with AF (16.2%). Co-morbidities included diabetes (33.6%), heart failure (14.7%), and COPD (9.0%) with 33.3% precluded from transvenous devices. Pericardial effusion occurred in 5 patients (1.24%). Of the 153 patients programmed to VDD mode with ≥30 days of device follow-up, median pacing percentage was 70.7% with 43.1% of patients having >90% pacing. The median percentage of ventricular paces preceded by atrial mechanical detection was 75% in the 66 patients with >90% ventricular pacing (Figure). The Micra AV leadless pacemaker was implanted with a high rate of success among patients with a high co-morbidity burden. Longer-term performance of the device will continue to be assessed in this ongoing trial.

Impact of right ventricular pacing site on the subcutaneous ICD sensing-a step towards personalised device therapy?

Patients with an existing subcutaneous implantable cardiac defibrillator (S-ICD) may develop a pacing indication. When transvenous pacing is not feasible, combining an S-ICD and a leadless pacemaker (LP) can be a reasonable option. There are reports of concomitant use of both devices. However, the effect of pacing on the S-ICD sensing is not well studied. We hypothesise that pacing changes R and T-wave amplitudes, causing changes in R:T ratios as perceived by a S-ICD, increasing the risk for T wave oversensing (TWO) during paced rhythm with a subsequent risk of inappropriate shocks. This is a prospective study in patients undergoing electrophysiological studies. Participants were fitted with a Holter®, and the leads were placed to correspond to the vectors of an S-ICD. The right ventricle was paced at four positions for 10 beats each at 8mA/2ms. The Holter® traces were analysed, using two-way analysis of variance (ANOVA) to assess the effect of pacing on the R:T ratio. Forty-seven patients (age 56.02 ± 16.02, 72% male) were enrolled (81% structurally normal heart, 15% dilated cardiomyopathy, 2% ischaemic cardiomyopathy, and 2% adult congenital heart disease). Age, sex, and aetiology had no effect on the R:T ratio. Pacing caused significant changes in the R:T ratio. There was no significant difference in the R:T ratios between the pacing sites (p < 0.001). Pacing alters the R:T ratio significantly in most patients, theoretically increasing the risk for TWO and inappropriate shocks. Tailored programming for both devices is important for concomitant use of LPs and S-ICDs.

Performance of transcatheter pacing system use in relation to patients' age.

Real-world safety data on the use of transcatheter pacing systems particularly in very elderly patients is still limited. The aim of this analysis was to investigate the effect of age on the safety and efficacy of leadless pacemaker implant. From May 2016 through July 2019, 577 patients were implanted with a leadless single-chamber pacemaker according to current pacing indication in 15 Italian cardiologic centers. The population was divided into age quartiles for evaluation, including (1) < 70years, (2) 70-77years, (3) 78-83years, and (4) ≥ 83years. Procedural data, complications, and electrical parameters were collected at baseline and during the follow-up. Procedural-related complication occurrence was very low (< 1.0%) and similar in the four subgroups according to age even if the older patients were more frail. No cardiac tamponade was reported. Among the groups, no difference was observed in procedural time, fluoroscopy time duration, and electrical parameters (mean pacing impedance: 750 ± 192 and 599 ± 156, mean pacing threshold: 0.7 ± 0.5 and 0.7 ± 0.6, and mean right ventricular sensing 10.7 ± 6.1 and 11.5 ± 4.8 at implant and last follow-up, respectively). The reported data demonstrated a high degree of safety during leadless implant across all patient ages. Procedural complications and device electrical measurements were similar among the different ages.

Patients Characteristic, Indications, and Complications of Permanent Pacemaker Implantation

Background: Permanent pacemaker implantation is a relatively safe procedure that significantly improves morbidity and mortality among patients with bradyarrhythmias. This study was conducted to determine the patients’ characteristics, indications, and complications of pacemaker implantation. Materials and Methods: This was a single-center, prospective study conducted in Azadi Heart Center, Duhok, Iraq between March 2013 and March 2020. All patients who had indications for permanent pacemaker implantation according to the current guidelines (AHA/ACC) were included and followed up for at least 1 year. Results: The study included 396 patients (242 males [61%] and 154 females [39%]) with a mean age of 65 ± 16 years. The most common presenting symptom was dizziness (63%). Atrioventricular block was the most common indication for pacing in 249 cases (63%), followed by sick sinus syndrome (SSS) in 138 patients (34.8%). The most common mode of pacing was DDD in 234 patients (59%). Among all patients undergoing permanent pacemaker implantation, 17 patients (4.25%) developed early and late complications. The most common early complication was pocket hematoma seen in four patients (1%), followed by pneumothorax in three patients (0.75%). Among late complications, painful shoulder was the most common affecting four patients (1%). Conclusions: Pacemaker implantation is a relatively safe procedure with a low complication rate. Elderly males were the most common group receiving permanent pacemaker. Dual-chamber (DDD) pacing mode was the most commonly used mode.

