Incidence and Time Course for Developing Heart Failure With High-Burden Right Ventricular Pacing

Drug-Induced Complete Atrioventricular Block in an Elderly Patient: A Case Report Highlighting Digoxin-Beta Blocker Interactions and a Paradoxical State

Complete atrioventricular (AV) block is a severe conduction abnormality caused by intrinsic cardiac disease, ischemia, electrolyte imbalances, or drug interactions. Elderly patients on multiple medications are particularly vulnerable to polypharmacy-related interactions. This case report describes an 82-year-old female presenting to the emergency department with fatigue, syncope, and disorientation. Her medical history included atrial fibrillation, hypertension, and heart failure, with a medication regimen of digoxin 0.25 mg given daily 5 days out of 7, metoprolol 50 mg twice daily, lisinopril 10 mg daily, furosemide 40 mg daily, and spironolactone 50 mg daily. Clinical examination revealed bradycardia and a holosystolic murmur in the mitral valve area, while the electrocardiogram showed complete AV block at a ventricular rate of 35 bpm. Laboratory results indicated mild hyperkalemia (4.9 mmol/L). Suspecting a digoxin-beta-blocker interaction, antiarrhythmic therapy was discontinued. Within three days, the AV block resolved, transitioning to atrial fibrillation with a high ventricular rate. Bisoprolol was introduced for rate control, and hemodynamic stability was achieved. The patient was discharged with a revised medication regimen and showed no recurrence of AV block. This case emphasizes the importance of recognizing drug interactions as a reversible cause of AV block and using drug interaction checkers to manage polypharmacy, especially in elderly patients with multiple comorbidities. It also highlights the rare and paradoxical combination of atrial flutter and complete AV block.

Post-Implant Global Longitudinal Strain as a Predictor of Pacing-Induced Cardiomyopathy in Patients with Preserved Ejection Fraction Undergoing Pacemaker Placement

Background

Right ventricular (RV) pacing exacerbates heart failure and increases cardiac mortality in patients with reduced ejection fraction (EF). However, its impact on left ventricular dysfunction in patients with preserved EF remains inconclusive. This study investigates the relationship between RV pacing, global longitudinal strain (GLS), and EF in patients with preserved EF.

Methods

This prospective registry study included patients with preserved EF (≥50%) undergoing de novo permanent pacemaker (PPM) implantation for atrioventricular block at Chosun University Hospital, South Korea, from 2018 to 2022. Echocardiographic evaluations were performed pre-implant, post-implant, and at 12 months, with follow-up visits every 3-6 months. Composite outcomes included cardiac death, heart failure hospitalization, pacing-induced cardiomyopathy (PICM), and biventricular pacing (BVP) upgrade.

Results

A total of 71 patients (28 males, mean age 73.1 years) were included. Following PPM implantation, significant declines in both EF and GLS were noted, especially in those with PICM. Over three years, 2 patients died, 6 were hospitalized, 7 developed PICM, and 3 underwent a BVP upgrade. Reduced post-implant GLS was an independent predictor of PICM (hazard ratios (HR) 1.715, 95% CI 1.174-2.504; p = 0.005). Receiver operating characteristic (ROC) analysis showed an area under curve (AUC) of 0.92 for GLS, with a GLS <-15.0 having 100% sensitivity and 80.9% specificity for predicting PICM.

Conclusions

Post-implant GLS is a reliable predictor of PICM in patients with preserved EF. Regular GLS monitoring can guide timely interventions, including guideline-directed medical therapy or BVP upgrades, to prevent deterioration and improve outcomes.

Risk factors and incidence of new-onset heart failure with conventional pacemaker implant: A nationwide study

Background

Studies have shown that the risk of new-onset heart failure (HF) is higher postimplantation for patients receiving right ventricular pacing.

Objective

This study aimed to investigate incidence, risk factors, and implications for long-term prognosis of new-onset HF in patients after pacemaker implantation.

Methods

Patients without pre-existing HF who received a pacemaker in Sweden during the period of 2005 to 2020 were identified via the nationwide Pacemaker Registry. Data were crossmatched with the population registry and national disease registries. The primary outcome was new-onset HF within 5 years, and a risk score for this was developed and validated.

Results

In all, 65,579 patients met the inclusion criteria (10,351 single-chamber ventricular and 55,228 dual-chamber pacemakers). A total of 13,792 (21.0%) patients were diagnosed with HF within 5 years postimplantation. Of these, 6244 (45.3%) were hospitalized for HF. Patients with new-onset HF were more likely to die within 5 years (41.2% vs 19.7%, P < .0001). Risk factors for new-onset HF included increasing age, male sex, hypertension, diabetes, atrial fibrillation, chronic lung and kidney disease, ischemic heart disease, and atrioventricular block. In a combined score using these variables, patients in the highest risk-score quartile had a hazard ratio of 5.36 (95% CI 4.91-5.86, P < .001) and an absolute risk of 32% for developing HF.

Conclusion

Pacemaker therapy is associated with >20% risk of new-onset HF within 5 years, and we identified 9 risk factors associated with the diagnosis of new-onset HF. The proposed score based on these variables can be used to identify patients at high risk for new-onset HF.

Permanent Pacemaker Implantation and Long-Term Outcomes of Patients Undergoing Concomitant Mitral and Tricuspid Valve Surgery

BACKGROUND

Tricuspid valve annuloplasty (TA) during mitral valve repair (MVr) is associated with increased risk of permanent pacemaker (PPM) implantation, but the magnitude of risk and long-term clinical consequences have not been firmly established.

OBJECTIVES

This study assesses the incidence rates of PPM implantation after isolated MVr and following MVr with TA as well as the associated long-term clinical consequences of PPM implantation.

METHODS

State-mandated hospital discharge databases of New York and California were queried for patients undergoing MVr (isolated or with concomitant TA) between 2004 and 2019. Patients were stratified by whether or not they received a PPM within 90 days of index surgery. After weighting by propensity score, survival, heart failure hospitalizations (HFHs), endocarditis, stroke, and reoperation were compared between patients with or without PPM.

RESULTS

A total of 32,736 patients underwent isolated MVr (n = 28,003) or MVr + TA (n = 4,733). Annual MVr + TA volumes increased throughout the study period (P < 0.001, trend), and PPM rates decreased (P < 0.001, trend). The incidence of PPM implantation <90 days after surgery was 7.7% for MVr and 14.0% for MVr + TA. In 90-day conditional landmark-weighted analyses, PPMs were associated with reduced long-term survival among MVr (HR: 1.96; 95% CI: 1.75-2.19; P < 0.001) and MVr + TA recipients (HR: 1.65; 95% CI: 1.28-2.14; P < 0.001). In both surgical groups, PPMs were also associated with an increased risk of HFH (HR: 1.56; 95% CI: 1.27-1.90; P < 0.001) and endocarditis (HR: 1.95; 95% CI: 1.52-2.51; P < 0.001), but not with stroke or reoperation.

