Risultati per: Il pacemaker si ricarica con il battito del cuore

Circulation, Volume 148, Issue Suppl_1, Page A13903-A13903, November 6, 2023. Background:Leadless pacemakers have gained popularity in providing permanent pacing in select patient populations. Pacemaker mediated tachycardia and arrhythmias have been well described in patients with dual chamber pacemakers, but up to this point not in leadless pacing.Case Description:A 91-year-old female with symptomatic bradycardia and 2:1 AV block underwent implantation of a Micra AV pacemaker programmed VDD 60-100 bpm. Five months later, she presented with decompensated heart failure with a heart rate of 88 bpm and a newly reduced left ventricular ejection fraction of 30%. Device interrogation showed 95% ventricular pacing, with 91% AV synchrony. The Micra was found to be tracking an atrial rhythm between 80-100 bpm more than 80% of the time (Figure 1A). RV pacing induced cardiomyopathy was suspected and she underwent placement of a bi-ventricular pacemaker. During implant, a short VA time was noted and changes in the V-V cycle length predicted changes in the A-A cycle length (Figure 1B). Micra ventricular pacing was held resulting in an AV paced rhythm from the CRT system and a drop in rate to 60 bpm (Figure 1C). These results indicate that the Micra pacemaker was tracking the atrial mechanical contraction (AM) from a retrograde conducted P-wave resulting in elevated heart rates from a pacemaker-driven arrhythmia.Discussion:In patients with poor AV conduction, intact VA conduction, and SA node dysfunction, Micra AV may create pacemaker mediated arrhythmia by tracking the AM of the retrograde conducted P-wave. Careful patient selection to avoid Micra AV placement in patients with SA node dysfunction, and close attention to the rate histogram on device interrogation may prevent development and facilitate recognition of this unique cause of pacemaker-mediated arrhythmia.

Circulation, Volume 148, Issue Suppl_1, Page A13000-A13000, November 6, 2023. Description of Case:A 76-year-old female with a past medical history of chronic atrial fibrillation and symptomatic tachycardia and bradycardia status-post dual-chamber pacemaker with right atrial and ventricular leads who presented with dyspnea on exertion. TTE showed normal biventricular function and no significant valvular abnormalities. Upon further evaluation of her pacemaker, she was found to have a very high ventricular capture threshold suggesting RV lead failure. The patient underwent RV lead replacement. The inspection of the pacemaker pocket during the procedure showed manual dislodgement of both tie-down sleeves and the pacemaker leads required untangling. A new RV lead was subsequently placed. Upon further imaging review, displacement of the previous RV lead was evident from initial placement. In addition, the patient had previously had a history of interval diaphragmatic stimulation as well. Overall, the presentation was felt to be consistent with Twiddler’s Syndrome.Discussion:Twiddler’s or Reel Syndrome occurs when conscious or subconscious self-manipulation and spinning of the pulse generator result in lead dislodgement and loss of pacing and pacemaker malfunction. The reeling of the leads around the generator can also cause stimulation of the brachial plexus or phrenic nerve stimulation and subsequent rhythmic arm twitching or diaphragmatic pacing, respectively. It has previously been reported in cases of single- and dual-chamber ICDs, deep brain stimulators, and spinal nerve stimulators with varying presentation. The diagnosis requires clinical suspicion based on history, physical exam, imaging, or surgical inspection suggesting the displacement of leads with evidence of coiling of the wires around the pacemaker. Treatment often requires revision and focus should be maintained on patient education for both primary and secondary prevention of Twiddler’s Syndrome.