Trends in Use of Single- vs Dual-Chamber Implantable Cardioverter-Defibrillators Among Patients Without a Pacing Indication, 2010-2018

Use of dual-chamber implantable cardioverter-defibrillator (ICD) systems among patients without a pacing indication is an example of low-value care given higher procedural risks, higher costs, and little evidence for benefit from an atrial lead. However, variation in the use of dual-chamber systems was present among patients without a pacing indication. To examine the temporal trends and hospital variation in use of single- and dual-chamber ICD implantation among patients without a pacing indication undergoing first-time ICD implantation. A multicenter cross-sectional study was conducted using the US National Cardiovascular Data Registry ICD Registry. A total of 266 182 patients undergoing initial implantation of a single- or dual-chamber transvenous ICD without a bradycardia pacing indication, class I or II cardiac resynchronization therapy indication, or history of atrial fibrillation or atrial flutter were included. The study was conducted from April 1, 2010, to December 31, 2018; data analysis was performed from October 19, 2020, to January 5, 2022. Implantation of a single- or dual-chamber ICD. Temporal trends among patients undergoing single- vs dual-chamber ICDs were determined using the Cochran-Armitage trend test, and hospital-level variation using adjusted hospital median odds ratios was examined. A total of 266 182 patients (single-chamber ICD, 134 925; dual-chamber ICD, 131 257) were included in this analysis; mean (SD) age was 58.0 (14.0) years and 91 990 patients (68.2%) were men. The use of dual-chamber ICDs decreased from 64.7% (n = 15 694) in 2010 to 42.2% (n = 9762) in 2018 (P < .001). Adjusted for patient characteristics, the median hospital-level proportion of single-chamber ICDs increased from 42.9% (95% CI, 42.6%-45.0%) in 2010 to 50.0% (95% CI, 47.8%-51.0%) in 2018. The median odds ratio for the use of dual-chamber ICDs, adjusted for patient characteristics, was 1.6 (95% CI, 1.6-1.8) in 2010 and 1.5 (95% CI, 1.5-1.8) in 2018, indicating decreasing but persistent variation in use. In this national study of US patients undergoing first-time ICD implantation without a clinical indication for an atrial lead, the use of dual-chamber devices decreased. However, institutional variability in the use of atrial leads persists, suggesting differences in individual or institutional cultures of real-world practice and opportunity to reduce this low-value practice.

Is the pacing site closer to the left ventricular septal endocardium in left bundle branch pacing or in left ventricular septal pacing?

Distinguishing between left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) is challenging. This study aimed to compare the echocardiographic distance from the pacing lead tip to the left ventricular (LV) septal endocardium between patients who underwent LBBP and those who underwent LVSP successfully. Fifty-nine consecutive patients (age 71.9 ± 12.0years, 35.6% male) with traditional indications for permanent cardiac pacing were included (LBBP group, n = 46; LVSP group, n = 13). Unipolar pacing from the final pacing sites generated narrow QRS complexes with a right bundle branch block pattern in all patients. After the procedure, a physician blinded to the group allocation performed echocardiographic measurements of the distance between the lead tip and the LV septal endocardium. The mean paced QRS duration was comparable between the LBBP group and the LVSP group (105.3 ± 15.6ms vs. 109.2 ± 9.6ms, P = 0.287). In the LBBP group, the interval from the left bundle branch potential to QRS onset was 28.7 ± 9.0ms. During diastole, the mean distance between the lead tip and the LV septal endocardium was 0.6 ± 0.9mm in the LBBP group and 3.0 ± 1.6mm in the LVSP group (P < 0.001). During systole, the distance was 1.5 ± 1.4mm in the LBBP group and 4.3 ± 2.6mm in the LVSP group (P < 0.001). The landing zone of the lead tip was closer to the LV septal endocardium in the patients who underwent LBBP. There is a need for real-time intraprocedural monitoring of the distance between the lead tip and the LV septal endocardium when performing LBBP.