CONCLUSIONS

Compared to isolated MVr, adding TA to MVr was associated with a higher risk of 90-day PPM implantation. In both surgical groups, PPM implantation was associated with an increase in mortality, HFH, and endocarditis.

A case of cardiogenic shock due to ventricular dyssynchrony resolved by atrial pacing

We present a case of a man with ischemic cardiomyopathy and single chamber implantable cardioverter-defibrillator who developed sinus arrest creating sudden dependence on right ventricular (RV) pacing. He presented with cardiogenic shock secondary to abrupt onset ventricular dyssynchrony from RV pacing, which required emergent stabilization and completely resolved with atrial pacing.

Learning objective

To establish a basic understanding of cardiogenic shock management. To reinforce the adverse effects associated with right ventricular pacing.

Optimizing Patient Selection for Physiological Pacing in Bradyarrhythmia: Factors Associated With High Ventricular Pacing Burden

Background

Right ventricular (RV) pacing is established as the most common ventricular pacing (VP) strategy for patients with symptomatic bradyarrhythmia. Some patients with high VP burden suffer deterioration of left ventricular (LV) function, termed pacing-induced cardiomyopathy (PICM). Patients who pace > 20% of the time from the RV apex are at increased risk of PICM, but independent predictors of increased RV pacing burden have not been elucidated in those who have a permanent pacemaker (PPM) inserted for bradyarrhythmia.

Methods

We aimed to identify factors that are associated with increased VP burden > 20%, hence determining those at risk for resultant PICM. In this retrospective cohort study, we identified the most recent 300 consecutive cardiac implantable electronic device (CIED) implants in our center and collected past medical history, electrocardiogram (ECG), echo, medication and pacemaker check data.

Results

A total of 236 individuals met inclusion criteria. Of the patients, 35% had RV pacing burden < 20%, while 65% had VP burden ≥ 20%; 96.2% of patients with complete heart block (CHB) paced > 20% (P = 0.002). Utilization of DDD or VVI (75.2% and 89.2% of patients, respectively) without mode switch algorithms was associated with VP > 20% (P < 0.001). Male or previous coronary artery bypass grafting (CABG) patients also statistically paced > 20%. Other factors trending towards significance included prolonged PR interval, atrial fibrillation or more advanced age.

Conclusion

High-grade atrioventricular (AV) block was associated with an RV pacing burden > 20% over 3 years but this was not consistent in patients with only transient episodes of high-grade AV block. We found a significant association between high VP% and male sex, previous CABG and the absence of mode switching algorithms.

Prediction of pacemaker-induced cardiomyopathy using a convolutional neural network based on clinical findings prior to pacemaker implantation

Risk factors for pacemaker-induced cardiomyopathy (PICM) have been previously reported, including a high burden of right ventricular pacing, lower left ventricular ejection fraction, a wide QRS duration, and left bundle branch block before pacemaker implantation (PMI). However, predicting the development of PICM remains challenging. This study aimed to use a convolutional neural network (CNN) model, based on clinical findings before PMI, to predict the development of PICM. Out of a total of 561 patients with dual-chamber PMI, 165 (mean age 71.6 years, 89 men [53.9%]) who underwent echocardiography both before and after dual-chamber PMI were enrolled. During a mean follow-up period of 1.7 years, 47 patients developed PICM. A CNN algorithm for prediction of the development of PICM was constructed based on a dataset prior to PMI that included 31 variables such as age, sex, body mass index, left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, severity of mitral regurgitation, severity of tricuspid regurgitation, ischemic heart disease, diabetes mellitus, hypertension, heart failure, New York Heart Association class, atrial fibrillation, the etiology of bradycardia (sick sinus syndrome or atrioventricular block) , right ventricular (RV) lead tip position (apex, septum, left bundle, His bundle, RV outflow tract), left bundle branch block, QRS duration, white blood cell count, haemoglobin, platelet count, serum total protein, albumin, aspartate transaminase, alanine transaminase, estimated glomerular filtration rate, sodium, potassium, C-reactive protein, and brain natriuretic peptide. The accuracy, sensitivity, specificity, and area under the curve of the CNN model were 75.8%, 55.6%, 83.3% and 0.78 respectively. The CNN model could accurately predict the development of PICM using clinical findings before PMI. This model could be useful for screening patients at risk of developing PICM, ensuring timely upgrades to physiological pacing to avoid missing the optimal intervention window.

Leadless Pacemaker Implantation, Focusing on Patients With Conduction System Disorders Post-Transcatheter Aortic Valve Replacement: A Retrospective Analysis

Background

Impairment of the conduction system is a common complication of transcatheter aortic valve replacement (TAVR), which is typically performed in elderly patients. A leadless pacemaker (LP) may be a suitable option in this frail population, but the available scientific data concerning the efficacy and safety of leadless pacing after TAVR are sparse. The purpose of this analysis was to evaluate the efficacy and safety of LP implantation in patients with relevant bradycardias after TAVR, compared to other indications.

Methods

Consecutive patients were retrospectively enrolled. Demographics, background heart diseases, interventional parameters, and follow-up data were collected.

Results

A total of 257 consecutive patients who underwent LP implantation were included. In 26 patients, the device was implanted due to bradycardias after TAVR (TAVR group), whereas the remaining 231 patients were in the population without previous TAVR (non-TAVR group). The mean implantation duration (56 ± 22 minutes in the TAVR group vs 48 ± 20 minutes in the non-TAVR group; P = not significant [NS]) and the implantation success rate (100% in the TAVR group vs 98.7% in the non-TAVR group; P = NS) were similar in the 2 cohorts. No significant differences occurred in pacing parameters (sensing, impedance, and threshold, respectively) between the 2 groups, either at implantation or during follow-up. A total of 8 major periprocedural complications (3.1% of patients in total; 3.8% in the TAVR group vs 3.0% in the non-TAVR group; P = NS) occurred within 30 days, without significant difference between the 2 groups.

Conclusions

LP implantation appears to be safe and effective in patients after TAVR, and therefore, this procedure is a suitable option for this often old and frail population.

Revisiting predictors of worse atrioventricular valve and left ventricular systolic function following pacemaker therapy

BACKGROUND

Predictors of worsening atrioventricular valve regurgitation and left ventricular (LV) systolic function after implantation of a leadless pacemaker (LPM) remain unclear compared with those of a transvenous pacemaker (TPM).

METHODS

We retrospectively analyzed 205 patients who were newly implanted with a permanent pacemaker (119 LPMs and 86 TPMs) and underwent transthoracic echocardiography before and 8 ± 5 months after implantation. We evaluated the worsening of tricuspid and mitral regurgitation (TR and MR), defined as at least one-grade aggravation in severity, and changes in LV ejection fraction (LVEF).

