Relationship between beat to beat interval and left ventricular function in patients with atrial fibrillation

In atrial fibrillation, the relation between the rhythm and volume of the pulse has long been of interest. However, changes in preload in this condition have not been fully addressed since beat to beat measurement of filling volume have been difficult until recently. In the present study, we evaluated left ventricular outflow and inflow velocity using pulsed Doppler echocardiography and correlated these results with the R-R interval in the individual patient. The study population consisted of 12 patients with atrial fibrillation, aged 36 to 69 years (mean 54 years). The etiology of atrial fibrillation was idiopathic in 10 and 2 patients had dilated cardiomyopathy. Stroke and filling volume were calculated as a pruduct of the flow velocity integral of left ventricular outflow and inflow velocity, and the cross-sectional area of aortic and mitral annulus, respectively. In 10 patients with idiopathic atrial fibrillation, significant positive correlations were observed between the preceding R-R interval and both the stroke volume and the filling volume of the preceding beat when the R-R interval was shorter than 600 msec. Stroke volume and filling volume of the preceding beat were almost constant, independent of the preceding R-R interval when the preceding R-R interval was longer than 600 msec, the interval necessary for the completion of the preceding rapid filling. In the same preceding R-R interval, a larger stroke volume was observed in a shorter pre-preceding R-R interval. In 2 patients with dilated cardiomyopathy no relationship could be observed between the preceding R-R interval and the filling volume of the preceding beat or the stroke volume. In patients with a normally functioning left ventricle (idiopathic atrial fibrillation), reduced cycle length and filling volume in the preceding cardiac cycle appear to be the underlying cause of the regulation of stroke volume, dependent on Starling's law. However, in patients with dilated cardiomyopathy no significant correlation was observed between the preceding R-R interval and both the filling volume of the preceding beat and the stroke volume. In these patients the left ventricle may have limited contractile reserve and altered diastolic re-coil forces possibly due to degenerative changes of myocardium. Pulsed Doppler echocardiography provides a non-invasive method of evaluating the instantaneous changes in left ventricular flow dynamics caused by atrial fibrillation and understanding its fundamental mechanism.     

非瓣膜性心房颤动患者及窦性心律者左心耳排空流速与左房功能参数的相关性研究

目的 应用经食管超声心动图(TEE)检测非瓣膜性心房颤动(以下简称房颤)患者及窦性心律者左心耳排空流速(LAAFV)，探讨其与经胸超声心动图(TTE)所测左房功能参数的相关性。方法 选取我院窦性心律者60例(窦性心律组)和非瓣膜性房颤患者30例(房颤组)。应用TTE获取左房收缩末期前后径(LADd_前后)、左右径(LADd_左右)、上下径(LADd_上下)，以及左室舒张末期内径、左室射血分数(LVEF)；斑点追踪技术获取左房储器期应变(LASr)、管道期应变(LAScd)、泵功能期应变(LASct)，以及左室整体纵向应变(LVGLAS)、左房收缩末期最大容积(LAVmax);TEE检测LAAFV。比较两组上述各参数的差异；分析窦性心律组和房颤组LAAFV与TTE所测左房功能参数的相关性。结果 房颤组LVEF、LVGLAS、LASr、LAScd、LASct、LAAFV均小于窦性心律组，LADd_前后、LADd_左右、LADd_上下、LAVmax均大于窦性心律组，两组比较...     

An Analysis of Post-Pacing R-R Intervals During Atrial Fibrillation

Bursts of ventricular pacing at cycle lengths of 350-260 ms were introduced during atrial fibrillation in nine patients, and the post-pacing R-R intervals were compared to the R-R intervals of spontaneous QRS complexes. In eight of nine patients, the mean post-pacing R-R interval was 126-199 ms longer than the mean spontaneous R-R interval (p less than 0.005). Spontaneous runs of aberrantly conducted supraventricular complexes were recorded during atrial fibrillation in one patient. The mean R-R interval following the runs of aberrantly conducted supraventricular complexes was significantly longer than the mean R-R interval of spontaneous narrow QRS complexes (p less than 0.001), but not significantly different than the mean post-pacing R-R interval. The findings of this study suggest that the R-R interval that follows a wide-complex tachycardia during atrial fibrillation is unlikely to be of value in differentiating ventricular tachycardia from aberrantly conducted supraventricular complexes. Analysis of R-R intervals that follow bursts of ventricular pacing suggests that there is likely to be considerable overlap between the R-R intervals that follow runs of ventricular tachycardia and the spontaneous R-R intervals during atrial fibrillation. Furthermore, even when the post-tachycardia R-R interval clearly exceeds the longest spontaneous R-R interval during atrial fibrillation, this is still of little diagnostic value, because a long pause may occur after either a run of ventricular tachycardia or a run of aberrantly conducted QRS complexes of supraventricular origin.     

