Recurrence of atrial tachyarrhythmias in implantable cardioverter-defibrillator recipients

BACKGROUND: Because the natural history of atrial tachyarrhythmia (AT) is not known in patients with implantable cardioverter-defibrillators (ICDs) but without device-based atrial therapies, we aimed to describe the characteristics and recurrence of AT in such patients. METHODS: In this multicenter trial, 269 patients with standard indications for ICD placement and 2 episodes of AT in the preceding year received a dual-chamber ICD capable of logging AT. Patients were randomly assigned to 3-month periods of atrial therapies "on" or "off." This analysis considered only the 118 patients with atrial therapies programmed off at ICD placement. RESULTS: Fifty-eight patients (49%) had at least 1 AT episode longer than 1 minute, and 21 (18%) had at least 1 prolonged episode (>24 hours). The median episode frequency for each patient (episodes per month) was 1.8 episodes longer than 1 minute, 0.8 longer than 1 hour, and 0 longer than 24 hours. The median AT burden was 12.2 hours per month. CONCLUSIONS: Patients with standard ICD indications and history of AT have infrequent episodes, frequent short episodes, or prolonged episodes of AT-atrial fibrillation. However, the clinical characteristics examined did not distinguish among the groups. Improved diagnostic tools may help identify patients at risk for development of AT, thereby allowing specific therapies to be targeted to each group of patients.     

Innovative techniques for placement of implantable cardioverter-defibrillator leads in patients with limited venous access to the heart

BACKGROUND: Because of venous occlusion, intracardiac shunting, previous surgery, or small size placement of implantable cardioverter-defibrillator (ICD) leads may not be possible using traditional methods. The purpose of this study was to evaluate and describe innovative methods of placing ICD leads. METHODS: The records of all patients undergoing ICD implantation at our institution were reviewed to identify patients with nontraditional lead placement. Indications for ICD, method of lead and coil placement, defibrillation thresholds, complications, and follow-up results were reviewed retrospectively. RESULTS: Eight patients (aged 11 months to 29 years) were identified. Six patients with limited venous access to the heart (four extracardiac Fontan, one bidirectional Glenn, one 8 kg 11-month-old) underwent surgical placement of an ICD coil directly into the pericardial sac. A second bipolar lead was placed on the ventricle for sensing and pacing. Two patients with difficult venous access had a standard transvenous ICD lead inserted directly into the right atrium (transatrial approach) and then positioned into the ventricle. All patients had a defibrillation threshold of <20 J, although one patient required placement of a second coil due to an elevated threshold. There have been no complications and two successful appropriate ICD discharges at follow-up (median 22 months, range 5-42 months). CONCLUSIONS: Many factors may prohibit transvenous ICD lead placement. Nontraditional surgical placement of subcutaneous ICD leads on the pericardium or the use of a transatrial approach can be effective techniques in these patients. These procedures can be performed at low risk to the patient with excellent defibrillation thresholds.     

新发的不同类型心力衰竭合并心房颤动的临床特点和远期预后分析

目的 探讨新发的不同类型心力衰竭合并心房颤动(AF)的临床特点以及临床结局。方法 本研究为回顾性观察性研究,连续纳入在2017年7月至2020年7月在宣城市人民医院心血管内科住院并首次确诊为射血分数降低心力衰竭(HFrEF)或射血分数中间范围型心力衰竭(HFmrEF)患者。本研究以是否合并AF分为：HFrEF合并AF组(n=41),HFrEF合并非AF组(n=59),HFmrEF合并AF组(n=58),HFmrEF合并非AF组(n=35)。比较4组的临床特点和临床不良事件。应用多元Cox回归分析HFmrEF和HFrEF患者合并AF对临床不良事件影响。结果 共入选193例患者,平均随访时间为(28.87±11.13)个月。(1)4组在性别、年龄、尿酸、脑钠肽前体N末端(NT-proBNP)、左室舒张末期内径(LVEDD)、左心房内径(LAD)、左心室缩短分数、CHA₂DS₂-VASc评分、心功能分级(NYHA)、β受体阻滞剂使用率、利尿剂使用率和主要不良心脑血管事件发生率差异有统计学意义(均P<0.05);(2)多元Cox回归分析显示：N...     