RESULTS

Worsening TR occurred more frequently in the LPM group compared to the TPM group (33% vs. 20%, p = .04); however, there was no significant difference between the two groups regarding worsening MR (26% vs. 18%, p = .18) and LVEF change (-2 ± 10% vs. -3 ± 8%, p = .40). In multivariable analysis, independent predictors for worsening TR, MR, and LVEF after implantation were found to be (1) the change from sinus rhythm at baseline to atrioventricular asynchronous right ventricular (RV) pacing (odds ratio [OR]: 5.68, 95% confidence interval [CI]: 1.94-16.70, p < .01); (2) the change from non-pacing ventricular contraction at baseline to RV pacing (OR: 2.42, 95% CI: 1.12-5.24, p = .02); and (3) a higher RV pacing burden (β: -0.05, 95% CI: -0.08--0.02, p < .01), respectively.

CONCLUSION

Worsening TR, MR, and LVEF after pacemaker implantation were not associated with the type of pacing device but loss of atrioventricular synchrony or dependency on RV pacing.

The estimated glomerular filtration rate predicts pacemaker-induced cardiomyopathy

Clinical predictors for pacemaker-induced cardiomyopathy (PICM) (e.g., a wide QRS duration and left bundle branch block at baseline) have been reported. However, factors involved in the development of PICM in patients with preserved left ventricular ejection fraction (LVEF) remain unknown. This study aimed to determine the risk factors for PICM in patients with preserved LVEF. The data of 113 patients (average age: 71.3 years; men: 54.9%) who had echocardiography before and after pacemaker implantation (PMI) among 465 patients undergoing dual-chamber PMI were retrospectively analyzed. Thirty-three patients were diagnosed with PICM (18.0/100 person-years; 95% CI 12.8-25.2). A univariate Cox regression analysis showed that an estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m2 (HR 3.47; 95% CI 1.48-8.16) and a past medical history of coronary artery disease (CAD) (HR 2.76; 95% CI 1.36-5.60) were significantly associated with the onset of PICM. After adjusting for clinical variables, an eGFR ≤ 30 mL/min/1.73 m2 (HR 2.62; 95% CI 1.09-6.29) and a medical history of CAD (HR 2.32; 95% CI 1.13-4.80) were independent risk factors for developing PICM. A medical history of CAD and low eGFR are independent risk factors for PICM in patients with preserved LVEF at baseline. These results could be helpful in predicting a decreased LVEF by ventricular pacing before PMI. Close follow-up by echocardiography is recommended to avoid a delay in upgrading to physiological pacing, such as cardiac resynchronization therapy or conduction system pacing.

Pacing induced cardiomyopathy: recognition and management

Right ventricle (RV) apex continues to remain as the standard pacing site in the ventricle due to ease of implantation, procedural safety and lack of convincing evidence of better clinical outcomes from non-apical pacing sites. Electrical dyssynchrony resulting in abnormal ventricular activation and mechanical dyssynchrony resulting in abnormal ventricular contraction during RV pacing can result in adverse LV remodelling predisposing some patients for recurrent heart failure (HF) hospitalisation, atrial arrhythmias and increased mortality. While there are significant variations in the definition of pacing induced cardiomyopathy (PIC), combining both echocardiographic and clinical features, the most acceptable definition for PIC would be left ventricular ejection fraction (LVEF) of <50%, absolute decline of LVEF by ≥10% and/or new-onset HF symptoms or atrial fibrillation (AF) after pacemaker implantation. Based on the definitions used, the prevalence of PIC varies between 6% and 25% with overall pooled prevalence of 12%. While most patients undergoing RV pacing do not develop PIC, male sex, chronic kidney disease, previous myocardial infarction, pre-existing AF, baseline LVEF, native QRS duration, RV pacing burden, and paced QRS duration are the factors associated with increased risk for PIC. While conduction system pacing (CSP) using His bundle pacing and left bundle branch pacing appear to reduce the risk for PIC compared with RV pacing, both biventricular pacing and CSP may be used to effectively reverse PIC.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

The therapeutic benefit of upgrade to cardiac resynchronization therapy in patients with pacing-induced cardiomyopathy

Background

Pacing-induced cardiomyopathy (PICM) is an important cause of heart failure in patients with a right ventricular pacing burden. Recent evidence suggests that an upgrade to cardiac resynchronization therapy (CRT) may confer benefit in PICM.

Objective

To assess the extent and identify predictors of improvement following upgrade to CRT in patients with PICM.

Methods

We retrospectively analyzed 43 patients undergoing CRT upgrade for PICM over the 10-year period of 2011 to 2021 at our center. All patients with PICM who underwent device upgrade from a dual- or single-chamber ventricular pacemaker to CRT were included. PICM was defined as a decrease of ≥10% in left ventricular ejection fraction (LVEF), resulting in an LVEF <50% among patients with ≥20% Right ventricular pacing burden without an alternative cause for cardiomyopathy.

Results

LVEF significantly improved from 28.7% preupgrade to 44.3% post-CRT upgrade (P < .01). Of 37 patients with severe LV dysfunction, 34 (91.9%) improved to an LVEF >35% and 13 (35.1%) improved to an LVEF >50%. The LV end-diastolic diameter decreased from 5.9 cm preupgrade to 5.4 cm postupgrade (P < .01). Using linear regression, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use was associated with significant LVEF improvement (+7.21%, P = .05). We observed a low rate of complications, and 1 in 4 CRT upgrades required venoplasty (n = 10 of 43, 23.3%).

Conclusion

We provide further evidence for the benefit of CRT upgrade in the management of patients with PICM.

His bundle combined with deep septal left bundle branch area pacing for atrial fibrillation prior to atrioventricular node ablation

Background

To mitigate the risk of dyssynchrony-induced cardiomyopathy, international guidelines advocate His bundle pacing (HBP) with a ventricular backup lead prior to atrioventricular node ablation in treatment-refractory atrial fibrillation and normal left ventricular ejection fraction. As a result of concerns with long-term pacing parameters associated with HBP, this case series reports an adopted strategy of HBP combined with deep septal left bundle branch area pacing (dsLBBAP) in this patient cohort, enabling intrapatient comparison of the two pacing methods.

