Long-Term Impact of Right Ventricular Pacing on Left Ventricular Systolic Function in Pacemaker Recipients With Preserved Ejection Fraction: Results From a Large Single-Center Registry

Dual-chamber pacing confers better myocardial performance and improves clinical outcomes compared to single-chamber pacing

The deleterious effects of long term right ventricular pacing are increasingly being recognized today. Current clinical practice favors the implantation of dual-chamber permanent pacemaker which maintains atrioventricular synchrony and is associated with better quality of life. However, despite the popular belief and common sense surrounding the superiority of dual-chamber pacing over single chamber pacing, the same has never been conclusively verified in clinical trials. Some observational evidence however, does exists which supports the improved cardiac hemodynamics, lower the rate of atrial fibrillation, heart failure and stroke in dual-chamber pacing compared to single-chamber pacing. In the index study by Haque et al, right ventricular pacing, particularly in ventricular paced, ventricular sensed, inhibited response and rate responsive pacemaker adversely impacted the left ventricular functions over 9-months compared to dual pacing, dual sensing, dual responsive and rate responsive pacemaker. Although there are key limitations of this study, these findings does support a growing body of evidence reinstating the superiority of dual chamber pacing compared to single chamber 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.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

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.

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.

Predictors of right ventricular pacing-induced left ventricular dysfunction in pacemaker recipients with preserved ejection fraction

BACKGROUND

Pacing is an effective treatment in the management of patients with bradyarrhythmias. Chronic right ventricular pacing may cause electrical and mechanical dyssynchrony leading to a deterioration of left ventricular ejection fraction (LVEF). This deterioration of LVEF has been described as pacing-induced cardiomyopathy (PICM). The incidence of PICM has been described by many studies, ranging between 10% and 26%. Predictors for PICM are not yet established-studies were limited by variations in the definition of PICM and the follow-up period. The authors studied the incidence and predictors of PICM in patients with preserved LVEF who underwent pacemaker implantation.

PATIENTS AND METHODS

This retrospective study included 320 patients that underwent single- or dual-chamber pacemaker implantation, with a mean follow up period of 4.7 ± 2.0 years. Implantable cardioverter defibrillator and cardiac resynchronization therapy patients were excluded from this study. Individuals that had a baseline LVEF ≥ 50% before implantation in transthoracic echocardiography were included in the study.

RESULTS

Of the 320 patients included in the study, 45% were male, with a mean age 55.5 years. The incidence of PICM was 7.5%. Wider native QRS duration, particularly > 140 ms (P < 0.001), wider paced QRS (pQRS) duration > 150 ms (P < 0.001), low normal ejection fraction < 56% pre-implantation (P = 0.023) and increased LV end diastolic diameter (LVEDD) > 53 mm and LV end systolic diameter (LVESD) > 38 mm (P < 0.001) predicted the development of PICM. There was no association between burden of right ventricular pacing (P = 0.782) or pacing site (P = 0.876) and the development of pacemaker-induced cardiomyopathy.

CONCLUSION

Right ventricular pacing-induced left ventricular dysfunction is not uncommon, with an incidence of 7.5%. Wider native and paced QRS durations, low normal ejection fraction (< 56%) pre-implantation and increased LVEDD and LVESD post implantation are the most important predictors for the development of PICM.

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.

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.

Chronology of cardiac dysfunction after permanent pacemaker implantation: an observational 2 year prospective study in North India

Background

The purpose of this study is to evaluate cardiac functions using transthoracic echocardiography, change in lead parameters and electrocardiogram (ECG) morphology in patients undergoing permanent pacemaker implantation over a follow-up period of 6 months.

Methods

This is a prospective study in patients undergoing permanent pacemaker implantation in a tertiary care hospital. Patients undergoing permanent pacemaker implantation were enrolled for up to one year and Echocardiographic parameters (by 2 blind operators) and ECG parameters were recorded at admission (within 24 h), before discharge (within 7 days of pacemaker implantation), after 1 month (± 7 days) and after 6 months (± 7 days) of follow-up.

