Permanent Cardiac Pacing Research Articles

Recurrence rate and predictors in non-ischemic reversible bradyarrhythmias.

Non-ischemic symptomatic reversible bradyarrhythmia is a poorly characterized yet common clinical challenge. This study aimed to assess the incidence and predictors of recurrence and the need for permanent cardiac pacing in patients with non-ischemic symptomatic reversible bradyarrhythmia. This prospective single-center study enrolled 124 consecutive adult patients with non-ischemic symptomatic reversible bradyarrhythmia who were followed up for up to 24 months after conservative management during index hospitalization. The primary endpoint was a recurrence of bradyarrhythmia requiring permanent cardiac pacing. The secondary endpoint was a composite of recurrence requiring permanent pacing, readmission, or death. Univariate and multivariate analyses were conducted to determine the predictors of the endpoints. Sinus node and atrioventricular node diseases were seen in 66.1% and 33.9% of patients, respectively. The most common causes of bradyarrhythmia were negative chronotropic drugs (58.1%) and hyperkalemia (55.6%). Permanent pacing was required in 21.8% of patients after a recurrence. Advanced atrioventricular block at presentation (HR: 6.10, 95% CI: 2.45-15.20, p < 0.001) and bifascicular block at discharge (HR: 3.63, 95% CI: 1.58-8.33, p = 0.002) during index hospitalization were significant independent predictors of recurrence requiring cardiac pacing. Non-ischemic symptomatic reversible bradyarrhythmia is associated with a high risk of recurrence. Permanent cardiac pacing should be considered during index hospitalization in patients with advanced atrioventricular block and/or bifascicular block.

Atrial standstill in a young patient treated with left bundle branch area pacing

Abstract Atrial standstill is a rare arrhythmogenic condition characterized by the absence of electrical and mechanical activity in the atria. The therapeutic options for these patients described in the current literature, in which no reversible cause is detected, are permanent cardiac pacing, anticoagulant, and heart failure treatment when the latter exists. We present a case of a young male with no personal or family history of cardiovascular disease, diagnosed with atrial standstill after multiple syncopal episodes, in whom, because of the high expected ventricular pacing percentage, we opted for conduction system pacing with left bundle branch area pacing.

LV systolic function assessment in conventional cardiac pacing: a simple and forgotten parameter - MAPSE

Abstract Background Mitral annular plane systolic excursion (MAPSE) was a widely used M-mode echocardiographic marker of left ventricular longitudinal systolic function. On the other hand, right ventricle (RV) apical pacing is associated with left ventricle (LV) dysfunction development due to dysynchronous activation, while non-apical pacing may provide a more physiological LV activation. The aim of this study is to ascertain the clinical usefulness of MAPSE in the assessment of LV contractile function in patients with permanent RV pacing. Methods Consecutive patients with indication for permanent cardiac pacing (with ventricular pacing percentages over 20% - Vp&amp;gt;20%) were retrospectively enrolled from 2019 to 2023. All patients were assessed by echocardiography with MAPSE, left ventricule ejection fraction (LVEF) and diastolic filling patterns being measured at the time of implant and at subsequent follow-ups. Results 359 patients (age range 41-80yo; mean age=60,5yo) were included, 244 men and 115 women, 173 implanted with single-chamber devices and 186 dual-chamber. 259 patients were paced from the RVA (right ventricle apex) and 62 had septal lead positioning. The mean follow-up period was 18±2 months. The results showed that a MAPSE cut off value of ≤10 mm was associated with a LVEF&amp;lt;42±2%, while MAPSE values &amp;gt;10mm were associated with LVEF&amp;gt;45±3% (p&amp;lt;0.01). RV septal pacing was associated with a higher average MAPSE value (14,28 mm) than RVA pacing (13,47). Conclusions MAPSE seems to corelate well with LVEF in RV conventional pacing. Younger patients with preserved LVEF and less than grade II diastolic dysfunction were not associated with a significant decrese in MAPSE value. However, older patients with HFmrEF and RVA pacing seem to have a more substantial reduction in MAPSE value, suggesting that non-apical or conduction system pacing might be beneficial in this subgroup. MAPSE seems to be a quick and reliable echocardiographic marker of LV systolic function in patients with permanent cardiac pacing. It may be used as an early predictive marker for heart failure in conventional RV paced patients.

