VVI Mode Research Articles

Inadvertent higher rate atrial pacing after dual chamber pacemaker implantation - what is the underlying mechanism?

Unexplained change in parameters, despite good lead positions or odd ECG patterns following implant should lead to suspicion of lead swap, amongst other possibilities. An easy way to confirm this is by paying careful attention to device EGMs and recording the ECG by switching off one channel, and pacing single channel (in either AAI or VVI mode).

Abstract Or118: Transcription Factor Gene Therapy for Treatment of Junctional Bradycardia in a Porcine Model of Complete Atrioventricular Block Following His Bundle Ablation

Background: Pacemaker implantation is standard treatment for patients with complete atrioventricular (AV) block. However, contraindications for device implantations create a need for alternative non-hardware cardiac pacing solutions. We developed a porcine model of complete heart block with junctional bradycardia to test a novel transcription factor-based gene therapy consisting of Tbx18, Shox2 and Tbx3 (TST). Somatic reprogramming of ventricular cardiomyocytes by TST induces pacemaker-like activity and provides biological pacing in vitro . Methods: Eight domestic swine (Yorkshire/Landrace) received catheter ablation of the AV node/His Bundle resulting in complete AV block, confirmed by dissociation of P and R waves on ECG. An implanted device pacemaker (VVI mode) maintained cardiac output during occurrences of junctional bradycardia below 50 bpm. Telemetric 3-lead ECG was recorded continuously. Subjects received TST gene therapy or control gene (GFP) via catheter-based intramuscular injection into the high right ventricular septum. Pacemaker usage and ECG were continuously monitored for 8 weeks. Results: Following AV node ablation, junctional escape rhythm decelerated into junctional bradycardia. After 3 weeks of AV block, 49.9 ± 13.1% of heartbeats were initiated by the device pacemaker. Upon reaching pacemaker dependence of 95% in an average of 27.9 ± 5.5 days, subjects received TST gene therapy or control injection. In subjects receiving TST therapy, daily pacemaker reliance decreased to 50% dependency in an average of 14.7 ± 2.3 days, while in GFP controls, daily pacemaker dependency at 50 bpm remained unchanged at >98% throughout follow-up. In TST-treated subjects, reductions in pacemaker dependence were associated with increases in ventricular rates exceeding 70 bpm. Efficacy of gene therapy waned after about one month; an improvement of >10% pacemaker dependency over two consecutive days was still observed on average 29.0 ± 4.1 days after TST injection. Conclusion: In a porcine model of complete AV block, ventricular junctional escape rhythm decelerated into bradycardia in less than one month. Subsequent gene therapy by TST injection into the high ventricular septum alleviated pacemaker dependency and enhanced heart rate for 29.0 ± 4.1 days. Somatic reprogramming of cardiomyocytes by TST gene delivery may provide a biological pacemaker alternative to hardware device implantation for therapeutic cardiac pacing.

Expérience du Sénégal sur les pacemakers reconditionnés : à propos de 161 patients au centre hospitalo-universitaire Aristide Le Dantec

IntroductionThe reuse pacemakers is a beneficial technique for patients in countries with a low economic standard of living where health care is almost non-existent. We offered to share the experience of Senegal on the reconditioning of pacemakers. MethodologyWe conducted a retrospective study over a period from January 2015 to December 2020 including all patients who benefited from a reconditioned pacemaker for primary implantation or reimplantation. The criteria for reconditioning pacemakers are the absence of dysfunction or damage and a residual battery life of more than 5 years of the pacemaker. Refurbished pacemakers are acquired either from deceased families or from extraction centers. Sterilization is carried out using phenoxypropanol + benzalkonium chloride solution, 70% ethanol and ethylene oxide. ResultsWe collected 161 patients during the study period, including 77 men (48%) and 84 women (52%), i.e. a M/F sex ratio of 0.94. The average age of the population was 65 years. Functional symptomatology was dominated by syncope in 54%. Electrocardiographically, 72% of patients were in complete atrioventricular block. A primary implantation was noted in 91.5% of patients. The vascular approach most used during implantation was cephalic in 49.5% of cases. In our series, we noted that 58% of patients had benefited from temporary stimulation before implantation. At implantation, single-chamber stimulation was used in 60% of patients and 46.5% of patients had programming in VVI mode. We had 5.5% major complications with 3% box infection occurring between 3 and 6 months post-implantation and 2.5% pacemaker syndrome. We noted 1 case of death linked to underlying heart disease. ConclusionReconditioning of cardiac pacemakers is a safe and beneficial therapeutic strategy for patients. In Senegal, reconditioning has shown satisfactory results. In our countries this technique can be an alternative for certain patients.

