Informational letters or postcards to initiate remote monitoring among veterans with pacemakers and implantable cardioverter-defibrillators: A randomized, controlled trial.

BACKGROUND: Remote monitoring (RM) of pacemakers and implantable cardioverter-defibrillators (ICDs) is a Class 1, Level of Evidence A recommendation because of its multitude of clinical benefits. However, RM adherence rates are suboptimal, precluding patients from achieving these benefits. There is a need for direct-to-patient efforts to improve adherence. METHODS: In this national randomized, controlled trial conducted in the Veterans Health Administration (VHA), 2120 patients with a pacemaker or ICD who had not sent an RM transmission for ≥1 year (and usually ≥3 years) while under VHA care for their device were randomly assigned to be mailed a postcard (n = 1076) or a detailed letter (n = 1044). The postcard described what RM does and its key benefits (reduced mortality and fewer in-person visits). The letter provided a similar message but included more details about RM benefits and the process. The primary outcome was an RM transmission sent within 90 days of mailing, and a secondary outcome was an RM transmission sent within 365 days. RESULTS: The primary outcome was achieved in 121 (11.3%) in the postcard and 96 patients (9.2%) in the letter group (p = .12). The secondary outcome was achieved in 266 (24.7%) and 239 (22.9%), respectively (p = .32). CONCLUSIONS: This randomized trial showed no significant difference in the proportion of chronically non-adherent patients who sent an RM transmission after receiving a low-cost postcard or a detailed, higher-cost letter encouraging their participation in RM. However, as only a minority of patients responded to either, further work is needed to engage patients in the life-saving benefits of RM.

Monitoring of Remotely Reprogrammable Implantable Loop Recorders With Algorithms to Reduce False-Positive Alerts.

BACKGROUND: Implantable loop recorders (ILRs) are increasingly placed for arrhythmia detection. However, historically, ≈75% of ILR alerts are false positives, requiring significant time and effort for adjudication. The LINQII and LUX-Dx are remotely reprogrammable ILRs with dual-stage algorithms using artificial intelligence to reduce false positives, but their utility in routine clinical practice has not been studied. METHODS AND RESULTS: We identified patients with the LINQII and LUX-Dx who were monitored by the Veterans Affairs National Cardiac Device Surveillance Program between March and June 2022. ILR programming was customized on the basis of implant indication. All alerts and every 90-day scheduled transmissions were manually reviewed. ILRs were remotely reprogrammed, as appropriate, after false-positive alerts or 2 consecutive same-type alerts, unless there was ongoing clinical need for that alert. Outcomes were total number of transmissions and false positives. We performed medical record review to determine if patients experienced any adverse clinical events, including hospitalization and mortality. Among 117 LINQII patients, there were 239 total alerts, 43 (18.0%) of which were false positives. Among 105 LUX-Dx patients, there were 300 total alerts, 115 (38.3%) of which were false positives. LINQIIs were reprogrammed 22 times, resulting in a decrease in median alerts/day from 0.13 to 0.03. LUX-Dx ILRs were reprogrammed 52 times, resulting in a decrease from 0.15 to 0.01 median alerts/day. There were no adverse clinical events that could have been identified by superior or earlier arrhythmia detection. CONCLUSIONS: ILRs with artificial intelligence algorithms and remote reprogramming ability are associated with reduced alert burden because of higher true-positive rates than prior ILRs, without missing potentially consequential arrhythmias.

Informational Postcards Increase Engagement with Remote Monitoring Among Veterans with Pacemakers and Implantable Cardioverter-Defibrillators: a Stepped-Wedge Randomized Controlled Trial.

