Canadian Trial of Physiological Pacing

Dual-chamber leadless pacemaker in complex adult congenital heart disease: a case report

Background

Atrioventricular block is common with adult congenital heart disease and pacemaker implantation is challenging. Atrioventricular synchronous pacing is important for better haemodynamics. This case reports the implantation of a dual-chamber leadless pacemaker in a patient with univentricular heart physiology and contributes to the literature regarding the management option in complex adult congenital heart disease patients with conduction abnormalities.

Case summary

A 25-year-old male with double inlet left ventricular, transposition of great arteries, hypoplastic aortic arch receive multiple surgeries including the Glenn shunt at the age of 1. He presented with 2:1 and 3:1 heart block at the age of 13 with a transvenous dual-chamber pacemaker implanted by pacing the superior vena cava stump and puncturing the Glenn shunt for the ventricular lead. A decade later, lead malfunctioned and the patient progressed to complete heart block. A subcutaneous implantable cardioverter defibrillator was implanted when he was 23 for monomorphic ventricular tachycardia. Given the anticipated challenges with transvenous lead extraction and epicardial pacemaker implantation, we implanted the novel dual-chamber leadless pacemakers which resulted in satisfactory atrioventricular synchronous pacing performance immediately post-op and 2 weeks after the procedure.

Discussion

We present a case of a novel dual-chamber leadless pacemaker implantation to maintain atrioventricular synchrony in the patient with complete heart block and univentricular physiology. This case illustrates an additional pacing option in complex adult congenital heart to maintain atrioventricular synchrony.

Five historical innovations that have shaped modern cardiothoracic surgery

Throughout history, many innovations have contributed to the development of modern cardiothoracic surgery, improving patient outcomes and expanding the range of treatment options available to patients. This article explores five key historical innovations that have shaped modern cardiothoracic surgery: cardiopulmonary bypass, surgical pacemakers, video assisted thoracic surgery, robotic surgery and mechanical circulatory support. We will review the development, impact and significance of each innovation, highlighting their contributions to the field of cardiothoracic surgery and their ongoing relevance in contemporary and perioperative practice.

Atrial mechanical contraction and ambulatory atrioventricular synchrony: Predictors from the OPTIVALL study

INTRODUCTION

The role that preprocedural factors have on atrioventricular synchrony (AVS) provided by leadless pacemakers requires investigation.

METHODS AND RESULTS

We aimed to assess the correlation between mitral inflow echocardiographic parameters and p-wave morphology with the accelerometer A4 signal amplitude. We also sought to identify clinical and echocardiographic predictors of optimal ambulatory AVS (≥85% of cardiac cycles). Forty-three patients undergoing Micra AV implant from June 2020 to March 2023 were prospectively enrolled. Baseline echocardiogram and 12-lead resting ECG were performed. Device follow-up was scheduled at 24 h, 1, 3, and 6 months and yearly after the implant. Ambulatory AVS was studied with a 24 h Holter monitor performed at 3 months follow-up in 35 patients who remained in VDD mode. A4 signal amplitude at 1 month correlated to peak A wave velocity (r = .376; p = .024) at echocardiogram, but no relationship was found with peak A' wave velocity, E/A, or E'/A' ratio. P-wave amplitude in lead I and aVF correlated to A4 signal amplitude at 1- and 3-months follow-up, respectively. Median AVS during 24 h of daily activities was 85.6 ± 7.6% and remained stable up to 100 bpm. Twenty-three out of 35 patients (65.7%) reached optimal ambulatory AVS. There was no association between mitral inflow echocardiographic parameters and optimal AVS. Diabetes (OR: 0.05, 95% CI: 0.01-0.47; p = .009) and chronic obstructive pulmonary disease (COPD) (OR: 0.06, 95% CI: 0.01-0.63; p = .019) strongly predicted ambulatory AVS <85%.

CONCLUSIONS

Diabetes and COPD should be considered when selecting candidates for Micra AV. Measurements of pulsed wave Doppler mitral inflow do not systematically reflect the behavior of the A4 signal amplitude.

Sinus Node Dysfunction

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications.