Electrocardiographic predictors of atrial mechanical sensing in leadless pacemakers

BackgroundLeadless pacemakers (LPs) capable of VDD pacing allow for atrioventricular synchrony through mechanical sensing of atrial contraction. However, mechanical sensing is less reliable and less predictable than electrical sensing. ObjectiveThe purpose of this study was to evaluate P-wave amplitude during sinus rhythm from preoperative 12-lead electrocardiograms (ECGs) as a predictor for atrial mechanical sensing in patients undergoing VDD LP implantation. MethodsConsecutive patients undergoing VDD LP implantation were included in this 2-center prospective cohort study. ECG parameters were evaluated separately and in combination for association with the signal amplitude of atrial mechanical contraction (A4). ResultsEighty patients (median age 82 years; female 55%; mean body mass index [BMI] 25.8 kg/m2) were included in the study and 61 patients in the A4 signal analysis (19 patients in VVI mode during follow-up). Absolute (aVL, aVF, V1, V2) and BMI-adjusted (I, II, aVL, aVF, aVR, V1, V2) P-wave amplitudes from baseline ECGs demonstrated a statistically significant positive correlation with A4 signal amplitude (all P <.05). A combined P-wave signal amplitude of at least 0.2 mV in V1 and aVL was predictive, with specificity of 83% (95% confidence interval 67%–100%) for A4 signal ≥1 m/s2. We found a significant correlation of A4 signal amplitude and overall atrioventricular synchrony (P = .013). ConclusionP-wave amplitudes in ECG leads aVL and V1 can predict A4 signal amplitude in patients with VDD LP and therefore the probability of successful AV synchronous pacing.

Single-Chamber and Dual-Chamber Pacemaker Devices in Adults with Moderate and Complex Congenital Heart Disease: A Single Tertiary Referral Center Experience.

The number of device implantation procedures has increased in adult patients with congenital heart disease (ACHD). Despite significant improvements in materials and implantation techniques, these patients are exposed to higher risk of device related complications than general population. Herein, we describe our single tertiary referral center experience on transvenous pacemaker (PM) implantation and follow-up in adult patients with moderate and complex congenital heart disease (CHD) as limited data are available on long-term outcome. We considered all adults with moderate and complex CHD aged more than 16 years who underwent transvenous single-chamber and dual-chamber PM implant for sinus node dysfunction or atrioventricular block between January 2013 to December 2022 at our Unit. Seventy-one ACHD patients were included in the study (mean age 38.6 ± 15.2 years, 64% with moderate CHD, 36% with complex CHD). Among 32 patients implanted with a dual chamber PM (DDD PM), 4 devices were reprogrammed in VDD mode, 3 in VVI and 2 in AAI mode during follow-up because of lead dysfunction or permanent atrial arrhythmia. In addition, 26 patients had a single chamber PM (AAI or VVI PM) and 13 patients had single-lead pacing system with a free-floating atrial electrode pair (VDD PM). Just one of 13 single-lead VDD PM was reprogrammed in VVI mode due to a low atrial sensing. In DDD PM group, 10 re-interventions were needed due to lead dysfunction (8 cases) and lead-related infective endocarditis (2 cases). Only 3 patients in the single-lead PM group developed lead dysfunction with 2 re-interventions needed, but no infective endocarditis was reported. The rate of long-term complications is high in moderate and complex ACHD with transvenous PM devices, and it is mainly lead-related. In our experience, the less leads implanted, the less complications will occur. Considering the heterogeneity of the ACHD population, transvenous single-chamber or dual-chamber PM device implantation should always be tailored on the single patient, balancing risks and benefits in this complex population.