BACKGROUND: Remote monitoring (RM) of pacemakers and implantable cardioverter-defibrillators (ICDs) reduces morbidity and mortality. However, many patients are not adherent to RM. OBJECTIVE: To test the effect of informational postcards on RM adherence. DESIGN/PATIENTS: Stepped-wedge randomized controlled trial among Veterans with pacemakers and ICDs. INTERVENTION: In wave 1, Veterans who had sent at least 1 transmission within the past 2 years but had become non-adherent were randomly assigned to receive a postcard or no postcard. Those receiving postcards were randomized to 1 of 2 messages: (1) a"warning" postcard describing risks of non-adherence or (2) an "encouraging" postcard describing benefits of adherence. In wave 2, Veterans who had either not received a postcard in wave 1 or had since become non-adherent were mailed a postcard (again, randomized to 1 of 2 messages). Patients who did not send an RM transmission within 1 month were mailed a second, identical postcard. MAIN MEASURES: Transmission within 70 days. KEY RESULTS: Overall, 6351 Veterans were included. In waves 1 and 2, postcards were mailed to 5657 Veterans (2821 "warning" messages and 2836 "encouraging" messages). Wave 1 included 2178 Veterans as controls (i.e., not mailed a postcard), some of whom received a postcard in wave 2 if they remained non-adherent. In wave 2, 3473 postcards were sent. Of the 5657 patients mailed a postcard, 2756 (48.7%) sent an RM transmission within 70 days, compared to 530 (24.3%) of 2178 controls (absolute difference 24.4%, 95% confidence interval [CI] 22.2%, 26.6%). Of those who sent a transmission, 71.8% did so after the first postcard. Transmission rates at 70 days did not significantly differ between "warning" and "encouraging" messages (odds ratio 1.04, 95% CI 0.92, 1.18). CONCLUSIONS: Informational postcards led to a 24.4% absolute increase in adherence at 70 days among Veterans with pacemakers and ICDs who were non-adherent to RM.

Barriers and Facilitators Associated With Remote Monitoring Adherence Among Veterans With Pacemakers and Implantable Cardioverter-Defibrillators: Qualitative Cross-Sectional Study.

BACKGROUND: The Heart Rhythm Society strongly recommends remote monitoring (RM) of cardiovascular implantable electronic devices (CIEDs) because of the clinical outcome benefits to patients. However, many patients do not adhere to RM and, thus, do not achieve these benefits. There has been limited study of patient-level barriers and facilitators to RM adherence; understanding patient perspectives is essential to developing solutions to improve adherence. OBJECTIVE: We sought to identify barriers and facilitators associated with adherence to RM among veterans with CIEDs followed by the Veterans Health Administration. METHODS: We interviewed 40 veterans with CIEDs regarding their experiences with RM. Veterans were stratified into 3 groups based on their adherence to scheduled RM transmissions over the past 2 years: 6 fully adherent (≥95%), 25 partially adherent (≥65% but <95%), and 9 nonadherent (<65%). As the focus was to understand challenges with RM adherence, partially adherent and nonadherent veterans were preferentially weighted for selection. Veterans were mailed a letter stating they would be called to understand their experiences and perspectives of RM and possible barriers, and then contacted beginning 1 week after the letter was mailed. Interviews were structured (some questions allowing for open-ended responses to dive deeper into themes) and focused on 4 predetermined domains: knowledge of RM, satisfaction with RM, reasons for nonadherence, and preferences for health care engagement. RESULTS: Of the 44 veterans contacted, 40 (91%) agreed to participate. The mean veteran age was 75.3 (SD 7.6) years, and 98% (39/40) were men. Veterans had been implanted with their current CIED for an average of 4.4 (SD 2.8) years. A total of 58% (23/40) of veterans recalled a discussion of home monitoring, and 45% (18/40) reported a good understanding of RM; however, when asked to describe RM, their understanding was sometimes incomplete or not correct. Among the 31 fully or partially adherent veterans, nearly all were satisfied with RM. Approximately one-third recalled ever being told the results of a remote transmission. Among partially or nonadherent veterans, only one-fourth reported being contacted by a Department of Veterans Affairs health care professional regarding not having sent a remote transmission; among those who had troubleshooted to ensure they could send remote transmissions, they often relied on the CIED manufacturer for help (this experience was nearly always positive). Most nonadherent veterans felt more comfortable engaging in RM if they received more information or education. Most veterans were interested in being notified of a successful remote transmission and learning the results of their remote transmissions. CONCLUSIONS: Veterans with CIEDs often had limited knowledge about RM and did not recall being contacted about nonadherence. When they were contacted and troubleshooted, the experience was positive. These findings provide opportunities to optimize strategies for educating and engaging patients in RM.

An Unexpected Pacemaker Response to Catheter Ablation: Failure of Pacing Pulse Delivery During Asynchronous Pacing Mode.

