Impact of anatomical features of the left atrial appendage on outcomes after cryoablation for atrial fibrillation

AimsPulmonary vein isolation (PVI) using cryoballoon has been accepted as a safe and effective method for treatment of atrial fibrillation (AF). Despite advances in catheter-based technologies, some patients still experience AF recurrence. In this study, we aimed to compare left atrial appendage (LAA) morphology in AF patients and subjects with sinus rhythm and also investigate the association between LAA morphology and success of PVI using cryoballoon in subjects with AF.MethodsIn this prospective study, 359 AF patients who underwent pre-ablation computed tomographic angiography (CTA) scan between January 2013–March 2016 were included as the patient group. 100 age and gender-matched subjects in sinus rhythm who had no AF episodes in 24-h Holter monitoring that underwent CTA were included as the control group.ResultsNon-chicken wing LAA morphology was more common in AF patients (p < 0.001). LAA was significantly deeper (p < 0.001) and short-axis diameter of LAA orifice and LAA orifice area were significantly larger (p < 0.001) in AF patients. Low take-off type morphology of LAA was more common in controls compared to AF patients (p = 0.006). At a median follow-up of 37 months, only longitudinal-axis left atrial diameter on CT (p = 0.003) and cauliflower-type LAA morphology (p = 0.004) were independent predictors of AF recurrence.ConclusionThis is the first study in the literature that investigates the relationship between anatomical variations of LAA and AF recurrence following cryoablation. Our findings demonstrate that cauliflower-type LAA morphology is associated with two-fold increased risk of AF recurrence.     

Assessment of blood stasis in left-atrial appendage with electron-beam CT: filling delay in atrial fibrillation

The left-atrial appendage (LAA) is the most frequent site of thrombus formation. The most probable reason is its anatomical structure and blood stasis. We hypothesized that peak time delay should occur in the LAA with stagnant blood flow. We measured peak time delay in LAA against left atrium with the flow-mode study of electron-beam CT for 49 patients (including 23 patients with atrial fibrillation [AF]). Volume-mode scannings were also performed to detect intracardiac thrombi. Patients with atrial fibrillation showed a larger value than those with sinus rhythm (P <0.01). Some AF patients with no filling of contrast media into the LAA and/or thrombus showed a larger value than the others. The value obtained by the flow-mode study might have the potential to assess blood stasis and to predict the jeopardized state in the LAA. Correspondence to: T. Nakanishi     

左心耳封堵术：预防心房颤动左心耳血栓的利刃

血栓栓塞性并发症是心房颤动致死、致残的主要原因,左心耳是心房颤动患者血栓形成的主要部位。抗凝及外科手术切除左心耳副作用及创伤大,患者难以接受。经皮导管介入行左心耳封堵术是近年来进展快速的预防心房颤动血栓栓塞的方法,具有创伤小、操作简单、耗时较少等优点。作者对国内外左心耳封堵术的相关研究进展作一介绍。     

实时三维超声心动图应用于房颤患者左心耳功能评价的价值

目的探讨实时三维超声心动图应用于房颤患者左心耳(left atrial appendage,LAA)功能的评价功能。方法选择2015年9月~2019年2月在本院住院患者188例,根据心律情况分为观察组(房颤)100例与对照组(窦性心律)88例,采用常规超声检查记录左心房(left atrium,LA)指标,采用实时三维超声心动图评定LAA功能并进行相关性分析。结果观察组的LAD值显著高于对照组(P<0.05),而LAEF与LAFI值显著低于对照组(P<0.05)。LAA含有丰富的梳状肌、肌小梁,形态各异,凹凸不平,分叶数目不等,两组左心耳分叶数目对比差异无统计学意义(P>0.05)。观察组的LAA-OL、LAA-OS、LAA-H、LAA-V值显著高于对照组(P<0.05)。在观察组中,直线相关分析显示LAA-OL、LAA-OS、LAA-H、LAA-V与LAD呈现正相关性,与LAEF与LAFI呈现负相关性(P<0.05)。结论实时三维超声心动图可准确评估房颤患者的LA容积与LAA功能,对判定患者病情与预测预后都具有重要价值。     