Cardiac implantable electronic devices in Bulgaria: results from the electronic registry BG-Pace for 2022

The current study analyses the activity on cardiac pacing in Bulgaria in 2022 based on data derived from a national registry of patients with cardiac implantable electronic devices (CIEDs).&amp;nbsp;Materials and methods.&amp;nbsp;Data from the national registry BG-Pace for 2022 was studied retrospectively. Demographic data, procedure and device type, pacing mode, etiology, symptoms, preimplantation ECG, number of implantations, and centre and operator volumes were analyzed.&amp;nbsp;Results:&amp;nbsp;Four thousand seven hundred seventy devices were implanted by 45 operators in 30 centers. Median age was 76 (IQR 69-82, 14-98) years, and male patients were 2843 (59,6%). The most significant number of implantations were carried out in the age group 70-79 years. The most commonly implanted CIEDs were antibradycardia devices - 578,8/million. Of them, conduction system pacing was used in 111 (2.3%). Implanted cardioverter-defibrillators demonstrated a growth compared to previous periods and reached 31.9/million. Cardiac resynchronization defibrillators implantations also shown a growth to 15.9/million. A considerable increase was found with implantable loop-recorders, which reached 8.8/million. Number of implantations per center was 115.5 (IQR 53-261.,3, 3-546), and 76,5 (IQR 36,8-154,8, 3-364) devices per operator. Dual chamber devices were most commonly implanted with a share of 83.1% in AVB I and II degrees, 72.5% in complete AVB, 82.6% in intraventricular conduction disturbances, and in 66.8% in patients with sick sinus syndrome. Pacing modes allowing for atrial sensing were most frequently implanted &amp;ndash; 62.4% of all implantations for conduction disturbances. There was a significant increase in the use of VVI mode with increasing age (P&lt;0.001).&amp;nbsp;Conclusion:&amp;nbsp;The national registry BG-Pace includes systematic clinical, demographical, and procedural&amp;nbsp;data for CIED implantations in Bulgaria. There is a growth in the implantation rates compared to previous periods, but they remain lower than the average number for Europe.

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.

The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Report 2022

The Pacemaker (PM) and Implantable Cardioverter-Defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the voluntary Italian collaborating centers. For the year 2022 main data about national PM and ICD implantation activity were obtained on the basis of European Cards and subsequently analyzed to create a standard report. PM Registry: data about 17 800 PM implantations were collected (14 191 first implants and 3609 replacements). The number of collaborating centers was 152. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). Main ECG indications included atrioventricular conduction disorders in 46.0% of first PM implants, sick sinus syndrome in 17.7%, atrial fibrillation plus bradycardia in 7.7%, other unspecified ECG and electrophysiological abnormalities in 43.0%. For first PM implants, pacing in DDDR mode was reported in 42.2%, followed by DDD mode (20.6%), VVIR mode (25.1%), VVI mode (11.1%) and finally VDD-VDDR (5.1%). Median value of longevity of explanted PMs was 8.3 years. ICD Registry: data about 5210 ICD implantations were obtained (3656 first implants and 1554 replacements). The number of collaborating centers was 301. Median age of treated patients was 72 years (63 quartile I; 79 quartile III). Primary prevention indication was reported in 72.4% of first implants, secondary prevention in 27.6% (cardiac arrest in 4.6% of records). A single-chamber ICD was used in 30.3% of first implants, dual-chamber ICD in 30.0% and biventricular ICD in 39.7%. Median value of longevity of explanted ICDs was 7.0 years. In the calendar year 2022, the Italian PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The ICD Registry documented a large use of prophylactic and biventricular ICDs, reflecting a favorable adherence in clinical practice to trials and guidelines. The ICD longevity and the number of recalls demonstrated a favorable trend.

