Leadless-Pacing-Induced Pacemaker Syndrome Managed with Atrial Leadless Pacing Device

Bradyarrhythmias are adequately treated with pacemakers. There are different pacing modes (single-chamber, dual-chamber, cardiac resynchronisation therapy [CRT] and conduction system pacing [CSP]) and a choice between leadless or transvenous pacemakers. The expected pacing need is important for determining optimal pacing mode and device type. This study aimed to evaluate atrial pacing (AP) and ventricular pacing (VP) percentages over time for the most common pacing indications. Included patients were aged ≥18 years with a dual-chamber rate-modulated [DDD(R)] pacemaker implantation and ≥1 year of follow-up at a tertiary centre between January 2008 and January 2020. Baseline characteristics, AP and VP at yearly follow-up visits up to 6 years after implantation were retrieved from the medical records. A total of 381 patients were included. Primary pacing indications were incomplete atrioventricular block (AVB) in 85 (22%), complete AVB in 156 (41%) and sinus node dysfunction (SND) in 140 (37%) patients. Mean age at implantation was 71±14, 69±17 and 68±14 years, respectively (p=0.23). Median follow-up was 42 months (25-68 months). Overall, AP was highest in SND with median 37% (7%-75%) versus 7% (1%-26%) in incomplete AVB and 3% (1%-16%) in complete AVB (p<0.001); VP was highest in complete AVB with median 98% (43%-100%) versus 44% (7%-94%) in incomplete AVB and 3% (1%-14%) in SND (p<0.001). Ventricular pacing significantly increased over time in patients with incomplete AVB and SND (both p=0.001). These results confirm the pathophysiology of different pacing indications, causing clear differences in pacing need and expected battery longevity. They may help guide optimal pacing mode and suitability for leadless or physiological pacing.

No reports on atrial leadless pacing have been demonstrated in patients with the Fontan palliation. We present the case of a patient with a Lateral tunnel Fontan palliation with leadless pacing system for symptomatic bradycardia in the setting of sinus node dysfunction. After internal review board approval, a retrospective case review was performed with follow-up of atrial leadless pacing in a patient with a Lateral tunnel Fontan. A 32-year-old male with a medical history of tricuspid atresia status post: Blalock-Taussig Shunt (BT) shunt, Glenn procedure, and Fontan surgery at 5 years of age presented with persistent atrial flutter and a history of symptomatic heart failure in the setting sick sinus syndrome with a dual chamber epicardial pacemaker procedure. After ablation of his intra-atrial re-entrant tachycardia he continued with symptomatic bradycardia in the setting of epicardial lead fracture. Implant values demonstrated an atrial threshold of 1 Volts (V) at 0.4 ms (ms), impedance at 820 ohms and sensing at < 1 mV. He was programmed AAIR (VVIR) 80-130 bpm, rate response of 2/7, and discharged on apixaban 5 mg twice a day. Follow-up at 4 months demonstrated no intracardiac thrombus, 98% atrial pacing, threshold of 0.75 V@0.15 ms, impedance of 590 ohms, and R-wave of 2.5 mV. The estimated device longevity was 17.2 years. Atrial leadless pacing is feasible in the lateral tunnel Fontan. Larger patient population data sets are needed to assess safety of this type of pacing long-term.

No reports on atrial leadless pacing have been demonstrated in patients with the extra-cardiac Fontan palliation. We present a case of a patient with an extra-cardiac Fontan and an alternative to pacing for symptomatic bradycardia in the setting of sinus node dysfunction. After internal review board approval, a retrospective case review was performed with follow-up of atrial leadless pacing in a patient with an extra-cardiac Fontan. A 19-year-old male with a medical history of dextro-transposition of the great arteries and valvar and sub-valvar pulmonary stenosis, hypoplastic pulmonary arteries, and an aberrant right coronary artery with eventual Glenn and Fontan palliation had intermittent sinus pauses with a failing epicardial pacemaker system. Given extremely low impedance values and eventual unipolar phrenic pacing after failed bipolar capture, he underwent an atrial pacing study and leadless pacemaker implant. Implant values demonstrated an atrial threshold of 5.5V at 0.4ms, impedance at 550ohms, and sensing at <1mV. He was programmed AAIR (VVIR) 60bpm and discharged on Xarelto 20mg once a day. Follow-up at 3 months demonstrated no intracardiac thrombus, 8% atrial pacing, threshold of 2.0V@0.4ms, impedance of 470ohms, and R-wave of 1mV. The estimated device longevity was 17.9 years at last follow-up. Atrial leadless pacing is feasible in the extracardiac Fontan patient from outside of the atrium with higher but acceptable capture threshold, without complication. Larger patient population data sets are needed to assess the safety of this type of pacing long-term.

