Electrophysiological control of ventricular rate during atrial fibrillation

Thirteen anesthetized canine subjects (17-29 kg) were used to demonstrate that mild cervical left vagal stimulation could control ventricular rate effectively during atrial fibrillation (AF). Two studies are presented. The first study used six subjects to demonstrate the inverse relationship between (manually applied) left vagal stimulation and ventricular excitation (R wave) rate during AF. As left vagal stimulation frequency was increased, ventricular excitation rate decreased. In these studies, a left vagal stimulus frequency of 0-10 per second reduced the ventricular excitation rate from > 200/min to < 50/min. The decreasing ventricular excitation rate with increasing left vagal stimulation frequency was universal, occurring in all 26 trials with the six subjects. This fundamental principle was used to construct an automatic controller for use in the second study, in which seven subjects were used to demonstrate that ventricular rate can be brought to and maintained within a targeted range with the use of an automatic (closed-loop) controller. A 45-minute record of automatic ventricular rate control is presented. Similar records were obtained in all seven subjects.     

最优心率方法在二尖瓣狭窄并心房颤动患者心率控制中的导向作用

目的　评价最优心率(Rapp)方法指导二尖瓣狭窄（MS）并心房颤动（AF）患者控制心率以改善心脏泵功能的可行性和作用。方法　以Rapp系列公式个体化地设定心率控制目标,并通过心率调节方法使心率接近Rapp,比较心率调节治疗前后临床及血流动力学变化。结果　所有病例接受心率调节治疗且无技术障碍,本组患者Rapp为（76.5±7.6）次/min,分布范围为58.7～98.7次/min,经心率调节治疗后临床状况及心脏泵功能改善。结论　按Rapp方法调节心率切实可行,MS并AF患者心率控制目标应个体化,该方法为引导临床个体化控制心率改善心功能提供了新方法。     

静脉注射地尔硫(艹卓)控制快速心房颤动心室率疗效观察

目的观察静脉注射地尔硫控制快速心房颤动(房颤)心室率的疗效及其安全性。方法66例快速房颤患者随机分为两组,治疗组34例静脉注射地尔硫,对照组32例静脉注射西地兰。结果治疗组及对照组总有效率分别为94.11%、68.75%,治疗组疗效明显优于对照组,差异有统计学意义(P<0.05)。无严重副作用发生。结论地尔硫较西地兰能更迅速、有效、安全地控制快速房颤的心室率。     

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)     

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.     

心房颤动患者药物治疗与导管消融治疗对其心室率与转复率的影响

目的:探讨药物治疗与导管消融治疗对心房颤动患者心室率与转复率的影响。方法:选取2012年12月至2013年9月上海复旦大学附属中山医院收治的心房颤动患者165例,随机分成两组,对照组进行药物治疗,研究组则进行导管消融治疗。观察对比患者的心房颤动症状发生情况,窦性心率维持率在1个月、3个月、6个月、12个月的变化情况及终点事件的发生情况。结果:研究组的心房颤动症状的复发率(39.5%)低于对照组(66.7%,P0.05);研究组的心窦性心率维持率1个月后(96.3%)、3个月后(90.1%)、6个月后(85.2%)、12个月后(77.8%)高于对照组(94.0%、75.0%、67.9%、53.4%,P0.05);研究组的终点事件发生率(8.6%)与对照组(10.7%)无明显差异。结论:经皮导管消融术治疗心房颤动临床效果显著优于药物治疗,能显著降低临床症状的复发率和提高窦性心律维持率,显著改善患者的生活质量。     

Comparison of sustained rate control in atrial fibrillation with rapid ventricular rate: Metoprolol vs. Diltiazem