Permanent epicardial pacing : a first line strategy in children

Abstract Background Permanent cardiac pacing in paediatric patients remains a challenge. According to the European Paediatric and Congenital Society (AEPC) recommendations, below 20 kg epicardial implantation is preferred, while above 20 kg endocardial implantation is given priority unless specific contraindication. In the literature, a weight at 15 kg is also found to be the minimal weight above which an endovascular implantation is considered. However, endovascular systems have been reported to be associated with a high risk of complications. Recent improvements in epicardial leads technology have significantly improved pacing thresholds (1-3), battery life and reduced the risk of re-intervention for epicardial lead dysfunction (4,5). Purpose The aim of the study is to evaluate the long-term results and efficacy of epicardial pacing in children and to investigate risk factors for epicardial lead dysfunction. Method We performed a retrospective, single-centre analysis of consecutive patients aged ˂18 years implanted with an epicardial PM between 2004 and 2020. The data collection included initial pacing parameters, at 1 month, 1 year, 2 years, and at last follow-up, as well as occurrence of early and late complications. Results A total of 101 patients (93 atrial and 131 ventricular epicardial) were analysed. The mean follow-up time was 6.2 years (range 2 days to 16.9 years). Median age at implantation was 4.2 years (IQ 0.3-8.8 years), median weight was 15.2 kg (IQ 5.2-28.0 kg). Congenital heart disease (CHD) was recorded in 59,4% of patients. Reasons for implantation were postoperative complete atrioventricular block (AVB) (40.6%), congenital AVB (37.6%), sinus dysfunction (7.9%), complete AVB with heart disease without surgery (7.9%), others (4%). Four patients had a system infection resulting in device extraction and reimplantation. The mortality rate was 15.8%, but no deaths was directly related to PM implantation or dysfunction. Detection values, impedances were stable over time, and the and average pacing thresholds remained ˂0,98±0,81 volt in the atrium and ˂ 1.57±0,89 volt in the ventricle. Lead survival was 96,7%, 90,7%, 82,3%, 74,5% at 1, 5, 8 and 10 years. The presence of CHD, weight ˂15kg, dual chamber implantation, implantation for postoperative BAV were not significant risk factors for lead dysfunction. In the group of patients implanted above 15kg the presence of a CHD significantly increased the risk of lead dysfunction (p=0.037) and all-cause reimplantation (p=0.010). In the group implanted above 15kg without any cardiopathy, the survival rate without lead dysfunction at 5 and 10 years was 100% and 90.9% respectively. Conclusion Epicardial pacing in children with steroid-eluting leads shows good long-term results with stable pacing parameters and good survival from lead dysfunction. For children implanted at a weight above 15 kg and without cardiopathy results with epicardial stimulation were excellent.Epicardial lead survival

Permanent Cardiac Pacing of the Right Ventricular Outflow Tract Guided by Real-time Assessment of Electromechanical Synchrony.

Permanent right ventricular apical pacing deteriorates cardiac systolic function in some patients. We investigated an alternative site for permanent pacemaker (PPM) lead positioning with the goal of achieving more physiological pacing. A total of 132 patients with bradyarrhythmias underwent PPM implantation at the right ventricular outflow tract (RVOT) with conventional active-fixation leads. A real-time cross-correlation analysis (CCA) was performed using the Synchromax® software (EXO Health, Seattle, WA, USA) to determine the optimal site for ventricular lead implantation based on the cardiac synchrony index. The follow-up period ranged from 6-36 months, and the following parameters were assessed: pacing capture threshold, lead stability, and the need for lead repositioning. Adequate parameters were achieved in 129 patients (98%), and there were no procedure-related complications. At follow-up, no leads were dislodged, pacing thresholds remained stable, and no lead required repositioning. Using real-time CCA as an intraoperative parameter during PPM implantation at the septal RVOT helps to achieve cardiac synchrony in the vast majority of cases. This technique is a simple, effective, and safe way to simplify and standardize PPM implantation at the RVOT.