Circulation, Volume 148, Issue Suppl_1, Page A13327-A13327, November 6, 2023. Introduction:Sinoatrial node (SAN) dysfunction commonly occurs in atrial cardiomyopathy (ACM: “tachy-brady syndrome”), often requiring pacemaker implantation, but mechanisms are unknown. Atrial-selective myosin light chain-4 (MYL-4) mutations cause familial ACM with a high rate of early SAN dysfunction and pacemaker requirement. We studied rats engineered with a knock-in MYL-4 clinical E11K mutation and addressed mechanisms of SAN dysfunction.Methods:Atrial electrical properties were assessed within vivoelectrophysiology (EPS),ex vivooptical mapping, SAN single-cell voltage and current clamp, Ca2+-handling with Ca2+-sensitive dye microscopy. Gene expression was assessed by qPCR and fibrosis with Masson-Trichrome stain.Results:E11K rats showed progressive SAN recovery-time increases (Fig. A) and conduction-slowing (Fig. B). SAN cells showed slowed phase-4 depolarization (Fig. C) and reduced pacemaker “funny” current (If) (Fig. D). Ca2+homeostasis was also affected, showing decreased Ca2+-transients (Fig. E). SAN also displayed remodeling with increased collagen deposition (Fig. F).Conclusions:ACM resulting from E11K mutation induces multimodal electrical and structural remodeling of the SAN region, worsening with age. These observations provide new insights into mechanisms of the clinically important tachy-brady syndrome associated with ACM.

Circulation, Volume 148, Issue Suppl_1, Page A15996-A15996, November 6, 2023. Introduction:Permanent pacemaker (PPM) implantation following Aortic Valve Replacement (AVR) is common. While AVR modality choice (i.e. surgical vs. transcatheter) affects PPM risk, identifying pre-operative factors associated with increased PPM risk can benefit enhanced risk assessment and care decisions.Methods:This study is a retrospective evaluation of pre-operative factors associated with PPM risk within 1-month post-AVR at a tertiary care centre (2014-2020). Pre-AVR conduction abnormalities were classified as left bundle (LBBB), right bundle branch blocks (RBBB), and other abnormalities (left anterior/posterior fascicular block, intraventricular conduction delay) in combination with RBBB, LBBB, or alone.Results:Of the 776 (mean age= 74, 66% male) patients, 89 (11.5%) subsequently received PPM. As per pre-AVR electrocardiogram, 76 (9.8) were not in sinus rhythm and 214 (27.6%) had conduction abnormalities, including: 81 (10.4%) LBBB and LBBB + other, 91 (11.7%) RBBB and RBBB + other, and 42 (5.4%) other abnormalities. Pre-AVR rhythm (18.4 vs. 10.7%, p=0.05) and conduction abnormalities (19.2 vs. 8.5%, p

Circulation, Volume 148, Issue Suppl_1, Page A14310-A14310, November 6, 2023. Introduction:Several algorithms have been proposed to reduce unnecessary right ventricular (RV) pacing, and their operations are based on two different mechanisms: (i) atrioventricular (AV) hysteresis (AVH) and (ii) DDD to AAI pacing mode change.Hypothesis:The purpose of our study was to evaluate the efficacy and safety of two ventricular pacing suppression algorithms: Intrinsic Rhythm Support (IRS) plus algorithm (using AVH, IRSplus) and VP suppression (DDD to AAI mode change) algorithm (VpS).Methods:This was a multicenter, randomized study conducted in 11 tertiary hospitals in South Korea. Patients with sinus node dysfunction and receiving dual-chamber permanent pacemaker implantation were included in this study. After the implantation, patients maintained a fixed AV interval for three months. The AV conduction time was determined as the “atrial pacing to ventricular sensing interval” observed from the marker channel during the PPM implantation was set as the sensed AV delay. The paced AV delay was set to be the sensed AV delay+30ms. Subsequently, patients were randomly assigned to either the VpS or IRSplus algorithm group and were followed for 12 months with assessments every 6 months.Results:A total of 118 patients were enrolled, and the total RV pacing percentage (Vp%) of the patients during the 3 months with a fixed AV interval was 10.9±16.0 on average. They were randomly assigned to VpS and IRSplus groups, with 62 and 56 patients in each group. Six months later, the average Vp% was 14.6±18.8 to 2.7±6.0, P