ObjectiveThe objective of this study was to compare sustained rate control with intravenous (IV) diltiazem vs. IV metoprolol in acute treatment of atrial fibrillation (AF) with rapid ventricular rate (RVR) in the emergency department (ED).MethodsThis retrospective chart review at a large, academic medical center identified patients with AF with RVR diagnosis who received IV diltiazem or IV metoprolol in the ED. The primary outcome was sustained rate control defined as heart rate (HR) < 100 beats per minute without need for rescue IV medication for 3 h following initial rate control attainment. Secondary outcomes included time to initial rate control, HR at initial control and 3 h, time to oral dose, admission rates, and safety outcomes.ResultsBetween January 1, 2016 and November 1, 2018, 51 patients met inclusion criteria (diltiazem n = 32, metoprolol n = 19). No difference in sustained rate control was found (diltiazem 87.5% vs. metoprolol 78.9%, p = 0.45). Time to rate control was significantly shorter with diltiazem compared to metoprolol (15 min vs. 30 min, respectively, p = 0.04). Neither hypotension nor bradycardia were significantly different between groups.ConclusionsChoice of rate control agent for acute management of AF with RVR did not significantly influence sustained rate control success. Safety outcomes did not differ between treatment groups.     

The acute effects of magnesium in atrial fibrillation and flutter with a rapid ventricular rate

A prospective, randomised, placebo controlled, double blinded trial to assess the efficacy of intravenous magnesium sulphate (20mmol over 30 minutes) versus placebo in patients presenting to the emergency department with rapid atrial fibrillation and flutter. The end points were slowing of the ventricular rate and reversion to sinus rhythm. A total of 41 patients were enrolled. The mean decrease in heart rate 30 minutes after commencing the infusion was 24.1/min for the magnesium group compared to 11.0/min for the placebo group (different at the 95% level of significance). The mean decrease in heart rate and the reversion rate four hours after commencing the infusion were the same at the 95% level of significance for the two groups. We conclude that magnesium has a significant effect in the acute slowing of ventricular rate but no effect in achieving reversion to sinus rhythm.     

Impact of respiration gating on image integration guided atrial fibrillation ablation

Background

Radiofrequency (RF) catheter ablation guided by electroanatomic mapping systems is an effective therapy for atrial fibrillation. However, it may be affected by respiration movements. The aim of this study was to determine the impact of respiratory gating on procedural parameters in patients undergoing catheter ablation of atrial fibrillation (AF).

Methods and results

One-hundred forty consecutive patients undergoing pulmonary vein isolation were admitted to study. Respiratory gating module (AccuResp algorithm, Carto3, Biosense Webster) was enabled in 70 patients and disabled in 70 patients during procedures. Successful pulmonary vein isolation and sinus rhythm were obtained in all patients. A significant reduction in total procedure times [median 77, interquartile range (IQR 66–95) min vs median 82 (IQR 72–104) min, p < 0.05] and fluoroscopy times [median 14 (IQR 9–17) min vs median 16 (IQR 12–22) min, p < 0.05] were observed in the respiratory gated group. Although ablation times (duration between the first and last ablation) were significantly shorter in respiratory gated group [median 37 (IQR 32–53) min vs median 48 (IQR 39–65) min, p < 0.05], total RF application durations were not different between two groups [median 1,554 (IQR 1,213–2,196) s vs median 1,802 (IQR 1,344–2,448) s, p = 0.11]. Difference in electroanatomical map reconstruction times was not significant [median 14 (IQR 12–16) min in gated group vs median 13 (IQR 10–18) min in nongated group, p = 0.19].

Conclusion

Respiratory gating significantly improves fluoroscopy and ablation times during electroanatomic mapping guided AF ablation. Respiratory gated maps may provide uninterrupted continuous ablation applications. Furthermore, using automatic respiratory gating module does not prolong mapping times.     

Verapamil plasma levels and ventricular rate response in patients with atrial fibrillation and flutter.