Outcomes of left bundle branch area pacing compared to His bundle pacing and right ventricular apical pacing in Japanese patients with bradycardia.

His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) emerge as better alternatives to right ventricular apical pacing (RVAP) in patients with bradycardia requiring permanent cardiac pacing. We aimed to compare the clinical outcomes of LBBAP, HBP, and RVAP in Japanese patients with bradycardia. A total of 424 patients who underwent successful pacemaker implantation (HBP, n = 53; LBBAP, n = 75; and RVAP, n = 296) were retrospectively enrolled in this study. The primary study endpoint was the cumulative incidence of heart failure hospitalization (HFH) during the follow-up. The success rate for implantation was higher in the LBBAP group than in the HBP group (94.9% and 81.5%, respectively). Capture threshold increase >1V during the follow-up occurred in the HBP and RVAP groups (9.4% and 5.1%, respectively), while it did not in the LBBAP group. The cumulative incidence of HFH was significantly lower in the LBBAP group than the RVAP (adjusted hazard ratio, 0.12 [95% confidence interval: 0.02-0.86]; p = .034); it did not differ between the HBP and RVAP groups (adjusted hazard ratio, 0.48 [95% confidence interval: 0.17-1.34]; p = .16). Advanced age, mean percent right ventricular pacing (per 10% increase), left ventricular ejection fraction <50%, and RVAP were associated with HFH. Compared to RVAP and HBP, LBBAP appeared more feasible and effective in patients with bradycardia requiring permanent cardiac pacing.

The lead implantation into the cardiac conduction system for permanent cardiac pacing: intraoperative visualization techniques

The cardiac conduction system pacing is a promising method of cardiac pacing. The thematic review highlights the issues of modern additional methods of intraoperative visualization, their advantages and limitations. The availability of additional intraoperative visualization techniques in complex situations and during the training phase is of great help. Their use makes it possible to reduce the number of false septal implantations, complications, and radiation exposure to the operator.

НАРУШЕНИЕ ПРОХОДИМОСТИ ВЕН ВЕРХНИХ КОНЕЧНОСТЕЙ У ПАЦИЕНТКИ С ПОКАЗАНИЯМИ К ИМПЛАНТАЦИИ ЭЛЕКТРОКАРДИОСТИМУЛЯТОРА (КЛИНИЧЕСКИЙ СЛУЧАЙ)

Today, permanent cardiac pacing is the most effective way to correct bradyarrhythmia. Most pacemaker leads are implanted through the veins of the upper extremities. Common vein access involves either a cephalic vein cutdown or a puncture of the subclavian or axillary veins. Implantation of leads may become technically difficult or unfeasible if there is an anomaly in the structure of the veins or, more often, occlusion/stenosis of the veins of the upper extremities after thrombosis. The article presents It is illustrated with the case of a 75-year-old patient with indications for pacemaker implantation presented by the article. The first implantation attempt was unsuccessful: extensive occlusion of the left subclavian vein (SCV) and stenosis of the right SCV were detected. The venous obstruction was asymptomatic. The patient underwent venography and was diagnosed with up to 90% luminal narrowing of the right SCV. Percutaneous transluminal angioplasty of the right SCV was performed; the residual stenosis was 50%. Subsequently, a dual-chamber pacemaker was successfully implanted into the patient; the postoperative period was uneventful. The vein obstruction could be related to a history of malignant neoplasm of the uterus. A brief literature review of various types of vascular access for pacemaker implantation and alternative implantation options complements the case report. Keywords: Pacemaker, venous thromboembolic complications, deep vein thrombosis, deep vein stenosis, angioplasty.