Results

A total of 96 patients (60.4% males and 39.6% female, mean age 66.65 years) were implanted with permanent pacemaker. The mean QRS duration was 133.18 ms and increased significantly to 146.03 ms by 6 months despite septal lead placement in majority (92%) of patients. The mean baseline ejection fraction of 51.47 decreased significantly to 47.83 by 6 months. Diastolic parameters like left atrial volume index, early to late diastolic transmitral flow velocity (E/A) and early diastolic mitral annular tissue velocity (E/e′) showed a significant increase (> 5%) from baseline by the end of first week. By the end of first month, systolic dysfunction of RV sets in with significant (> 5%) change from baseline in parameters like Right ventricle myocardial performance index, transannular plane systolic excursion and right ventricle systolic excursion velocity (RVS′).

Conclusion

We have observed that pacemaker recipients with baseline reduced left ventricle (LV) systolic functions perform significantly worse compared to those with baseline normal cardiac functions and had a higher rate of deterioration of LV function. RV dysfunction is the first abnormality that occurs, by 1 week followed by LV dysfunction which starts by 1 month and the diastolic dysfunctions precede the systolic dysfunction. QRS duration also showed a gradual increase despite septal lead placement in majority (92%) and lead parameters showed no significant change over 6 months.

Feasibility and Outcomes of Upgrading to Left Bundle Branch Pacing in Patients With Pacing-Induced Cardiomyopathy and Infranodal Atrioventricular Block

His bundle pacing (HBP) can reverse left ventricular (LV) remodeling in patients with right ventricular (RV) pacing-induced cardimyopathy (PICM) but may be unable to correct infranodal atrioventricular block (AVB). Left bundle branch pacing (LBBP) results in rapid LV activation and may be able to reliably pace beyond the site of AVB. Our study was conducted to assess the feasibility, safety, and outcomes of permanent LBBP in infranodal AVB and PICM patients. Patients with infranodal AVB and PICM who underwent LBBP for cardiac resynchronization therapy (CRT) were included. Clinical evaluation and echocardiographic and electrocardiographic assessments were recorded at baseline and follow-up. Permanent LBBP upgrade was successful in 19 of 20 patients with a median follow-up duration of 12 months. QRS duration (QRSd) increased from 139.3 ± 28.0 ms at baseline to 176.2 ± 21.4 ms (P < 0.001) with right ventricular pacing (RVP) and was shortened to 120.9 ± 15.2 ms after LBBP (P < 0.001). The mean LBBP threshold was 0.7 ± 0.3 V at 0.4 ms at implant and remained stable during follow-up. The left ventricular ejection fraction (LVEF) increased from 36.3% ± 6.5% to 51.9% ± 13.0% (P < 0.001) with left ventricular end-systolic volume (LVESV) reduced from 180.1 ± 43.5 to 136.8 ± 36.7 ml (P < 0.001) during last follow-up. LBBP paced beyond the site of block, which results in a low pacing threshold with a high success rate in infranodal AVB patients. LBBP improved LV function with stable parameters over the 12 months, making it a reasonable alternative to cardiac resynchronization pacing via a coronary sinus lead in infranodal AVB and PICM patients.

Prognostic factors of pacing-induced cardiomyopathy

Background:

The detrimental outcomes of right ventricular pacing on left ventricular electromechanical function ultimately result in heart failure, a phenomenon termed pacing-induced cardiomyopathy (PICM) in clinical research. This study aimed to validate prognostic factors that can be used to identify patients with higher susceptibility to progress to the stage of cardiomyopathy before pacemaker implantation.

Methods:

This observational analysis enrolled 256 patients between January 2013 and June 2016, 23 (8.98%) of whom progressed to PICM after 1 year of follow-up. A Cox proportional hazard model was used to analyze the prognostic factors associated with PICM. Dose-response analysis was used to evaluate the relationship between significant indicators in multifactor analysis and PICM.

Results:

The mean values of left ventricular ejection fraction before and after pacemaker implantation in 23 patients diagnosed with PICM were 62.3% and 42.7%, respectively. Univariate analysis showed that sex, atrio-ventricular block, paced QRS duration, and ventricular pacing percentage were significantly associated with PICM. In the multivariate analysis, male sex (hazard ratio: 1.20, 95% confidence interval [CI]: 1.09–1.33, P < 0.005), paced QRS duration (hazard ratio: 1.95 per 1 ms increase, 95% CI: 1.80–2.12, P < 0.001), and ventricular pacing percentage (hazard ratio: 1.65 per 1% increase, 95% CI: 1.51–1.79, P < 0.001) were independent prognostic factors associated with the development of PICM. The ventricular pacing percentage and paced QRS duration level defined by the dose-response analysis were positively associated with PICM (P < 0.05).