Circulation, Volume 148, Issue Suppl_1, Page A16163-A16163, November 6, 2023. Multiple previously published case reports highlighted the thromboembolic risks associated with permanent transvenous pacemaker leads. Even though mostly clinically silent, pacemaker lead associated thrombosis has been linked to fatal outcomes via pulmonary or paradoxical embolism in the case of large mobile RA or RV thrombi formation. There is a lack of consensus on the optimal strategy for managing this condition. Oral and IV anticoagulation, thrombolysis, surgical and percutaneous thrombectomy have been attempted previously with mixed results.A 72 year old gentleman with a history of CAD requiring PCI, paroxysmal atrial fibrillation, and AV node ablation with subsequent biventricular pacemaker implant was admitted to our hospital with a few weeks of worsening dyspnea, now present at rest. Surface echocardiogram showed multiple mobile echo densities in the right ventricle and right atrium, attached to the pacemaker leads, confirmed by TEE, most likely thrombi. The venous duplex was positive for right lower extremity DVT. Bilateral pulmonary emboli with mild right-sided heart strain were noted on CTA chest. The patient was initially treated with IV unfractionated heparin. We subsequently decided to start low-dose tPA infusion for 24 hrs, similar to current off-label protocols for mechanical prosthetic valves or bioprosthetic valve thrombosis. After an initial IV bolus of 5 mg, 1 mg/hour of alteplase was continued for 24 hours. Our team has decided to use percutaneous thrombectomy as a last resort.Follow-up ECHO immediately post tPA infusion showed complete thrombi resolution. The patient was asymptomatic at this point. He was discharged the following day on Lovenox and Coumadin.To our knowledge, this is the first case demonstrating complete resolution of pacemaker lead-associated thrombi by using a 24 hr low dose tPA infusion in addition to IV anticoagulation. This can be entertained as a simple conservative initial strategy in stable patients with pacemaker lead/catheter-associated intracardiac thrombi.

Circulation, Volume 148, Issue Suppl_1, Page A12729-A12729, November 6, 2023. Introduction:Increased age is associated with increased frailty and often worse postoperative outcomes. We aim to assess the safety of leadless pacemaker (LPM) insertion in the very elderly population.Methods:We queried the National Readmission Database years 2017-2020 for patients who underwent LPM insertion with the ICD10 code 02HK3NZ. Patients with age 90 or more were included in the nonagenarians group. Patient comorbidities were queried through the appropriate ICD 10 codes. We compared outcomes using multivariate logistic and linear regression, adjusting for patient comorbidities.Results:At baseline, nonagenarians had a higher prevalence of hypertension, history of stroke, A fib./A. flutter, dementia and hypothyroidism. The control group had more of diabetes, coronary disease, chronic kidney disease, chronic pulmonary disease, oxygen use, coagulopathy, anemia, obesity, substance abuse and chronic liver disease (Table 1).Compared to controls, nonagenarians were found to have shorter length of stay (-2.486 days, p

Circulation, Volume 148, Issue Suppl_1, Page A18832-A18832, November 6, 2023. Introduction:Bradycardia is a frequent cause of morbidity and mortality in spinal cord injury (SCI) patients and optimal timing of permanent pacemaker implant is unclear.Case Summary:A 67-year-old female with no cardiac history was admitted for fall of uncertain etiology complicated by severe cervical SCI and neurogenic shock. Despite emergent surgical decompression, the injury resulted in quadriplegia. Post-operatively, bradycardic arrest occurred requiring resuscitation and dependence on dopamine infusion. Rhythm strip from showed p-p slowing followed by high grade atrioventricular block with multiple blocked p waves. A decision was made for early intervention with implantation of a Micra leadless pacemaker (LPM) (Medtronic, Minneapolis, MN) for both hemodynamically significant bradycardia and backup to prevent bradycardic arrest. A LPM was successfully implanted without complication on hospital day 8. The pacemaker was set to VVI 60. Post operatively, the patient required intermittent pacing and tolerated dopamine weaning.Discussion:Bradycardia in SCI patients, especially those with high cervical and complete SCI, occurs due to unopposed parasympathetic activity, resulting in baseline sinus bradycardia. Even more concerning is the risk for sudden and unpredictable sinus arrest and/or AV block, which is a leading cause of mortality in the first year after SCI. While initial management of bradyarrhythmia in SCI patients may respond to pharmacologic intervention, temporary and/or permanent pacing may be indicated. Acute SCI patients may not be ideal candidates for traditional pacemakers since ICU and infectious complications are common in this cohort, but LPMs have extremely low risk of implant site and infectious complications and can be utilized earlier in the hospital course. Our case showcases this strategy of early leadless pacemaker implantation. Further study is needed to better evaluate the safety and efficacy of this strategy.