Current Role of Conduction System Pacing in Patients Requiring Permanent Pacing.

His bundle pacing (HBP) and left bundle branch pacing (LBBP) are novel methods of pacing directly pacing the cardiac conduction system. HBP while developed more than two decades ago, only recently moved into the clinical mainstream. In contrast to conventional cardiac pacing, conduction system pacing including HBP and LBBP utilizes the native electrical system of the heart to rapidly disseminate the electrical impulse and generate a more synchronous ventricular contraction. Widespread adoption of conduction system pacing has resulted in a wealth of observational data, registries, and some early randomized controlled clinical trials. While much remains to be learned about conduction system pacing and its role in electrophysiology, data available thus far is very promising. In this review of conduction system pacing, the authors review the emergence of conduction system pacing and its contemporary role in patients requiring permanent cardiac pacing.

Comparative evaluation of permanent cardiac pacing modes in patients with arrhythmic variant of coronary artery disease (bradyarrhythmia)

Aim – to analyze and compare the results of permanent cardiac pacing therapy in patients with arrhythmic variant of coronary artery disease (CAD) (grade II – III AV block and sinus node weakness syndrome).&#x0D; Material and methods. We studied the results of examination of 63 patients with arrhythmic variant of coronary artery disease (sinus node weakness syndrome and AV block), who received pacing therapy in VVI and DDD modes in the Department of Rhythm and Conduction Disorders of the Republican Clinical Hospital No. 4. All patients underwent clinical, laboratory and instrumental tests in accordance with federal clinical guidelines for CAD, rhythm and conduction disorders.&#x0D; Results. The left ventricular ejection fraction (LVEF) in patients with pacemakers in VVI mode was 9% lower when compared to LVEF in DDD mode. Mitral regurgitation was 47.6% more common in patients having VVI mode than DDD mode. In patients with the VVI regimen, the interventricular septal asynchrony was 25.1% more common and was accompanied by more pronounced left ventricle hypertrophy and dysfunction. Pacemaker syndrome was observed in 3 (7.5%) patients with VVI stimulation mode, stopped by reimplantation of a two-chamber frequency–adaptive pacemaker, and in 1 (4.35%) patient with DDD mode, eliminated by reprogramming.&#x0D; Conclusion. In patients with coronary artery disease, the effectiveness of pacing in correction of the cardiac rhythm and conduction depends on the treatment mode. Disorders of myocardial contractility are more pronounced in patients with VVI mode, if compared to DDD mode.

Permanent pacemaker implantations among patients with spinal cord injury in the United States

Abstract Background Acute spinal cord injury (SCI) is associated with severe cardiovascular complications. Information regarding the need for permanent cardiac pacing in SCI patients is scarce and based on case reports and small case series. We aimed to investigate the extent of permanent pacemaker (PPM) implantation procedures as well as to identify predictors for PPM insertion among SCI patients in a U.S contemporary, nationwide, all-comer registry. Methods Using the National Inpatient Sample (NIS) database, patients hospitalized with a primary diagnosis of SCI in the US between 2016-2019 and underwent PPM implantation were identified. Patients with cardiac implantable electronic device in-situ were excluded. Baseline demographics, clinical characteristics, injury type, in-hospital procedures and outcomes including time to PPM implantation, length of stay and mortality were collected. Outcome analysis performed after propensity score matching (PSM). Predictors of PPM implantation were identified via a multivariable logistic regression model. Results A total of 35880 patients, were hospitalized with a primary diagnosis of SCI during the study period, and 240 (0.7%) received a PPM. Median age of patients receiving PPM was 69 years, 75% were males, and 67% had high level SCI injury (level C1-5). Time to PPM implantation was 9 days (IQR 4-19). PPM implantation was associated with higher rates of cervical spine injuries, traumatic brain injury (TBI), chest and upper limbs injuries, respiratory failure and other signs of severe illness. Longer hospital stay and higher in-hospital mortality rate was observed in patients receiving a PPM. Multivariate analysis identified the following independent risk factors for PPM implantation: cervical SCI [OR 77.07 (11.13-553.42), p&amp;lt;0.001], TBI [OR 3.84(1.59-9.28), p=0.003] and tracheostomy/respiratory ventilation&amp;gt; 96 h [OR 31.766(7.91-127.54), p=&amp;lt;0.001]. Conclusion Cervical SCI, need for tracheostomy and prolonged mechanical ventilation were the strongest predictors for PPM implantation in patients hospitalized for SCI in a nationwide registry.