The relation between mitral annulus motion and left ventricular ejection fraction in atrial fibrillation

Mitral annulus motion (MAM) has recently been introduced as an index of left ventricular function. Previous studies have shown a good agreement between MAM (mm) × 5 and ejection fraction in middle‐aged and elderly patients. These studies only included patients with sinus rhythm, while patients with atrial fibrillation were excluded. In the present study, MAM was reduced in patients with atrial fibrillation while ejection fraction (EF) did not differ from age‐matched control patients with sinus rhythm. The ‘conversion factor’ (EF/MAM) was 7·2 in the group with atrial fibrillation and 5·1 in controls with sinus rhythm. This difference must be taken into account when MAM is used to estimate left ventricular function in patients with atrial fibrillation. Patients with atrial fibrillation had lower stroke volume and higher heart rate than patients with sinus rhythm. A decreased systolic long‐axis shortening was found (P<0·005) compared to patients with sinus rhythm, but no difference in short‐axis diameter shortening.     

Differentiation of Arrhythmias in the Dog by Measurement of Activation Sequence Using an Atrial and Two Ventricular Electrodes

Timing of atrioventricular activation and ventricular dispersion identifies and discriminates between beats of different origin. In eight dogs, three bipolar epicardial electrodes recorded left atrial and left and right ventricular depolarizations simultaneously during arrhythmias induced by programmed electrical stimulation and coronary artery occlusion and release. The interval between the left atrial and left ventricular intrinsic deflections (V₁-V₂) and between the left ventricular and right ventricular intrinsic deflections (V₁-V₂) of each heat was measured. Recordings were of normal sinus rhythm (NSR) (mean of five beats in 8/8 dogs), atrial flutter (AFL) (five beats of one episode), atrial fibrillation (AF) (144 beats in 29 episodes in 7/8), monomorphic ventricular tachycardia (MVT) (24 beats with six morphologies in 2/8), polymorphic ventricular tachycardia (PVT) (63 beats in 15 episodes in 5/8) and premature ventricular contractions (PVC) (29 beats with 29 morphologies in 5/8). Supraventricular rhythms can be differentiated from ventricular rhythms by V₁-V₂ timing. The mean difference in V₁-V₂ during AFL and AF vs NSR was 1 ms (range of 0–3 ms). The change from sinus during MVT ranged from 38 to 43 ms (m 31 ms) and during PVC 10 to 75 ms (m 38 ms). Thirty-five of 35 of these ectopic ventricular morphologies exhibited 10 ms or more timing difference compared to corresponding beats of NSR. PVT was consistently distinguished from supraventricular rhythms and MVT by the variability of V₁-V₂,A-V₁ intervals can be used to distinguish supraventricular arrhythmias from sinus rhythm; a 32 ms difference existed for AFL. AF could be detected by the variability in AV₁. One atrial and two ventricular leads can provide a means of differentiating normal sinus rhythm from supraventricular and ventricular arrhythmias that may be applicable to implantable antitachycardia devices.     

Dual Atrio-ventricular Nodal Pathways and Atrial Fibrillation

The determinants of the ventricular rate during atrial fibrillation were studied in a group of eleven patients demonstrating dual A-V nodal pathways during atrial stimulation. The shortest R-R interval and the mean ventricular cycle length during at least 1 min of pacing-induced atrial fibrillation were compared: a) to the effective and functional refractory period of the fast pathway; b) to the effective refractory period of the slow pathway determined during atrial stimulation, at two or more different basic cycle lengths of pacing; and c) to the shortest cycle length during atrial stimulation followed by 1:1 A-V conduction. A group of 8 patients not demonstrating dual A-V nodal pathway-curves during atrial stimulation was used as a control. In both groups the shortest R-R interval during atrial fibrillation was best predicted by the shortest cycle length followed by 1:1 A-V conduction during atrial stimulation. The mean ventricular cycle length during atrial fibrillation was not accurately predicted by any of the variables studied. The similar results in patients with and without dual A-V nodal pathways suggest that concealed conduction from one to another A-V nodal pathway does not play a role in determining the ventricular response during atrial fibrillation in patients with dual A-V nodal pathways.     