256层螺旋CT检测持续性房颤病人左心房血栓的优化扫描方案

目的 旨在优化256层螺旋CT扫描方案以检测持续性房颤病人左心房（LA）血栓。 方法 前瞻性选取因持续性房颤入院并需行射频消融术的病人125例,其中男71例,女54例,平均年龄（58.2±8.19）岁,将其随机平均分为A-E 5组,每组25例。所有病人术前均行多层螺旋CT（MSCT）和经食管超声心动图（TEE）检查。MSCT检查采用前瞻性心电门控Bolus-Tracking扫描并对相同扫描范围进行延迟二次扫描,A~E组的延迟时间分别取15、25、35、45和55 s。对影像质量进行主观评分,测量并计算各组LA、左心耳（LAA）、左上肺静脉（LSPV）、左下肺静脉（LIPV）、右上肺静脉（RSPV）、右下肺静脉（RIPV）的平均CT值、对比噪声比（CNR）和信噪比（SNR）。采用单因素方差分析或卡方检验比较5组病人的基本资料和影像质量客观评价指标,采用Kappa一致性检验分析2名影像诊断医师对5组扫描方案的影像质量主观评分的一致性。以TEE检查结果为金标准,计算各组MSCT诊断LA血栓的敏感度、特异度、准确度、阳性预测值和阴性预测值。采用受试者操作特征（ROC）曲线分析各组MSCT检出LA血栓的诊断效能,计算ROC曲线下面积（AUC）。 结果 采用25 s延迟时间进行二次扫描（B组）诊断LA血栓的敏感度（78.6%）、特异度（95.9%）、准确度（90.1%）、阳性预测值（88.1%）、阴性预测值（92.5%）和曲线下面积（AUC）（0.893）均最高。2名医师对A、B、C、E组的影像质量主观评分的一致性均较好（均κ≥0.75）,D组评分的一致性中等。对各血管的CT影像进行客观评价,A、B、C组的平均CT值均高于D、E组（均P<0.05）,其中B组的LA、LAA、RSPV、RIPV 平均CT值最高,A组的LSPV、LIPV平均CT值最高。5组间CNR和SNR的差异均无统计学意义（均P>0.05）。 结论 采用延迟二次扫描的256层螺旋CT扫描方案可以有效检出持续性房颤病人的LA血栓,推荐延迟时间采用25 s。     

Dual-source CT coronary angiography in patients with atrial fibrillation: Comparison with single-source CT

Objective

To evaluate the performance of dual-source computed tomography (DSCT) for the visualization of the coronary arteries in a population with atrial fibrillation (AF) compared to single-source CT (SSCT) and to explore the impact of patients’ heart rate (HR) on image quality (IQ) and reconstruction timing.

Methods

Thirty consecutive patients (11 male, 19 female; 69.0 ± 9.2 years old) with suspected coronary artery disease and permanent AF were examined on a DSCT scanner (120 kV, 400 mAs/rot, 0.33 s rotation time, 64 × 0.6 mm collimation, pitch 0.20–0.28, Siemens Somatom Definition). Patients were divided into two groups: low and medium HR group (HR ≤ 80 bpm, n = 14) and high HR group (HR > 80 bpm, n = 16). Five of the patients also underwent conventional coronary angiography (CAG). The raw data from both tube detector arrays were reconstructed as DSCT data using a routine algorithm (temporal resolution of 83 ms). The raw data from one tube detector array was reconstructed separately on the same system using a routine single source algorithm (temporal resolution of 83–165 ms) and defined as virtual SSCT data. Image quality was assessed using a four-point grading scale from excellent (1) to non-assessable (4).