Possibilities of the merge technique for intraoperative imaging in a lead implantation into the cardiac conduction system for permanent cardiac pacing: interim results of the study

Introduction. A lead implantation into the cardiac conduction system (CCS) is currently the most physiological method of pacing. However, despite the availability of specialized lead and delivery systems, the proportion of non-targeted implantations is very significant. There is a need for an intraoperative visualization technique. The lead position is monitored by electrophysiological and fluoroscopic methods, which, obviously, are not enough.Aim: To optimize the implantation of leads in the conduction system of the heart through the use of intraoperative merge visualization technique (IVT).Material and methods. Two study groups are formed as part of the protocol of a prospective study. In the patients of the study group leads were implanted into the CCS using the IVT; in the control group - by traditional method. After implantation, in all patients the position of the lead using a transthoracic echocardiography (TTE), ECG was assessed. Computed tomography (CT) was performed in patients of study group before and after implantation. In patients of control group CT was performed after implantation.Results. The full study protocol was completed in 10 patients of the study group and in 10 patients of the control group. All patients of the study group confirmed the lead implantation into the interventricular septum (IVS) using TTE and CT; into the CCS using ECG. The duration of the surgery was 87.5 [70; 120] min, fluoroscopy time – 225 [125; 421] sec. Complications, non-target implantations were not registered. In the control group, the duration of the surgery was 100 [100;110] min, the time of fluoroscopy was 775 [500;1230] sec.; stimulation of the CCS was confirmed in 4 (40%) patients; recorded 2 (20%) cases of perforation of the IVS, 1 (10%) case of implantation in the area of the apical part of the right ventricle, 1 (10%) intraoperative dislocation of the right ventricular lead, 1 (10%) case of hemopericardium in the early postoperative period. The average measurement error according to the intraoperative imaging technique compared with MSCT: the distance from the LV endocardium to the lead was 0.98 ± 0.51 mm, the distance from the lead to the tricuspid valve ring was 3.1 ± 0.92 mm. According to trans-thoracic echocardiography, there weren’t structural and functional changes in the tricuspid valve, newly emerged local areas of the myocardium with impaired contractility were detected in patients of the two groups. There weren’t significant changes in sensitivity thresholds, stimulation, and postoperative dislocations of the leads.Conclusions. The use of IVT allows to reduce the number of “off-target” implantations, the time of fluoroscopy, the radiation exposure of the operator and the duration of the surgery.

Ganglionated plexi ablation in the right atrium for the treatment of cardioinhibitory syncope.

Neurocardiogenic syncope, also called vasovagal syncope, represents one of the clinical manifestations of neurally mediated syncopal syndrome. Generally, the prognosis of the cardioinhibitory form of neurocardiogenic syncope is good, but quality of life is seriously compromised in patients who experience severe forms. Drug therapy has not achieved good clinical results and very heterogeneous data come from studies regarding permanent cardiac pacing. In this scenario, the ganglionated plexi ablation has been proposed as an effective and safe method in patients with cardioinhibitory neurocardiogenic syncope, especially in young patients in order to avoid or prolong, as much as possible, the timing of definitive cardiac pacing. Certainly, making this procedure less extensive and limiting the ablation in the right atrium (avoiding the potential complications of a left atrial approach) and at level of anatomical regions of the most important ganglionated plexy, considered 'gateway' of the sino-atrial and atrio-ventricular node function (through the recognition of specific endocardial potentials), could be very advantageous in this clinical scenario. Finally, randomized, multicentre, clinical trials on a large population are needed to better understand which is the best ablation treatment (right-only or bi-atrial) and provide evidence for syncope guidelines.