Atrial fibrillation: primary prevention, secondary prevention, and prevention of thromboembolic complications: part 1

Atrial fibrillation (AF), is the most common sustained cardiac arrhythmia. It was once thought to be benign as long as the ventricular rate was controlled, however, AF is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a MEDLINE search to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched via the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare noninvasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

EHRA expert consensus document on the management of arrhythmias in frailty syndrome, endorsed by the Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), Latin America Heart Rhythm Society (LAHRS), and Cardiac Arrhythmia Society of Southern Africa (CASSA)

There is an increasing proportion of the general population surviving to old age with significant chronic disease, multi-morbidity, and disability. The prevalence of pre-frail state and frailty syndrome increases exponentially with advancing age and is associated with greater morbidity, disability, hospitalization, institutionalization, mortality, and health care resource use. Frailty represents a global problem, making early identification, evaluation, and treatment to prevent the cascade of events leading from functional decline to disability and death, one of the challenges of geriatric and general medicine. Cardiac arrhythmias are common in advancing age, chronic illness, and frailty and include a broad spectrum of rhythm and conduction abnormalities. However, no systematic studies or recommendations on the management of arrhythmias are available specifically for the elderly and frail population, and the uptake of many effective antiarrhythmic therapies in these patients remains the slowest. This European Heart Rhythm Association (EHRA) consensus document focuses on the biology of frailty, common comorbidities, and methods of assessing frailty, in respect to a specific issue of arrhythmias and conduction disease, provide evidence base advice on the management of arrhythmias in patients with frailty syndrome, and identifies knowledge gaps and directions for future research.

Single-lead VDD pacing: a literature review on short-term and long-term performance

INTRODUCTION

VDD pacing system was introduced more than 30 years ago. Its use is considered by the 2021 European Society of Cardiology guidelines on cardiac pacing as a potential alternative to dual chambers system for patients with atrioventricular block and normal sinus node function.

AREAS COVERED

In this article, we performed a narrative review of current literature in order to identify the strengths and weaknesses of this pacing system. VDD system allows the maintenance of AV synchronous pacing and its hemodynamic advantages. Some disadvantages may be related to the non-negligible incidence of atrial undersensing and the possible subsequent need for upgrade to DDD system. On the other hand, shorter implantation time and lower complications rate may be advantages.

EXPERT OPINION

In the modern pacing era, VDD pacing system struggles to find its own space. However, it may still be considered as a valuable alternative to a dual-chamber pacemaker for selected patients, in specific clinical scenarios.

Optimizing atrial sensing parameters in leadless pacemakers: Atrioventricular synchrony achievement in the real world

BACKGROUND

Performance of the leadless pacemaker capable of atrioventricular (AV) synchronous pacing in de novo patients warrants further investigation.

OBJECTIVE

The aims of this study were to assess what programming changes are needed to achieve proper atrial tracking and to study the percentage of AV synchrony (AVS) the device can provide under real-world conditions.

METHODS

Consecutive patients undergoing Micra AV implantation between June 2020 and November 2021 were studied. Reprogramming of atrial sensing parameters during follow-up was performed by following device counters. AVS was studied with an ambulatory 24-hour Holter monitor and automatically analyzed by an electrocardiogram delineation system. The primary end point was AVS ≥85% of total cardiac cycles during 24-hour Holter electrocardiogram monitoring.

RESULTS

Thirty-one patients who remained in VDD mode were studied, and all of them required manual reprogramming. The automatic A3 window end was deactivated, and a fixed and short value was set in all patients throughout follow-up. AVS significantly increased from 68.7% ± 14.7% at 24-hour follow-up to 83.9% ± 7.4% at 1-month visit (P = .001). At 1-month visit, shorter A3 window end time (P = .019), higher A4 threshold (P = .011), and deactivation of the automatic A3 window (P = .054) were independently related to higher AVS. A total of 2,291,953 Holter-recorded cardiac cycles were analyzed. Median AVS during 24-hour daily activities was 87.6% (interquartile range 84.5%-90.6%). Twenty of 26 patients (79.6%) reached AVS ≥85% of cardiac cycles.

CONCLUSION

High rates of AVS can be achieved in real-world patients undergoing leadless pacing. Manual reprogramming of the atrial sensing parameters is essential to optimize mechanically sensed atrial tracking.