Methods and Results

Eight patients aged 72 ± 10 years (left ventricular ejection fraction 53 ± 4%) underwent successful combined HBP and dsLBBAP implant prior to AV node ablation. Intrinsic QRS duration was 118 ± 46 ms. When compared to dsLBBAP, HBP had lower sensed ventricular amplitude (2.4 ± 1.1 vs. 15 ± 5.3 V, p = .001) and lower lead impedance (522 ± 57 vs. 814 ± 171ohms, p = .02), but shorter paced QRS duration (101 ± 20 vs. 119 ± 17 ms, p = .02). HBP pacing threshold was 1.0 ± 0.6 V at 1 ms pulse width, and dsLBBAP pacing threshold was 0.5 ± 0.2 V at 0.4 ms pulse width. Five patients underwent cardiac CT showing adequate dsLBBAP ventricular septal penetration (8.6 ± 1.3 mm depth, 2.4 ± 0.5 mm distance from left ventricular septal wall). No complications occurred during a mean follow-up duration of 121 ± 92 days.

Conclusions

Combined HBP and dsLBBAP pacing is a feasible approach as a pace and ablate strategy for atrial fibrillation refractory to medical therapy.

Pacing-induced cardiomyopathy: A systematic review and meta-analysis of definition, prevalence, risk factors, and management

Pacing-induced cardiomyopathy is a potential complication of right ventricular pacing. Definition varies between studies and the optimal management approach is uncertain. We aimed to characterize definition, prevalence, risk factors, and treatment strategies of pacing-induced cardiomyopathy (PiCM). We performed a systematic review and meta-analysis of studies that evaluated PiCM after pacemaker implantation identified through a literature search of PubMed and EMBASE up to March 2022. We collected data on the study definition of PiCM and calculated pooled prevalence across studies. Meta-analysis with random effects modeling was used to assess the association between potential risk factors and PiCM, reported as odds ratio with 95% confidence interval. Twenty-six studies (6 prospective studies) with a total of 57,993 patients (mean/median age range was 51-78 years; female 45%) were included in the final analysis. Fifteen unique definitions of PiCM were reported. The pooled prevalence of PiCM was 12% (95% confidence interval 11%-14%). In meta-analysis, risk factors included male sex, history of myocardial infarction, chronic kidney disease, atrial fibrillation, baseline left ventricular ejection fraction, native QRS duration, right ventricular pacing percentage, and paced QRS duration. Treatment strategies identified included biventricular cardiac resynchronization therapy (6 studies) and His-bundle pacing (3 studies). Definition of PiCM varied significantly between studies. More than 1 in 10 patients with chronic right ventricular pacing developed PiCM. Key risk factors included baseline left ventricular ejection fraction, native QRS duration, RV pacing percentage, and paced QRS duration. The optimal management strategy has yet to be defined. Further research is needed to define and treat this understated complication.

Long term clinical outcomes in patients requiring cardiac pacing due to congenital complete heart block

Background

Isolated congenital complete heart block (CCHB) is rare cardiac condition associated with maternal Anti-Rho antibodies. It is managed with permanent pacemaker insertion. We sought to determine the long-term outcomes of individuals with CCHB who had undergone pacemaker insertion.

Methods

A database search was performed at a UK tertiary cardiac referral centre. The online medical records of patients with CCHB were analysed for pacing requirements and complications, echocardiographic data, and clinical status.

Results

A total of 72 patients (female n = 46) were identified, 20% of whom were autoantibody positive. Mean age of initial implantation was 15.5 years (SD 12.7) with mean follow up of 21 years (SD 8.3). 88% of patients were NYHA class I at censure of data. Major adverse cardiac events (MACE) were observed in 2 patients with 0% mortality throughout the follow up period. 16 patients (22.2%) developed cardiomyopathy, of which 15 had CRT devices inserted.Five patients had device related infections and 7 required system extractions. Mean left ventricular ejection fraction on most recent echocardiogram was 53.7% (SD 8.40) with no significant change compared with their historic scan. Mild tricuspid regurgitation was the most frequently observed valvular pathology, identified in 28% of patients. Only 2 patients (2.7%) had severe valve incompetence but neither required surgical intervention.

Conclusion

Long-term outcomes for patients with congenital complete heart block who undergo pacemaker insertion are highly favourable. Despite high pacing requirements over an extended period, the incidence of MACE and pacing related complications is low. Cardiac function and valvular competence are largely preserved but dilated cardiomyopathy remains a late concern in a minority; ongoing clinical surveillance is paramount in this population.

Generating Evidence to Support the Physiologic Promise of Conduction System Pacing: Status and Update on Conduction System Pacing Trials

Conduction system pacing avoids the potential deleterious effects of right ventricular pacing in patients with bradycardia and provides an alternative approach to cardiac resynchronization therapy. We focus on the available observational and randomized evidence and review studies supporting the safety, feasibility, and physiologic promise of conduction system approaches. We evaluate the randomized data generated from the available clinical trials of conduction system pacing, which have led to the recent inclusion of CSP in international guidelines. The scope for future randomized trials will building on the physiologic promise of conduction system approaches and offering information on clinical end points is explored.

Pacing Burden and Clinical Outcomes Following Transcatheter Aortic Valve Replacement - A Real-World Registry Report

INTRODUCTION

Conflicting data exists regarding the prognostic significance of permanent pacemaker (PPM) implantation following TAVR.

OBJECTIVE

Evaluate whether PPM implantation post TAVR is associated with adverse outcomes.

METHODS

A retrospective analysis of a cohort comprised of patients enrolled to a prospective registry between 2008-2019. Participants were allocated into three groups: patients without prior pacemaker (n=930, 75%), patients with previous pacemaker implantation (n=118, 10%) and those with pacemaker implantation following TAVR (n=191, 15%). Primary outcome included death and heart failure hospitalizations at 1 year. Secondary outcomes included death and heart failure hospitalizations stratified by pacing burden.

RESULTS

A total of 1239 patients underwent TAVR with median follow up of 2.3 years (IQR 1-4). Patients with previous and new pacemaker implantation were older [84 (80-88), 84 (80-88), 82 (78-86), p-0.009)], and had lower baseline LVEF (50%±15%, 55%±12%, 56%±12%, p<0.001). Patients who underwent new pacemaker implantations had higher combined outcome of death and heart failure hospitalizations (21%,12% ,14%, p-0.01). New pacemaker implantation was associated with almost twice the risk of 1-year mortality (HR-1.85, 95% C.I 1.13-3.02, p-0.014). Pacing burden, however, was not associated with the primary outcome. Furthermore, no significant difference was observed at long term follow up [cumulative probability to develop primary endpoint at 3 years was 57%±2% (without PPM), 57%±6% (prior PPM), 54%±4% (new PPM), p-0.52].

CONCLUSION

Pacemaker implantation following TAVR is associated with higher 1-year adverse outcome, but this attenuates over time, suggesting that competing factors may play a role. Interestingly, pacing burden is not associated with adverse clinical course.

Population-Level Impact of the Guidelines Update on Patient Selection and Outcomes After Cardiac Resynchronization Therapy

OBJECTIVES

This study sought to analyze the impact of the American College of Cardiology, American Heart Association, and Heart Rhythm Society (ACC/AHA/HRS) guidelines for cardiac resynchronization therapy with defibrillator (CRT-D) update on utilization and efficacy of CRT-D.