Conclusions:

Our findings indicated that paced QRS duration and ventricular pacing percentage were the most sensitive prognostic factors for PICM.

[Different phenotypes of mitral regurgitation in patients with right apical ventricular pacing: an echocardiographic approach in a heterogeneity of clinical scenarios]

The presence of mitral regurgitation (MR) in patients with right ventricular apical pacing can be the result of multiple phenomena. On the one hand, this stimulation causes an asynchronous activation of the left ventricle (LV) and the papillary muscles, leading to a deterioration of the LV ejection fraction and causing an inadequate closure of the valve apparatus. However, there is a wide heterogeneity of ischemic and non-ischemic myocardial conditions that can coexist with mechanical alteration of the LV and the mitral valve leading to or worsening MR in these patients, which can make the etiological determination of valvular regurgitation difficult. Transthoracic echocardiography study allows comprehensive evaluation of mitral valve regurgitation and ventricular function parameters and mechanical asynchrony as a result of artificial pacing. The comprehensive study of these phenomena is relevant in clinical decision-making to define those patients who benefit from cardiac resynchronization therapy to alleviate symptomatic MR.

Effects of long-term right ventricular apex pacing on left ventricular dyssynchrony, morphology and systolic function

BACKGROUND

Right ventricular apex (RVA) is still the most common implanted site in the world. There are a large number of RVA pacing population who have been carrying dual-chamber permanent pacemaker (PPM) over decades. Comparison of left ventricular dyssynchrony, morphology and systolic function between RVA pacing population and healthy population is unknown.

METHOD

This case-control study enrolled 61 patients suffered from complete atrioventricular block (III°AVB) for replacement of dual-chamber PPM. Then, 61 healthy controls matched with PPM patients in gender, age, follow-up duration and complications were included. The lead impedance, pacing threshold and sensing were compared between at implantation and long-term follow-up. Left ventricular (LV) dyssynchrony, morphology and systolic function were compared between RVA pacing population (RVA group) and healthy population (healthy group) at implantation (baseline) and follow-up. And clarify the predictors of LV systolic function in RVA group at follow-up.

RESULTS

After 112.44 ± 34.94 months of follow-up, comparing with parameters at implantation, atrial lead impedance decreased significantly (690 ± 2397 Ω vs 613 ± 2257 Ω， p = 0.048); atrial pacing threshold has a increased trend and P-wave amplitude has a decreased trend, but there was no statistical differences; while, RVA ventricular lead threshold increased significantly (0.50 ± 0.23 V vs 0.91 ± 0.47 V， p < 0.001), impedance (902 ± 397 Ω vs 680 ± 257 Ω，p < 0.001) and R-wave amplitude (11.71 ± 9.40mv vs 7.00 ± 6.91 mv， p < 0.001) decreased significantly. Compared with healthy group, long-term RVA pacing significantly increased ventricular dyssynchrony (mean QRS duration, 156.21 ± 29.80 ms vs 97.08 ± 15.70 ms， p < 0.001), left atrium diameter (LAD, 40.61 ± 6.15 mm vs 37.49 ± 4.80 mm，p = 0.002), left ventricular end-diastolic diameter (LVEDD, 49.15 ± 5.93 mm vs 46.41 ± 3.80 mm，p = 0.003), left ventricular hypertrophy (LVMI, 121.86 ± 41.52 g/m2 vs 98.41 ± 25.29 g/m2，p < 0.001), significantly deteriorated degree of tricuspid regurgitation (p < 0.001), and significantly decreased left ventricular ejection fraction (LVEF, 61.38 ± 8.10% vs 64.64 ± 5.85%, p = 0.012), but after long-term RVA pacing, the mean LVEF was still more than 50%. Long-term RVA group LVEF was negatively correlated with preimplantation LVMI (B = -0.055，t = -2.244，p = 0.029), LVMI at follow-up (B = -0.081，t = -3.864，p = 0.000) and tricuspid regurgitation at follow-up (B = -3.797，t = -3.599，p = 0.001).

CONCLUSION

In conclusion, although long-term RVA pacing has significantly effects on left ventricular dyssynchrony, morphology and systolic function in III°AVB patients, the mean LVEF is still >50%. High preimplantation LVMI can predict the decline of LVEF.