Atrial Pacing Affects Left Atrial Morphological and Functional Parameters Early after Pacemaker Implantation

Background and Objectives: Chronic atrial stimulation might impair left atrial (LA) function. We aimed to assess the impact of atrial pacing burden on LA volumetric and functional parameters after implantation of a dual-chamber pacemaker. Materials and Methods: The prospective study included 121 subjects with sinus node disease (SND) or atrioventricular block (AVB) that received a dual-chamber pacemaker. After device implantation, the subjects were divided into three groups: (1) SND with a lower rate (LR) set to 60 bpm and rate response enabled; (2) AVB with an LR set to 60 bpm and no rate response; and (3) AVB with an LR set to 40 bpm and no rate response. Subjects were followed at one and three months. Two subsets of patients with high and low atrial pacing burdens accompanied by low ventricular pacing percentage were analyzed. LA function was evaluated with volumetric and strain parameters from transthoracic echocardiography. Results: The high atrial low ventricular pacing group consisted of 38 subjects, and the low atrial low ventricular group consisted of 22 subjects. When looking at the change in volumetric parameters, we observed a tendency for volumes to increase in both groups; however, only minimal LA volume reached statistical significance at three months in the high atrial pacing group. A trend towards the lowering of an active emptying fraction at one month (p = 0.076) became significant at three months (p = 0.043), and was also only observed in the same group. Moreover, a decrease in the tendency to reach statistical significance at three months for reservoir and contractile strain parameters and stiffness index was only observed in the high atrial pacing group. Meanwhile, in the low atrial pacing burden group, all parameters remained significantly unchanged. Conclusions: The burden of right atrial pacing in patients with preserved left ventricular function negatively influences functional and morphologic LA parameters. Moreover, negative effects take place soon after pacemaker implantation and appear to be sustained.

Short Term Outcomes with Dual Chamber versus Single Chamber Pacing for Atrioventricular Block - A Crossover Trial

A total of 42 patients were studied for primary outcomes of quality of life and 6MWD between VVIR and DDD modes. At end of 2 months after device implantation, randomization was done and the device was programmed to VVIR or DDD modes. At the end of 2 months in this mode QOL and functional was assessed and the patient was switched to other mode. The same protocol was followed at the end of 2 months. We found no difference in functional capacity and quality of life between the two pacing modes. None of the patients developed pacemaker syndrome and there was no preference for any of the modes.

Sinus Node Dysfunction

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications.

Cardiac Stimulation in the Third Millennium: Where Do We Head from Here?

Over the years, pacemakers have evolved from a life-saving tool to prevent asystole to a device to treat heart rhythm disorders and heart failure, aiming at improving both cardiac function and clinical outcomes. Cardiac stimulation nowadays aims to correct the electrophysiologic roots of mechanical inefficiency in different structural heart diseases. This has led to awareness of the concealed risks of customary cardiac pacing that can inadvertently cause atrioventricular and inter-/intra-ventricular dyssynchrony, and has promoted the development of new pacing modalities and the use of stimulation sites different from the right atrial appendage and the right ventricular apex. The perspective of truly physiologic pacing is the leading concept of the continued research in the past 30 years, which has made cardiac stimulation procedure more sophisticated and challenging. In this article, we analyze the emerging evidence in favor of the available strategies to achieve an individualized physiologic setting in bradycardia pacing.

Uso Racional dos Cabos-Eletrodos na Estimulação Cardíaca Artificial

Introdução: Os dispositivos cardíacos eletrônicos implantáveis (DCEIs) são terapia consagrada para o tratamento de bradiarritmias, prevenção de morte súbita ou insuficiência cardíaca. Desde o primeiro implante de marcapasso transvenoso há mais de 60 anos, ocorreram avanços tecnológicos dos dispositivos e melhorias nas técnicas cirúrgicas. No entanto esse tipo de terapia ainda está associado a complicações significativas, a maioria relacionada ao implante dos cabos-eletrodos transvenosos. Objetivo: apresentar uma reflexão sobre como praticar o uso racional do implante de cabos-eletrodos e propor estratégias e alternativas para postergá-lo ou evitá-lo, com base nos conhecimentos atuais nos diversos campos da estimulação cardíaca artificial. Métodos: Revisão da literatura que utilizou artigos de 1995 a 2019, de diversas plataformas e revistas. Conclusão:Há a expectativa de que nos próximos anos ocorram avanços tecnológicos e de conhecimento no campo da estimulação leadless, permitindo que esses dispositivos sejam incorporados na prática clínica de maneira rotineira. Atualmente, se o implante de eletrodos ventriculares nos casos de doença do nó sinusal com condução atrioventricular preservada for racionalizado, o implante de eletrodos atriais nos cardiodesfibriladores implantáveis (CDI) sem necessidade de estimulação antibradicardia ou dos eletrodos ventriculares nos casos sem a necessidade de estimulação antitaquicardia (ATP) considerando o implante de CDIs subcutâneos, este artigo terá cumprido o seu papel.

