Relationship of the esophagus and aorta to the left atrium and pulmonary veins: Implications for catheter ablation of atrial fibrillation

BACKGROUND: A potential complication during ablation of atrial fibrillation (AF) is damage to adjacent structures such as the esophagus and aorta. Fatal atrio-esophageal fistulas have developed after surgery- or catheter-based AF ablation procedures. OBJECTIVES: The purpose of this study was to analyze multidetector computed tomography (MDCT) angiographic images to determine the anatomic relationship of the aorta and esophagus to the left atrium (LA). METHODS: Sixty-five subjects underwent CT imaging using a 16-slice MDCT scanner: 24 with paroxysmal AF, 21 with chronic AF, and 20 "control" subjects without a history of AF. Measurements assessed included LA diameters, width of the esophagus and aorta in contact with the posterior LA wall, and distance from the esophagus to the four pulmonary veins (PVs), spine, and LA endocardium. RESULTS: Mean LA diameters were significantly larger in patients with AF vs the control group (P = .003 for anteroposterior diameter; P = .009 for transverse diameter). The anterior aspect of the esophagus was directly apposed to the LA in all cases (contact width 18.9 +/- 4.4 mm). The position of the esophagus varied in the posterior mediastinum but on average was closer to the ostia of the left PVs (P = .0001). The descending aorta was in contact with the LA and/or left PVs in 50 of 65 subjects. The esophagus was closer to the spine in the chronic AF vs control group (P = .007), likely due to increased LA dimension. CONCLUSION: In addition to its ability to assess PV anatomy, preprocedural MDCT imaging can investigate the variable relationship of adjacent structures, such as the esophagus and aorta to the LA and PVs.     

Morphologic characteristics of the left atrial appendage, roof, and septum: implications for the ablation of atrial fibrillation

Introduction: The left atrium (LA) ablation in different regions, including LA appendage (LAA), LA roof, and LA septum, has recently been proposed to improve the success rate of treating patients with atrial fibrillation (AF). The purpose of this study was to investigate the anatomy of LAA, LA roof, and LA septum, using computed tomography (CT).
Methods and Results: Multidetector CT scan was used to depict the LA in 47 patients with drug-refractory paroxysmal AF (39 males, age = 50 ± 12 years) and 49 control subjects (34 males, age = 54 ± 11 years). The area of LAA orifice, neck, and the length of roof line were greater in AF group than in control subjects. Three types of LAA locations and two types of LAA ridges were observed. Higher incidence of inferior LAA was noted in AF patients. The different morphologies of LA roof were described. Roof pouches were revealed in 15% of AF and 14% of controls. Moreover, we found septal ridge in 32% of AF and 23% of controls.
Conclusions: Considerable variations of LAA and LA roof morphologies were demonstrated. Peculiar structures, including roof pouches and septal ridges, were delineated by CT imaging. These findings were important for determining the strategy of AF ablation and avoiding the procedure-related complications.     

External and endoluminal analysis of left atrial anatomy and the pulmonary veins in three-dimensional reconstructions of magnetic resonance angiography: the full insight from inside

Introduction: The detailed knowledge of the individual pulmonary vein (PV) anatomy may help to prevent serious complications during PV isolation (PVI). The purpose of this study was to determine the geometry of the PV ostia and their spatial relation to adjacent structures in external (ex 3D) and endoluminal (en 3D) three-dimensional reconstructions of magnetic resonance angiographies (MRAs).
Methods and Results: Ex 3D and en 3D of the left atrium (LA) and the PVs of 28 patients were calculated. Diameters and the shape of PV ostia were assessed. In addition, the distances between ipsilateral PV ostia, the LA isthmus line, the roof line and the distance between the left PV and the LA appendage (LAA) were measured. Both ex 3D and en 3D are useful tools to determine the dimensions and the geometry of PVs. En 3D facilitates the identification of common PV ostia (15/28 patients). In en 3D, ipsilateral PV ostia are separated by a narrow myocardial ridge of less than 4 mm in 19/38 PVs (mean 4.3 ± 1 mm; 4.6 ± 2 mm with ex 3D). LAA and the LPV ostia are separated by a ridge of less than 4 mm in 12/28 PVs measured with en 3D (4.8 ± 2 mm; 6.4 ± 2 mm with ex 3D).
Conclusions: Both ex 3D and en 3D reconstructions of MRA precisely visualize the complex LA anatomy. Exact determination of PV ostial geometry is facilitated with en 3D and provides important anatomical information for the PVI strategy. According to our data, individual encircling of every PV is strongly discouraged.     