Radiofrequency (RF) ablation can be a source of electromagnetic interference (EMI) for cardiovascular implantable electronic devices (CIEDs). The response of CIEDs to this type of EMI can be variable and unpredictable. We report a case with an uncommon response where there was a failure to deliver pacing pulses to both atrial and ventricular pacing leads during RF ablation close to the atrial lead even when the pacemaker was set to pace asynchronously. We also explain the mechanism behind this unusual pacemaker response.

Ventricular arrhythmia detection for contemporary Biotronik and Abbott implantable cardioverter defibrillators with markedly prolonged detection in Biotronik devices.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) are typically programed with both ventricular tachycardia (VT) and ventricular fibrillation (VF) treatment zones. Biotronik and Abbott ICDs do not increment the VT counter when the tachycardia accelerates to the VF zone, which could result in a prolonged delay in tachycardia detection. METHODS: Patients with Biotronik and Abbott ICDs receiving care at Veterans Affairs facilities in Northern California were identified. Patient information and device tracings for patients with any ICD therapies were examined to assess for possible delayed tachycardia detection. RESULTS: Among 52 patients with Biotronik ICDs, 8 (15%) experienced appropriate ICD therapy over a median follow-up of 29 months. Among 68 patients with Abbott ICDs, 26 (38%) experienced appropriate ICD therapy over a median follow-up of 83 months. Three of the patients with Biotronik ICDs who received appropriate therapy experienced a delay in VT/VF detection due to the tachycardia rate oscillating between the VT and VF treatment zones (longest 31.2 s on detection), compared with four of the patients with Abbott ICDs (longest 4.1 s on the detection and 8 s on redetect). One of the patients with a Biotronik ICD experienced recurrent syncope associated with delayed detection and another died on the day of delayed detection. One of the patients with an Abbott ICD experienced syncope. CONCLUSIONS: Because contemporary Biotronik and Abbott ICDs freeze the VT counters when tachycardia is in the VF zone, ICD therapies can be markedly delayed when the tachycardia oscillates between the VT and VF zone.

Cardiovascular implantable electronic device lead safety: Harnessing real-world remote monitoring data for medical device evaluation.

BACKGROUND: Current methods to identify cardiovascular implantable electronic device lead failure include postapproval studies, which may be limited in scope, participant numbers, and attrition; studies relying on administrative codes, which lack specificity; and voluntary adverse event reporting, which cannot determine incidence or attribution to the lead. OBJECTIVE: The purpose of this study was to determine whether adjudicated remote monitoring (RM) data can address these limitations and augment lead safety evaluation. METHODS: Among 48,191 actively monitored patients with a cardiovascular implantable electronic device, we identified RM transmissions signifying incident lead abnormalities and, separately, identified all leads abandoned or extracted between April 1, 2019, and April 1, 2021. We queried electronic health record and Medicare fee-for-service claims data to determine whether patients had administrative codes for lead failure. We verified lead failure through manual electronic health record review. RESULTS: Of the 48,191 patients, 1170 (2.4%) had incident lead abnormalities detected by RM. Of these, 409 patients had administrative codes for lead failure, and 233 of these 409 patients (57.0%) had structural lead failure verified through chart review. Of the 761 patients without administrative codes, 167 (21.9%) had structural lead failure verified through chart review. Thus, 400 patients with RM transmissions suggestive of lead abnormalities (34.2%) had structural lead failure. In addition, 200 patients without preceding abnormal RM transmissions had leads abandoned or extracted for structural failure, making the total lead failure cohort 600 patients (66.7% with RM abnormalities, 33.3% without). Patients with isolated right atrial or left ventricular lead failure were less likely to have lead replacement and administrative codes reflective of lead failure. CONCLUSION: RM may strengthen real-world assessment of lead failure, particularly for leads where patients do not undergo replacement.

Strategies to enhance remote monitoring adherence among patients with cardiovascular implantable electronic devices.