An expert consensus document on the management of cardiovascular manifestations of Fabry disease

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by pathogenic variants in the α-galactosidase A (GLA) gene that leads to reduced or undetectable α-galactosidase A enzyme activity and progressive accumulation of globotriaosylceramide and its deacylated form globotriaosylsphingosine in cells throughout the body. FD can be multisystemic with neurological, renal, cutaneous and cardiac involvement or be limited to the heart. Cardiac involvement is characterized by progressive cardiac hypertrophy, fibrosis, arrhythmias, heart failure and sudden cardiac death. The cardiac management of FD requires specific measures including enzyme replacement therapy or small pharmacological chaperones in patients carrying amenable pathogenic GLA gene variants and more general management of cardiac symptoms and complications. In this paper, we summarize current knowledge of FD-related heart disease and expert consensus recommendations for its management.

Incidence of permanent pacemaker implantation after valve replacement surgery : Cardiac structure and function at 1-year follow-up

BACKGROUND

Our study aimed to explore the incidence and risk factors of permanent pacemaker implantation (PPI) after valve replacement surgery (VR). The influence of long-term pacemaker dependency on cardiac structure and function at the 1‑year follow-up was also assessed.

METHODS

The demographic and surgical data of all consecutive patients who underwent VR between 2013 and 2016 were collected. Univariate and multivariate analyses were performed to identify variables independently associated with PPI after VR. A 1‑year follow-up was undertaken of patients who underwent dual-chambers pacemaker after VR because of complete atrioventricular block (AVB). Long-term pacemaker dependency and recovery of cardiac structure and function were evaluated.

RESULTS

There were 5320 consecutive patients with VR. The incidence of postoperative PPI was 2.42%. Multivariate analysis indicated that among the 62 patients who underwent PPI due to AVB and sick sinus syndrome, isolated aortic valve replacement (AVR; OR: 2.24, p < 0.05), VR combined with ventricular septal defect (VSD) repair (OR: 6.78, p < 0.05), and VR with aortic root and arch surgery (OR: 4.14, p < 0.05) were independent predictors of PPI after surgery. In total, 89.6% (43/48) of the survivors showed pacemaker dependency. Of these 43 patients, 24 had enlarged left heart before VR. Compared with preoperative values, the left atrial and left ventricular end-diastolic diameter post-PPI decreased significantly, while left ventricular ejection fraction was not significantly different.

CONCLUSION

Isolated AVR, VR concomitant with VSD repair, and VR with aortic root and arch surgery are independent predictors of PPI after VR. The majority of patients do not recover from AVB disorders and there is no significant negative effect on recovery of cardiac structure and function.

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

Collapse

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.

Very long-term prognosis in patients with right ventricular apical pacing for sick sinus syndrome

Objective

The impact of right ventricular (RV) apical pacing on very long-term cardiac prognosis is little known. In this study, we retrospectively evaluated the relationship between RV apical pacing and cardiovascular events (CEs) in patients with sick sinus syndrome (SSS) and left ventricular ejection fraction (LVEF) >35%.

Methods

Total of 532 consecutive pacemaker recipients with SSS and LVEF >35% were divided into two groups according to the mean cumulative per cent RV apical ventricular pacing (mean %VP) (<50%; non-VP group vs ≥50%; VP group) and occurrence of CE was compared using Kaplan-Meier analysis between two groups. Cox hazard model was used to assess predictors of CE after adjusting explanatory variables such as age, atrial fibrillation (AF) and structural heart disease (SHD).

Results

Mean %VP was 86.0% and 8.2% in VP and non-VP groups, respectively (p<0.001). During mean follow-up of 13.4±7.0 years, CE occurred in 131 patients and more frequently in VP than non-VP group (p<0.001). However, the VP group was no longer associated with CE after taking into account other variables in multivariate analysis, which revealed AF (HR (HR)=2.08), SHD (HR=4.97), low LVEF (HR=0.98 for every 1% increase) and high age (HR=1.03 for every year of age) were independent predictors for CE. Regarding patients with SHD and/or AF and those aged ≥75 years, Kaplan-Meier curves showed both groups had similar prognosis.

Conclusions

Cardiac prognosis of patients with RV apical pacing was poor, but after adjusting for other predictors of CE, RV apical pacing was not a prognostic factor in patients with SSS with LVEF >35%.