Close relationship between the bronchi and pulmonary veins: implications for the prevention of atriobronchial fistula after atrial fibrillation ablation

Introduction: Atrio-bronchial fistula (ABF) can be a rare but potentially lethal complication following the catheter ablation of atrial fibrillation (AF). Understanding the extent of the contact between the bronchial tree and pulmonary veins (PVs) is critical to avoid this complication. We investigated the anatomic relationship between the four PVs and bronchial tree using multi-detector computed tomography (MDCT) images.
Methods and Results: Seventy patients with drug refractory AF were included. They underwent 16-slice MDCT before the ablation. The spatial relationship between the bronchus and PVs was demonstrated by the multi-planar images. The bronchus was in direct contact with four PVs in the vast majority of patients. The mean distances between the bronchus and the ostia of right superior, left superior, right inferior, and left inferior PV were 7.1 ± 5.5, 3.5 ± 4.8, 12.3 ± 5.6, and 17.9 ± 6.8 mm, respectively. Patients were categorized into two groups: Group I: proximal contact (<5 mm from the PV ostium) and Group II: distal contact (>5 mm from the PV ostium). For the right superior pulmonary vein (RSPV), the Group I patients were associated with thinner connective tissue between them (P = 0.001), a larger RSPV (17.2 ± 2.2 vs 15.5 ± 2.1 mm, P < 0.001), and right inferior pulmonary vein (RIPV) diameter (15.9 ± 1.9 vs 14.6 ± 1.6 mm, P < 0.01). For the left superior pulmonary vein (LSPV), the Group I patients were associated with an older age (P = 0.02).
Conclusion: Isolation of the superior PVs may carry the potential risk of bronchial damage. The clinical or anatomic characteristics associated with the proximal contact between the bronchi and superior PVs can provide useful information to prevent this complication.     

Characterization of conduction recovery across left atrial linear lesions in patients with paroxysmal and persistent atrial fibrillation

Background: Left atrial (LA) linear lesions are effective in substrate modification for atrial fibrillation (AF). However, achievement of complete conduction block remains challenging and conduction recovery is commonly observed. The aim of the study was to investigate the localization of gap sites of recovered LA linear lesions.
Methods and Results: Forty-eight patients with paroxysmal (n = 26) and persistent/permanent (n = 22) AF underwent repeat ablation after pulmonary vein (PV) isolation and LA linear ablation at the LA roof and/or mitral isthmus due to recurrences of AF or flutter. In 35 patients, conduction through the mitral isthmus line (ML) had recovered whereas roof-line recovery was observed in 30 patients. The gaps within the ML were distributed to the junction between left inferior PV and left atrial appendage in 66%, the middle part of the ML in 20%, and in 8% to the endocardial aspect of the ML while only 6% of lines showed an epicardial site of recovery. The RL predominantly recovered close to the right superior PV (54%) and less frequently in the mid roof or close to the left PV (both 23%). Reablation of lines required significantly shorter RF durations (ML: 7.24 ± 5.55 minutes vs 24.08 ± 9.38 minutes, RL: 4.24 ± 2.34 minutes vs 11.54 ± 6.49 minutes; P = 0.0001). Patients with persistent/permanent AF demonstrated a significantly longer conduction delay circumventing the complete lines than patients with paroxysmal AF (228 ± 77 ms vs 164 ± 36 ms, P = 0.001).
Conclusions: Gaps in recovered LA lines were predominantly located close to the PVs where catheter stability is often difficult to achieve. Shorter RF durations are required for reablation of recovered linear lesions. Conduction times around complete LA lines are significantly longer in patients with persistent/permanent AF as compared to patients with paroxysmal AF.     

Further evidence of a close anatomical relation between the oesophagus and pulmonary veins.