Feasibility and outcomes of Micra implant after cardiac implantable electronic device extraction

Abstract Funding Acknowledgements Type of funding sources: None. Background The specific and well-known design features of leadless pacing system (Micra Transcatheter Pacing System, M-TPS) have suggested his use in patients that previously underwent transvenous lead extraction (TLE) for any reason. The study aimed to investigate feasibility and long-term outcomes of M-TPS implant in patients underwent TLE. Methods Patients undergone M-TPS implantation in our Institution from May 2014 to September 2022 were included in the study. All patients fulfilled standard criteria for PM implantation (VVI or VDD mode). Follow-up (FU) was scheduled at discharge, after 1 month and every 6 months thereafter and electrical parameters were checked. Major complications were defined as life-threatening events, requiring surgical intervention or any event causing significant hemodynamic instability or resulting in death. Study population was divided between "naïve pacing" and "post-extraction" patients. Results We enrolled 193 patients (76.7% males), 57 (29.5%) received M-TPS implantation after TLE, needed because of infection in 91.4% of cases. Indications for pacing were permanent AF with bradycardia in 107 (55.5%) patients, complete AVB in 59 (30.5%), symptomatic sinus node dysfunction in 20 (10%), and advanced AVB or bifascicular bock in 7 (4%). There were no statistically significant differences between groups for demographics characteristics and primary PM implant indications, except mean age at implant that was significantly inferior in the post-extraction group [80 (IQR 75-84) vs 78 (IQR 72-83), p=0.04]. Implant procedure was successful in all and no complications were recorded. No differences between groups in procedure duration [40 (IQR 30-50) vs 45 (30-65) min, p=0.34], fluoroscopy time [9 (6-14) vs 9 (6-11) min, p=0.31] and single device delivery (64.9% vs 67.9%, p=0.35) were observed. The mean FU was 12 (1-36) months, maximum 8 years. Pacing variables at implantation [pacing threshold 0.5 (0.38-0.63) vs 0.5 (0.38-0.88) V/0.24 ms, p=0.15; impedance 720 (600-837) vs 675 (615-825) Ohm, p=0.51; R wave amplitude 9 (6.25-12.87) vs 8.2 (5.65-12) mV, p=0.47], discharge [pacing threshold 0.38 (0.38-0.63) vs 0.38 (0.38-0.63) V/0.24 ms, p=0.27; impedance 685 (580-770) vs 610 (560-750) Ohm, p=0.16; R wave amplitude 10.25 (7.2-14.5) vs 9.3 (6.5-16.5) mV, p=0.6], and at 6 months [pacing threshold 0.5 (0.38-0.5) vs 0.5 (0.38-1.25) V/0.24 ms, p=0.64; impedance 580 (520-680) vs 570 (510-640) Ohm, p=0.63; R wave amplitude 11.9 (8.2-16.4) vs 11.7 (9-20) mV, p=0.68; battery voltage 3.09 (3.05-3.11) vs 3.09 (3.04-3.13) V, p=0.71] did not show differences. Conclusion M-TPS is an efficacious and safe alternative to conventional PM, with the main advantage of the absence of transvenous leads and a surgically created subcutaneous pocket, avoiding all the related complications. These devices are a reliable alternative after TLE, with similar electrical performances than those observed in patients who did not previously received pacing.

Chatterjee phenomenon in a patient with heart failure with preserved ejection fraction: a case report