The reuse of cardiac pacemakers and defibrillators: A convoluted history in an era of global health.

Following the development of permanent transvenous cardiac pacing in the 1960s, the costs of pacemakers quickly led to their reuse in both developed countries and in low-and middle-income countries (LMIC). Legal, ethical, and industrial factors gradually resulted in the termination of reuse in developed countries. Without health care budgets to pay for costly pacemaker technologies, nongovernmental organizations (NGOs), and other groups have provided support to physicians and hospitals treating patients with heart block in LMICs. Multiple other academic and private groups have also assisted such patients in LMICs. Pacemaker companies have provided physicians and hospitals with new devices (that have an expired package date or through charitable donations). Greater care of preparing and cleaning refurbished devices have demonstrated overwhelmingly the safety and effectiveness of reused devices. More recently, cardiac resynchronization therapy and implantable cardioverter-defibrillatorshave also been reused in patients in LMICs. While the globalization of noncommunicable diseases continues, patients with rhythm disorders in LMICs can no longer be left behind. While patients in developed countries only receive new devices to treat rhythm disorders, the practice of reused cardiac implantable electronic deviceswill expand in LMICs, until equal access to device technologies be made available to all.

The hybrid permanent cardiac pacing in a patient with high infection risk

Infective complications of permanent cardiac pacing severely influence long-term outcomes despite system removal and targeted antibiotics. In-hospital mortality reaches 4,6 % and 1-year 14-17%. A case of a 68-year-old patient was described. The patient suffered from infective endocarditis, which caused the extraction of a formerly implanted standard dual-chamber pacemaker and insertion of bioprosthesis of the aortic valve and epicardial DDD system implantation. After 9 years during follow-up increase of impedance and threshold on ventricular lead have been observed. Due to temporal pacemaker dependency, the decision was made to implant a leadless MICRA AV device with preservation of active atrial pacing through an epicardial DDD system programmed to AAI mode. No procedural complications were observed. There was no electrical interference between implanted systems.

High-pass filter settings and the role and mechanism of discrete ventricular electrograms in left bundle branch pacing.

The characteristics of discrete intracardiac electrogram (EGM) in selective left bundle branch (SLBB) pacing (SLBBP) have not been described in detail previously. This study aimed to examine the effect of different high-pass filter (HPF) settings on discrete local ventricular components in an intracardiac EGM and to analyze its possible mechanisms. This study included 144 patients with indications of permanent cardiac pacing. EGMs were collected at four different HPF settings (30, 60, 100, and 200 Hz) with a low-pass filter at 500 Hz, and their possible mechanisms were analyzed. LBBP was successfully achieved in 91.0% (131/144) of patients. SLBBP was achieved in 123 patients. The occurrence rates of discrete local ventricular EGM were 16.7, 33.3, 72.9, and 85.4% for HPF settings of 30, 60, 100, and 200 Hz, respectively. The analysis of discrete EGM detection showed significant differences between the different HPF settings. By using the discrete local ventricular component and isoelectric interval as the SLBB capture golden standard, the results of EGMs revealed that the 30 Hz HPF has a sensitivity of 19% and specificity of 100%. The 60 Hz HPF had a sensitivity of 39% and a specificity of 100%. The 100 Hz HPF had a sensitivity of 85% and a specificity of 100%. The 200 Hz HPF had a sensitivity of 100% and specificity of 100%. An optimal HPF setting of 200 Hz is recommended for discrete local ventricular EGM detection. A discrete local ventricular EGM should exhibit an isoelectric interval. A steep deflection and high-frequency ventricular EGM morphology nearly identify an intrinsic EGM morphology.

Eligibility of patients with temporary paced rhythm for a subcutaneous implantable cardioverter-defibrillator.