Background: Remote monitoring (RM) of patients with cardiovascular implantable electronic devices (CIEDs) (pacemakers and implantable cardioverter-defibrillators) has a Class 1, Level of Evidence A Heart Rhythm Society recommendation. Yet RM adherence varies widely across settings, and factors associated with variation are not understood. Objective: The purpose of this study was to identify strategies for supporting RM across Veterans Health Administration (VHA) facilities. Methods: In a national evaluation, we surveyed and interviewed 27 nurses, medical instrument technicians, and advanced practice providers across 26 VHA facilities (following approximately 15,000 CIED patients). Participants were selected based on overall patient adherence by facility, which ranged from 46%-96%. Questions covered RM adherence strategies, manufacturer resources, organizational characteristics, and workflows for optimizing adherence. Results: All clinicians reported that RM adherence was extremely important (53.8%), very important (34.6%), or important (11.5%) for improving patient outcomes. High performing facilities prioritized consistent patient education about RM and evaluated nonadherence using dashboards and manufacturer web sites. High performing facilities instituted clear standard operating procedures that defined staff responsibilities and facilitated efficient contact with nonadherent patients and then family members by phone and then mail. Clinicians based at high performing facilities spent twice as many hours per week (9.1) on average managing RM adherence compared to other facilities (4.5). Effective communication (internally and with non-VHA care partners) and use of CIED manufacturer resources were essential. Facilities that were not high performing rarely used these strategies. Conclusion: Clinicians can support high RM adherence by emphasizing patient education, regularly assessing and addressing nonadherence using staff protocols, and engaging CIED manufacturers.

Factors associated with remote monitoring adherence for cardiovascular implantable electronic devices.

BACKGROUND: Professional societies strongly recommend remote monitoring (RM) of all cardiac implantable electronic devices, and higher RM adherence is associated with improved patient outcomes. However, adherence with RM is suboptimal. OBJECTIVE: The purpose of this study was to better understand factors associated with RM adherence. METHODS: We linked RM data from the Veterans Affairs National Cardiac Device Surveillance Program to clinical data for patients monitored between October 25, 2018, and October 24, 2020. RM adherence was defined as the percentage of days covered by an RM transmission during the study period. Patients were classified into 3 categories: complete (100% of days covered by an RM transmission), intermediate (above median in patients with <100% adherence), and low (below median in patients with <100% adherence) adherence. We used multivariable logistic regression to examine patient, device, and facility characteristics associated with adherence. RESULTS: In 52,574 patients, average RM adherence was 71.9%. Only 30.9% (16,224) of patients had complete RM adherence. Black or African American patients had a lower odds of complete RM adherence than white patients (odds ratio 0.88; 95% confidence interval 0.82-0.94), and Hispanic or Latino patients had a lower odds of complete RM adherence (odds ratio 0.79; 95% confidence interval 0.70-0.89) than non-Hispanic or Latino patients. Dementia, depression, and posttraumatic stress disorder were associated with a lower odds of RM adherence. CONCLUSION: There are significant disparities in RM adherence by race, ethnicity, and neuropsychiatric comorbidities. These findings can inform strategies to improve health equity and ensure that all patients with cardiac implantable electronic devices receive the evidence-based clinical benefits of RM.

Implantable cardioverter-defibrillator placement among patients with left ventricular ejection fraction ≤35 % at least 40 days after acute myocardial infarction.

Background: Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death among patients with persistently reduced (≤35 %) left ventricular ejection fraction (LVEF) at least 40 days following acute myocardial infarction (AMI). Few prior studies have used LVEF measured after the 40-day waiting period to examine primary prevention ICD placement. Methods: We sought to determine factors associated with ICD placement among patients who met LVEF criteria post-MI within a large integrated health care system in the U.S by conducting a retrospective cohort study of Veteran patients hospitalized for AMI from 2004 to 2017 who had documented LVEF ≤35 % from echocardiograms performed between 40 and 455 (90 days +1 year) days post-MI. We used multivariable logistic regression to examine factors associated with ICD placement. Results: Of 12,893 patients with LVEF ≤35 % at least 40 days post-MI, 2176 (16.9 %) received an ICD between 91- and 455-days post-MI. Younger age, fewer comorbidities, revascularization with PCI, and greater use of GDMT were associated with increased odds of receiving an ICD. However, half of patients treated with a beta-blocker, ACE inhibitor or angiotensin receptor blocker, and mineralocorticoid receptor antagonist prior to LVEF assessment did not receive an ICD. Eligible Black patients were less likely (odds ratio 0.80, 95 % confidence interval 0.69-0.92) to receive an ICD than White patients. Conclusion: Many factors affect ICD placement among Veteran patients with a confirmed LVEF ≤35 % at least 40 days post-MI. Greater understanding of factors influencing ICD placement would help clinicians ensure guideline-concordant care.