Leadless pacemaker implantation after lead extraction for cardiac implanted electronic device infection.

Cardiac implanted electronic device (CIED) pocket and systemic infection remain common complications with traditional CIEDs and are associated with high morbidity and mortality. Leadless pacemakers may be an attractive pacing alternative for many patients following complete hardware removal for a CIED infection by eliminating surgical pocket-related complications as well as lower risk of recurrent complications. To describe use and outcomes associated with leadless pacemaker implantation following extraction of a CIED system due to infection. Patient characteristics and postprocedural outcomes were described in patients who underwent leadless pacemaker implantation at Duke University Hospital between November 11, 2014 and November 18, 2019, following CIED infection and device extraction. Outcomes of interest included procedural complications, pacemaker syndrome, need for system revision, and recurrent infection. Among 39 patients, the mean age was 71 ± 17 years, 31% were women, and the most frequent primary pacing indication was complete heart block (64.1%) with 9 (23.1%) patients being pacemaker dependent at the time of Micra implantation. The primary organism implicated in the CIED infection was Staphylococcus aureus (43.6%). Nine of the 39 patients had a leadless pacemaker implanted before or on the same day as their extraction procedure, and the remaining 30 patients had a leadless pacemaker implanted after their extraction procedure. During follow-up (mean 24.8 ± 14.7 months) after leadless pacemaker implantation, there were a total of 3 major complications: 1 groin hematoma, 1 femoral arteriovenous fistula, and 1 case of pacemaker syndrome. No patients had evidence of recurrent CIED infection after leadless pacemaker implantation. Despite a prior CIED infection and an elevated risk of recurrent infection, there was no evidence of CIED infection with a mean follow up of over 2 years following leadless pacemaker implantation at or after CIED system removal. Larger studies with longer follow-up are required to determine if there is a long-term advantage to implanting a leadless pacemaker versus a traditional pacemaker following temporary pacing when needed during the periextraction period in patients with a prior CIED infection.

Risk factors for developing pacing induced LV dysfunction: Experience from a tertiary center in the UK.

The risk factors for developing pacing induced left ventricular dysfunction (LVD) in patients with high burden of right ventricular pacing (RVP) is poorly understood. Therefore, in the present study, we aimed to assess the determinants of pacing induced LVD. Our data were retrospectively collected from 146 patients with RVP>40% who underwent generator change (GC) or cardiac resynchronization therapy (CRT) upgrade between 2016 and 2019 who had left ventricular ejection fraction (EF) ≥50% at initial implant. A total of 75 patients had CRT upgrade due to pacing induced LVD (EF<50%) and 71 patients with preserved LV function (EF≥50%) had a GC. Primary indication for pacing in both groups was complete heart block. Male predominance (p=.008), prior myocardial infarction (MI) (p=.001), atrial fibrillation (AF) (p=.009), chronic kidney disease (CKD) (p=.005), and borderline low systolic function (BLSF) (EF 50%-55%) (p=.04) were more prevalent in the CRT upgrade group. Presence of AF (odds ratio [OR]=3.05, 95% confidence interval [CI] 1.42-6.58; p=.004), BLSF (OR=3.8, 95% CI 1.22-11.8; p=.02), and male gender (OR=2.41, 95% CI 1.14-5.08; p=.02) were independent predictors for RVP induced LVD. Age (OR=1.08, 95% CI 1.02-1.14; p=.005) and BLSF (OR=5.33, 95% CI 1.26-22.5; p=.023) were independent predictors of earlier development of LVD after implant. Our results suggested that AF, BLSF, and male gender are predictors for development of pacing induced LVD in patients with high RVP burden. LVD can occur at any time after pacemaker implant with BLSF and increasing age associated with earlier development of LVD.

Conduction system pacing following septal myectomy: Insights into site of conduction block.