The acute effect of verapamil on the ventricular rate in atrial fibrillation and flutter was studied in 15 patients, 13 of whom had heart rate inadequately controlled with digitalis. Plasma concentrations were measured 5 and 10 min after intravenous doses of 0.075 mg/kg and 0.15 mg/kg verapamil. In 9 patients who were clinically compensated, the 0.075-mg dose alone decreased the ventricular rate to under 100/min (responders); in the remaining 6, who had acute congestive heart failure manifested by orthopnea, rales, and pulmonary congestion, ventricular rates were above 100/min after the 0.075-mg dose (nonresponders). The 6 nonresponders received the 0.15-mg dose 30 min later. In all, the response was greater when plasma drug concentration rose after the high dose, although the rate decrease was smaller than in the 9 compensated patients who received the low dose. These results can be explained by assuming an antagonism of the verapamil effect by sympathetic stimulation in nonresponders.     

116例慢性心房颤动患者心室率增快的诱因调查

目的：探讨慢性房颤患者急性心室率增快的诱因,为临床及时干预、治疗提供指导。方法：回顾性分析急诊收治的116例慢性房颤急性心室增快的临床资料。结果：116例患者中,肺部感染诱发慢性房颤急性心室率增快居首位,占52．59％,其他为急性胃肠炎,情绪改变、疼痛、疲劳与劳累,尿潴留等。结论：慢性房颤急性心室率增快均有相关诱因参与触发,关注并及时干预,去除诱因,对控制心室率具有重要意义。其中14例患者去除诱因后,达到了心室率减慢的治疗效果,占12．07％。     

胺碘酮与毛花苷C控制快速房颤心室率的疗效对比研究

目的对比研究胺碘酮与毛花苷C控制快速房颤心室率的疗效。方法对52例快速房颤患者随机分成两组,每组26例,分别静脉应用胺碘酮与毛花苷C。结果胺碘酮组与毛花苷C组总有效率分别为84.6%、57.7%,用药后心室率下降幅度分别为36.5%、25.8%,差异有统计学意义(P<0.05);平均起效时间分别为(22.8±7.6)和(51.2±9.8)min(P<0.01)。结论胺碘酮较毛花苷C更能迅速有效地控制快速房颤心室率。     

Preprocedural ventricular rate predicts subsequent sick sinus syndrome after ablation for long-standing persistent atrial fibrillation

Background: Concealed sick sinus syndrome may become manifest after restoration of sinus rhythm by ablation in patients with long-standing persistent atrial fibrillation (AF). The purpose of this study was to investigate the association between the preprocedural ventricular rate during AF and sinus node function in patients with long-standing persistent AF. Methods: Consecutive patients (n = 102) who underwent ablation for long-standing persistent AF were enrolled. We measured the ventricular rate during AF before ablation in the absence of antiarrhythmic drugs. Sinus node function was assessed by electrophysiological study and serial Holter recordings after ablation. Results: Patients in the lowest quartile of ventricular rate during AF had longer corrected sinus node recovery time (1.06 ± 1.39 seconds) than those in the other quartiles (0.54 ± 0.31 seconds; P = 0.006) and lower mean heart rate on 24-hour Holter recording 3 months after ablation (68 ± 9 beats/min vs 75 ± 10 beats/min, P = 0.01). During a mean follow-up of 23 ± 10 months, sick sinus syndrome necessitating permanent pacemaker implantation developed in five (5%) patients, and multivariate analysis revealed that a low ventricular rate during AF rate was an independent risk factor for sick sinus syndrome (odds ratio = 0.90 for a 1 beat/min increase in AF rate, P = 0.04). Conclusions: A low preprocedural ventricular rate during AF indicates the existence of sinus node dysfunction after restoration of sinus rhythm by ablation in patients with long-standing persistent AF. (PACE 2012; 35:1074-1080).     

Low-dose diltiazem in atrial fibrillation with rapid ventricular response

Objectives

Diltiazem is one of the most commonly used medications to control the rapid ventricular response in atrial fibrillation (AF). The recommended starting dose is an intravenous bolus of 0.25 mg/kg over 2 minutes. To avoid hypotension, we have empirically used a lower dose of diltiazem. We compared the efficacy and safety of different doses of diltiazem in rapid AF.