BackgroundSingle chamber atrial pacing (AAI) provides a disease-specific treatment for sick sinus syndrome (SSS) but has largely been replaced by DDD pacing. With the advent of leadless atrial pacemakers (PM), there is growing interest in long-term follow-up data in patients with SSS and an AAI pacemaker.PurposeTo assess the incidence of system upgrade in patients treated with AAI-PM for SSS during long-term follow-up.MethodsThis is an analysis of prospectively enrolled patients undergoing implantation of an AAI-PM. Wenckebach block point (WBP) was measured at implantation and serially during follow up.ResultsWe included 178 patients (58% female, median age at implantation 77 [71–83] years). The median follow-up duration was 6.5 [2.0–9.7] years. Twenty-three patients (13%) received a system upgrade to a DDD system, corresponding to a yearly upgrade rate of 2.0%. Median time to system upgrade was 5.2 [1.6–8.7] years. Reasons for system upgrade were higher-degree AVB (39%), atrial arrhythmias (35%), low WBP (17%), and syncope (9%). Median WBP at implantation was 130 [120–140] bpm, showing a significant decline over time in the upgrade-group compared to the rest of the cohort with 103 [91–130] bpm vs. 130 [120–130] bpm (p = 0.011).ConclusionIn this cohort of patients undergoing AAI-PM implantation for SSS, upgrade to a DDD system was low during long-term follow-up. Therefore, AAI pacing for the treatment of SSS may be considered a patient-tailored treatment option, especially in light of novel leadless pacing therapies.Graphical abstractCentral Illustration: AF = atrial fibrillation; AT = atrial tachycardia; AVB = atrioventricular block; WBP = Wenckebach block point; AAI = single-chamber atrial stimulationSupplementary InformationThe online version contains supplementary material available at 10.1007/s10840-025-02061-4.

Shortness of breath in a patient with complete heart block and permanent pacemaker: A case of effective pacemaker reprogramming

To estimate the effectiveness and cost-effectiveness of dual-chamber pacemakers versus single-chamber atrial or single-chamber ventricular pacemakers in the treatment of bradycardia due to sick sinus syndrome (SSS) or atrioventricular block (AVB). Electronic databases and relevant Internet sites. Contact with device manufacturers and experts in the field. A systematic review was carried out of randomised controlled trials (RCTs). The quality of selected studies was appraised using standard frameworks. Meta-analyses, using random effects models, were carried out where appropriate. Limited exploration of heterogeneity was possible. Critical appraisal of economic evaluations was carried out using two frameworks. A decision-analytic model was developed using a Markov approach, to estimate the cost-effectiveness of dual-chamber versus ventricular or atrial pacing over 5 and 10 years as cost per quality-adjusted life-year (QALY). Uncertainty was explored using one-way and probabilistic sensitivity analyses. The searches retrieved a systematic review of effectiveness and cost-effectiveness published in 2002, four parallel group RCTs and 28 cross-over trials. Dual-chamber pacing was associated with lower rates of atrial fibrillation, particularly in SSS, than ventricular pacing, and prevents pacemaker syndrome. Higher rates of atrial fibrillation were seen with dual-chamber pacing than with atrial pacing. Complications occurred more frequently in dual-chamber pacemaker insertion. The cost of a dual-chamber system, over 5 years, including cost of complications and subsequent clinical events in the population, was estimated to be around 7400 pounds. The overall cost difference between single and dual systems is not large over this period: around 700 pounds more for dual-chamber devices. The cost-effectiveness of dual-chamber compared with ventricular pacing was estimated to be around 8500 pounds per QALY in AVB and 9500 pounds in SSS over 5 years, and around 5500 pounds per QALY in both populations over 10 years. Under more conservative assumptions, the cost-effectiveness of dual-chamber pacing is around 30,000 pounds per QALY. The probabilistic sensitivity analysis showed that, under the base-case assumptions, dual-chamber pacing is likely to be considered cost-effective at levels of willingness to pay that are generally considered acceptable by policy makers. In contrast, atrial pacing may be cost-effective compared with dual-chamber pacing. Dual-chamber pacing results in small but potentially important benefits in populations with SSS and/or AVB compared with ventricular pacemakers. Pacemaker syndrome is a crucial factor in determining cost-effectiveness; however, difficulties in standardising diagnosis and measurement of severity make it difficult to quantify. Dual-chamber pacing is in common usage in the UK. Recipients are more likely to be younger. Insufficient evidence is currently available to inform policy on specific groups who may benefit most from pacing with dual-chamber devices. Further important research is underway. Outstanding research priorities include the economic evaluation of UKPACE studies of the classification, diagnosis and utility associated with pacemaker syndrome and evidence on the effectiveness of pacemakers in children.