Circulation, Volume 148, Issue Suppl_1, Page A11516-A11516, November 6, 2023. Background:Leadless pacemakers (LP) represent an emerging modality for treating bradyarrhythmias. We performed a meta-analysis and systematic review comparing safety and efficacy outcomes of Micra LP and transvenous pacemakers (TVP).Methods:A literature search was performed. The primary efficacy endpoints were successful implantation rate and acceptable capture threshold of

Circulation, Volume 148, Issue Suppl_1, Page A15725-A15725, November 6, 2023. Background:Despite being an essential procedure with rising use in the United States, the availability and accessibility of procedural care for a permanent pacemaker are not known. We investigated access to pacemaker implantation among Medicare beneficiaries.Methods:US Medicare physician claims from 2020, and county population characteristic data from AHRQ were used to evaluate the density of providers and beneficiaries across states and counties. For each US zip code, we determined the closest pacemaker implantation center using the haversine formula, then assessed the travel duration for each route using the Google Maps API.Results:There was a median of 5 providers performing pacemaker placement per 100,000 individuals over 65 years across all states, with an IQR of 4.5 to 6. At the county level, only 20% of counties in the US had a center offering transvenous pacemaker implantation, and 4% had a center offering leadless pacemakers. Individuals in metropolitan counties drove a median 29 (IQR 18 – 47) minutes to reach a center for pacemaker implantation, while those in non-metropolitan counties drove a median of 72 (IQR 52 – 102) minutes. In counties where >25% of the population is ≥65 years old, the median drive time to a pacemaker center is 86 (IQR 57 – 126) minutes. Residents of counties with a lower median household income (Spearman’s r = 0.45, p < 0.001) and a higher percentage of residents using public insurance had longer drive time to a pacemaker center (r = 0.23, p < 0.001). Out of the estimated 55,356,000 individuals ≥65 years old in the United States, 20,000,000 (36%) had to drive more than one hour, and 4,383,955 (8%) had to drive more than two hours to a site where a pacemaker implantation procedure is performed.Conclusion:Over one-third of the population in the United States has significant access issues to basic electrophysiologic care, highlighting the need for increased resources and improved accessibility.

Circulation, Volume 148, Issue Suppl_1, Page A14930-A14930, November 6, 2023. Introduction:Flecainide toxicity (FT) is an uncommon yet potentially lethal complication. We report a case of FT precipitated by acute kidney injury (AKI) in a patient with paroxysmal atrial fibrillation (AF) and a permanent pacemaker (PPM), who presented with wide complex tachycardia (WCT) and PPM under-sensing.Case presentation:An above 85-year-old female with paroxysmal AF and a PPM presented with an episode of unresponsiveness. While en route to the ED via ambulance, she had another episode associated with hemodynamic instability precipitated by a WCT. She regained consciousness after 1 biphasic DC shock. An EKG in the ED revealed sinus rhythm with atrial under-sensing and pacing spikes during ventricular refractory period (see picture). Laboratory data were consistent with AKI and normal electrolytes levels. PPM interrogation showed atrial under-sensing. Flecainide was discontinued and following drug washout the EKG changes resolved and the QRS normalized. She was discharged on amiodarone with no recurrence of arrhythmias on follow up.Discussion:Flecainide is Class 1C Antiarrhythmic drug that blocks fast the sodium channels. Prolongation of PR interval and QRS duration, in addition to supraventricular and ventricular arrhythmias, may occur with FT. Left ventricular dysfunction, myocardial scar, and high serum levels are considered risk factors for proarrhythmia. The drug half-life is prolonged in patients with renal disease/AKI. There are limited data on PPM malfunction due to FT, but it may cause increased pacing thresholds and failure to capture. Sodium bicarbonate, lidocaine, and ECMO have been used in treatment.Conclusion:FT can lead to lethal arrhythmias and PPM malfunction. Since flecainide serum levels are not always readily available, its diagnosis can be challenging. Therefore, physicians should be aware of the clinical presentation and EKG changes that accompany FT.