Health-Related Quality of Life in the Spironolactone to Reduce ICD Therapy (SPIRIT) Trial.

To describe health related quality of life (HRQOL) and symptoms in the SPIRIT trial and determine effects of implantable cardioverter defibrillator (ICD) shocks on HRQOL over 24 months. Ninety participants aged 66 ± 10 years, 96% men, 75% with NYHA class II, with an ICD were randomized to spironolactone 25 mg (N = 44) or placebo (N = 46). HRQOL was measured every 6 months for 24 months using: Patient Concerns Assessment (PCA), Short Form Health Survey-Veterans Version (SF-36V), and Kansas City Cardiomyopathy Questionnaire (KCCQ). Linear mixed modeling compared changes in HRQOL over-time and ANCOVA compared HRQOL between those getting an ICD shock or not. Over 24-months, there were no differences in HRQOL between the spironolactone versus placebo groups. Those with at least one ICD shock reported significantly lower HRQOL and more symptoms at 6- and 24-months. Patients receiving one or more ICD shocks reported significant reductions in HRQOL and higher symptoms.

Dexmedetomidine Sedation for Paroxysmal Supraventricular Tachycardia Ablation Is Not Associated With Alteration of Arrhythmia Inducibility.

BACKGROUND: Dexmedetomidine (Dex) is an attractive agent for procedural sedation due to its unique pharmacodynamic profile, specifically affording predictable sedation without concurrent respiratory depression. However, Dex has previously been reported to prevent or terminate arrhythmias. The purpose of this study was to investigate paroxysmal supraventricular tachycardia (PSVT) inducibility and homeostatic stability during electrophysiology studies (EPSs) and ablation when a standardized Dex protocol was used as the primary sedation agent. METHODS: We performed a retrospective review of 163 consecutive procedures for PSVT ablation that received Dex as the primary sedative with adjunct fentanyl and midazolam boluses (DEX-FENT-MIDAZ). This cohort was compared to 163 consecutive control procedures wherein strictly fentanyl and midazolam were used for sedation. The primary outcome reviewed was PSVT inducibility assessed before ablation. Reviewed secondary outcomes included level of sedation and intraprocedure hemodynamics and oxygenation. RESULTS: The arrhythmia profiles of the DEX-FENT-MIDAZ and control cohorts were very similar. The overall incidence of a "negative" EPSs in which arrhythmia was not induced was 24% in the DEX-FENT-MIDAZ group and 26% in the control group (P = .7). Unintended deep sedation was significantly less with DEX-FENT-MIDAZ (4.3% vs 27%; P ≤ .0001). However, DEX-FENT-MIDAZ use was associated with a higher incidence of intraprocedure hypotension. CONCLUSIONS: Dex sedation during EPSs is not associated with a reduction in PSVT inducibility. The therapeutic utility of Dex during EPS arises from the predictable sedation Dex affords but is associated with an increased incidence of intraprocedure hypotension.

Effectiveness of dual external direct current cardioversion for initial cardioversion in atrial fibrillation.

INTRODUCTION: Dual external direct current cardioversion (dual-DCCV) is a rhythm control strategy for persistent atrial fibrillation (AF), involving simultaneous delivery of two shocks from two defibrillators. The long-term effectiveness of this approach has not been studied in the biphasic cardioversion era. METHODS: Seventy-seven consecutive patients at a single center were identified to receive dual-DCCV at the time of their initial cardioversion for AF, when maximum output standard external direct current cardioversion failed in two vectors. Logistic regression was used to analyze risk factors for dual-DCCV in a historical control group of 77 patients undergoing standard cardioversion and Cox proportional hazard models were used to compare time to AF recurrence. RESULTS: The dual-DCCV group had a significantly larger body mass index (BMI), but similar AF duration and left atrial size as controls. Multivariable logistic regression revealed that BMI and absence of prior paroxysmal AF were risk factors for dual-DCCV (P < 0.05). There was no difference observed between dual-DCCV and control groups (adjusted hazard ratio = 0.57; P = .12) after adjusting for number of shocks and age. Transient hypoxia was the only acute complication in either group (P > .999). CONCLUSION: Dual-DCCV appears to be a safe and effective cardioversion strategy for patients with AF. The need for dual-DCCV in the treatment of AF appears to be influenced more by body habitus than atrial substrate.