心力衰竭并发心房颤动患者不同心室率与B型脑钠肽的关系探讨

目的探讨心力衰竭并发心房颤动患者不同心室率与B型脑钠肽(BNP)的相关性。方法入选本院心血管科62例心力衰竭患者,根据是否并发心房颤动分为3组:A组(n=20),为单纯心力衰竭患者;B组(n=20),并发慢性心房颤动(心室率小于100次/min);C组(n=22),并发快速心房颤动(心室率大于100次/min)。比较3组患者一般情况、心率及血浆BNP水平。结果 C组患者心率明显高于A组和B组,差异有统计学意义(P<0.01)。C组患者血浆BNP水平明显高于A组、B组,差异有统计学意义(P<0.01);B组患者血浆BNP水平明显高于A组,差异有统计学意义(P<0.01)。结论心房颤动患者心室率的加快会导致BNP水平的升高。     

心房颤动患者高凝状态研究

目的研究心房颤动(房颤)患者高凝相关指标及影响因素,探讨其临床意义。方法根据房颤患者是否有心力衰竭分为两组:房颤1组为无心力衰竭者(30例),房颤2组为有心力衰竭者(30例)。具器质性心脏病且心功能正常的窦性心律患者(40例)为窦性心律组,另选33例正常健康者为正常对照组。在慢性房颤患者、心脏病无房颤患者和健康正常人中,用酶联免疫法测定血浆D二聚体、用全自动血凝分析仪测定血浆纤维蛋白原(fibrinogen,Fg)。结果房颤1组患者D二聚体为474.5μg/L(220.0~843.9μg/L),房颤2组患者血浆D二聚体为657.9μg/L(365.8~1 448.6μg/L),明显高于窦性心律组271.6μg/L(186.6~426.2μg/L)和正常对照组179.5μg/L(131.4~235.1μg/L),(P<0.05)。房颤1组患者血浆Fg(3.74±0.76)g/L和房颤2组患者血浆Fg(4.25±0.95)g/L明显高于窦性心律组(3.26±0.80)g/L和正常对照组(2.97±0.72)g/L,(P<0.05)。与房颤1组比,房颤2组患者D二聚体、Fg显著升高(P<0.05)。与左房内径<40 mm的房颤患者比,左房内径≥40 mm的房颤患者D二聚体、Fg升高(P<0.05)。结论房颤患者存在着高凝状态,并且心力衰竭和左房扩大增加房颤的高凝状态,这些异常可能与房颤患者血栓形成和(或)栓塞事件相关。     

Effect of coexisting cardiovascular disease on the long-term efficacy and safety of the implantable atrial defibrillator

The long-term efficacy and safety of implantable atrial defibrillator (IAD) therapy in patients with AF and cardiovascular disease is unclear. The aim of this study was to evaluate the efficacy and safety of IAD therapy in patients with and without coexisting cardiovascular disease. In 115 patients implanted with an IAD, 85 patients had cardiovascular disease: 41 (48%) patients had 1 cardiovascular abnormality, 29 (35%) patients had 2, 13 (15%) patients had 3, and 2 (2%) patients had 4 different cardiovascular abnormalities. The device was programmed into a rhythm monitoring mode for the first 3-month postimplant period. All defibrillation therapy was performed under physician supervision to monitor safety and efficacy. After this initial monitoring period, patients were allowed to activate their device away from the hospital or clinic. A total of 357 spontaneous AF episodes occurred in 83 (72%) patients during observed operation and the mean shock efficacy was 93.5+/-20.3% (lower 95% confidence interval [CI] 89.8%). As of the lastfollow-up, 58 (55%) patients had transition to receive nonphysician observed therapy. Forty-two (72%) patients had experienced 332 episodes of AF for which theyhad received device therapy away from the hospital/clinic (mean shock efficacy 90.5+/-39.7%). The presence of hypertension, valvular heart disease, and ischemic heart disease did not affect the shock efficacy of the IAD during physician observed and nonobserved therapy (P > 0.05). However, the presence of congestive heart failure was associated with a lower clinical efficacy during observed and nonobserved therapy (P < 0.05). Overall, 5,262 shocks have been delivered with the IAD without any episode of proarrhythmia. The observed proarrhythmic risk was 0%, with an estimated maximum proarrhythmic risk of 0.06% per shock (95% upper CI). A stand-alone IAD appears to be safe in the presence of cardiovascular disease. The lower clinical efficacy for AF associated with congestive heart failure might be related to a higher rate of early reinitiation of AF after defibrillation.     