BACKGROUND

In September 2012, the ACC/AHA/HRS guidelines for CRT-D were modified to include left bundle branch block (LBBB) as a Class I indication.

METHODS

The IBM Watson MarketScan Database was queried between January 1, 2003, and December 31, 2018, for CRT-D implants or upgrades. The primary outcome was heart failure (HF) hospitalization following left ventricular lead implant. Secondary outcomes included all-cause mortality and device-related lead revision.

RESULTS

A total of 27,238 patients were analyzed: 18,384 pre-update and 8,854 post-update. Mean age was 69 ± 11 years, 73% men, and 98% with history of HF hospitalization. The proportion of patients with LBBB increased from 29% to 55% (P < 0.001) after the update. Patients receiving CRT-D post-update demonstrated a greater prevalence of comorbidities, including atrial fibrillation (47% vs 40%; P < 0.001), diabetes mellitus (45% vs 39%; P < 0.001), chronic kidney disease (24% vs 15%; P < 0.001), and HF hospitalization in the year before CRT-D (40% vs 37%; P < 0.001). Despite greater baseline comorbidities, HF hospitalization significantly declined post-update (HR: 0.89; P < 0.001). Multivariate predictors of reduced HF hospitalization included angiotensin receptor neprilysin inhibitor prescription (HR: 0.48; P < 0.001) and presence of LBBB (HR: 0.71; P < 0.001). All-cause mortality was not significantly different between the 2 groups, and fewer lead revisions were noted post-update (0.6% vs 1.7%; P < 0.001).

CONCLUSIONS

The revised 2012 guidelines led to an increased proportion of LBBB patients receiving CRT-D at the population-level. This change was associated with reduced HF hospitalization, despite broadening therapy to patients with more comorbid conditions.

Clinical Outcomes of Left Bundle Branch Area Pacing in Comparison with Right Ventricular Septal Pacing in Patients with High Ventricular Pacing Ratio ≥40%

Background

Methods

Results

Conclusion

The short term influence of right ventricular pacing burden on echocardiographic and spiroergometric parameters in patients with preserved left ventricular ejection fraction

Background

The incidence of worsened clinical outcome due to high right ventricular (RV) pacing burden in patients with preserved left ventricular function remains controversial.

Objective

To investigate the impact of RV pacing on several echocardiographic and spiroergometric parameters.

Methods

In 60 pacemaker patients with preserved left ventricular ejection fraction (LVEF) serial echocardiographies and spiroergometries were performed over a time course of 12 months. Additionally, in 48 patients retrospective echocardiographic analyses of the LV- and RV function were carried out up to 24 months after pacemaker implantation.

Results

The patients were divided into two groups: The high RV pacing burden group (hRVP: ≥ 40%) and the low RV pacing group (lRVP < 40%) according to the definitions in previous randomized MOST and DAVID trials. After a period of 12-month pacemaker therapy no changes to left ventricular end diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD), LVEF, E/A-ratio; E/E′-ratio and tricuspid annular plane systolic excursion (TAPSE) could be revealed, independently of the RV pacing burden. Additionally, after 24-month long term follow-up there were no differences in LVEF and TAPSE in both groups. Accordingly, no relevant changes of peak exercise capacity, ventilatory anaerobic threshold or maximal oxygen consumption could be demonstrated independently of the RV pacing.

Conclusions

In pacemaker patients with preserved LVEF the burden of RV pacing has no adverse influence on several echocardiographic and spiroergometric surrogate parameters of pacemaker-induced cardiomyopathy after a follow-up of 12 to 24 month. Despite this, screening for pacemaker induced cardiomyopathy should be performed especially in the presence of new heart failure symptoms.

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

INTRODUCTION

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.

METHODS

Our data were retrospectively collected from 146 patients with RVP > 40% who underwent generator change (GC) or cardiac resynchronisation therapy (CRT) upgrade between 2016-2019 who had left ventricular ejection fraction (EF) ≥50% at initial implant.

RESULTS

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 = 0.008), prior myocardial infarction (MI) (p = 0.001), atrial fibrillation (AF) (p = 0.009), chronic kidney disease (CKD) (p = 0.005), and borderline low systolic function (BLSF) (EF 50-55%) (p = 0.04) were more prevalent in the CRT upgrade group. Presence of AF (OR = 3.05, 95% CI 1.42-6.58; p = 0.004), BLSF (OR = 3.8, 95% CI 1.22-11.8; p = 0.02) and male gender (OR = 2.41, 95% CI 1.14-5.08; p = 0.02) were independent predictors for RVP induced LVD. Age (OR = 1.08, 95% CI 1.02-1.14; p = 0.005) and BLSF (OR = 5.33, 95% CI 1.26-22.5; p = 0.023) were independent predictors of earlier development of LVD after implant.

CONCLUSIONS

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. This article is protected by copyright. All rights reserved.

Outcomes in Congenital and Childhood Complete Atrioventricular Block: A Meta-analysis

BACKGROUND

The long-term outcomes of patients with congenital and childhood complete atrioventricular block (CCAVB/ CAVB) after pacemaker implantation are unclear.

METHODS

We performed a meta-analysis of all the studies of CCAVB. A systematic search of PubMed and CENTRAL databases from 1^st January 1967 to 31^st January 2020 was performed. The quality of studies included was critically appraised using the Newcastle-Ottawa scale, and outcome data were analyzed using the restricted maximum likelihood function.

RESULTS

Twenty-nine studies were eligible for analysis, with a total of 1553 patients. The all-cause-mortality was 5.7 % [95% CI: 2.5-9.9%], while PICM was seen in 3.8% [95% CI: 1.2-7.2]. Diagnosis at birth [effect size (ES)(95%CI): -2.23 (-0.36 to -0.10); p<0.001], presence of congenital heart disease ([ES(95%CI): -0.67 (0.41 to 0.93); p<0.001], younger age at pacemaker implantation ([ES(95%CI): -0.01 (-0.02 to -0.001); p=0.02], and duration of pacing [ES(95%CI): -0.03 (-0.05 to -0.003); p=0.03], were associated with an higher mortality on binominal logistic regression. None of the parameters were significant on multivariate analysis.

CONCLUSION

Pooled proportional mortality in patients with CCAVB and CAVB is 5.7% with an infrequent incidence of PICM (3.8%) in the paced patients with AVB suggesting that pacing in these patients is an effective management strategy with a low incidence of long-term side effects. Registry and randomized data can throw additional light regarding the natural history and appropriate management strategy in these patients. This article is protected by copyright. All rights reserved.