To the Editor

It is well known that during permanent ventricular pacing atrial arrhythmias and embolic complications occur much more frequently in comparison to permanent atrial or sequential pacing. Hemodynamic disturbances caused by ventriculoatrial conduction (VAC) are thought to be responsible for those complications. The aim of this study was to compare the left atrial size and its wall motion in three groups of patients with sick sinus syndrome. Group 1: 58 patients with VVI pacing and VAC observed (22 males, 36 females, aged 31-86, mean 62.3). Group 2: 43 patients with primary AAI pacing (13 males, 30 females, aged 27-74, mean 57.8). Group 3: 13 patients with AAI or DDD replacing the primary VVI mode due to pacemaker syndrome and/or heart failure, all with VAC present during VVI pacing (7 males, 6 females, aged 26-80, mean 59.8). Two-dimensional/M-mode echocardiography was performed in all these patients. In group 1 mean diastolic as well as mean systolic atrial diameters were significantly greater (P less than 0.005) and wall motion significantly smaller (P less than 0.005) in comparison to the other groups. Left atrial wall motion amounted to only 7.4% of the mean diastolic diameter in this group. Mean left atrial diastolic and systolic diameters and wall motion in patients with pacemakers preserving atrioventricular synchrony (group 2 and group 3) were almost identical and wall motion amounted to about 22% of the diastolic diameter in both these groups. We conclude that ventriculoatrial conduction leads to significant enlargement of left atrium and to the atrial wall-motion decrease. This predisposes to arrhythmias and embolic complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Deterioration of left ventricular ejection fraction and contraction synchrony during right ventricular pacing in patients with left bundle branch block

Patients with congenital heart disease are at increased risk for requiring cardiac pacing during their lifetime. We present the first described case of using two leadless pacing systems manufactured by separate companies implanted within the same patient to provide atrial and ventricular pacing due to complex congenital anatomy. A 27-year-old male with dextrocardia with double outlet right ventricle, subaortic ventricular septal defect, and pulmonary stenosis status-post pulmonary valve replacement complicated by ventricular pacing dependence and subsequent atrial pacing dependence after atriotomy-based atypical flutter ablation developed recurrent mediastinitis and pocket infection with erosion despite prolonged antibiotic treatment. Due to atrial and ventricular pacing dependence, a comprehensive congenital care team concluded the need for lead extraction and replacement of pacemaker via leadless peacemaking device. Laser-lead extraction and temporary atrial pacemaker placement was performed. Afterward, a transesophageal echocardiogram guided implantation of both a Micra AV 2 (Medtronic) leadless pacemaker in the interventricular septum within the right ventricle and an Aveir (Abbott) leadless pacemaker in the superior base of the right atrial appendage was performed with successful pacing. Although there is no communication between these devices, atrial-mechanical ventricular pacing was reliable with good implant thresholds, impedances and sensing from both devices. Our case demonstrates the feasibility of using dual leadless pacing modalities to simultaneously pace someone at complex, prohibitive risk for temporary permanent or permanent pacemaker devices.

Leadless Atrial Pacing Targeting Bachmann's Bundle for Atrial Resynchronization

Although atrial pacing is the most “physiological” pacing mode, pacemaker syndrome (PMS) may develope during this type of pacing. Our purpose was to demonstrate the presence of AAIR PMS by means of Holter monitoring. 54 pts (35 male, age: 38 - 79) underwent AAIR pacemaker implantation. Indication for pacing was sinus bradycardia in 38 pts, tacycardia-bradycardia syndrome in 16 pts. Antiarrhythmic drug treatment was applied only in pts with tachy-brady syndrome. Single chamber atrial pacemaker was implanted in 36 pts, while 18 pts received a dual chamber pacemaker programmed to AAIR mode. All the patient were regularly followed, and Holter monitorong, exercise test, and quality of life was evaluated at least once a year. Five pts developed permanent atrial fibrillation, the follow-up time of the remaining 49 pts was 7-74 months (mean 36 month). The exercise capacitiy and the quality of life improved in all patients, but 12/49 pts developed unexpected fatigue during heavy exercise. Holter monitorong was useful in the diagnosis: paradoxical sudden AV prolongation resulted in an AAIR pacemaker syndrome in these cases. Reducing the rate response could eliminate the symptoms in 9 pts, while the modification of antiarrhythmic treatment and reprograming the pacemaker was necessary in 3 other pts. Overprogramming (to high rate response) the pacemaker may result in AAIR pacemaker syndrome. Holter monitoring is a useful method in the diagnosis of AAIR pacemaker syndrome.