Prospective evaluation of catheter ablation in patients with implantable cardioverter defibrillators and multiple inappropriate ICD therapies due to atrial fibrillation and type I atrial flutter

The high incidence of inappropriate therapies due to drug refractory supraventricular tachycardia remains a major unsolved problem of the ICD. Most of the inappropriate therapies for supraventricular tachycardia are caused by AF and type I atrial flutter with rapid ventricular response. The purpose of this prospective study was to determine the usefulness of AVN modulation or ablation for rapid AF and ablation of the tricuspid annulus-inferior vena cava (TA-IVC) isthmus for type I atrial flutter in ICD patients with frequent inappropriate ICD interventions. Eighteen consecutive patients were enrolled in this study. Twelve patients received a mean of 34 +/- 36 antitachycardia pacing (ATP) and 41 +/- 32 shock therapies for rapid AF during 49 +/- 39 months, and 6 patients a mean of 111 +/- 200 ATP and 11 +/- 8 shock therapies for type I atrial flutter during 52 +/- 37 months preceding ablation procedure. Modification of the AVN was successful in 10 (83%) of 12 AF patients, in 2 (17%) patients ablation of the AVN was performed. A complete TA-IVC isthmus block was achieved in 5 (83%) of 6 atrial flutter patients. Three (25%) AF patients had 11 +/- 24 recurrences of ATP and 0.4 +/- 1.1 shock therapies for rapid AF during 15 +/- 7 months. None of the atrial flutter patients had recurrences of inappropriate therapies for type I atrial flutter during 14 +/- 8 months, but two (33%) patients had inappropriate ICD therapies for type II atrial flutter or rapid AF. There was an overall mean incidence of 18 +/- 22 inappropriate ICD therapies per 6 months before and 4 +/- 9 per 6 months after the ablation procedure (P < 0.05). In conclusion, radiofrequency catheter modification or ablation of the AVN for rapid AF and ablation for atrial flutter type I are demonstrated to be highly effective in the majority of ICD patients with drug refractory multiple inappropriate ICD therapies.     

Continuous versus intermittent monitoring of ventricular rate in patients with permanent atrial fibrillation

Background: Ventricular rate control (VRC) is an important treatment strategy for patients with permanent atrial fibrillation (AF). We assessed the prevalence of poor VRC and the adequacy of various intermittent monitoring regimens to accurately characterize VRC during permanent AF. Methods: We retrospectively analyzed data from dual chamber implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT‐D) patients in the Medtronic Discovery? Link having permanent AF (AF burden >23 hours/day) and ≥365 consecutive days of device data. Poor VRC was defined as a day with the mean ventricular rate during AF >100 beats/minute (bpm) for ICD patients and >90 bpm for CRT‐D patients. Intermittent monitoring regimens were simulated from continuous device data by randomly selecting subsets of days in which data were available for analysis. Assessments of poor VRC were computed after replicating 1,000 simulations. Results: ICD (n = 1,902, age = 71 ± 10) and CRT‐D (n = 3,397, age = 72 ± 9) patients were included and followed for 365 days. The prevalence of poor VRC was 24.8% among ICD patients and 28.6% among CRT‐D patients. Significantly more patients were identified as having poor VRC with continuous monitoring compared to all intermittent monitoring regimens (sensitivity range = 8%–31%). Furthermore, 11.6% of ICD patients and 17.9% of CRT‐D patients experienced ≥7 days with poor VRC, to which the sensitivities of annual 7‐ and 21‐day recordings were <7% and <20%, respectively. Conclusions: A significant proportion of permanent AF patients experience poor VRC that would be missed with random intermittent monitoring. Whether improved knowledge of VRC with continuous monitoring will lead to improved outcomes compared to intermittent monitoring requires further study. (PACE 2012;1–7)     

Clinical outcomes of acute stroke patients with atrial fibrillation

Evaluation of: Kazumi K, Yasuyuki I, Kensaku S, Takeshi I, Shinji Y, Junya A. IV-tPA therapy in acute stroke patients with atrial fibrillation. J. Neurol. Sci. 276(1–2), 6–8 (2009).