Permanent His-bundle pacing in the right atrium in a patient with a Mobitz II atrioventricular block: a case presentation

Background

This case report presents a patient diagnosed with sick sinus syndrome who was successfully treated with permanent His-bundle pacing (PHBP).

Case presentation

A 36-year-old man was transferred to our hospital due to recurrent syncope. He was diagnosed with sick sinus syndrome based on the 24-h Holter and a history of syncope. He was admitted to hospital and successfully treated with PHBP. The postoperative examination showed that the pacing rhythm, pacemaker pacing and perception function were normal. He was discharged without any complications after a successful pacemaker implantation.

Conclusions

We described a case in which PHBP may become an optimal approach to the management of patients with sick sinus syndrome. Right ventricular pacing has been attempted with inconsistent efficacy outcomes. HBP provides a promising alternative pacing option that might provide symptom resolution to patients with sick sinus syndrome.

Left bundle branch pacing: An evolving site for physiological pacing

For patients with symptomatic bradyarrhythmia, cardiac pacing is the only appropriate treatment option. Electrical and mechanical dyssynchrony caused by traditional right ventricular apical pacing leads to left ventricular dysfunction and atrial arrhythmias. Physiological pacing stimulates natural cardiac conduction, resulting in synchronized ventricular contraction. Even if His bundle pacing (HBP) is an ideal physiological pacing modality, it is technically not always feasible because of high capture thresholds, disease in the distal His bundle, and follow-up troubleshooting issues. Left bundle branch pacing (LBBP) has been proposed as a viable alternative to HBP since it provides lead stability, a low and stable pacing threshold, and correction of distal conduction system disease.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

Rapidly progressive heart failure after dual-chamber pacemaker implantation

Pacing-induced cardiomyopathy (PICM) consists of heart failure (HF) associated with a drop in the left ventricular ejection fraction (LVEF) in the setting of high-burden right ventricular pacing, with presentation that may range from subclinical to severe. Time to manifestation can go from weeks to years after device implantation. Treatment typically consists in an upgrade to a cardiac resynchronisation therapy (CRT) or His bundle pacing (HisP). Several risk factors for PICM have been described and should be considered before pacemaker (PM) implantation, as thorough patient selection for de novo CRT or HisP, may preclude its manifestation. We present the case of an 82-year-old patient presenting with acute congestive HF and new severely reduced LVEF, 30 days following dual chamber PM implantation for high-grade atrioventricular block. Treatment with HF medication and upgrade to a CRT permitted rapid resolution of the symptoms and normalisation of the LVEF at 1-month follow-up.

Pacemaker Induced Cardiomyopathy: An Overview of Current Literature

Pacemaker induced cardiomyopathy (PICM) is commonly defined as a reduction in left ventricular (LV) function in the setting of right ventricular (RV) pacing. This condition may be associated with the onset of clinical heart failure in those affected. Recent studies have focused on potential methods of identifying patients at risk of this condition, in addition to hypothesizing the most efficacious ways to manage these patients. Newer pacing options, such as His bundle pacing, may avoid the onset of PICM entirely.

Long-term outcomes in young patients with atrioventricular block of unknown aetiology

Aims

Atrioventricular block (AVB) of unknown aetiology is rare in the young, and outcome in these patients is unknown. We aimed to assess long-term morbidity and mortality in young patients with AVB of unknown aetiology.

Methods and results

We identified all Danish patients younger than 50 years receiving a first pacemaker due to AVB between January 1996 and December 2015. By reviewing medical records, we included patients with AVB of unknown aetiology. A matched control cohort was established. Follow-up was performed using national registries. The primary outcome was a composite endpoint consisting of death, heart failure hospitalization, ventricular tachyarrhythmia, and cardiac arrest with successful resuscitation. We included 517 patients, and 5170 controls. Median age at first pacemaker implantation was 41.3 years [interquartile range (IQR) 32.7–46.2 years]. After a median follow-up of 9.8 years (IQR 5.7–14.5 years), the primary endpoint had occurred in 14.9% of patients and 3.2% of controls [hazard ratio (HR) 3.8; 95% confidence interval (CI) 2.9–5.1; P < 0.001]. Patients with persistent AVB at time of diagnosis had a higher risk of the primary endpoint (HR 10.6; 95% CI 5.7–20.0; P < 0.001), and risk was highest early in the follow-up period (HR 6.8; 95% CI 4.6–10.0; P < 0.001, during 0–5 years of follow-up).

Conclusion

Atrioventricular block of unknown aetiology presenting before the age of 50 years and treated with pacemaker implantation was associated with a three- to four-fold higher rate of the composite endpoint of death or hospitalization for heart failure, ventricular tachyarrhythmia, or cardiac arrest with successful resuscitation. Patients with persistent AVB were at higher risk. These findings warrant improved follow-up strategies for young patients with AVB of unknown aetiology.

DDD mode-switching and loss of atrioventricular synchrony evokes heart failure: A rare but possible trigger of pacing-induced cardiomyopathy

Pacing-induced cardiomyopathy (PICM), defined as left ventricular dysfunction, occurs in the setting of chronic, high burden right ventricular pacing. We describe an unusual case of PICM. A 64-year-old man underwent a medical check-up and was diagnosed with complete atrioventricular block (AVB) with regular and slow ventricular contractions at 38 beats/min (bpm). The patient underwent a pacemaker implantation with a dual-chamber pacing (DDD) pacemaker. This patient had no symptoms or signs of PICM during complete AVB or the period after undergoing dual-chamber pacing. However, PICM developed within a short time after the onset of atrial flutter (AFL). During AFL, the automatic mode switch of the DDD pacemaker to the DDIR mode worked normally, and the ventricles were paced with a stable and regular rate (60 bpm). Despite the administration of ß-blockers and diuretics, his symptoms and status did not improve. After the elimination of the AFL and restoration of AV synchrony with a DDD mode by catheter ablation, the deteriorated condition rapidly improved. In this patient, the coexistence of the loss of AV synchrony and high burden RV pacing during AFL might have caused this unusual PICM. Learning objective: Even when patients have no symptoms or signs of pacing-induced cardiomyopathy (PICM) during complete atrioventricular block or the period after undergoing dual-chamber pacing, automatic mode-switching to the DDI mode during atrial tachyarrhythmias could rapidly cause PICM. PICM could occur with a much more rapid time course than the historical model of PICM where cardiomyopathy may take several years to develop. Much attention should be paid during the follow-up to patients receiving DDD pacemakers to avoid any unusual PICM as in this case.

Prevalence and predictors of pacing-induced cardiomyopathy in young adult patients (<60 years) with pacemakers

INTRODUCTION

Clinical trials and observational studies of pacing-induced cardiomyopathy (PICM) have largely included elderly patients with mean age >70 years. The prevalence and predictors of PICM in younger patients (age < 60 years) after pacemaker implantation are not known.