The article presents a case report of the Chatterjee phenomenon after implantation of a pacemaker in a patient with heart failure with preserved ejection fraction. During hospitalization in a specialized cardiology hospital, the patient's electrocardiogram (ECG) showed atrial fibrillation (AF) with a ventricular rate of 49 bpm, ST segment depression of 1 mm in I, II, V4-V6 leads. Taking into account the data of 24-hour ECG monitoring (pauses up to 5,2 seconds with AF) and Stokes-Adams syndrome equivalents, a decision was made to implant a single-chamber pacemaker. Immediately after the pacemaker implantation, AF was registered on the ECG with a pacemaker VVI mode of 60 pulses/min. On the second day after intervention, the pacemaker was reprogrammed in the form of reducing the minimum pacing rate from 60 to 45 pulses/min. On the third day after pacemaker implantation, altered terminal ventricular complex part was detected in the form of negative T waves in I, II, III, aVF, V2-V6 leads, as well as ST segment depression in V3-V6 to 1,5 mm. Differential diagnosis of the identified abnormalities with other clinical conditions accompanied by impaired repolarization processes according to ECG data was carried out. In dynamics, normalization of the ECG picture after 2,5 months was demonstrated.

The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Report 2021

The Pacemaker (PM) and Implantable Cardioverter-Defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the voluntary Italian collaborating centers. For the year 2021 main data about national PM and ICD implantation activity were obtained on the basis of European Cards and subsequently analyzed to create a standard report. PM Registry: data about 18 631 PM implantations were collected (15879 first implants and 2752 replacements). The number of collaborating centers was 121. Median age of treated patients was 82 years (76 quartile I; 87 quartile III). Main ECG indications included atrioventricular conduction disorders in 26.8% of first PM implants, sick sinus syndrome in 12.2%, atrial fibrillation plus bradycardia in 9.6%, other unspecified ECG and electrophysiological abnormalities in 43.0%. For first PM implants, pacing in DDDR mode was reported in 46.5%, followed by DDD mode (20.6%), VVIR mode (15.0%), VVI mode (9.0%) and finally VDD-VDDR (5.8%). Median value of longevity of explanted PMs was 8.9 years. ICD Registry: data about 6878 ICD implantations were obtained (4708 first implants and 2170 replacements). The number of collaborating centers was 345. Median age of treated patients was 72 years (70 quartile I; 75 quartile III). Primary prevention indication was reported in 86.3% of first implants, secondary prevention in 13.7% (cardiac arrest in 4.4% of records). A single-chamber ICD was used in 32.1% of first implants, dual-chamber ICD in 30.3% and biventricular ICD in 37.6%. Median value of longevity of explanted ICDs was 6.9 years. In the calendar year 2021, the Italian PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The ICD Registry documented a large use of prophylactic and biventricular ICDs, reflecting a favorable adherence in the clinical practice to trials and guidelines. The ICD longevity and the number of recalls demonstrated a favorable trend. In order to increase and optimize the cooperation of Italian PM and ICD implanting centers, the online data entry (https://www.aiac.it/riprid) should be adopted at large scale.

Epidemiology of Pacemaker Implantation among Patients in Tanta University Hospitals

Background: This study describes cardiac pacing activity during 2021: demographic data of patients underwent permanent pacemaker implantation (PPM), risk factors, clinical presentations, indications, mode of pacing, and complications post PPM implantation. Cardiac pacemakers have become the common treatment of symptomatic bradycardia or high-grade atrioventricular block.&#x0D; Methods: The study was carried out at the department of cardiology Tanta University Hospitals. 102 patients were included in this study. This study was done over a period of six months from October 2020 until April 2021 and follow up for 6 months. All the data about the patients underwent permanent pacemaker implantation were collected by the coordinator in the participating cardiac center.&#x0D; Results: The most frequent risk factors of PPM implantation was hypertension (69%), followed by diabetes mellitus (29%), coronary artery disease (21%), chronic kidney disease (18%), hypothyroidism (6%), cardiomyopathy (3%), valvular heart disease (2%) and congenital heart disease (1%). The most common indication is complete heart block (69%), followed by second degree heart block "mobeitz type 2" (13%), slow atrial fibrillation (7%), symptomatic heart failure patients with LVEF ≤ 35% , QRS ≥ 150 ms (6%), trifascicular block (3%), sick sinus syndrome (2%). The most frequent mode of pacing used in our study was DDD mode (63%), followed by VVI mode (32%) with (78%) sinus rhythm and (22%) atrial fibrillation rhythm, then CRT-D (4%). Overall complication rate (9%) within 6 months. In our study the most common complication is infection (5%), followed by haematoma (1%), lead fracture (1%), pneumothorax (1%), and lead displacement (1%).&#x0D; Conclusion: Approximately three-quarters of the patients related to atrioventricular block underwent permanent pacemaker implantaion. Approximately more than half of pacemakers related to patients underwent permanent pacemaker implantation were dual chamber pacemakers. Infection is the most common complication in our study and this is important for strict infection control measures.