Stroke is the leading cause of disability and the second most common cause of death worldwide. The care and treatment of stroke patients have evolved over the last two decades, with increasing use of thrombolysis (e.g., intravenous tissue plasminogen activator in acute stroke patients), which has improved survival and recovery following stroke. The article under evaluation offers a greater insight into the relationship of clinical outcome of stroke and atrial fibrillation after tissue plasminogen activator infusion.     

Comparison of ICD shock rates in Japanese and non‐Japanese patients in the PainFree SST study

Background

The PainFree Smart Shock Technology (SST) study showed a low implantable cardioverter‐defibrillator (ICD) inappropriate shock rate. However, the majority of patients were from Western countries with patient characteristics different from those in Japan. ICD shock rates using the novel SST algorithms in Japanese patients are still unknown.

Methods

All 2,770 patients in the PainFree SST study (Japan [JPN]: N = 181, other geographies [OJPN]: N = 2,589) were included in this analysis.

Results

Japanese patients had higher average left ventricular ejection fraction (P < 0.0001), higher prevalence of secondary prevention indications (P < 0.0001), nonischemic cardiomyopathy (P < 0.0001), and permanent atrial fibrillation (P < 0.0001). The appropriate shock rate at 12 months was not different between JPN and OJPN: 6.4% and 6.3%, respectively (P = 0.95). The inappropriate shock rate at 12 months was significantly higher in Japanese patients (2.9% vs 1.7%, P = 0.017). However, after propensity score matching to adjust for the difference in baseline characteristics, the difference in inappropriate shock rate was not statistically significant (P = 0.51).

Conclusions

There was no difference in the appropriate shock rate between Japan and other geographies. The inappropriate shock rate in Japan was low, although it was slightly higher compared to other geographies due to baseline characteristics, including a higher prevalence of permanent AF. There was not a statistically significant difference after adjusting for baseline characteristics.

     

Accuracy of atrial tachyarrhythmia detection in implantable devices with arrhythmia therapies

The clinical application of atrial tachyarrhythmia (AT) episode data stored by implantable devices is presently limited by the high proportion of inappropriate detection. We quantified the percentage of inappropriate AT detection in two implantable devices with AT diagnostics and therapies via meta-analysis of stored AT episodes from a number of clinical trials. The AT500 and GEM III AT, contain dual chamber logic to discriminate AT from ventricular tachycardia and far-field R wave (FFRW) oversensing using dual chamber bipolar electrograms. A subset of data from four clinical trials of 1,142 patients was considered. Manual analysis was performed on 21,553 stored episodes with atrial EGM and marker channel from 409 patients with stored episodes and the market-released device detection configuration. The percentage of episodes with inappropriate detection and termination was evaluated and compared between septal and nonseptal lead locations. The percentage of inappropriately detected episodes receiving ATP therapy was also determined. The percentage of episodes appropriately detected and the percentage of net episode duration (i.e., burden) recorded by the device were also determined from a separate analysis of 24-hour Holter recordings from a subset of 40 patients from one trial. Adjusted estimates of the percentage of appropriate [corrected] detection were 95.3% (93.5-96.7; 95% CI) for AT500 and 95.7% (84.3-98.9) for GEM III AT. Inappropriate detection was primarily due to FFRW oversensing or brief runs of premature atrial contractions (PACs). The device detected 100% of the sustained atrial arrhythmia episodes and 95.3% (range 76.1-99.9) of the net AT duration observed on the Holter recordings. AT detection was not influenced by atrial lead location. Appropriate detection of normal sinus rhythm at episode termination was 83.7% (80.7-86.3) for AT500 and 92.1% (84.5-96.2) for GEM III AT. Accurate detection and discrimination of FFRWs validates the reliability of AT diagnostic data and decreases the risk of inappropriate device therapy.     