METHODS

Adults (18-59 years) who received single-chamber ventricular or dual-chamber pacemakers at Vanderbilt University Medical Center from 1986 to 2015 were included. Patients without documented ventricular pacing burden and patients with baseline left ventricular ejection fraction (LVEF) <35% were excluded. PICM was defined as LVEF decrease of ≥ 10% and LVEF < 50% during follow-up with right ventricular pacing ≥20%, and without alternative explanations for cardiomyopathy.

RESULTS

A total of 325 patients were included in the study. During a median follow-up duration of 11.5 (Interquartile range 7-17) years, 38 patients (11.7%) developed PICM (1.3 per 100 patient-year). Older age (HR 2.5 for age ≥50 years, p = .013), reduced baseline LVEF (HR 2.4, p = .022), and preimplant AVB (HR 2.7, p = .007) were associated with an increased risk of PICM in the multivariate analysis. Furthermore, baseline AF conferred an increased risk of PICM only in patients without preimplant AVB but not patients with pre-implant AVB.

CONCLUSIONS

The incidence of PICM in young patients was low, but PICM could occur more than a decade after pacemaker implantation. Older age, baseline reduced LVEF, and preimplant AVB were associated with an increased risk of PICM in the young patient cohort.

The therapeutic effects of upgrade to cardiac resynchronization therapy in pacing-induced cardiomyopathy or chronic right ventricular pacing patients: a meta-analysis

Pacing-induced cardiomyopathy (PICM) or heart failure accompanied with chronic right ventricular pacing (CRVP-HF) has no established treatments. We aimed to carry out a meta-analysis of published studies about the therapeutic effects of the upgrade to cardiac resynchronization therapy (CRT) in patients of PICM/CRVP-HF. The PUBMED, EMBASE, MEDLINE, OVID databases, and Cochrane Library were systemically searched for relevant publications. Data about the improvements of left ventricular ejection fraction (LVEF), NYHA functional class (NYHA-FC), and the CRT response rate was extracted and synthesized. Mean difference (MD), odds ratio, and standard mean difference (SMD) with 95% confidence interval (CI) were calculated as the effect size by both fixed and random effect models. We included sixteen studies (four about PICM and twelve about CRVP-HF). The total sample size of PICM/CRVP-HF patients was 924. Upgrade to CRT improved the LVEF by 10.87% (95%CI, 8.90 to 12.84%) and reduce the NYHA-FC by around one class (MD, -1.25; 95%CI, -1.43 to -1.06) in PICM/CRVP-HF patients overall. Upgrade to CRT seemed to improve LVEF no less than de-novo CRT (SMD 0.24; 95%CI 0.05 to 0.43; P < 0.05). This meta-analysis suggested that upgrade CRT could improve the cardiac function in PICM/CRVP-HF patients. This strategy may be considered in these patients but require more evidence about the efficacy and procedure-related complications from prospective studies or randomized controlled trials.

Permanent His Bundle Pacing in Patients With Congenital Complete Heart Block: A Multicenter Experience

OBJECTIVES

This study retrospectively assessed the safety and efficacy of permanent His bundle pacing (HBP) in patients with congenital complete heart block (CCHB).

BACKGROUND

HBP has become an accepted form of pacing in adults. Its role in CCHB is not known.

METHODS

Seventeen patients with CCHB who underwent successful HBP were analyzed at 6 academic centers between 2016 and 2019. Nine patients had de novo implants, and 8 patients had previous right ventricular (RV) leads. Three RV paced patients had reduced left ventricular ejection fractions at the time of HBP. Implant/follow-up device parameters, New York Heart Association functional class, QRS duration, and left ventricular ejection fraction data were analyzed.

RESULTS

Patients' mean age was 27.4 ± 11.3 years, 59% were women, and mean follow-up was 385 ± 279 days. The following parameters were found to be statistically significant between implant and follow-up, respectively: impedance, 602 ± 173 Ω versus 460 ± 80 Ω (p < 0.001); and New York Heart Association functional class, 1.7 ± 0.9 versus 1.1 ± 0.3 (p = 0.014). In patients with previous RV pacing, HBP resulted in a significant decrease in QRS duration: 167.1 ± 14.3 ms versus 118.3 ± 13.9 ms (p < 0.0001). In de novo implants, HBP resulted in increases in QRS duration compared with baseline: 111.1 ± 19.4 ms versus 91.0 ± 4.8 ms (p = 0.016). Other parameters exhibited no statistically significant differences. During follow-up, 2 patients required lead revision due to elevated pacing thresholds.

CONCLUSIONS

HBP seems to be safe and effective, with improvement in clinical outcomes in patients with CCHB. Larger studies with longer follow-up periods are required to confirm our findings.

Incidence and Clinical Outcomes of Pacing Induced Cardiomyopathy in Patients With Normal Left Ventricular Systolic Function and Atrioventricular Block

Patients with preserved left ventricular (LV) ejection function (EF) and atrioventricular block (AVB) who are anticipated for high-burden of right ventricular (RV) pacing possess a risk to develop pacing-induced cardiomyopathy (PIC) and adverse clinical outcomes. Hence, the aim of the study is to evaluate the incidence, predictors, and clinical outcomes of RV PIC in patients with preserved LVEF, AVB, and high-burden of RV pacing. One thousand and thirteen patients with second or third-degree AVB underwent first time pacemaker implantation between January 2002 and August 2016. A total of 203 patients with a newly implanted pacemaker, normal baseline LVEF, and high burden of RV pacing were included in the present study. Follow-up echocardiography was examined for a new decrease in LVEF of 10% or higher. Alternative causes for cardiomyopathy were ruled out. Patient characteristics, echocardiographic measurements, device clinic data, mortality, and hospitalizations for heart failure were collected and compared between the PIC and the non-PIC groups. Fifty-one patients (25%) developed LV dysfunction with 22 patients (11%), showing LVEF < 40%. During a mean follow-up of 49.2 months, the risk of heart failure hospitalization or all-cause mortality was significantly higher in the PIC group versus non-PIC group (35.3% vs 19.1%, p = 0.009). In conclusion the incidence of PIC in patients with normal LVEF and AVB, who are anticipated for high-burden of RV pacing is high. PIC in patients with a previously normal LV function is associated with unfavorable long-term clinical outcomes, including higher rates of heart failure hospitalizations and all-cause mortality.

Pacing-induced cardiomyopathy: just the tip of the iceberg?

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Incidence of heart failure after pacemaker implantation: a nationwide Danish Registry-based follow-up study

Aims

The objective of the current study is to investigate the risk of heart failure (HF) after implantation of a pacemaker (PM) with a right ventricular pacing (RVP) lead in comparison to a matched cohort without a PM and factors associated with this risk.