The effect of atrial fibrillation intervention on nocturnal respiratory events in elderly patients with persistent AF

BACKGROUND

Sleep-disordered breathing (SDB) and atrial fibrillation (AF) are associated. This study investigated the impact of AF intervention on 6-month home sleep testing data.

METHODS

Sixty-seven patients (aged 66 to 86, 53% male) with persistent AF were randomized (1:1:1) to direct current cardioversion (DCCV) (22 patients), permanent pacemaker (PPM) + atrioventricular node ablation (AVNA) + DCCV (22 patients) or AF ablation (23 patients). Baseline and 6-month multichannel home sleep tests with the Watch-PAT200 (Itamar Medical Lts., Caesarea, Israel) were recorded. Implantable cardiac monitors (ICMs) (Medtronic Reveal XT, Minneapolis, Minnesota) in the DCCV and AF ablation groups, and PPM Holters in the 'pace and ablate' group were utilized to assess cardiac rhythm beat-to-beat throughout the study period.

RESULTS

The prevalence of moderate-to-severe SDB [apnoea-hypopnoea index (AHI) ≥ 15/h] was 60%. At 6 months there was no change in AHI, Epworth sleepiness scale, sleep time, % REM sleep, respiratory desaturation index or central apnoeic events. Twenty-five patients (15 AF ablation, 9 DCCV and 1 following DCCV post-AVNA) maintained SR at 6 months confirmed on ICMs in these patients. AHI fell from 29.8 ± 26.6/h to 22.2 ± 20.4/h; P = 0.049.

CONCLUSIONS

SDB is highly prevalent in patients with persistent AF. Restoration of sinus rhythm, and the associated long-term recovery of haemodynamics, is associated with a significant reduction in AHI. This implicates reversal of fluid shift from the lower limbs to the neck region, a key mechanism in the pathogenesis of SDB.

When to choose cardiac resynchronization therapy in chronic heart failure: type and duration of the conduction delay

Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure (HF), impaired left ventricular (LV) function, and wide QRS complex. The initial randomized clinical trials, which led to the widespread use of CRT, selected patients on the basis of QRS duration, not focusing on QRS morphology. However, recent evidences emphasized the role of left bundle branch block morphology in patients that underwent CRT in order to predict better response to therapy. Moreover, conventional right ventricular apical pacing might have long-term detrimental effects on cardiac structure and LV function, possibly leading to the development of HF. Therefore, current guidelines recommend upgrade from conventional pacemaker or implantable cardioverter-defibrillator to CRT or de novo CRT in patients with high (or expected high) percentage of ventricular pacing and reduced EF. We reviewed current knowledge on candidates’ selection for CRT based on conduction delays that lead to electrical and mechanical dyssynchrony of the left ventricle.

Paced QRS morphology predicts incident left ventricular systolic dysfunction and atrial fibrillation

BACKGROUND

The prognostic significance of paced QRS complex morphology on surface ECG remains unclear. This study aimed to assess long-term outcomes associated with variations in the paced QRS complex.

METHODS

Adult patients who underwent dual-chamber pacemaker implantation with 20% or more ventricular pacing and a 12-lead ECG showing a paced complex were included. The paced QRS was analyzed in leads I and aVL. Long-term clinical and echocardiographic outcomes were compared at 5 years.

RESULTS

The study included 844 patients (43.1% female; age 75.0 ± 12.1). Patients with a longer paced QRS (pQRS) duration in lead I had a lower rate of atrial fibrillation (HR 0.80; p = 0.03) and higher rate of systolic dysfunction (HR 1.17; p < 0.001). Total pacing complex (TPC) duration was linked to higher rates of ICD implantation (HR 1.18; p = 0.04) and systolic dysfunction (HR 1.22, p < 0.001). Longer paced intrinsicoid deflection (pID) was associated with less atrial fibrillation (HR 0.75; p = 0.01), more systolic dysfunction (HR 1.17; p < 0.001), ICD implantation (HR 1.23; p = 0.04), and CRT upgrade (HR 1.23; p = 0.03). Exceeding thresholds for TPC, pQRS, and pID of 170, 146, and 112 ms in lead I, respectively, was associated with a substantial increase in systolic dysfunction over 5 years (p < 0.001).

CONCLUSIONS

Longer durations of all tested parameters in lead I were associated with increased rates of left ventricular systolic dysfunction. ICD implantation and CRT upgrade were also linked to increased TPC and pID durations. Paradoxically, patients with longer pID and pQRS had less incident atrial fibrillation.