Presence of accessory left atrial appendage/diverticula in a population with atrial fibrillation compared with those in sinus rhythm: a retrospective review

Accessory left atrial appendages and atrial diverticula have an incidence of 10–27%. Their association with atrial fibrillation needs to be confirmed. This study determined the prevalence, number, size, location and morphology of accessory left atrial appendages/atrial diverticula in patients with atrial fibrillation compared with those in sinus rhythm. A retrospective analysis of 47 consecutive patients with atrial fibrillation who underwent 320 multidetector Coronary CT angiography (CCTA) was performed. A random group of 47 CCTA patients with sinus rhythm formed the control group. The presence, number, size, location and morphology of accessory left atrial appendages and atrial diverticula in each group were analysed. Twenty one patients had a total of 25 accessory left atrial appendages and atrial diverticula in the atrial fibrillation group and 22 patients had a total of 24 accessory left atrial appendages and atrial diverticula in the sinus rhythm group. Twenty-one atrial diverticula were identified in 19 patients in the atrial fibrillation group and 19 atrial diverticula in 17 patients in the sinus rhythm group. The mean length and width of accessory left atrial appendage was 6.9 and 4.7 mm, respectively in the atrial fibrillation group and 12 and 4.6 mm, respectively, in the sinus rhythm group, P = ns (not significant). The mean length and width of atrial diverticulum was 4.7 and 3.6 mm, respectively in the atrial fibrillation group and 6.2 and 5 mm, respectively in the sinus rhythm group (P = ns). Eighty-four % and 96% of the accessory left atrial appendages/atrial diverticula in the atrial fibrillation and sinus rhythm groups were located along the right anterosuperior left atrial wall. Accessory left atrial appendages and atrial diverticula are common structures with similar prevalence in patients with atrial fibrillation and sinus rhythm.     

压力-应变环对射血分数正常的心房颤动患者射频消融术前后左心室心肌做功的评价

目的应用左心室压力-应变环（PSL）量化评价左心室射血分数（LVEF）正常的心房颤动患者射频消融术前、术后的左心室心肌做功指数。 方法这是一项回顾性研究。选取2020年1月至2020年12月于安徽医科大学第二附属医院就诊的LVEF正常的持续性心房颤动患者37例,所有患者均行心房颤动射频消融术。另选取同期37例健康者为对照组。所有心房颤动患者均在射频消融术前及术后3~6个月内行超声心动图检查。采集并获取心房颤动患者及对照组的常规超声心动图参数,以及左心室整体纵向应变（GLS）、整体做功指数（GWI）、整体有效功（GCW）、整体无效功（GWW）、整体做功效率（GWE）,分析比较心房颤动患者术前、术后及对照组3组的常规超声心动图参数以及压力-应变参数的差异。 结果心房颤动患者术前、术后及对照组LVEF比较,差异无统计学意义（P＞0.05）。心房颤动组术前GLS、GWI、GCW及GWE低于对照组,GWW高于对照组,差异均有统计学意义（P均＜0.05）。与术前比较,心房颤动组射频消融术后的GLS、GWI、GCW及GWE升高,GWW减低（P均＜0.05）;术后参数与对照组比较,GLS、GWI、GCW差异均无统计学意义（P均＞0.05）;但GWW高于对照组、GWE低于对照组,差异均有统计学意义（P均＜0.05）。 结论PSL可以定量评估LVEF正常的心房颤动患者术前及术后的左心室心肌做功改变,早期检测持续性心房颤动患者的心肌受损情况。早期行射频消融术恢复窦性心律,可以有效改善此类患者早期心肌受损。     

The Effects of Reverse Atrial Electrical Remodeling on Atrial Defibrillation Thresholds