BACKGROUND: Atrio-oesophageal fistula has been reported as a rare but life-threatening complication of ablation of atrial fibrillation (AF). Therefore, the position of the oesophagus in relation to the left atrium (LA) is of major importance for AF ablation. METHODS AND RESULTS: In order to investigate the possible anatomical variability between the oesophagus and the left atrium, multidetector-row spiral computed tomography (MDCT) of 60 healthy males (age 58.1+/-5.1 years; LA diameter 5.4+/-0.7 x 3.8+/-0.6 cm; LA volume 60.5+/-15.4 ml) was analyzed. The distance between the oesophagus and the ostia of the pulmonary veins (PV) ranged between 0 and 50.7 mm. Especially for the left PV, the oesophagus was closer than 5 mm to the ostia in 29 cases (48%; n = 24 for left superior PV; n = 10 for left inferior PV; n = 0 for right superior PV; n = 1 for right inferior PV). In addition, the oesophagus was very close to the LA wall (0.8+/-0.9 mm; range 0-3.3 mm). Intraobserver variability was 1.1+/-0.7 mm or 3.5%. CONCLUSION: The position of the oesophagus in relation to the LA and the PV demonstrates high variability. In many cases, the oesophagus is very close to the ostia of the PVs and lies only a short distance from the LA wall. Thus, an anatomical localization of the oesophagus may be critical before or during AF ablation to prevent atrio-oesophageal fistula, especially as there is a need for transmural atrial lesions.     

Comparison of contrast enhanced 64-slice computed tomography and transesophageal echocardiography in detection of left atrial thrombus in patients with atrial fibrillation

BACKGROUND AND OBJECTIVE: Recent advances in multi-slice computed tomography (MSCT) have allowed an improved analysis of left atrial (LA) and left atrial appendage (LAA) anatomy prior to catheter ablation of atrial fibrillation (AF). However, data regarding the ability of MSCT to identify LA/LAA thrombus are limited. This prospective study compared the efficacy of 64-slice contrast-enhanced computed tomography (64CCT) with transesophageal echocardiography (TEE) of the heart in the identification of LA/LAA thrombus. MATERIALS AND METHODS: One-hundred and seventy consecutive patients scheduled for first-time catheter ablation of paroxysmal (n = 120) or persistent (n = 50) AF were enrolled for study. Each patient underwent non-gated 64CCT and TEE of the heart for exclusion of LA/LAA thrombus prior to ablation procedure. RESULTS: Fourteen cases (8.2%) of LA/LAA thrombi were interpreted by 64CCT (ten false-positive, four true positive), whereas 11 actual thrombi (6.5%) were detected by TEE (seven false-negative by 64CCT) in the same population. Maximal dimension of TEE identified thrombi did not differ between the false-negative by 64CCT group and the true-positive group (17 +/- 6 vs. 18 +/- 5 mm P = 0.677). Results indicated 64CCT sensitivity = 36.4%, specificity = 93.7%, positive predictive value = 28.6%, and negative predictive value = 95.5% in the detection of LA/LAA thrombus. The Kappa value in evaluating the agreement between 64CCT and TEE for detection of LA/LAA thrombus was 0.267. CONCLUSION: Compared to gold standard TEE, 64CCT was shown to be less reliable in the detection of LA/LAA thrombus prior to catheter ablation in patients with AF.     

TISSUE CHARACTERIZATION TO DIFFERENTIATE PATHOLOGICAL FROM PHYSIOLOGICAL HYPERTROPHY IN PATIENTS WITH HYPERTENSION AND ATHLETES

Precedents: In pathological left ventricular (LV) hypertrophy (H) of hypertensive patients (P) there is a deposition of collagen. Myocardial fibrosis is one of the factors responsible for systolic and diastolic dysfunction. Athletes increase their ventricular mass as physiological ventricular H. Integrated backscatter (IB) demonstrates changes in myocardial acoustic properties, depending upon their composition and function.
Objectives: (1).Assess the capability of IB to differentiate physiological from pathological H. (2).Correlate IB with overall and regional systolic and diastolic functions.
Methods: Group I(GI):13 hypertensive P with an LV mass index (LVMI)>124 gr/m², Group II(G2):11 athletes, Group III(G3): 8 volunteers. We determined overall systolic and diastolic functions and regional function of the basal septum, IB and cyclic variation of the IB (CVIB) of the posterior wall.
Results: Age (years): G1:52 ± 15, G2:28 ± 8 G3:35 ± 8 p = 0.000; Sex: G1:m/f 12/1, G2: m/f 9/2, G3: m/f 4/4, LVMI: G1: 180.1 ± 58 gr/m², G2:130.2 ± 20 gr/m² G3: 90.2 ± 16 gr/m² p = 0.000. Left atrial area (LAA): G1: 22 ± 4 cm², G2: 18.8 ± 1.8 cm², G3: 15.8 cm² p = 0.001, mid-wall shortening fraction (MWSF): G1:26.9 ± 3.5, G2:27.5 ± 4 G3:25 ± 3 p = NS; CVIB: G1:5,3 ± 2,5 G2:7.6 ± 2,1 G3:6.4 ± 1.1 P = 0.048.Correlation of IB and MWSF, p = NS; IB and MWSF p = NS, IB and CVIB:-0.56 p = 0.005.  