Leadless pacemakers were developed to reduce complications associated with transvenous pacemaker implant and long-term follow-up. Since initial market release, however, there have been registry and single-center reports documenting improvements in implant technique, reduced complication rates, and new patient populations studied. Most studies have demonstrated a further reduction in complication rates and safe implant in those on continuous anticoagulation. Perforation rates are decreasing but still occur and risk factors include BMI < 20kg/m2, age ≥ 85years, females, history of heart failure, indication not including atrial fibrillation, and chronic lung disease. Device infections are exceedingly rare, even in those undergoing infected transvenous devices at the same time. For appropriate patients, leadless pacing is a safe and reasonable option, especially if atrial-based sensing or pacing is not needed. Future iterations may include VDD pacing, atrial pacing, dual-chamber pacing, biventricular pacing, and device-device communication.

Introduction Until recently leadless pacemakers (PM) did not support atrial pacing. A novel dual chamber leadless PM system now provides treatment option for a wide range of indications. Single-chamber atrial stimulation (AAI) for the treatment of symptomatic sick sinus syndrome (SSS) is scarcely used due to concerns about the potential development of atrioventricular block (AVB) and development of paroxysmal atrial fibrillation (AF). Long-term follow-up data of AAI-PM is however scarce. Little is known about the role of serial Wenckebach block point (WBP) measurements in AAI-PM patients for risk stratification. Purpose To assess the incidence of dual chamber upgrade of patients treated with AAI-PM for SSS during long-term follow-up and to investigate the role of serial WBP measurements for risk stratification. Methods Prospectively enrolled patients undergoing implantation of an AAI-PM between October 2002 and December 2023. WBP was measured at implantation and serially during follow up. Results We included a total of 178 patients, of which 58% were female and the median age at implantation was 78 [IQR 71 – 83] years. The median follow-up duration was 6.5 [IQR 2.0 – 9.7] years. 24 patients (13.5%) received a system upgrade to DDD including 3 patients (1.7%) with a mode change to ventricular pacing only (VVI). Adjusted for years of follow-up the upgrade rate was 2.1% per year. Median time to system upgrade was 5.2 [IQR 1.6 – 8.7] years. Reasons for system upgrade were high-degree AVB (38%), low WBP (17%), atrial arrhythmias (33%), unclear syncope (8%) and infection (4%). Median WBP at implantation was 130 [120 – 140] bpm, showing a significant decline over time in the upgrade-group with 105 [95 – 130] bpm compared to the rest of the cohort with 130 [120-130] bpm (p = 0.009). A decline in WBP &amp;gt;20 bpm was found in 17.9% patients and a decline of 10-20 bpm in 33.7% of patients. New-onset atrial arrythmias were found in 36 patients (20%), 29% in the upgrade group and 19% in the rest of the cohort (p = 0.3). Neither age at implantation, sex, WBP at implantation, nor atrial arrhythmia prior to implantation were predictive for the need of a future system upgrade. Conclusion In this cohort of patients undergoing AAI-PM implantation for SSS, a system upgrade was required in 2% per year. The WBP remained stable in 48% of patients. Therefore, AAI-PM due to SSS emerges as a judicious and secure therapeutic modality, warranting increased consideration in the light of new treatment options for leadless pacing.

A 51-year-old woman underwent implantation of a dual chamber pacemaker 10 years ago, for symptomatic intermittent second-degree type II AV block. She remained free of symptoms during follow-up. Recently, she underwent pacemaker replacement because of battery depletion (Adapta ADDR01, Medtronic Inc., Minneapolis, MN, USA). Given intact AV conduction at the time of intervention, the Managed Ventricular Pacing mode algorithm (MVP, Medtronic), which provides AAI(R) pacing with ventricular monitoring and backup DDD/R pacing as needed, was programmed with a lower rate limit of 60 ppm and an upper rate limit of 130 ppm. Ten days after the procedure, the patient complained of asthenia, dyspnea, and presyncope. ECG at pacemaker interrogation revealed sinus tachycardia with second-degree type II AV block (Fig. 1). Atrial pacing artifacts with atrial capture are seen dissociated from the native QRS complexes. Pacemaker interrogation revealed pacing and sensing thresholds as well as impedances within normal range. In our patient, the repetitive atrial pacing during ventricular systole led to pacemaker syndrome and symptoms resolved by reprogramming the device to AV sequential pacing without MVP. What is the mechanism of atrial stimulation dissociated from the native QRS complexes?