MANGRUM, J.M., et al. : The Effects of Reverse Atrial Electrical Remodeling on Atrial Defibrillation Thresholds. The implantable atrial defibrillator is a developing therapeutic option for paroxysmal atrial fibrillation, but shock related discomfort continues to be a limiting factor. To further characterize successful defibrillation, the relationship between reverse atrial electrical remodeling and internal atrial defibrillation thresholds in canines with chronic atrial fibrillation was examined. Testing was performed in 21 dogs. Chronic atrial fibrillation was induced in eight dogs by creating moderate mitral regurgitation and rapidly pacing the right atrium for ≥ 6 weeks. The atrial fibrillation cycle length, atrial effective refractory period, refractory period dispersion, and internal atrial defibrillation thresholds were determined after establishment of chronic atrial fibrillation after 4 hours of sinus rhythm postcardioversion and 7 days of sinus rhythm postcardioversion. These measurements were then compared to a normal population of 13 dogs. The atrial defibrillation thresholds were 6.6 J (1.9–10.1 J) initially, 2.9 J (1.5–3.7 J) after 4 hours of sinus rhythm, and 0.9 J (0.4 – 1.3 J) after 7 days of sinus rhythm (  P = 0.04  ). This decrease was associated inversely with the atrial effective refractory period (  P < 0.03  ), and atrial fibrillation cycle length (  P < 0.05  ), and with a decrease in atrial refractory period dispersion after 7 days of sinus rhythm (  P = 0.04  ). These electrophysiological measurements reached normal population levels by 7 days. Atrial defibrillation thresholds decrease as atrial reverse electrical remodeling occurs and this reduction corresponds to increased atrial fibrillation cycle length, increased atrial refractoriness, and decreased refractory period dispersion.     

Paradoxical effect of respiration on ventricular rate in atrial fibrillation

1. In 50 subjects with atrial fibrillation we have attempted to demonstrate variation of ventricular rate with respiration, as evidence of cardioregulatory reflex activity. 2. The electrocardiogram was recorded for 3 min during spontaneous respiration. The presence of respiratory variation of R-R intervals was analysed by multiple regression against a cosine function (cosinor analysis), making it possible to determine the phase of respiration when the intervals were longest. 3. Variation in ventricular rate with respect to respiration was demonstrated (P less than 0.05) in seven (14%) cases. On average, R-R intervals were longest at the end of inspiration; this contrasts with sinus rhythm where P-P, P-R and R-R intervals are longest around the time of end-expiration. 4. These results suggest that in atrial fibrillation the beat-to-beat ventricular rate may be under the influence of cardioregulatory reflexes, but the effect of respiration is weak and paradoxical.     

Assessment of left atrial volumes in sinus rhythm and atrial fibrillation using the biplane area-length method and cardiovascular magnetic resonance imaging with TrueFISP.

OBJECTIVES: To determine whether the biplane area-length method can be used for the evaluation of left atrial volumes and ejection fraction with cardiovascular magnetic resonance imaging (CMR) by TrueFISP in normal subjects and patients with atrial fibrillation. BACKGROUND: Atrial fibrillation is the most common arrhythmia in elderly patients. Left atrial size and volumes play an important role in predicting short and long-term success after cardioversion. METHODS: Fifteen healthy subjects (mean age 65.6+/-6.4 years) and 18 patients (mean age 67.2+/-8.8 years) with atrial fibrillation were examined by CMR (Magnetom, Siemens, Erlangen, Germany). Images were acquired by TrueFISP using the horizontal and vertical long-axis plane to measure left atrial end-diastolic and end-systolic areas and longitudinal dimensions. Volumes were determined with commercially available software. Left atrial end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) were determined by the biplane area-length method and compared to findings obtained by the standard short-axis method. Images were acquired and analyzed a second time in the patients with atrial fibrillation. RESULTS: There was no difference in age between men and women (p=0.147) and healthy subjects and patients (p=0.128) included in the study. EDV and ESV were significantly higher and SV and EF significantly lower in patients with atrial fibrillation than in healthy subjects (p < or = 0.009), regardless of the method used. The values obtained for EDV and ESV by the biplane area-length method were significantly higher in both healthy subjects (p<0.001) and patients with atrial fibrillation (p<0.001) than those obtained by the standard short-axis approach, whereas SV (p> or = 0.057) and EF (p> or = 0.118) did not differ significantly. In the second investigation in patients with atrial fibrillation, ESV, SV, and EF did not differ significantly between the two methods (p> or =0.481). Assessment of interobserver variability revealed good agreement in the findings of the two observers, both in normal sinus rhythm and atrial fibrillation (overall variability 0.8+/-6.5%). CONCLUSIONS: The biplane area-length method can be used in CMR images obtained by TrueFISP to assess left atrial volumes and ejection fraction in normal subjects and patients with varying cardiac cycle length, as in atrial fibrillation.     