Impact of high-grade atrioventricular block and cumulative frequent pacing on atrial arrhythmias

BACKGROUND

The relationship between high-grade atrioventricular block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized. We hypothesized HGAVB and pacing may have significant impact on incidence and prevalence of AAs by modulating atrial substrate.

OBJECTIVE

To determine impact of HGAVB and pacing on AAs including atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT).

METHODS

All consecutive patients who underwent dual-chamber pacemaker implantation for HGAVB from 2005 to 2011 at the University of Chicago were included. AAs and percent of pacing were detected through device interrogation. Patients' data were collected from electronic medical records and clinic visits.

RESULTS

A total of 166 patients (mean age 71 ± 15 years; 54% female, 56% African American) were studied. AF was documented in 27% of patients before pacemaker implantation. During a mean 5.8 ± 2.2 years of follow-up, 47% had device-detected AF, 10% AFL, and 26% AT. New-onset AF was documented in 40 of the 122 patients without prior AF (33%). Continuous (≥ 99%) right ventricular pacing was associated with significantly decreased AF prevalence (34% vs 59%, P = 0.005), and correlated with lower incidence (26% vs 41%, P = 0.22). Pacing suppressed AF in 14% of patients with baseline AF; those patients had lower atrial pacing (3.2% vs 45%, P < 0.0001). Left atrial dilation was the only independent predictor of AF with frequent pacing (P = 0.009).

CONCLUSIONS

HGAVB is associated with high incidence and prevalence of AAs with and without pacing. Cumulative frequent (≥99%) ventricular pacing reduces risk of AF in patients with HGAVB.

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.

Genetic Mechanisms Contribute to the Development of Heart Failure in Patients with Atrioventricular Block and Right Ventricular Apical Pacing

Right ventricular apical (RVA) pacing can lead to progressive left ventricular dysfunction and heart failure (HF), even in patients with normal cardiac structure and function. Our study conducted candidate gene screening and lentivirus transfected neonatal rat cardiomyocytes (NRCMs) to explore the genetic and pathogenic mechanisms of RVA pacing induced cardiomyopathy in third degree atrioventricular block (III AVB) patients. We followed 887 III AVB patients with baseline normal cardiac function and RVA pacing. After a median follow-up of 2.5 years, 10 patients (four males, mean age 47.6 ± 10.0 years) were diagnosed with RVA pacing induced HF with left ventricular ejection fraction (LVEF) reducing dramatically to 37.8 ± 7.1% (P  < 0.05). Candidate genes sequencing found cardiomyopathy associated genetic variations in all ten HF patients and six SCN5A variations in 6 of 20 control patients. Transfected NRCMs of Lamin A/C mutations (R216C and L379F) disrupted Lamin A/C location on nucleus membrane and finally resulted in increased apoptotic rate after serum starvation. In conclusion, cardiomyopathy associated genetic variations play an essential role in occurrence of newly onset HF in the III AVB patients with RVA pacing. RVA pacing, serving as extra stimulator, might accelerate the deterioration of cardiac structure and function.

Early Right Ventricular Apical Pacing-Induced Gene Expression Alterations Are Associated with Deterioration of Left Ventricular Systolic Function

The chronic high-dose right ventricular apical (RVA) pacing may have deleterious effects on left ventricular (LV) systolic function. We hypothesized that the expression changes of genes regulating cardiomyocyte energy metabolism and contractility were associated with deterioration of LV function in patients who underwent chronic RVA pacing. Sixty patients with complete atrioventricular block and preserved ejection fraction (EF) who underwent pacemaker implantation were randomly assigned to either RVA pacing (n = 30) group or right ventricular outflow tract (RVOT) pacing (n = 30) group. The mRNA levels of OPA1 and SERCA2a were significantly lower in the RVA pacing group at 1 month's follow-up (both p < 0.001). Early changes in the expression of selected genes OPA1 and SERCA2a were associated with deterioration in global longitudinal strain (GLS) that became apparent months later (p = 0.002 and p = 0.026, resp.) The altered expressions of genes that regulate cardiomyocyte energy metabolism and contractility measured in the peripheral blood at one month following pacemaker implantation were associated with subsequent deterioration in LV dyssynchrony and function in patients with preserved LVEF, who underwent RVA pacing.