A concomitant use of a pacemaker and a subcutaneous implantable cardioverter-de-fibrillator (S-ICD) may be required in some patients. Our study aimed to evaluate the influence of permanent cardiac pacing on the morphology of the QRS complex in the context of S-ICD screening. One hundred patients with cardiac electronic implantable devices (CIEDs) were included in whom S-ICD screening could be performed both during intrinsic and paced rhythm. The positive result of screening during spontaneous rhythm for at least one vector (in both supine and standing positions) was obtained in 80% and for 2 vectors in 59% of patients. Positive screening during paced rhythm for at least one vector was recorded in 36% of patients (78% right ventricular and 22% biventricular pacing) and for 2 vectors in 15% of patients (93% right ventricular and 7% biventricular pacing). At least one vector acceptable during both types of rhythm and in both positions was recorded in 23% of patients and at least 2 vectors in 8% of patients. The use of S-ICD in patients with paced ventricular rhythm is associated with a serious risk of inappropriate sensing due to different QRS morphology during intrinsic and paced rhythm, and it is particularly high in patients in whom periods of spontaneous rhythm interchange with periods of ventricular pacing. That risk has been hardly acknowledged in available reports, but according to our data, it is significant, and therefore it should be considered during S-ICD screening.

Study of Electrophysiological Properties of Atrioventricular Node in Permanent Cardiac Pacing under Influence of Trimetazidine Dihydrochloride

INTRODUCTION: Dual-chamber cardiac pacing permits to maintain permanent atrial-ventricular synchronization. Physiological sequence of propagation of the impulse from atria to ventricles is provided with an artificial delay analogous to delay of propagation of excitation through the atrioventricular (AV) node of a heathy individual. The delay interval is formed so that to minimize stimulation of the right ventricle. This preserves the left ventricular ejection fraction, reduces the risk of development of the chronic heart failure (CHF) and of atrial fibrillation, and increases functional abilities of the patient. On the other hand, critical increase in the atrioventricular delay leads to pacemaker syndrome: impairment of circulation function, shortness of breath, reduced tolerance to exercise, dizziness, syncopal state. The question of the influence of the permanent electrical pacing on the AV node conduction remains unsolved.&#x0D; AIM: To study the effect of trimetazidine dihydrochloride on the AV node conduction in conditions of permanent cardiac pacing, to determine the effect of cardiac pacing on the AV node in the studied time period.&#x0D; MATERIALS AND METHODS: The study involved 86 patients. The AV node activity was assessed by antegrade intraoperative determination of Wenckebach point on the basis of electrocardiography data in 2448 hours after pacemaker implantation, in 68 hours, 7, 14, 9 and 180 days after intake of trimetazidine dihydrochloride and in 7, 14, 21 and 30 days after its cancellation. To compare the extent of influence of the studied drug on the AV node activity, the patients were divided to three groups depending on the basic pathology: group 1 ― patients with the sick sinus node syndrome (n = 38, 44.2%); group 2 ― patients with II degree AV block (n = 25, 29.1%); group 3 ― patients with III degree AV block (n = 23, 26.7%).&#x0D; RESULTS: Trimetazidine dihydrochloride improved the electrophysiological properties of the AV node in the first and second groups: increase in the mean value of Wenckebach point antegrade in the first group was in total 3.26% (р = 0.022), in the second group 4.68% (р = 0.001). In the third group of patients no improvement was noted, but it should be said that under the action of this drug, in 4 of 23 patients with III degree AV block, antegrade AV conduction appeared (р = 0.236).&#x0D; CONCLUSION: Trimetazidine dihydrochloride has a positive effect on the AV node activity as early as in 68 hours of intake, which reaches maximum in 3 weeks. Cardiac pacing had no effect on AV node within the follow-up period (6 months).