Results

IQ of the DSCT data was significantly better than that of the virtual SSCT data (mean score 1.33 ± 0.61 vs. 1.80 ± 1.02; Z = −8.755, P = 0.000). 98.6% of the segments shown in DSCT were diagnostic, compared with 89.9% of the segments in virtual SSCT, χ² = 32.595, P = 0.000. In DSCT group, IQ of low HR group was also better than that of high HR group, although the difference was not as big (mean score 1.25 ± 0.52 vs. 1.38 ± 0.66; Z = −2.227, P = 0.026). The mean HR of low HR group and high HR group were 67.4 ± 8.5 beats per minute (bpm) and 94.2 ± 8.8 bpm (t = −8.499, P = 0.000). The range of the variation of HR was higher in high HR group than in low HR group (mean difference between maximum and minimum HR 79.5 ± 21.0 vs. 49.9 ± 21.1 bpm; t = −3.845, P = 0.001). In 23 (77%) patients optimal IQ was achieved within one phase for all three main arteries. In low HR group, the optimal phase was distributed evenly between diastole and systole; but in high HR group, the optimal phase shifted to systole in most cases (92%). In five cases these results were compared to CAG results to look for the ability to identify stenosis with a diameter reduction of more than 50% of the lumen. With DSCT it was possible to diagnose 20 of 21 stenosis and 48 of 49 non-stenosed vessel segments correctly. With SSCT 19 of 21 stenosis and 45 of 49 non-stenosed vessel segments were diagnosed correctly according to CAG.

Conclusion

Due to its high temporal resolution, DSCT provides images of full diagnostic image quality in patients with AF, which otherwise would be excluded from CT examinations. The number of assessable segments for DSCT is still somewhat less than in non-AF patients, but in opposition to SSCT still valid for routine diagnostic imaging. Patients’ HR had impact on IQ and reconstruction timing.     

Noninvasive gadolinium-enhanced three dimensional computed tomography coronary angiography

RATIONALE AND OBJECTIVES: Although the use of gadolinium (Gd)-based contrast agents for angiographic studies of abdominal aorta, renal vasculature, and digital subtraction angiography has been reported, no studies have shown their diagnostic efficacy and image quality in coronary computed tomography angiography (CTA). The aim of this study is to evaluate the image quality of Gd-based contrast agents during coronary CTA. MATERIALS AND METHODS: A phantom study was done to evaluate the attenuation of serial dilutions of Gd and iodinated agents. This study was done on a 64-slice multirow detector CT (MDCT) scanner and e-speed scanner and CT attenuation Hounsfield units (CTHU) were compared. We evaluated 35 consecutive patients who underwent Gd-enhanced CTA. CTHU of aorta was measured at first, mid, and lowest slice levels with and without contrast administration. The image quality was graded on the basis of visualization of the coronary arteries (scale I-III; III demonstrating diagnostic image quality of the distal-most vessels). In a substudy, four patients with borderline renal insufficiency underwent CTA using Gd and iodinated contrast agents admixed in a 50:50 ratio. RESULTS: The phantom study showed that enhancement of various dilutions of Gd and iodine resulted in near identical CTHU with both e-speed and 64-slice scanners (r(2) > or = 0.997). Mean CTHU with contrast at the top slice was 116 HU, at middle slice was 125 HU, and at the lower slice was 93 (111.14 +/- 22). Quality evaluation showed 2 grade III, 9 grade II, and 24 grade I images (average quality of images 1.35). Mean CTHU was 222. CONCLUSION: Gd-enhanced contrast medium provides adequate enhancement of coronary vasculature, allowing for diagnostic evaluation of coronary arteries with new CT systems. Use of newer generations of multirow detector CT scanners should further enhance the quality of images.     