  TABLE     

9.

Changes in left atrial anatomy due to respiration: impact on three-dimensional image integration during atrial fibrillation ablation     

Ector J  De Buck S  Loeckx D  Coudyzer W  Maes F  Dymarkowski S  Bogaert J  Heidbüchel H 《Journal of cardiovascular electrophysiology》2008,19(8):828-834

Introduction: Patient respiration influences the accuracy of image integration approaches used during atrial fibrillation (AF) ablation procedures. We assessed both absolute and relative changes in left atrial (LA) and pulmonary venous (PV) anatomy due to respiration and their implications for 3D image integration.
Methods and Results: Intensity-based segmentation of the LA and PVs was performed on cardiac computed tomography (CT) images obtained during both inspiration and expiration in 16 patients referred for AF ablation. A 3D LA-PV surface model was reconstructed for each respiratory phase. Absolute and relative respiratory motion components were evaluated from corresponding landmarks in both models. The mean 3D respiratory motion distance for all four PVs was 19 ± 9 mm. The most important motion component was in the inferior direction, with a mean inferior motion distance of 15 ± 8 mm. The mean 3D respiratory motion of the PV centers due to relative geometrical changes was small at the ostial level (2.6 ± 1.4 mm, 95% CI 2.3-3.0 mm) but significantly larger at the level of the first PV bifurcation (4.0 ± 2.3 mm, 95% CI 3.4-4.6 mm, P < 0.001). Relative geometrical changes of the LA body were most pronounced in regions near the mitral valve, resulting in a changed configuration of the mitral annulus during inspiration.
Conclusions: Respiration causes important movements of the PVs and LA. Relative changes in LA–PV geometry are most pronounced in the distal PVs and in the LA body near the mitral valve. Therefore, these regions should be avoided during registration of pre- and per-procedural images unless they are acquired in the same phase of respiration.     

10.

Relation of fibrillatory wave amplitude with hemostatic abnormality and left atrial appendage dysfunction in patients with chronic nonrheumatic atrial fibrillation   总被引：3，自引：0，他引：3  

Nakagawa K  Hirai T  Shinokawa N  Uchiyama Y  Kameyama T  Takashima S  Fujiki A  Asanoi H  Inoue H 《Japanese circulation journal》2001,65(5):375-380

Large left atrium (LA) and LA appendage (LAA) dysfunction are known to relate to cardiogenic thromboembolism, so the present study investigated the relation of the atrial fibrillatory wave (F wave) amplitude to hemostatic markers and LAA function. Transthoracic and transesophageal echocardiographic studies were performed in 82 consecutive patients with chronic, nonrheumatic atrial fibrillation (AF). Patients were divided into 2 groups according to F wave amplitude in lead V1 on the 12-lead ECG: coarse AF (the greatest amplitude of F wave > or =1 mm, n=44) and fine AF (<1 mm, n=38). Plasma levels of thrombin-antithrombin III complex, D-dimer, platelet factor 4 and beta-thromboglobulin were determined. Compared with patients with coarse AF, those with fine AF had lower LAA peak flow velocity (p<0.05) and higher prevalence of embolic cerebral infarction (50% vs 27%, p<0.05). Platelet activity did not differ between the 2 groups; however, plasma levels of thrombin-antithrombin III complex and D-dimer were significantly higher in patients with fine AF than in those with coarse AF (p<0.05). Multiple logistic regression analysis showed that fine AF was independently associated with cerebral embolism. Therefore, the presence of fine F wave in V1 would be a useful marker of LAA dysfunction and hypercoagulability, and indicate a risk for cerebral embolism in patients with chronic, nonrheumatic AF.     