Inhibition of bradycardia pacing and detection of ventricular fibrillation due to far-field atrial sensing in a triple chamber implantable cardioverter defibrillator

Oversensing of intracardiac signals or myopotentials may cause inappropriate ICD therapy. Reports on far-field sensing of atrial signals are rare, and inappropriate ICD therapy due to oversensing of atrial fibrillation has not yet been described. This report presents a patient with a triple chamber ICD and a history of His-bundle ablation who experienced asystolic ventricular pauses and inappropriate detection of ventricular fibrillation due to far-field oversensing of atrial fibrillation. Several factors contributed to the complication, which resolved after reduction of the ventricular sensitivity.     

ICD围术期未停口服抗凝药的临床观察和护理

目的探讨植入型心律转复除颤器（ICD）围术期未停口服抗凝药的临床观察和护理。方法回顾ICD植入术35例患者,其中围术期未停抗凝药15例,总结护理要点和并发症的处理方法。结果 35例行ICD植入术患者均痊愈出院,随访患者无不良反应和并发症。结论术前全面评估患者围术期是否停用或替代抗凝剂,同时做好患者教育及凝血监测工作,术后严密观察术区情况,发现异常及时处理。     

心房纤颤心室率对心力衰竭患者血清NT-proBNP浓度的影响

目的 探讨心房纤颤(简称房颤)心室率对心力衰竭患者血清N-端脑利钠肽前体(NT-proBNP)浓度的影响.方法入选101例心力衰竭患者,按心电图诊断分为快速型房颤组(心室率大于100次/分,n=33)、普通型房颤组(心室率60～100次/分,n=32)和窦性心律组(n=36),再按纽约心脏病协会(NYHA)心功能分级标准分为心功能Ⅱ、Ⅲ和Ⅳ级3个亚组.采用胶体金法检测受试者血清NT-proBNP浓度并进行统计学分析.结果快速型房颤组、普通型房颤组及窦性心律组患者血清NT-proBNP浓度随NYHA心功能分级增加呈增高趋势,每组各亚组间比较差异有统计学意义(P＜0.05).窦性心律组、普通型房颤组、快速型房颤组患者血清NT-proBNP浓度在一定程度上呈增高趋势,但组间比较差异无统计学意义(P>0.05).在相同心功能分级亚组,快速型房颤组患者血清NT-proBNP浓度显著高于窦性心律组和普通型房颤组(P＜0.05),而普通型房颤组与窦性心律组比较,差异无统计学意义(P>0.05).结论 血清NT-proBNP浓度与心力衰竭严重程度相关;房颤对心力衰竭患者血清NT-proBNP浓度有一定影响,房颤心室率增快(超过100次/分)对血清NT-proBNP浓度影响越明显.     

Clinical significance of the atrial fibrillation threshold in patients with paroxysmal atrial fibrillation

AF threshold and the other electrophysiological parameters were measured to quantify atrial vulnerability in patients with paroxysmal atrial fibrillation (PAF, n = 47), and those without AF (non-PAF, n = 25). Stimulations were delivered at the right atrial appendage with a basic cycle length of 500 ms. The PAF group had a significantly larger percentage of maximum atrial fragmentation (%MAF, non-PAF: mean +/- SD = 149 +/- 19%, PAF: 166 +/- 26%, P = 0.009), fragmented atrial activity zone (FAZ, non-PAF: median 0 ms, interquartile range 0-20 ms, PAF: 20 ms, 10-40 ms, P = 0.008). Atrial fibrillation threshold (AF threshold, non-PAF: median 11 mA, interquartile range 6-21 mA, PAF: 5 mA, 3-6 mA, P < 0.001) was smaller in the PAF group than in the non-PAF group. Sensitivity, specificity, and positive predictive value of electrophysiological parameters were as follows, respectively: %MAF (cut off at 150%, 78%, 52%, 76%), FAZ (cut off at 20 ms, 47%, 84%, 85%), AF threshold (cut off at 10 mA, 94%, 60%, 81%). There were no statistically significant differences between the non-PAF and PAF groups in the other parameters (effective refractory period, interatrial conduction time, maximum conduction delay, conduction delay zone, repetitive atrial firing zone, wavelength index), that were not specific for PAF. In conclusion, the AF threshold could be a useful indicator to evaluate atrial vulnerability in patients with AF.