PO-632-06 REAL-TIME EX-VIVO RADIOTHERAPY IMPACTS ON PACEMAKER FUNCTION ARE MINIMAL

There is a paucity of data regarding the safety of radiotherapy in patients with pacemakers and the impact of linear accelerator parameters is unclear. To assess the function of pacemakers when exposed to different linear accelerator parameters. Pacemakers (2 single, 1 dual chamber) were exposed to radiation at dose rates 0.2-11.8Gy/min. Dose rate was modulated by adjusting the distance from the beam edge, linear accelerator pulse repetition rate (rep rate) and distance from source. Noise amplitude, pacemaker output, and device behavior during irradiation were assessed in VVI or DDD modes. Each device was irradiated 28 times for 10 seconds. Noise amplitude on bipolar (Bi) channel increased with dose rate (r2=0.3611, p<0.0001, B) and on unipolar (Uni) channel decreased with rep rate (r2 = 0.09, p<0.01; C). On both channels noise amplitude decreased with distance from field edge (Bi r2 = 0.53, p<0.01; Uni r2 = 0.42, p<0.01; D). No over-sensed events occurred in response to radiation induced background noise. Low frequency signals on the Uni and Bi channels were observed with beam on and off (E), resulting in over-sensed events only when directly in the radiation beam and sensing Uni. When directly in the beam, oversensing of A pacing on the V sensing Uni channel was observed leading to pacing inhibition (F). Post-radiation exposure interrogation was unremarkable revealing no evidence of device malfunction. Pacemaker malfunctions when directly in photon radiation beam are related to oversensing and crosstalk phenomena preferentially affecting the unipolar sensing channel. There was no evidence of long-term device malfunction upon repeated interrogations despite multiple exposures.

Under-sensing by a temporary pacemaker after cardiac surgery and ventricular fibrillation

An 80-year-old man with a 6-month-history of shortness of breath on minimal exertion and fatigue was admitted to our unit for a planned operation to replace his stenotic aortic valve. The surgery was uneventful and a temporary ventricular epicardial pacing lead was placed on the free wall of the right ventricle. The patient remained haemodynamically stable in sinus rhythm post-surgery and was extubated 8 h later. The following day he was transferred from intensive care to our high dependency unit with the temporary epicardial pacemaker in VVI mode: stimulation amplitude 10 V, sensitivity 1 mV, and back-up pacing rate of 44 beats per min. A pacing check at that time showed no problems.

Clinical analysis of temporary pacemaker implantation in 13 children.

BackgroundAt present, temporary pacemaker implantation is very common in the treatment of cardiovascular diseases in adults. However, the number of pediatric pacemakers implanted is still relatively small, and relevant research is also far less than that of adults. This study aimed to explore the application of temporary pacemakers in children with acute and critical cardiovascular diseases.MethodsThe clinical data of children with cardiovascular diseases who were treated with temporary pacemakers in Tianjin Children’s Hospital from October 2017 to February 2021 were analyzed retrospectively.ResultsA total of 13 children with cardiovascular diseases were included in this study, including 4 males and 9 females, mean age of 71.2±56.3 months, and median body weight of 15.5 kg. There were 9 children with endocardial pacing and 4 children with epicardial pacing. The types of diseases included fulminant myocarditis (n=8), complete atrioventricular block (CAVB; n=1), and arrhythmias after open heart surgery (n=4). The median time from onset to admission was 1.0 days in children with endocardial pacing and there was cardiac arrest in 2 children, heart failure in 9 children, cardiogenic shock in 8 children, and Adams-Stokes attack in 7 children. The median time from admission to implantation of temporary pacemakers was 3.0 h and the operation time was 55.0±19.4 min. All 4 children with epicardial pacing had pacemakers implanted during operation because of CAVB. The pacing mode was VVI mode. The initial perceptual voltage was 1–2 mv, the output voltage was 5v, and the pacing frequency was 70–145 bpm. A total of 11 children reverted to sinus rhythm within 5.0 (1.8–34.0) h and the working time of temporary pacemakers was 134.0 (15.0–191.0) h. There was poor pacing in 2 children and catheter displacement in 1 child during pacing. A total of 12 children were followed up for 20.0±12.5 months and 1 was lost to follow-up. During the follow-up period, the cardiac functions were basically normal and no new arrhythmia appeared.ConclusionsTemporary pacemakers have the advantage of simple operation, definite effect, and safety which has a remarkable effect in the treatment of acute and critical cardiovascular diseases in children.