Circulation, Volume 148, Issue Suppl_1, Page A13661-A13661, November 6, 2023. Introduction:Complete Heart Block (CHB) is a commonly observed post-procedural complication associated with Transcatheter aortic valve replacement (TAVR) and Surgical aortic valve replacement (SAVR). Since 2016, limited data exists on In-hospital outcomes of TAVR and SAVR cases and rates of development of CHB.Methods:National Inpatient Sample 2016-2020 was used to identify and group TAVR and SAVR cases using appropriate ICD codes. Logistic regression was used to compare baseline characteristics and in-hospital outcomes.Results:590,615 patients underwent aortic valve replacement (AVR) from 2016-2020, of which 49.6% were TAVR and 50.4% were SAVR. The most common diagnosis for AVR in both groups was nonrheumatic trileaflet aortic stenosis (AS) (86.6% in TAVR group and 53.5% in SAVR group, p

Circulation, Volume 148, Issue Suppl_1, Page A17823-A17823, November 6, 2023. Background:Tricuspid valve repair has been advocated in patients undergoing mitral valve surgery who have not only preoperative severe TR but also for tricuspid annular dilatation (TAD) of >40 mm. We sought to analyze the impact of the type of tricuspid annuloplasty ring on the atrial arrhythmia behavior and the incidence of permanent pacemaker implantations in patients undergoing mitral valve annuloplasty.Methods:We performed a retrospective review of 408 patients underwent combined tricuspid and mitral valve annuloplasty in our institution between the years 2007 and 2014.Patients were 68,8 ± 10,7 years old, 67% male, 33% female. A total of 325 patients met the inclusion criteria; 201 received three-dimensional (3D) rigid ring (group 1) and 124 received ring annuloplasty with flexible bands (group2). The distribution of the preoperative and perioperative variables was similar.Results:There was no statistical difference in the incidence of high-grade heart conduction disorders lasting more than 3 days postoperatively (13.4% in group 1 and 12.9% in group 2; P = 0.89). Likewise, there was no difference in theincidence of postoperative atrial fibrillation between the two groups (41.2% in group 1 and 37.1% in group 2; P = 0.45). On the other hand, there was statistical difference in the incidence of permanent pacemaker implantation between the two groups (12.9% in group 1 and 25.8% in group 2; P = 0.003). Likewise, there was difference in the incidence of sick sinus syndrome between the two groups (0.01% in group 1 and 16.1% in group 2; P < 0.00001).Conclusion:The need for permanent pacemaker implantation and the incidence of sick sinus syndrom may be increased after the use of flexible tricuspid annuloplasty ring in the setting of mitral valve surgery.Moreover, the present study found no association between the use of Flexible tricuspid annuloplasty ring and a higher incidence of postoperative atrial fibrillation or high-grade heart conduction disorders.Further large-scale randomized controlled studies are needed to elucidate the Impact of the type of tricuspid annuloplasty ring.

Circulation, Volume 148, Issue Suppl_1, Page A12244-A12244, November 6, 2023. Introduction:Some studies suggested gender differences in procedural complication rates and long-term outcomes for trans-venous pacemakers. Little is known about gender differences associated with leadless pacemaker (LP) implantation.Methods:We reviewed all Medtronic Micra LP implants at our institution from 9/2014 to 9/2022. Device parameters (R wave sensing, impedance, and capture threshold), right ventricular pacing burden (RVP), left ventricular ejection fraction (LVEF), and 30-day adverse events post implant were obtained.Results:Among 489 patients, 50.9% were men. Mean follow-up was 1.7 ± 1.5 years. Women were older than men at the time of LP implant (78.1 ± 14.7 vs 75.5 ± 15.3 years old, p=0.04). There were no significant differences in R wave sensing and RVP between genders. Impedance and LVEF were higher in women and capture thresholds were higher in men at both baseline and last follow up. Despite significant differences in device parameters between genders, differences were small and not clinically relevant in most cases (Figure). Mean number of device deployments required at implant was similar: women 1.3 ± 0.6 vs men 1.4 ± 0.9, p=0.16). Implant related complications were similar between women and men: access site hematoma (5 vs 9, p=0.42), pseudoaneurysm (0 vs 2, p=0.49), cardiac perforation (2 vs 1, p=0.62), 30-day re-hospitalization (16 vs 25, p=0.19) and 30-day mortality (16 vs 17, p=0.99). LVEF decreased over time in both genders (Figure). During follow-up, 4 women and 6 men required transvenous cardiac resynchronization therapy (CRT) implantation (p=0.75) and 4 women vs 2 men required transvenous dual chamber pacemaker implantation (p=0.44).Conclusion:Outcomes of leadless pacemaker implantation are similar between women and men. Long-term device function is excellent in both genders. However, about 3% of all patients required device upgrade, highlighting the need for close electrophysiology follow-up after LP implant in both genders.