Practice Variation in Anticoagulation Prescription and Outcomes After Device-Detected Atrial Fibrillation.

BACKGROUND: Device-detected atrial fibrillation (AF) is associated with increased risk of stroke; however, there are no clearly defined thresholds of AF burden at which to initiate oral anticoagulation (OAC). We sought to describe OAC prescription practice variation in response to new device-detected AF and the association with outcomes. METHODS: We performed a retrospective cohort study using data from the Veterans Health Administration linked to remote monitoring data that included day-level AF burden. We included patients with cardiac implantable electronic devices and remote monitoring from 2011 to 2014, CHA2DS2-VASc score ≥2, and no prior stroke or OAC receipt in the preceding 2 years. We determined the proportion of patients prescribed OAC within 90 days after new device-detected AF across a range of AF thresholds (≥6 minutes to >24 hours) and examined site variation in OAC prescription. We used multivariable Cox proportional hazards regressions to determine the association of OAC prescription with stroke by device-detected AF burden. RESULTS: Among 10 212 patients with cardiac implantable electronic devices, 4570 (45%), 3969 (39%), 3263 (32%), and 2469 (24%) had device-detected AF >6 minutes, >1 hour, >6 hours, and >24 hours, respectively. For device-detected AF >1 hour, 1712 patients met inclusion criteria (72±10 years; 1.5% female; CHA2DS2-VASc score 4.0±1.4; HAS-BLED score 2.6±1.1). The proportion receiving OAC varied based on device-detected AF burden (≥6 minutes: 272/2101 [13%]; >1 hour: 273/1712 [16%]; >6 hours: 263/1279 [21%]; >24 hours: 224/818 [27%]). Across 52 sites (N=1329 patients), there was substantial site-level variation in OAC prescription after device-detected AF >1 hour (median, 16%; range, 3%-67%; median odds ratio, 1.56 [95% credible interval, 1.49-1.71]). In adjusted models, OAC prescription after device-detected AF >24 hours was associated with reduced stroke risk (hazard ratio, 0.28; 95% CI, 0.10-0.81; P=0.02), although the propensity-adjusted model was significant when AF lasted at least 6 minutes. CONCLUSIONS: Among veterans with cardiac implantable electronic devices, device-detected AF is common. There is large practice variation in 90-day OAC initiation after new device-detected AF, with low rates of treatment overall, even for episodes that last >24 hours. The strongest association of OAC with reduction in stroke was observed after device-detected AF >24 hours. Randomized trials are needed to confirm these observational findings.

Impact of Physiologic Pacing Versus Right Ventricular Pacing Among Patients With Left Ventricular Ejection Fraction Greater Than 35%: A Systematic Review for the 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