Septal myectomy for obstructive hypertrophic cardiomyopathy (HCM) is associated with conduction block; however, the electrophysiological characteristics of conduction block have not been well characterized. The aim of study was to assess the feasibility and safety of His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) in patients with septal myectomy-associated conduction block. Patients with HCM and indications for pacing or cardiac resynchronization therapy after septal myectomy were included. Electrophysiological mapping was performed to identify the site of block. The success rates and pacing characteristics of HBP and LBBAP were also recorded. The echocardiographic data and complications were documented and tracked during follow-up. Ten patients with atrioventricular block (AVB) or left bundle branch block (LBBB) post-myectomy were included in the study. The site of block was infranodal in the nine patients with AVB. HBP failed due to the lack of distal His bundle capture (N = 7) or LBBB correction (N = 3). LBBAP was successful in nine patients and failed in one. QRS duration narrowed from 163.3 ± 16.6 ms after surgery to 123.6 ± 15.8 ms during LBBAP (p < .001). The mean depth of the leads was 13.3 ± 4.0 mm (range from 10 to 20 mm). At a mean follow-up of 5.3 ± 3.9 months, pacing parameters and left ventricular ejection fraction remained stable. Electrophysiological mapping revealed that the site of block was infra-Hisian and not correctable with HBP in patients with HCM post-myectomy. LBBAP appears to be a more feasible physiological strategy for these patients.

Single-Chamber Leadless Cardiac Pacemaker in Patients Without Atrial Fibrillation: Findings From Campania Leadless Registry.

Introduction:Little is known about the clinical performance of single-chamber leadless pacemaker (LLPM) in patients without atrial fibrillation (AF) as pacing indication. The aim of this study was to describe the clinical characteristics of patients who underwent single chamber LLPM implantation at three tertiary referral centers and to compare the safety and effectiveness of the single-chamber LLPM among patients with or without AF.Materials and Methods:All the consecutive patients who underwent LLPM implantation at three referral centers were analyzed. The indications to LLPM in a real-world setting were described. The study population was divided into two groups according to AF as pacing indication. We assessed the procedure-related complications; moreover, we compared syncope, cardiac hospitalization, pacemaker syndrome, and all-cause death recurrence during the follow-up between patients with and without AF as pacing indication.Results:A total of 140 consecutive patients (mean age, 76.7 ± 11.24 years, men 64.3%) were included in the study. The indication to implantation of LLPM was permanent AF with slow ventricular response (n: 67; 47.8%), sinus node dysfunction (n: 25; 17.8%), third atrioventricular block (AVB) (n: 20; 14.2%), second-degree AVB (n: 18; 12.8%), and first degree AVB (n: 10; 7.1%). A total of 7 patients (5%) experienced perioperative complications with no differences between the AF vs. non-AF groups. During a mean follow-up of 606.5 ± 265.9 days, 10 patients (7.7%) died and 7 patients (5.4%) were reported for cardiac hospitalization; 5 patients (3.8%) experienced syncope; no patients showed pacemaker syndrome. No significant differences in the clinical events between the groups were shown. The Kaplan–Meier analysis for the combined endpoints did not show significant differences between the AF and non-AF groups [hazard ratio (HR): 0.94, 95% CI: 0.41–2.16; p = 0.88].Conclusion:Our real-world data suggest that LLPM may be considered a safe and reasonable treatment in patients without AF in need of pacing. Further studies are needed to confirm these preliminary results.

JCS/JHRS 2021 guideline focused update on non-pharmacotherapy of cardiac arrhythmias.

JCS/JHRS 2021 guideline focused update on non-pharmacotherapy of cardiac arrhythmias.

Reconditioned and new pacemakers in low-resource countries: A pilot study

Abstract Introduction: Cardiac pacemakers have brought a paradigm shift to the management of symptomatic bradyarrhythmia. It has led to a dramatic reduction in morbidity and mortality from cardiovascular disease over the many decades. Despite these merits, pacemakers remain unaffordable and beyond reach for many patients in low-and middle-income countries (LMICs) including Nigeria. These challenges and regulatory obstacles may be overcome with postmortem pacemaker reuse if they are proven to be feasible and safe as cost-effective strategy to provide life-saving therapy to patients in LMICs. The aim of this pilot study was to review the usefulness of reconditioned pacemakers among patients that could not afford new devices. Materials and Methods: A total of 16 patients were recruited for the pilot study. These included patients with a pacing indication who could not afford a new pacemaker or a battery change. The 16 patients were grouped into A and B. Group B had 8 patients that received new pacemaker batteries. Group A comprised 8 patients who received refurbished pacemaker batteries. All the pacemaker leads used in the study for both the groups were new. Implant charges were free. Ethical approval was got from the University of Port Harcourt Teaching Hospital, and the Cardiocare Multispecialty Hospital, Abuja, before commencement of the study. The refurbished pacemaker batteries were donated by the relatives of deceased patients, with a minimum 70% of remaining battery life. The donated pacemaker batteries were received from Pace4 life and My Heart Your Heart, University of Michigan, Michigan, United States. These reconditioned batteries were resterilized. Pacemaker functions were rechecked before and after sterilization. The devices were programmed on nonpacing (ODO) mode with adaptive pacing mode swift off. These devices were shipped to us for use. All sterile techniques were followed during implantation. Data were collected on wound healing and device malfunction during implant and follow-up for 3 months. Results: The average age for the patients was 62 ± 13 years. There was no pocket hematoma among both the groups. There were no complications during the 1–3-month follow-up period. There was no evidence of lead or battery malfunction among the two groups. The means of battery longevity for the new and refurbished pacemakers were 10.38 and 10.57 years, respectively. There was no statistical difference between the pulse generator longevity among new and refurbished pacemakers with P = 0.681. There was no infection and device malfunction in the 3 months. Conclusion: The reused pacemaker batteries are safe and do no increased risk of infection and malfunction. This provides an effective option for patients who cannot afford a new device or a replacement battery.