Efficacy of pre-scan beta-blockade and impact of heart rate on image quality in patients undergoing coronary multidetector computed tomography angiography

OBJECTIVE: While beta-blockers are routinely administered to patients prior to coronary computed tomography angiography (CTA), their effectiveness is unknown. We therefore assessed the efficacy of beta-blockade with regards to heart rate (HR) control and image quality in an unselected patient cohort. METHODS: We studied 150 consecutive patients (104 men/46 female; mean age, 56+/-13 years) referred for coronary CTA. Intravenous metoprolol (5-20mg) was administered to patients with a HR >65 beats per minute (bpm). The goal HR was defined as an average HR <65 bpm without a single measurement above 68 bpm. RESULTS: Overall, 45% (68/150) of patients met the HR criteria for beta-blocker administration of which 76% (52/68) received metoprolol (mean dose 12+/-10mg). Of the 52 patients who received beta-blocker versus the 98 who did not, 18 (35%) versus 62 (64%) patients achieved the goal HR, respectively. All patients who achieved the target HR had an evaluable CTA while five patients who did not achieve the target HR had at least one non-evaluable coronary artery due to motion artifact. There was also a significant reduction in any motion artifact among those who achieved the goal HR as compared to those who did not (p=0.001). Logistic regression revealed an increase in the odds of stair step artifact of 11.6% (95% CI: 2.4% decrease, 27.5% increase) per 1 bpm increase in the standard deviation of scan HR. CONCLUSION: Overall, efficacy of beta-blocker administration to reach target HR is limited. Improvements in CT scanner temporal resolution are mandatory to achieve consistently high image quality independent of HR and beta-blocker administration.     

Value of multislice computed tomography angiography of the thorax in preparation for catheter ablation for the treatment of atrial fibrillation: the impact of unexpected cardiac and extracardiac findings on patient care

Objective

In patients referred for catheter ablation for the treatment of atrial fibrillation, multislice computed tomography angiography of the thorax is routinely performed to assess pulmonary vein anatomy. We sought to investigate the incidence of unexpected cardiac and extracardiac findings in this select patient population and to establish how these findings influence subsequent patient care.

Methods

Ninety-five patients (mean age 62 ± 10 years, 35% female) referred to our institution for ablation therapy for atrial fibrillation between July 2003 and October 2007 underwent multislice computed tomography angiography of the thorax. Radiologists interpreted all images. Need for additional testing, consultation and eventual diagnosis were assessed by electronic record review.

Results

A total of 83 (5 cardiac, 78 extracardiac) unexpected findings were observed in 50/95 (53%) of patients. The findings prompted 23 additional tests (5 cardiac, 18 noncardiac) in 15/95 (16%) of patients and 8 subsequent referrals in 7/95 (7%) patients. In 6 patients the findings significantly altered future patient care and resulted in postponement of ablation therapy in 4 patients. In 2 patients, extracardiac findings (pulmonary emboli and adenocarcinoma of the lung) were of potentially life-saving consequence.

Conclusions

In patients undergoing multislice computed tomography angiography of the thorax in anticipation of planned catheter ablation therapy for the treatment of atrial fibrillation, unexpected findings are common and of potentially significant value. In comparison, there is a higher prevalence of unexpected extracardiac, rather than cardiac findings. Further investigation of these findings may lead to postponement of ablation therapy, but may also be of potentially lifesaving consequence.     

MDCT in the diagnostic algorithm in patients with symptomatic atrial fibrillation

Atrial fibrillation(AF) is the most common supraventricular arrhythmia and a major cause of morbidity.Arrhythmogenic foci originating within the pulmonary veins(PVs) are an important cause of both paroxysmal and persistent AF.A variety of endovascular and surgical techniques have been used to electrically isolate the PV from the left atrium.Pulmonary venography for localization of the PV ostium can be difficult to perform during the ablation procedure.While the anatomy of the PV is patientspecific,non-invasive imaging techniques may provide useful diagnostic information prior to the intended intervention.In this context,multidetector computed tomography(MDCT) visualization of the left atrial and PV anatomy prior to left atrial ablation and PV isolation is becoming increasingly important.MDCT imaging provides pre-procedural information on the left atrial anatomy,including atrial size and venous attachments,and it may identify potential post-procedural complications,such as pulmonary vein stenosis or cardiac perforations.Here,we review the relevant literature and present the current"state-of-the-art"of left atrial anatomy,PV ostia as well as the clinical aspects of refractory AF with MDCT imaging protocols and procedural aspects of PV ablation.     