Methods

A retrospective chart review was undertaken in patients who presented to the emergency department with rapid AF. Patients were divided into 3 groups according to diltiazem dosage: low dose (≤0.2 mg/kg), standard dose (>0.2 and ≤0.3 mg/kg), and high dose (>0.3 mg/kg). We compared the rates of therapeutic response (adequate rate control) and complications (such as hypotension). Multivariate regression analysis was used to determine the effect of diltiazem dose on the occurrence of complications.

Results

A total of 180 patients were included in the analysis. There were no significant differences in the rates of therapeutic response for the low-, standard-, and high-dose groups (70.5%, 77.1%, and 77.8%; P = .605). The rates of hypotension in the low-, standard-, and high-dose groups were 18%, 34.9%, and 41.7%, respectively. After adjusting confounding variables, the rate of hypotension was significantly lower in the low-dose group in comparison with the standard-dose group (adjusted odds ratio, 0.39; 95% confidence interval, 0.16-0.94).

Conclusions

Low-dose diltiazem might be as effective as the standard dose in controlling rapid AF and reduce the risk of hypotension.     

用多普勒超声测算二尖瓣狭窄并心房颤动患者的最优心率

目的 探讨二尖瓣狭窄（MS）并心房颤动（AF）患者使心室率与左室充盈量直辖市从而改善心脏泵功能的方法。方法 在二尖瓣水平以多普勒超声体积血流方法建立以心室率为变量的心输出量方程。结果 通过数学方法导出最优心率和最大心输出量公式。结论 该系列公式为深化MS并AF血流动力学的认识并估算心脏泵功能提供了新的方法,为临床定量化,个体化地控制心室率提供了科学的依据。     

Adenosine induced atrial fibrillation precipitating polymorphic ventricular tachycardia

An 86-year-old female developed supraventricular tachycardia 36 hours after a myocardial infarction (MI). She developed atrial fibrillation and polymorphic ventricular tachycardia (PVT) following administration of 12 mg of adenosine. The PVT caused hemodynamic instability with no response to cardioversion, but termination with procainamide. The heart is vulnerable to hemodynamically unstable, possibly lethal, PVT early after MI under some circumstances. This vulnerability may be exposed following administration of adenosine. Extra caution is warranted when using adenosine in the post-MI period.     

Moderate physical exercise: a simplified approach for ventricular rate control in older patients with atrial fibrillation

Aims  This prospective pilot-study was performed to assess whether regular moderate physical activity elevates the parasympathetic tone to the atrio-ventricular node and decreases VR during permanent AF. Background  Adequate ventricular rate (VR) control in patients with permanent atrial fibrillation (AF) is not easy to accomplish. Methods  10 patients (mean age 59 ± 10 years) with permanent AF (duration: 10 ± 8 years) underwent moderate physical exercise adjusted to their individual physical capability (45 min walking/jogging twice a week). To analyze VR control physical exercise tests and Holter-ECG recordings were performed before and after 4 months. In addition, stepwise lactate tests and psycho-pathometric examinations were obtained. Results  After 4 months of training, there was a trend toward a decrease of mean VR in 24 h Holter-ECGs by 12% from 76 ± 20 to 67 ± 12 bpm (P = 0.05) while there was no significant decrease of the minimal VR (38 ± 8 vs. 36.3 ± 4.5 bpm, P = 0.54). At a lactate threshold of 2 mmol/l there was a trend towards an increase of the running speed from 105 ± 11 to 116 ± 12 m/min (P = 0.05). A significant VR decrease of 8% (range 5–10%) was observed at almost all exercise levels during exercise treadmill testing. Increases of exercise capacity and decreases of VR were accompanied by subjective improvements of health perception. Conclusion  Regular moderate physical activity decreases VR at rest and during exercise while increasing exercise capacity. Physical training should be taken into account for ventricular rate control during AF. The study was supported by the German Atrial Fibrillation Competence Network (AFCN) funded by the Fedral Ministry of Education and Research (FMBI). A. Blumberg and J. Plisiene contributed equally to this study.