Methods and results

All patients without a known history of HF who had a PM implanted with an RVP lead between 2000 and 2014 (n = 27 704) were identified using Danish nationwide registries. An age- and gender-matched control cohort (matched 1:5, n = 138 520) without PM and HF was identified to compare the risk. Outcome was the cumulative incidence of HF including fatal HF within the first 2 years of PM implantation, with all-cause mortality and myocardial infarction (MI) as competing risks. Due to violation of proportional hazards, the follow-up period was divided into three time-intervals: <30 days, 30–180 days, and >180 days–2 years. The cumulative incidence of HF including fatal HF was observed in 2937 (10.6%) PM patients. Risks for the three time-intervals were <30 days [hazard ratio (HR) 5.98, 95% CI 5.19–6.90], 30–180 days (HR 1.84, 95% CI 1.71–1.98), and >180 days (HR 1.11, 95% CI 1.04–1.17). Among patients with a PM device, factors associated with increased risk of HF were male sex (HR 1.33, 95% CI 1.24–1.43), presence of chronic kidney disease (CKD) (HR 1.64, 95% CI 1.29–2.09), and prior MI (1.77, 95% 1.50–2.09).

Conclusions

Pacemaker with an RVP lead is strongly associated with risk of HF specifically within the first 6 months. Patients with antecedent history of MI and CKD had substantially increased risk.

Adverse Consequences of Right Ventricular Apical Pacing and Novel Strategies to Optimize Left Ventricular Systolic and Diastolic Function

Several studies have focused on the deleterious consequences of Right Ventricular Apical (RVA) pacing on Left Ventricular (LV) function, mediated by pacing-induced ventricular dyssyn-chrony. Therapeutic strategies to reduce the detrimental consequences of RVA pacing have been pro-posed, that includes upgrading of RVA pacing to Cardiac Resynchronization Therapy (CRT), alterna-tive Right Ventricular (RV) pacing sites, minimal ventricular pacing strategies, as well as atrial-based pacing. In developing countries, single chamber RV pacing still constitutes a majority of cases of permanent pacing, and assessment of the optimal RV pacing site is of paramount importance. In chronically-paced patients, it is crucial to maintain as close and normal LV physiological function as possible, by minimizing ventricular dyssynchrony, reducing the chances for heart failure and other complications to develop. This review provides an analysis of the deleterious immediate and long-term consequences of RVA pacing, and the most recent available evidence regarding improvements in pacing options and strategies to optimize LV diastolic and systolic function. Furthermore, the place of advanced echocardiography in the identification of patients with pacing-induced LV dysfunction, the potential role of a new predictor of LV dysfunction in RV-paced subjects, and the long- term out-comes of patients with RV septal pacing will be explored

Pacing-Induced Cardiomyopathy

Pacing-induced cardiomyopathy (PICM) is a well described phenomenon that occurs in a minority of patients exposed to high-burden right ventricular (RV) pacing. Although several risk factors may identify patients at increased risk of PICM, many individuals tolerate high-burden RV pacing for many years without obviously deleterious effects, and the ability to identify those at highest risk remains insufficient. Treatment of PICM has primarily involved upgrade to cardiac resynchronization therapy once signs of cardiomyopathy manifest. The emergence of His bundle pacing may offer an opportunity to prevent PICM before it occurs.

Increased healthcare utilization associated with complete atrioventricular block in pacemaker patients

Purpose

The purpose of the current study is to characterize and quantify the impact of complete atrioventricular block (cAVB) on heart failure hospitalization (HFH) and healthcare utilization in pacemaker (PM) patients.

Methods

Patients ≥ 18 years implanted with a dual-chamber PM from April 2008 to March 2014 were selected from the MarketScan® Commercial and Medicare Supplemental claims databases. Patients with ≤ 1-year continuous MarketScan enrollment prior to and post-implant, and those with prior HF diagnosis were excluded. Patients were dichotomized into those with cAVB, defined as a 3rd degree AVB diagnosis or AV node ablation in the year prior to PM implant, versus those without any AVB (noAVB). Post-implant HFH and associated costs were compared based on inpatient claims.

Results

The study cohort included 21,202 patients, of which 14,208 had no AVB and 6994 had cAVB, followed for 2.39 and 2.27 years, respectively. Patients with cAVB were associated with a significantly increased risk of cumulative HFH (HR 1.59 [95% CI 1.35–1.86] p < 0.001) and significantly higher costs ($636 [609–697] vs $369 [353–405] per pt-year, p < 0.001) compared to those with no AVB.

Conclusions

Among dual-chamber PM patients without prior HF, cAVB is associated with a significantly increased risk of HFH and greater HF-related healthcare utilization. Identifying patients at high risk for HF in the setting of RV pacing, and potentially earlier use of biventricular or selective conduction system pacing, may reduce HF-related healthcare utilization.

Electronic supplementary material

The online version of this article (10.1007/s10840-018-0336-0) contains supplementary material, which is available to authorized users.

Clinical Outcomes After Ablation of the AV Junction in Patients With Atrial Fibrillation: Impact of Cardiac Resynchronization Therapy

Background

Patients with atrial fibrillation (AF) often undergo AV junction ablation (AVJA) and pacemaker implantation. Right ventricular (RV) pacing contributes to increased risk of heart failure (HF), which may be mitigated by biventricular pacing. We sought to determine the impact of AVJA concurrent with RV versus biventricular pacemaker implantation on AF and HF hospitalizations.

Methods and Results

The MarketScan Commercial and Medicare Supplemental claims database was used to select 18‐ to 100‐year‐old patients with AF with pacemaker implantation. Patients were divided into those with an RV and a biventricular pacemaker and further into those who did (AVJA⁺) or did not undergo concurrent ablation. Separately, the AVJA⁺ group was divided into those receiving RV versus biventricular pacemakers. AF and HF hospitalization rates were compared between groups after matching on demographics, comorbidities, and baseline hospitalization rates. The study included 24 361 patients, with RV (n=23 377) or biventricular (n=984) pacemakers; 1611 patients underwent AVJA. AVJA⁺ was associated with reduced AF hospitalization risk (RV hazard ratio [HR], 0.31; P<0.001; biventricular HR, 0.20; P=0.003) compared with no AVJA. However, HF hospitalization risk was increased for RV (HR, 1.63; P=0.001), but not biventricular (HR, 0.98; P=0.942), pacemakers. In AVJA⁺ patients, biventricular pacing was associated with reduced risk of HF hospitalization versus RV pacing (HR, 0.62; P=0.017).

Conclusions

In a large cohort of patients with AF, AVJA⁺ significantly reduced AF hospitalizations, irrespective of whether an RV or a biventricular pacemaker was implanted. However, AVJA was associated with a marked HF hospitalization increase in patients with an RV pacemaker, which was ameliorated with biventricular pacing.