Computed tomography measurement of the left atrial appendage for optimal sizing of the Watchman device

IntroductionPercutaneous left atrial appendage (LAA) occlusion is an emerging treatment option for patients with non-valvular atrial fibrillation who cannot tolerate oral anticoagulation. The Watchman device (Boston Scientific Corporation, Natick, MA, USA) is deployed at the ostium of the LAA, and an appropriately sized device is critical for successful occlusion. However, standardized imaging protocols for device sizing have not been established.ObjectivesWe investigated the clinical utility of a standardized imaging protocol, with pre-procedural multi-detector cardiac computed tomography (MDCT), and intra-procedural transesophageal echocardiography (TEE), for Watchman device sizing.MethodsPatients who underwent Watchman device implantation between 2010 and 2016 at our center, and who had pre-procedural MDCT and intra-procedural TEE were included. MDCT measurements (CTmax, CTmin, CTmean), and TEE measurement (TEEmax) of the LAA ostium were determined for each case, and correlated with the final size of the Watchman device implanted. Demographic data and clinical outcomes were collected.ResultsThe study included 80 patients (mean age: 75 ± 9.6 years; male: 68%; mean CHA2DS2-VASc score: 4.5 ± 1.4). CTmax of the LAA ostium correlated strongly with the final deployed Watchman device size (Spearman's rho: 0.81, p < 0.001), while TEEmax of the LAA ostium showed only moderate correlation with the final deployed Watchman device size (Spearman's rho: 0.61, p < 0.001). Implantation success rate was 100%. At a mean duration of follow-up of 197 days, there were no device-related complications (device embolization, cardiac perforation and pericardial tamponade). At follow-up, the vast majority of patients (76 patients; 95%) had either no or trivial (≤3 mm) residual peri-device leak on TEE.ConclusionsA standardized imaging protocol for assessment of Watchman device implantation incorporating pre-procedural MDCT and intra-procedural TEE, was associated with excellent procedural outcomes at a mean duration of follow-up of 197 days.     

血管造影术结合经食管超声心动图对左心耳形态的分析

目的 探讨血管造影术结合经食管超声心动图(TEE)在左心耳(LAA)大小及形态分析中的应用价值.方法 38例行LAA造影术患者术前行TEE检查,由2名观察者分别测量LAA开口最大径、深度,观察LAA形态,并与LAA造影术进行对比.结果 LAA造影术测量LAA开口径为(18.8±3.9) mm,2名TEE观察者测量分别为(17.8±3.8) mm、(18.6±4.0) mm,与LAA造影术测值的相关系数(r)分别为0.90、0.98 (P＜0.01);LAA造影术测量LAA深度为(25.5±5.7)mm,TEE分别为(26.5±6.1) mm、(26.5±5.9) mm,与LAA造影术测值的r分别为0.93、0.92 (P＜0.01).TEE观察者之间Bland-Altman分析一致性较好.LAA造影显示LAA为鸡翅型15例,仙人掌型11例,风向袋型7例,菜花型5例,分别占39.5％、28.9％、18.4％、13.2％,其中35例与TEE一致,一致性达92.1％.结论 LAA血管造影术结合TEE更有助于观察LAA的大小及解剖形态,测量具有准确性及可靠性.     

房颤导管消融联合左心耳封堵治疗后新发并发症影响因素的分析

目的 探讨非瓣膜性房颤患者在"一站式"治疗中新发并发症的影响因素及术中经食管超声心动图的应用.方法 选取射频消融联合左心耳封堵术的非瓣膜性房颤患者88例,围手术期行经食管超声心动图检查,术中结合X线造影指导Wantchman封堵器选择及释放,评估治疗效果及露肩、残余分流等新发并发症的影响因素.结果 术中及术后左心耳封堵...     