Rational Use of Leads in Artificial Cardiac Pacing

Introduction: Cardiovascular implantable electronic device (CIEDs) are a proven therapy for the treatment of bradyarrhythmias, prevention of sudden death or heart failure. Since the first transvenous pacemaker implantation more than 60 years ago, technological advances in devices and improvements in surgical techniques have occurred. However, this type of therapy is still associated with significant complications, most of them related to the implantation of transvenous leads. Objective: To present a reflection on how to practice the rational use of lead implantation and propose strategies and alternatives to delay or avoid it, based on the current knowledge in the various fields of artificial cardiac stimulation. Methods: Review of literature that used articles from 1995 to 2019, from several platforms and periodicals. Conclusion: There is an expectation that in the coming years there will be technological and knowledge advances in the field of leadless stimulation, allowing these devices to be incorporated into clinical practice in a routine manner. Currently, if the implantation of ventricular electrodes in cases of sinus node disease with preserved atrioventricular conduction is rationalized, the implantation of atrial electrodes in implantable cardioverter-defibrillators (ICD) without the necessity of antibradicardia stimulation or ventricular electrodes in cases without the necessity of antitachycardia stimulation (ATP) considering the subcutaneous ICD implantation, this article will have fulfilled its role.

Are atrial high rate episodes (AHREs) a precursor to atrial fibrillation?

Abstract

Atrial high rate episodes (AHREs), also termed, subclinical atrial tachyarrhythmias or subclinical atrial fibrillation (AF) are an important cardiovascular condition. Advancement in implantable cardiac devices such as pacemakers or internal cardiac defibrillators has enabled the continuous assessment of atrial tachyarrhythmias in patients with an atrial lead. Patients with device-detected AHREs are at an elevated risk of stroke and may have unmet anticoagulation needs. While the benefits of oral anticoagulation for stroke prevention in patients with clinical AF are well recognised, it is not known whether the same risk–benefit ratio exists for anticoagulation therapy in patients with AHREs. The occurrence and significance of AHRE are increasingly acknowledged but these events are still not often acted upon in patients presenting with stroke and TIA. Additionally, patients with AHRE show a significant risk for major adverse cardiovascular events (MACE) including acute heart failure, myocardial infarction, cardiovascular hospitalisation, ventricular tachycardia/fibrillation, which is dependent on AHRE burden. In this review, we present an overview of this relatively new entity, its associated thromboembolic risk and its management implications.

Graphic abstract

Understanding non-response to cardiac resynchronisation therapy: common problems and potential solutions

Heart failure is a complex clinical syndrome associated with a significant morbidity and mortality burden. Reductions in left ventricular (LV) function trigger adaptive mechanisms, leading to structural changes within the LV and the potential development of dyssynchronous ventricular activation. This is the substrate targeted during cardiac resynchronisation therapy (CRT); however, around 30-50% of patients do not experience benefit from this treatment. Non-response occurs as a result of pre-implant, peri-implant and post implant factors but the technical constraints of traditional, transvenous epicardial CRT mean they can be challenging to overcome. In an effort to improve response, novel alternative methods of CRT delivery have been developed and of these endocardial pacing, where the LV is stimulated from inside the LV cavity, appears the most promising.

Leadless pacemakers - The path to safer pacing?

Endocardial transvenous permanent pacemakers (TVPs) are a mainstay within cardiology and used to treat a range of bradyarrhythmias. However, their use is associated with potential complications both at the time of implantation and longer term. The concept of a leadless pacemaker, where a self-contained device is placed within the right ventricle, has obvious attractions. Two leadless systems have been developed, though only one is currently available. Results from clinical trials have been promising but a number of hurdles need to be circumvented before leadless devices can usurp TVPs. At present, use is restricted to specialist centres, for a limited indication and for patients in whom conventional implantation is contraindicated. This article provides a contemporary critique of design types, evidence base and existing limitations of this nascent technology.