慢性房颤患者射频消融术后左心房和左心室远期结构变化简

目的探讨慢性房颤患者射频消融术后左心房、左心室远期结构变化。方法50例经射频消融治疗的房颤患者根据复发情况分为复发组（n=18）与未复发组（n=32）,对比两组患者术前、术后12个月左房前后径、左右径、上下径,左心房最大容积、左心室舒张末期内径、左心室收缩末期内径、左室射血分数。结果术前、术后随访12个月比较左房前后径、左右径、上下径,左心房最大容积、左心室舒张末期内径、左心室收缩末期内径、左室射血分数比较,复发组差异无统计学意义（P〉0．05）,未复发组差异具有统计学意义（P〈0．05）。结论射频消融术治疗房颤具有显著疗效,复律并维持窦性心律对于逆转左心房、左心室重构,提高左室功能均具有重要意义。     

Late improvement in ventricular performance following internal cardioversion for persistent atrial fibrillation: an argument in support of concealed cardiomyopathy

The aim of the study was to evaluate the time course of atrial and ventricular function improvement following internal atrial cardioversion in patients with structural heart disease. Twenty-nine patients with chronic persistent atrial fibrillation (AF) and underlying structural heart disease were followed by serial echocardiograms performed at 1 and 6 hours, 1 day, 1, 2, and 3 weeks, and 1, 2, 3, and 6 months after successful cardioversion. Sinus rhythm was maintained at 6 months in 24 patients. Following cardioversion the time course of left atrial mechanical function (peak A wave, percent A wave filling) differed from that of left ventricular ejection fraction: peak A wave values (cm/s) increased significantly at 1 week (51 +/- 23 vs 35 +/- 15 at 1 hour, P < 0.05), percent A wave filling (%) increased significantly at 2 weeks (34 +/- 12 vs 22 +/- 9 at 1 hour, P < 0.05), whereas left ventricular ejection fraction (%) increased later (at 1 month 60 +/- 14 vs 55 +/- 14 at baseline, P < 0.05 and at 2 months 60 +/- 14 vs 56 +/- 14 at 1 hour, P < 0.05). In conclusion, restoration of sinus rhythm results in an improvement in left ventricular ejection fraction during follow-up, even in patients with structural heart disease without fast ventricular rates at baseline. The dissociation between the time course of atrial and ventricular function improvement suggests that the latter was partly due to regression of a concealed form of cardiomyopathy and/or of a ventricular dysfunction due to chronic AF.     

Entrainment of Ventricular Tachycardia by Sinus Rhythm

Entrainment of ventricular tachycardia (VT) may be manifest as fixed and progressive QRS fusion with ventricular and, rarely, atrial pacing. Only a single example of spontaneous VT entrainment by another rhythm, rapid atrioventricular nodal tachycardia, has been reported. This article describes an example of fixed and progressive QRS fusion between conducted sinus rhythm and VT consistent with entrainment. In contrast to entrainment with pacing, entrainment of VT by sinus rhythm occurred with drug-mediated arrhythmia slowing and demonstrated progressive QRS fusion at a constant cycle length. However, it did not demonstrate unfused but entrained QRS complexes. The resulting short PR interval and wide QRS mimicked a preexcited rhythm.     

经食管超声心动图组织多普勒评价左心耳功能

目的观察窦性心律和心房纤颤（房颤）患者经食管超声心动图左心耳脉冲组织多普勒的图像特点,结合脉冲多普勒初步研究使用组织多普勒技术评价左心耳功能的价值。 方法窦性心律和房颤患者各15例均经食管超声心动图检查,房颤患者根据有无心房血栓或心房血流浓密自显影分为2组,并将经食管超声心动图的指标进行比较。 结果窦性心律患者的左心耳血流频谱和脉冲组织多普勒图像为可测量的三相波;房颤患者则表现为无规律的可测量的多相波。左心耳血流速度在各组间均有显著性差异;脉冲组织多普勒指标在窦性心律和房颤患者中有显著性差异,在有血栓和心房血流自显影的房颤患者中进一步降低或有进一步降低的趋势。 结论经食管超声心动图检查能获得可测量的左心耳（包括房颤患者）组织多普勒图像,可作为分析左心耳功能的重要补充。     