Left atrial appendage closure guided by 3D computed tomography printing technology: A case control study

BackgroundWe sought to evaluate the additional value of left atrial appendage (LAA) 3D printing derived from computed tomography (CCT) in determining the size for LAA occlusion (LAAO) devices as compared to standard measurement by using occurrence of LAA leak as endpoint.MethodsWe evaluated 6 patients with LAA leak (cases) and 14 matched patients without LAA leak (controls) after LAAO. For each group, a patient-specific 3D printed model of LAA was manufactured using CT pre-operative images. The size recommended by the 3D printed model was compared with the size of the implanted device.ResultsCompared to the 3D printed model, 55% of the devices were underestimated, the two sizing approaches agreed in 35% of the patients, while the 3D printed model overestimated the size in 10% of patients. The prevalence of LAA leak was significantly higher in the subset of patients with underestimation of prosthesis implanted with the standard approach as compared to the other patients (p = 0.019).Conclusion3D printing of the LAA may provide additional value to standard practice for LAAO device prosthesis sizing with the potential impact to reduce LAA leak.     

128层CT冠状动脉成像对左心室功能的评价

目的:应用冠状动脉成像原始数据,了解左心室形态变化,评价整体左心室功能。方法:收集90例患者冠状动脉成像原始数据,行MPR,观察左心室形态和各心肌节段的变化,并应用心功能分析软件自动计算出左心室收缩末期容积(ESV)、舒张末期容积(EDV)和射血分数(EF)。根据冠状动脉、左心室形态及整体左心室功能,将所有患者分为对照组、冠心病组、左心室肥厚组及心功能衰竭组,结合各组左心室形态变化,将左心室ESV、EDV和EF进行统计学比较和分析。结果:对照组患者冠状动脉和左心室形态正常;冠心病组左心室壁局限性增厚7例和变薄13例;左心室肥厚组左心室缩小、心室壁增厚;心功能衰竭组心室扩大、室壁普遍变薄。对照组、冠心病组、左心室肥厚组、心功能衰竭组平均EDV和ESV分别为(133.58±14.91)mL、(51.33±11.06)mL;(130.68±11.53)mL、(56.16±8.24)mL;(97.59±8.18)mL、(29.53±4.78)mL;(229.40±50.64)mL、(171.27±60.64)mL。冠心病组与对照组平均EDV和ESV比较,差异无统计学意义,左心室肥厚组及心功能衰竭组与对照组比较,差异均有统计学意义(P0.001)。对照组、冠心病组、左心室肥厚组、心功能衰竭组EF分别为(61.25±5.83)%、(56.37±6.79)%、(68.94±5.36)%和(26.33±8.30)%,差异均有统计学意义。结论:应用冠状动脉成像原始数据,结合冠状动脉及左心室形态改变,无创评价左心室整体功能,实用而可行,可为临床提供更多有价值的信息。     

State of the art paper: Cardiac computed tomography of the left atrium in atrial fibrillation

The clinical spectrum of atrial fibrillation means that a patient-individualized approach is required to ensure optimal treatment. Cardiac computed tomography can accurately delineate atrial structure and function and could contribute to a personalized care pathway for atrial fibrillation patients. The imaging modality offers excellent spatial resolution and has been utilised in pre-, peri- and post-procedural care for patients with atrial fibrillation. Advances in temporal resolution, acquisition times and analysis techniques suggest potential expanding roles for cardiac computed tomography in the future management of patients with atrial fibrillation. The aim of the current review is to discuss the use of cardiac computed tomography in atrial fibrillation in pre-, peri- and post-procedural settings. Potential future applications of cardiac computed tomography including atrial wall thickness assessment and epicardial fat volume quantification are discussed together with emerging analysis techniques including computational modelling and machine learning with attention paid to how these developments may contribute to a personalized approach to atrial fibrillation management.