Procedural safety and long-term follow-up after pacemaker implantation in nonagenarians

BACKGROUND

The rate of pacemaker (PM) implantations is constantly growing. Since life expectancy of the population is projected to increase, a large number of nonagenarian patients will need PM implantation. We aimed at analyzing short- and long-term outcomes after PM implantation in nonagenarians.

METHODS

Patients aged ≥90 years referred for PM implantation from 2004 to 2017 were included. The primary clinical endpoint was total mortality. Secondary endpoints included procedure-related and in-hospital complications.

RESULTS

A total of 172 patients were included (92.6 ± 2.1 years, from 90.0 to 101.4 years). Procedure duration was 50.0 ± 19.7 minutes. Most of the patients had VVI devices implanted (143 pts, 83.1%) and mean hospital stay was 3.5 ± 1.5 days. Nine patients (5.2%) had short-term device-related complications and 29 patients (16.8%) had post-procedural complications, non-related to the implantation, including four leading to patients' death. During a follow-up of 22.5 months (interquartile range: 7.3-38.0), 94 patients (54.7%) died. Survival rates were 82.9% (95% confidence interval [CI]: 76.0-88.0), 73.7% (95% CI: 65.7-80.1) and 37.5% (95% CI: 27.5-47.5) after 1, 2, and 5 years, respectively. The Charlson comorbidity index was a predictive factor of procedural complications (odds ratio = 1.33; 95% CI: 1.05-1.69, P = 0.02) while having a complication (hazard ratio [HR] = 4.04; 95% CI: 1.79-9.11, P = 0.001) and atrial fibrillation (HR = 1.63; 95% CI: [1.02-2.63], P = 0.043) were predictors of post-implantation death.

CONCLUSION

PM implantation in nonagenarians is safe, with a low risk of procedural complications, but many comorbidities-related complications can occur. Caution should be taken in this old and frail population since complications significantly impact patients' survival.

Heart Rhythm Society: expert consensus statements-part 1

One of the most important roles for professional societies in medicine is assembling multiple stakeholders and experts to develop documents that can help guide and define policies and strategies for best medical care. Each year the Heart Rhythm Society (HRS) develops several consensus documents that address critical clinical subjects that have been identified by input from HRS members and HRS committees. Over the past 5 years, HRS has produced documents with multiple professional societies from around the world, and although the topics chosen for exploration center around arrhythmia management, the reviews and recommendations made in the documents are important for clinical cardiologists and generalists who are not arrhythmia specialists. When an internist or other primary care provider identifies a patient who may be having symptoms from an arrhythmia, the referral first is made to the clinical cardiologist and only later, if necessary, does an arrhythmia specialist become involved. These expert consensus statements are developed for specific clinical questions regarding arrhythmia management where there is controversy or uncertainty, often with less data from randomized controlled trials to help guide recommendations, which must then be made by extrapolation of existing data, observational data, and expert opinion. In this 2-part review, the consensus statements developed by the HRS over the past 5 years that pertain to adults are discussed in part 1; part 2 focuses on consensus statements that HRS has developed in conjunction with the Pediatric and Congenital Electrophysiology Society that address arrhythmia issues in children and adults with congenital heart disease.

Atrial high-rate episodes and stroke prevention

While the benefit of oral anticoagulants (OACs) for stroke prevention in patients with atrial fibrillation (AF) is well established, it is not known whether oral anticoagulation is indicated in patients with atrial high-rate episodes (AHRE) recorded on a cardiac implantable electronic device, sometimes also called subclinical AF, and lasting for at least 6 min in the absence of clinically diagnosed AF. Clinical evidence has shown that short episodes of rapid atrial tachycarrhythmias are often detected in patients presenting with stroke and transient ischaemic attack. Patients with AHRE have a higher likelihood of suffering from subsequent strokes, but their stroke rate seems lower than in patients with diagnosed AF, and not all AHRE episodes correspond to AF. The prognostic and pathological significance of AHRE is not yet fully understood. Clinical trials of OAC therapy are being conducted to determine whether therapeutic intervention would be beneficial to patients experiencing AHRE in terms of reducing the risk of stroke.

Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie

Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV endocardial pacing configuration). Overall, physiological age, general status and comorbidities rather than chronological age per se should be the decisive factors in making a decision about device implantation selection for survival and well-being benefit in elderly patients.

Clinical, Echocardiographic, and Electrocardiographic Predictors of Persistent Atrial Fibrillation after Dual-Chamber Pacemaker Implantation: An Integrated Scoring Model Approach

Persistent atrial fibrillation (PeAF) predictors after dual-chamber pacemaker (PM) implantation remain unclear. We sought to determine these predictors and establish an integrated scoring model. Data were retrospectively reviewed for 649 patients (63.8 ± 12.3 years, 48.6% male, mean CHA₂DS₂–VASC score 2.7 ± 2.0) undergoing dual-chamber PM implantation. PeAF was defined as documented AF on two consecutive electrocardiograms acquired ≥7 days apart. During a 7.1-year median follow-up (interquartile range 4.5–10.1 years), 67 (10.3%) patients had PeAF. Multivariable analysis showed the following independent predictors of future PeAF: ischemic stroke or transient ischemic accident history (hazard ratio [HR] 2.03, 95% confidence interval [CI] 1.03–3.50, p = 0.040), atrial fibrillation/flutter history (HR 1.80, 95% CI 1.01–3.20, p = 0.046), sinus node disease (HR 2.24, 95% CI 1.16–4.35, p = 0.016), left atrial enlargement (>45 mm, HR 2.14, 95% CI 1.26–3.63, p = 0.005), and time in automatic mode switching >1% at first follow-up interrogation (HR 2.58, 95% CI 1.51–4.42, p < 0.001). An integrated scoring model combining these predictors showed good discrimination performance at the seven-year follow-up. (C-statistic 0.716, 95% CI 0.629–0.802, p < 0.001). Significantly greater seven-year PeAF incidences were seen in patients with higher scores (2–5) than in those with lower scores (0–1) (22.8% ± 3.8% vs. 5.3% ± 1.7%, p < 0.001). In conclusion, an integrated scoring model combining clinical, echocardiographic, and electrocardiographic characteristics is useful for predicting future PeAF in patients with a dual-chamber PM.

Very Low Ventricular Pacing Rates Can Be Achieved Safely in a Heterogeneous Pacemaker Population and Provide Clinical Benefits: The CANadian Multi-Centre Randomised Study-Spontaneous AtrioVEntricular Conduction pReservation (CAN-SAVE R) Trial

BACKGROUND

It is well recognized that right ventricular apical pacing can have deleterious effects on ventricular function. We performed a head-to-head comparison of the SafeR pacing algorithm versus DDD pacing with a long atrioventricular delay in a heterogeneous population of patients with dual-chamber pacemakers.

METHODS AND RESULTS

In a multicenter prospective double-blinded randomized trial conducted at 10 centers in Canada, 373 patients, age 71±11 years, with indications for dual chamber DC pacemakers were randomized 1:1 to SafeR or DDD pacing with a long atrioventricular delay (250 ms). The primary objective was twofold: (1) reduction in the proportion of ventricular paced beats at 1 year; and (2) impact on atrial fibrillation burden at 3 years, defined as the ratio between cumulative duration of mode-switches divided by follow-up time. Statistical significance of both co-primary end points was required for the trial to be considered positive. At 1 year of follow-up, the median proportion of ventricular-paced beats was 4.0% with DDD versus 0% with SafeR (P<0.001). At 3 years of follow-up, the atrial fibrillation burden was not significantly reduced with SafeR versus DDD (median 0.00%, interquartile range [0.00% to 0.23%] versus median 0.01%, interquartile range [0.00% to 0.44%], respectively, P=0.178]), despite a persistent reduction in the median proportion of ventricular-paced beats (10% with DDD compared to 0% with SafeR).

CONCLUSIONS

A ventricular-paced rate <1% was safely achieved with SafeR in a population with a wide spectrum of indications for dual-chamber pacing. However, the lower percentage of ventricular pacing did not translate into a significant reduction in atrial fibrillation burden.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/ Unique identifier: NCT01219621.

Temporary biventricular pacing improves bypass graft flows in coronary artery bypass graft patients with permanent atrial fibrillation

OBJECTIVES

We have previously demonstrated the impact of univentricular pacing modalities on bypass graft flow (BGF) in the coronary artery bypass graft (CABG) patient with permanent atrial fibrillation (AF). The aim of the present study was to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing in patients with and without severe left ventricular dysfunction.