BACKGROUND: It is unclear whether physiologic pacing by either cardiac biventricular pacing (BiVP) or His bundle pacing (HisBP) may prevent adverse structural and functional consequences known to occur among some patients who receive right ventricular pacing (RVP). AIM: Our analysis sought to review existing literature to determine if BiVP and/or HisBP might prevent adverse remodeling and be associated with structural, functional, and clinical advantages compared with RVP among patients without severe left ventricular dysfunction (>35%) who required permanent pacing because of heart block. METHODS: A literature search was conducted using MEDLINE (through PubMed) and Embase to identify randomized trials and observational studies comparing the effects of BiVP or HisBP versus RVP on measurements of left ventricular dimensions, left ventricular ejection fraction (LVEF), heart failure functional classification, quality of life, 6-minute walk, hospitalizations, and mortality. Data from studies that met the appropriate population, intervention, comparator, and outcomes of interest were abstracted for meta-analysis. Studies that reported pooled outcomes among patients with LVEF both above and below 35% could not be included in the meta-analysis because of strict relationships with industry procedures that preclude retrieval of industry-retained unpublished data on the subset of patients with preserved left ventricular function. RESULTS: Evidence from 8 studies, including a total of 679 patients meeting the prespecified criteria for inclusion, was identified. Results were compared for BiVP versus RVP, HisBP versus RVP, and BiVP+HisBP versus RVP. Among patients who received physiologic pacing with either BiVP or HisBP, the LV end-diastolic and end-systolic volumes were significantly lower (mean duration of follow-up: 1.64 years; -2.77 mL [95% CI -4.37 to -1.1 mL]; p=0.001; and -7.09 mL [95% CI -11.27 to -2.91; p=0.0009) and LVEF remained preserved or increased (mean duration of follow-up: 1.57 years; 5.328% [95% CI: 2.86%-7.8%; p<0.0001). Data on clinical impact such as functional status and quality of life were not definitive. Data on hospitalizations were unavailable. There was no effect on mortality. Several studies stratified results by LVEF and found that patients with LVEF >35% but ≤52% were more likely to receive benefit from physiologic pacing. Patients with chronic atrial fibrillation who underwent atrioventricular node ablation and pacemaker implant demonstrated clear improvement in LVEF with BiVP or HisBP versus RVP. CONCLUSION: Among patients with LVEF >35%, the LVEF remained preserved or increased with either BiVP or HisBP compared with RVP. However, patient-centered clinical outcome improvement appears to be limited primarily to patients who have chronic atrial fibrillation with rapid ventricular response rates and have undergone atrioventricular node ablation.

Impact of physiologic pacing versus right ventricular pacing among patients with left ventricular ejection fraction greater than 35%: A systematic review for the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

BACKGROUND: It is unclear whether physiologic pacing by either cardiac biventricular pacing (BiVP) or His bundle pacing (HisBP) may prevent adverse structural and functional consequences known to occur among some patients who receive right ventricular pacing (RVP). AIM: Our analysis sought to review existing literature to determine if BiVP and/or HisBP might prevent adverse remodeling and be associated with structural, functional, and clinical advantages compared with RVP among patients without severe left ventricular dysfunction (>35%) who required permanent pacing because of heart block. METHODS: A literature search was conducted using MEDLINE (through PubMed) and Embase to identify randomized trials and observational studies comparing the effects of BiVP or HisBP versus RVP on measurements of left ventricular dimensions, left ventricular ejection fraction (LVEF), heart failure functional classification, quality of life, 6-minute walk, hospitalizations, and mortality. Data from studies that met the appropriate population, intervention, comparator, and outcomes of interest were abstracted for meta-analysis. Studies that reported pooled outcomes among patients with LVEF both above and below 35% could not be included in the meta-analysis because of strict relationships with industry procedures that preclude retrieval of industry-retained unpublished data on the subset of patients with preserved left ventricular function. RESULTS: Evidence from 8 studies, including a total of 679 patients meeting the prespecified criteria for inclusion, was identified. Results were compared for BiVP versus RVP, HisBP versus RVP, and BiVP+HisBP versus RVP. Among patients who received physiologic pacing with either BiVP or HisBP, the LV end-diastolic and end-systolic volumes were significantly lower (mean duration of follow-up: 1.64 years; -2.77 mL [95% CI -4.37 to -1.1 mL]; p=0.001; and -7.09 mL [95% CI -11.27 to -2.91; p=0.0009) and LVEF remained preserved or increased (mean duration of follow-up: 1.57 years; 5.328% [95% CI: 2.86%-7.8%; p<0.0001). Data on clinical impact such as functional status and quality of life were not definitive. Data on hospitalizations were unavailable. There was no effect on mortality. Several studies stratified results by LVEF and found that patients with LVEF >35% but ≤52% were more likely to receive benefit from physiologic pacing. Patients with chronic atrial fibrillation who underwent atrioventricular node ablation and pacemaker implant demonstrated clear improvement in LVEF with BiVP or HisBP versus RVP. CONCLUSION: Among patients with LVEF >35%, the LVEF remained preserved or increased with either BiVP or HisBP compared with RVP. However, patient-centered clinical outcome improvement appears to be limited primarily to patients who have chronic atrial fibrillation with rapid ventricular response rates and have undergone atrioventricular node ablation.