Physiological vs. non-physiological heart pacing as assessed by ultra-high-frequency ECG

Abstract Background The dyssynchrony related to permanent cardiac pacing is the main reason for heart failure in some patients. Physiological pacing techniques as His bundle pacing (HBP), left bundle branch pacing (LBBP), and left ventricular myocardial septal pacing (LVSP) were shown to improve clinical outcomes in patients with pacemakers. Due to specific lead placement in the area close to conductive tissue, several different ventricular capture types are possible during them. Method We studied the effect of these pacing modalities on ventricular synchrony using ultra-high-frequency ECG (UHF-ECG), which is a novel tool for ventricular depolarization visualization. Several parameters of dyssynchrony were calculated and compared between studied ventricular capture types. Results We showed ventricular depolarization during nonselective HBP to be equivalent to selective HB pacing. Next, we demonstrated the nonselective HBP in the area below the tricuspid valve leads to the best interventricular synchrony from all other RV pacing locations. We also compared UHF-ECG-derived parameters of ventricular depolarization during HBP, LBBP, and LVSP, and we showed that both pacing types from the left septal area are less physiological than HBP. nsLBBP and sLBBP deteriorate interventricular dyssynchrony, and LVSP leads to less physiological left ventricular depolarization than HBP. Conclusion UHF-ECG is an effective tool that can be used in clinical practice to assess the electrical dyssynchrony caused by cardiac pacing. Furthermore, its real-time implementation allows recognizing between physiological vs. non-physiological pacing during an implant procedure. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic

Mobitz type I 2nd degree atrioventricular (Wenckebach) block and cardiovascular death using 978,901 12 lead ECGs recordings

Abstract Background Mobitz type I 2nd degree atrioventricular (AV) block (Wenckebach) is usually considered benign. Guidelines recommend permanent cardiac pacing for patients with Mobitz type II second degree AV block (Mobitz II), but for patients with Wenckebach, permanent pacing is only indicated if the AV block causes symptoms or if the conductions delay occurs below the bundle of His. However, these guidelines are based on evidence of modest quality and a consensus amongst experts (1). Purpose This study aims to investigate if Wenckebach really is benign by comparing the risk of cardiovascular death for patients with Wenckebach to patients with normal ECGs. Methods This retrospective cohort study included 978,901 ECGs obtained from general practitioners in Denmark from 01/02/2001 to 31/10/2014. Index date was the day of the ECG recording and the patients were followed until death or end of follow up at December 2019. The association between Wenckebach and cardiovascular death was analyzed using: 1) multivariate Cox models adjusted for age and comorbidities, 2) cause-specific Cox models and 3) cumulative risk and cause-specific hazard function plots, compared to matched controls. Information about comorbidities, pacemaker, indications, and death was retrieved from Danish nationwide registries. Results From the 978,901 ECG recordings, we found 262 patients with Wenckebach, 131 patients with Mobitz II, and 229,056 patients with normal ECGs. In Wenckebach, Mobitz II, and normal ECG the median age was 76, 80, and 50 years, 76%, 63%, and 41% were male, 25%, 16%, and 3% had diabetes, 35%, 30%, and 8% had hypertension, respectively. During a mean follow-up of 11.2 years, cardiovascular death occurred in a total of 11,301 patients: 77 (29%) patients with Wenckebach, 40 (31%) patients with Mobitz II, and 11,184 (5%) patients with normal ECGs. In a matched cohort 262 Wenckebach patients were matched with 520 controls with normal ECGs. In the multivariate Cox model, Wenckebach was associated with cardiovascular death (HR: 2.14 [95% CI: 1.46–3.13], P&amp;lt;0.001). Furthermore, in multivariate cause-specific Cox analysis with non-cardiovascular death and pacemaker as competing risk, Wenckebach was still associated with cardiovascular death (HR: 2.27 [95% CI: 1.37–3.75], P=0.001). Furthermore, the results showed that 43% of the Wenckebach patients received pacemaker with a median time to pacemaker from ECG recording being 252 days. The vast majority of the Wenckebach patients who received pacemaker had a higher degree AV block than Wenckebach as indication for the implantation. Conclusion Wenckebach on routine ECG was associated with a significant higher hazard rate of cardiovascular death compared to matched controls with normal ECGs. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Danish Heart Association