METHODS

In 43 CABG patients [mean age 69.5 ± 1.3 years; ejection fraction (EF) 49 ± 2%] with AF, we analysed coronary vascular resistances (CVRs) and the contemporary changes in the BGF obtained during right ventricular outflow tract (RVOT), right- (RV), left- (LV) and right-left ventricular pacing (biventricular pacing, BiVP) using the ultrasonic transit-time methodology.

RESULTS

BiVP resulted in the highest percentage decrease of CVR in the overall study group by 17.5 ± 3.0% (P < 0.001), followed by RVOT pacing with 13.9 ± 3.9%. Accordingly, the highest mean BGF was achieved during BiVP, resulting in a 21.6 ± 2.6% increase when compared with no pacing and 16 ± 3.7% when compared with RV pacing. Analysis of patients according to their preoperative LV function (EF ≥50%, n = 26; EF <50%, n = 17) showed significantly lower CVR (P < 0.037) and higher BGF during BiVP in patients with lower EF.

CONCLUSIONS

Placement of an additional LV pacing wire offered a significant improvement in BGF by minimizing CVR in patients with AF and poor EF.

Honing in on optimal ventricular pacing sites: an argument for his bundle pacing

OPINION STATEMENT

Frequent ventricular pacing is often or completely unavoidable in patients with high-grade or complete heart block. Over time, patients with high-burden RV pacing are at risk for developing symptomatic cardiomyopathy due to pacing-induced ventricular dyssynchrony. Growing awareness of this concern has generated interest in alternative pacing sites like the septum and outflow tract, the thinking being that these sites will more closely mimic His-Purkinje-mediated ventricular activation. Numerous studies have met with mixed results likely due to the fact that-to quote Marvin Gaye-there ain't nothing like the real thing. Herein lies the advantage of His bundle pacing (HBP), as it is the only pacing modality capable of physiological ventricular activation. HBP has been demonstrated to be safe and reliable in various forms of AV block with minimal drawbacks, namely modestly higher pacing thresholds when compared with other RV sites. Additionally, HBP is a truly physiologic alternative to biventricular pacing to effect cardiac resynchronization therapy (CRT), a concept supported by small observational and prospective studies. In our view, His bundle pacing should be considered in nearly all patients requiring ventricular pacing.

Permanent dual chamber epicardial pacemaker implantation in two dogs with complete atrioventricular block

Between November 2013 and December 2013, two dogs with complete atrioventricular (AV) block had a permanent, dual chamber epicardial pacing system implanted. Steroid-eluting unipolar, button-type epicardial leads(a) were sutured to the right atrial appendage and right ventricular wall via a right thoracotomy in both dogs. The pacemakers were programmed in VDD mode. Permanent dual chamber epicardial pacemaker implantation was successful in both dogs with no intra-operative complications. One dog had an acute onset of neurologic signs two days post-operatively that resolved within 24 h. Both dogs have had complete resolution of the clinical signs related to the bradyarrhythmia, and one dog has had complete resolution of chylothorax. One dog had a major lead complication characterized by intermittent loss of capture that resolved by increasing the pacemaker output. Based on the outcome of these two cases, implantation of permanent dual chamber epicardial pacing systems is possible in dogs providing an alternative to dual chamber transvenous systems.

Focus on right ventricular outflow tract septal pacing

Experimental and clinical studies have shown that right ventricular apical pacing may result in long-term deleterious effects on account of its negative impact on left ventricular remodeling through desynchronization. This risk appears more pronounced in patients with even moderate left ventricular dysfunction and generally occurs after at least 1 year of pacing. As right ventricular apical pacing may be associated with the development of organic mitral insufficiency, other sites that allow for more physiological stimulation, such as right ventricular outflow tract septal pacing, have been developed, with good feasibility and reproducibility. However, the prospective randomized studies and meta-analyses to date have only demonstrated a modest effect on ejection fraction in the medium term, without any significant effect on quality of life and morbimortality. However, the absence of a favorable effect for right ventricular outflow tract septal pacing compared with right ventricular apical pacing in terms of clinical manifestations and patient prognosis appears to be more associated with the designs of these studies, which were not homogeneous with regard to methodology used, judgment criteria, follow-up and, especially, statistical power. Two randomized prospective multicentre studies are currently ongoing in order to evaluate the favorable effect of infundibular septal pacing, when considering the indirect negative effects of right ventricular apical pacing as reported in the literature.