Relationship Between QT Interval Duration and Electrical Induction of Ventricular Tachycardia

The relation of inducible ventricular tachycardia (VT) to QT interval duration of ventricular paced rhythm has not been evaluated. To clarify this relation we measured corrected QT interval duration (QT_C) during sinus rhythm and QT interval duration during ventricular paced rhythm (QT-V) in patients with coronary artery disease without (non-VT group = group B) and with inducible VT (VT group = group A). Duration of QT-V was greater in the VT group (n = 20) compared with non-VT group (n = 20) during ventricular pacing at cycle lengths of 600 ms (424 ± 26 vs 396 ± 19 ms, P < 0.01), of 500 ms (407 ± 20 vs 383 ± 21 ms, P < 0.01), and of 400 ms (390 ± 21 vs 362 ± 17 ms, P < 0.001). During sinus rhythm the mean values of QT_C were similar in both groups (408 ± 25 vs 413 ± 20 ms, NSJ. During ventricular stimulation the percentage of patients with values of QT-V exceeding 380 ms was 35% in non-VT group and 95% in VT group (P <0.01) at cycle length of 500 ms and 5% versus 60%, respectively, (P < 0.01), at cycle length of 400 ms. Thus, a trend toward longer QT values of ventricular paced rhythm exists in patients with inducible VT.     

Termination of Tachycardias by Transesophageal Electrical Pacing

To evaluate the therapeutic significance of noninvasive transesophageal pacing for termination of tachycardias the method of rapid atrial or ventricular transesophageal pacing was used in 233 patients with different tachycardiac arrhythmias. We were able to terminate atrial flutter in 136 of 162 patients by transesophageal rapid atrial stimulation (conversion to sinus rhythm in 75 cases, induction of atrial fibrillation in 61 cases). Atrial tachycardias were interrupted in 17 of 23 patients (sinus rhythm in 11 cases, atrial fibrillation in six cases). AV reciprocating/AV nodal supravenrricular reentry tachycardias were terminated in 62 of 63 patients (sinus rhythm in 58 cases, atrial fibrillation in four cases). By transesophageal rapid ventricular pacing ventricular tachycardias could be terminated in ten of 15 patients. The success rate of transesophageal pacing was influenced by the pacing rate, by the type of tachycardiac arrhythmia inclusive by the type of atrial flutter and by the tachycardia's cycle length. Because the success rates are comparable with invasive technique and the procedure is simpler, the noninvasive transesophageal antitachycardiac pacing should be respected as the method of the first choice in patients with supraven-tricular tachycardias.     

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.     

Rate Stabilization by Right Ventricular Pacing in Patients with Atrial Fibrillation

A recent study of de Jongste has demonstrated the lengthening of short R-R intervals in patients with atrial fibrillation by right ventricular pacing. We have further analyzed the data from this study and specifically looked at the effect of right ventricular pacing on the R-R interval instability and heart rate. At the cost of only a slight increase in mean heart rate, a major reduction of the R-R interval instability can be obtained by right ventricular pacing. Based on these findings, we have developed and evaluated an automatic pacing rate algorithm, which continuously varies the stimulation rate in order to stabilize the otherwise irregular rhythm in patients with atrial fibrillation.     

老年心房颤动患者心脏结构和功能改变的超声心动图分析

目的 观察老年心房颤动（房颤）患者与实性心律患者心脏结构和功能的改变。方法 用多普勒超声心动图技术分析1166例60岁以上老年人的心脏情况；房颤患者与窭性心律患者比较。阵发性房颤患者与持续房颤患者比较。结果 老年房颤患者左心房和左心室扩大。左心室射血分数减低，瓣膜退行性改变及血流动力学改变的发生率高于窦性心律者（P〈0．05或P〈0．01）；老年房颤患者的房室径及面积与窭性心律患者问差异有显著性（P〈0．01）；持续房颤患者的左心房前后径和面积与阵发房颤患者间差异有显著性（P〈0．05）。结论 心脏结构和功能的改变可能是老年房颤发生和发展的危险因素之一。