11.

Aging dilates atrium and pulmonary veins: implications for the genesis of atrial fibrillation   总被引：1，自引：0，他引：1  

Pan NH  Tsao HM  Chang NC  Chen YJ  Chen SA 《Chest》2008,133(1):190-196

BACKGROUNDS: Aging plays a critical role in the pathophysiology of atrial fibrillation (AF). The left atrium (LA) and pulmonary veins (PVs) are essential components for the genesis and maintenance of AF. The purpose of this study was to investigate the effects of aging on the AF substrate and the initiator (PVs). METHODS: A total of 180 patients undergoing multidetector CT were enrolled and classified into six groups according to the decade of their age. LA, LA appendage (LAA), and orifice of the four PVs were measured. RESULTS: The LA anterior-posterior diameter and wall thickness became increased with aging after the age of 50 years (p < 0.001). Similarly, the LAA and four PV trunks also became dilated after the patients were > 50 years old (p < 0.001). The anterior wall was consistently thicker than the posterior wall in each group. Aging also increased both anterior and posterior wall thickness after the patients became > 50 years old. However, LA diameter, PV diameter, and LA wall thickness in the patients aged 70 to 79 years and > 80 years did not significantly differ. Age correlated well with the four PVs, LA diameter, and wall thickness with linear regression. CONCLUSIONS: Age significantly determines LA and PV structures. These findings show the important contributing effects involved in aging-induced AF in the general population.     

12.

Incidence and Predictors of Left Atrial Thrombus Prior to Catheter Ablation of Atrial Fibrillation     

DANIEL SCHERR  M.D.  †  DARSHAN DALAL  M.D.  M.P.H.  KARUNA CHILUKURI  M.D.  JUN DONG  M.D.  Ph  .D.  ‡  DAVID SPRAGG  M.D.  CHARLES A. HENRIKSON  M.D.  SAMAN NAZARIAN  M.D.  ALAN CHENG  M.D.  RONALD D. BERGER  M.D.  Ph  .D.  THEODORE P. ABRAHAM  M.D.  HUGH CALKINS  M.D.  JOSEPH E. MARINE  M.D. 《Journal of cardiovascular electrophysiology》2009,20(4):379-384

Background: Transesophageal echocardiography (TEE) is commonly used prior to catheter ablation of atrial fibrillation (AF) in order to exclude left atrial (LA) thrombus. However, the incidence and predictors of LA thrombus detected with TEE have not been systematically examined in this setting.
Methods: This study included 732 cases (mean age 57 ± 11 years; 23% female; 353 persistent AF) in 585 consecutive patients referred for catheter ablation of AF. Patients were anticoagulated for at least 4 weeks prior to the procedure and then bridged with enoxaparin. TEE was performed in all cases within 24 hours prior to ablation.
Results: Preprocedural TEE revealed LA thrombus in 12 of 732 cases (1.6%), all located in the LA appendage. Among these 12 patients, 9 had persistent AF and 3 had paroxysmal AF. All patients with thrombus had an LA size ≥ 4.5 cm. LA thrombus was present in 0.3%, 1.4%, and 5.3% of patients with CHADS₂ scores of 0, 1, and ≥ 2, respectively. In multivariate analysis, a CHADS₂ score ≥ 2 and larger LA diameter remained significant predictors of LA thrombus.
Conclusions: Despite oral anticoagulation treatment, there is a small but significant incidence of LA thrombus by TEE prior to AF ablation. A CHADS₂ score ≥ 2 and larger LA diameter are independent predictors of LA thrombus in this patient population, while type of AF or rhythm at the time of TEE is not. The risk of LA thrombus is low in patients with a CHADS₂ score of 0 and in patients with an LA diameter < 4.5 cm.     

13.