His bundle pacing: initial Slovenian single-centre experience

Background: High right ventricular (RV) pacing burden may promote left ventricular dysfunction. Recently, His bundle pacing (HBP) has emerged as an alternative method to RV pacing that provides physiological ventricular activation by directly stimulating the conduction system.&#x0D; Methods: Consecutive 75 patients (male 61.3%, age 65 ± 14 yrs, preserved ejection fraction 53.8%, atrial fibrillation (AF) 56%) in whom HBP was attempted at our centre between May 2018 and September 2020 were included. Acute implant success rate, complications and mid-term outcomes were assessed.&#x0D; Results: Permanent HBP was acutely successful in 69 patients (92%). There were no acute procedure-related complications. Most common indication was AF with rapid ventricular response (38.7%) where HBP was performed in conjunction with atrioventricular node ablation. Median fluoroscopy time was lower during the second half of implants (6.35 (2.7 – 47) vs. 5.4 (1.3 – 13.6) minutes; p = 0.004). His capture parameters remained stable during the median follow-up of 193 (59 – 342) days. Eleven patients (11/69, 15.9%) with initially successful procedure experienced a significant rise in HBP threshold. Three patients (3/69, 4.3%) needed HBP lead revision or deactivation.&#x0D; Conclusion: Our initial experience indicates that HBP is feasible and safe in various pacing indications. Further randomized clinical trials with long-term follow-up are needed to provide the grounds for wider clinical application of this promising physiological pacing technique.

Risk and predictors of mortality after implantable cardioverter-defibrillator implantation in patients with sarcoid cardiomyopathy

Implantable cardioverter-defibrillators (ICDs) are recommended for patients with cardiac sarcoidosis (CS) with an indication for pacing, prior ventricular arrhythmias, cardiac arrest, or left ventricular ejection fraction <35%, but data on outcomes are limited. Using data from the National Cardiovascular Data Registry ICD Registry between April 1, 2010 and December 31, 2015, we evaluated a propensity matched cohort of CS patients implanted with ICDs versus non-ischemic cardiomyopathies (NICM). We compared mortality using Kaplan-Meier survival curves and Cox proportional hazards models. We identified 1,638 patients with CS and 8,190 propensity matched patients with NICM. The rate of death at 1 and 2 years was similar in patients with CS and patients with NICM (5.2% vs 5.4%, P = 0.75 and 9.0% vs 9.3%, P = 0.72, respectively). After adjusting for other covariates, patients with CS had similar mortality at 2 years after ICD implantations compared with NICM patients (RR 1.03, 95% CI 0.87-1.23). Among patients with CS, multivariable logistic regression identified 6 factors significantly associated with increased 2-year mortality: presence of heart failure (HR 1.92, 95% CI 1.44-3.22), New York Heart Association (NYHA) Class III heart failure (HR 1.68, 95% CI 1.16-2.45), NYHA Class IV heart failure (HR 3.08, 95% CI 1.49-6.39), atrial fibrillation/flutter (HR 1.66, 95% CI 1.17-2.35), chronic lung disease (HR 1.64, 95% CI 1.17-2.29), creatinine >2.0 mg/dL (HR 4.07, 95% CI 2.63-6.30), and paced rhythm (HR 2.66, 95% CI 1.07-6.59). Mortality following ICD implantation was similar in CS patients compared with propensity matched NICM patients. Presence of heart failure, NYHA class, atrial fibrillation/flutter, chronic lung disease, renal dysfunction, and paced rhythm at time of implantation were all predictors of increased 2-year mortality among CS patients with ICDs.