Circulation, Volume 148, Issue Suppl_1, Page A16688-A16688, November 6, 2023. Introduction:It would be useful to judge whether the device can sense atrial systole or not before an implantation of a VDD leadless pacemaker (Micra AVRT, Medtronic, US).Hypothesis:Mechanical atrial amplitude for Micra AVRTassociated with atrial construction at implantation location.Methods:Echocardiographic measurements were performed to quantify the atrial motion of the interventricular septum in patients who received leadless pacemaker implantation. We visually divided the septum into five segments from the base to the apex. The myocardial velocity of each segment measured on tissue doppler imaging (TDI) was defined as EV1, 2, 3, 4, and EV5 (m/s), respectively.Results:Fourteen patients (79.5 years, 8 males) receiving Micra AV from November 2021 to February 2023 at our institution were analyzed. The average myocardial velocity of atrial contraction at each site tended to decrease as getting closer to apex (EV1:8.9, EV2:8.0, EV3:7.0, EV4:5.8, EV5:3.5 cm/s) as shown in Figure. The implantation location was estimated from fluoroscopy and postoperative echocardiography, and mechanical atrial amplitude (A4) and the local EV were compared; Patients with lower than 2.0 m/s2A4 had also lower the local EV than others. (3.6 vs 5.9 m/s, p=0.037).Conclusions:Preprocedural estimation of mechanical atrial amplitude of Micra AV is possible on septal TDI.

Circulation, Volume 148, Issue Suppl_1, Page A15374-A15374, November 6, 2023. Introduction:Leadless pacemakers (LPM) offer several benefits over transvenous pacemakers, including lower risks of infection and vascular complications. However, their limited battery life and long-term retrieval challenges restrict their use in younger patients.Aims:We aim to extend the battery life of LPM by harvesting energy from right ventricular (RV) pressure fluctuations through a housing made of biocompatible piezoelectric materials, which can transduce pressure into voltage and thus recharge the battery.Methods:Cylindrical prototypes (n = 3) of LPM housing were fabricated using polyvinylidene fluoride (PVDF) with a thickness of 100 μm and a polyetherimide insulator wrapped around an aluminum rod, representing the LPM (1A). Our prototypes were sealed with epoxy (1B) and their dimensions (radius 9.5 mm, length 26 mm) were comparable to that of the Micra LPM (Medtronic). Prototypes were placed in a pulsatile cardiac pressure simulator (1C) and subjected to RV systolic/diastolic pressures at 1 Hz. A pressure transducer and an oscilloscope simultaneously recorded the simulator’s pressure and prototype’s transduced voltage respectively (1D). Impedance matching was performed, and an optimal resistance of 39 MΩ (1E) was identified for energy harvesting.Results:At oscillating “RV” pressures of 40 and 0 mmHg, our prototype generated 4 V (1D), corresponding to 52.5 nW of harvested power on an impedance-matched circuit. Under an assumed pacing output of 1.0 V at 0.24 ms and a pacing impedance of 500 Ω, each pacing stimulus requires 480 nW. Thus, our prototype can harvest 10.9% of the energy required to power an LPM.Conclusion:A first-generation PVDF-based energy-harvesting LPM housing can harvest approximately 10% of the power needed for pacing from RV systolic/diastolic pressures, marginally prolonging battery life. Future work will focus on increasing energy harvesting through material selection, device structure, and circuit design.