Evaluation of erectile dysfunction in permanent pacemaker implanted patients with cardiac rhythm disorder prediagnosis

Background and aims

To evaluate the anxiety, depression and related psychogenic erectile dysfunction that might be developed before and after pacemaker implantation in patients with cardiac arrhythmias.

Material and methods

Thirty permanent pacemaker implanted male patients, were enrolled to study between September 2006 and September 2008. Erectile function domain questions of International Index of Erectile Function (IIEF‐6) and Hospital Anxiety and Depression Scale (HAD) questionnaires were applied to patients, 6 months before pacemaker implantation (BP6) and on month 1 (AP1) and 6 after application (AP6). Patients were included in a multidisciplinary cardiac rehabilitation-adaptation program with a duration of 1–2 months. Patients were evaluated in subgroups.

Results

Mean age was 51.5 ± 10.3. Most frequent diagnosis was observed as AV block in etiology. The mean IIEF values were changed 22.8→20.2→24.6 in BP6, AP1 and AP6 time frames consecutively. However, the mean HAD-Anxiety scores were evaluated as 8.1→17.0→7.3 and the mean HAD-Depression as 3.9→7.9→8.9 consecutively in the same time frames.

Conclusion

Cardiac arrhythmia plus permanent pacemaker implantation, increased anxiety and depression of patients and decreased erectile function at AP1; however, the improvement in cardiac symptoms at AP6 with the possible positive effects of rehabilitation program, helps to reduce anxiety and increased IIEF scores, although there was still a slight increase in depression levels.

Bradyarrhythmias in the elderly

Over the next decade, there will be a dramatic increase in the number of elderly people in the United States and in most parts of the world. With this increase, there will be an accompanying increase in patients with sinus node dysfunction and atrioventricular block; therefore, it will be essential for health care personnel to have a basic knowledge of bradyarrhythmias and the considerations required for managing these rhythms in elderly patients. In particular, comprehensive assessment before decisions on medical and device-based management is critical and must take into account social issues and the presence of comorbid conditions.

Permanent His-bundle pacing maintains long-term ventricular synchrony and left ventricular performance, unlike conventional right ventricular apical pacing

AIMS

Right ventricular apical pacing (RVAP) may be deleterious, determining abnormal left ventricular (LV) electrical activation and progressive LV dysfunction. Permanent His-bundle pacing (HBP) has been proposed to prevent this detrimental effect. The aim of our study was to compare the long-term effects of HBP on LV synchrony and systolic performance with those of RVAP in the same group of patients.

METHODS

Our analysis included 26 patients who received both an HBP lead and an RVAP lead, as backup, in our electrophysiology laboratory between 2004 and 2007. After implantation, all devices were programmed to obtain HBP. An intra-patient comparison of the effects of HBP and RVAP on LV dyssynchrony and function was performed at the last available follow-up examination.

RESULTS

After a mean of 34.6 ± 11 months, the pacing modality was temporarily switched to RVAP. During RVAP, LV ejection fraction significantly decreased (50.1 ± 8.8% vs. 57.3 ± 8.5%, P < 0.001), mitral regurgitation significantly increased (22.5 ± 10.9% vs.16.3 ± 12.4%; P = 0.018), and inter-ventricular delay significantly worsened (33.4 ± 19.5 ms vs. 7.1 ± 4.7 ms, P = 0.003) in comparison with HBP. However, the myocardial performance index was not statistically different between the two pacing modalities (P = 0.779). No asynchrony was revealed by tissue Doppler imaging during HBP, while during RVAP the asynchrony index was significantly higher in both the four-chamber (125.8 ± 63.9 ms; P = 0.035 vs. HBP) and two-chamber (126 ± 86.5 ms; P = 0.037 vs. HBP) apical views.

CONCLUSION

His-bundle pacing has long-term positive effects on inter- and intra-ventricular synchrony and ventricular contractile performance in comparison with RVAP. It prevents asynchronous pacing-induced LV ejection fraction depression and mitral regurgitation.