JCS/JHRS 2021 guideline focused update on non-pharmacotherapy of cardiac arrhythmias.

JCS/JHRS 2021 guideline focused update on non-pharmacotherapy of cardiac arrhythmias.

Yes Is No

Yes Is No

The radiofrequency interference on CRT-D functioning during AV node ablation: An educational case.

We have described some unusual findings of radiofrequency interference with ICD functioning during AV nodal ablation, guiding the reader to the possible explanation of the phenomena.

Clinical worsening due to inappropriate automatic mode switch during biventricular pacing: What is the mechanism?

We describe a case of a 65-year-old gentleman with nonischemic cardiomyopathy and left bundle branch block who underwent cardiac resynchronization therapy device. After becoming a responder initially, he experienced significant clinical worsening on follow-up. Device interrogation revealed several long episodes of inappropriate automatic mode switch (AMS) entry due to far-field R wave oversensing resulting in loss of atrioventricular synchrony. Moreover, pacing in VVI mode with consistent VA conduction taking place during the AMS episodes was also found to be detrimental, which helped in sustaining the episodes and produced pacemaker syndrome like phenomenon. Attempts made to resolve the issue by prolonging the post-ventricular atrial blanking period was unsuccessful, hence we adjusted the atrial channel sensitivity to troubleshoot the problem.

Outcomes of single‑lead VDD pacemakers in atrioventricular blocks: The OSCAR study

BackgroundVDD pacemakers are regarded as a second choice in patients with atrio-ventricular blocks mainly due to the potential failure of atrial sensing, leading to a loss of atrio-ventricular synchrony. This single-centre study aimed to evaluate the prevalence of loss of atrial sensing and its potential determinants in patients with VDD pacemakers. Method142 patients with an implanted VDD device underwent long-term follow-up with clinical evaluation, electrocardiogram, device interrogation and echocardiogram. ResultsOver a long follow-up period [median 110 (68–156) months], 17 patients (12%) in sinus rhythm presented loss of atrial sensing. This was most often intermittent, but three patients required a permanent switch to VVI mode. ECG showed higher prevalence of interatrial blocks (50% vs 26.6%, p = 0.057) and longer P wave duration (116 ± 19 vs 105 ± 15 ms, p = 0.019) in patients with loss of atrial sensing. Echocardiography revealed larger left atrial (LA) volumes (p < 0.05) in patients with loss of atrial sensing, and lower LA ejection fraction (0.40 vs 0.47, p = 0.0037) and expansion index (0.63 ± 0.26 vs 0.90 ± 0.31, p = 0.003). P wave duration on ECG proved to be independently associated with loss of atrial sensing on multivariable analysis (OR 1.062, 95% CI 1.015–1.110; p = 0.008). The prevalence of atrial fibrillation and subsequent switch to VVI mode was high (16%). ConclusionsIn the long-term follow-up, the loss of atrial sensing is present in 12% of patients with implanted VDD pacemakers. ECG and echocardiographic parameters may serve as screening tools for the detection of atrial myopathy which is associated with the loss of atrial sensing.