Percutaneous Mitral Commissurotomy in Acute Pulmonary Edema     

AÏCHA AOUAD  M.D.    RAJAE BENNANI  M.D.    RACHID GHANNAM  M.D.    ADIL BENSOUDA  M.D.    JAMAL EDDINE SRAIRI  M.D.    REDOUANE MESBAHI  MD.    NAÏMA EL  HAITEM  M.D.  MOHAMED BENOMAR  M.D. 《Journal of interventional cardiology》2000,13(2):113-115

From January 1994 to July 1998, percutaneous mitral commissurotomy was performed in 520 patients. Of these patients, 7 (4 men and 3 women aged 31 ± 5.6 years) were dilated in an emergency situation of intractable pulmonary edema caused by severe mitral stenosis. Three patients required mechanical ventilatory support. Percutaneous mitral commissurotomy was performed with the Inoue balloon. The dilatation of the valve was undertaken even though the echocardiographic score of the valve was high. Percutaneous mitral commissurotomy resulted in an increase in the mitral valve area from 0.72 ± 0.18 cm² to 1.95 ± 0.18 cm² (P = 0.011) with a concomitant reduction in pulmonary artery systolic pressure from 82.5 ± 16.4 mmHg to 46.7 ± 11.6 mmHg (P = 0.018). One patient died (he had two cardiac arrests before the dilatation). During follow-up (mean 18 months), one patient presented with a restenosis, one an aggravation of mitral insuflciency grade, and four were in NYHA functional Class II. Thus, percutaneous mitral commissurotomy can be considered as a treatment of choice in patients with intractable pulmonary edema caused by severe mitral stenosis.     

14.

P wave dispersion and left atrial appendage function for predicting recurrence after conversion of atrial fibrillation and relation of p wave dispersion to appendage function   总被引：6，自引：0，他引：6  

Dogan A  Kahraman H  Ozturk M  Avsar A 《Echocardiography (Mount Kisco, N.Y.)》2004,21(6):523-530

BACKGROUND: We investigated P wave dispersion and left atrial appendage (LAA) function for predicting atrial fibrillation (AF) relapse, and the relationship between P wave dispersion and LAA function. METHODS: Sixty-four consecutive patients with AF lasting /=5 days, LA size >/=45 mm, maximum P wave duration >/=112 ms, P wave dispersion >/=47 ms, spontaneous echo contrast, minimum LAA area >/=166 mm(2), and LAA emptying velocity <36 cm/sec were univariate predictors of recurrence (each P < 0.05). By multivariate analysis, LA size (P = 0.02), P wave dispersion (P < 0.001), and LAA emptying flow (P = 0.01) identified patients with recurrent AF. Their positive predictive values were 91, 97, and 72%, respectively. CONCLUSION: The increased P wave dispersion in addition to the dilated LA and the depressed LAA emptying flow can identify patients at risk of recurrent AF after cardioversion.     

15.

Left atrial thickness under the catheter ablation lines in patients with paroxysmal atrial fibrillation: insights from 64-slice multidetector computed tomography     

Kazuyoshi Suenari  Yukiko Nakano  Yukoh Hirai  Hiroshi Ogi  Noboru Oda  Yuko Makita  Shigeyuki Ueda  Kenta Kajihara  Takehito Tokuyama  Chikaaki Motoda  Mai Fujiwara  Kazuaki Chayama  Yasuki Kihara 《Heart and vessels》2013,28(3):360-368

A detailed understanding of the left atrial (LA) anatomy in patients with atrial fibrillation (AF) would improve the safety and efficacy of the radiofrequency catheter ablation. The objective of this study was to examine the myocardial thickness under the lines of the circumferential pulmonary vein isolation (CPVI) using 64-slice multidetector computed tomography (MDCT). Fifty-four consecutive symptomatic drug-refractory paroxysmal AF patients (45 men, age 61 ± 12 years) who underwent a primary CPVI guided by a three-dimensional electroanatomic mapping system (Carto XP; Biosense-Webster, Diamond Bar, CA, USA) with CT integration (Cartomerge; Biosense-Webster) were enrolled. Using MDCT, we examined the myocardial thickness of the LA and pulmonary vein (PV) regions in all patients. An analysis of the measurements by the MDCT revealed that the LA wall was thickest in the left lateral ridge (LLR; 4.42 ± 1.28 mm) and thinnest in the left inferior pulmonary vein wall (1.68 ± 0.27 mm). On the other hand, the thickness of the posterior wall in the cases with contact between the esophagus and left PV antrum was 1.79 ± 0.22 mm (n = 30). After the primary CPVI, the freedom from AF without any drugs during a 1-year follow-up period was 78 % (n = 42). According to the multivariate analysis, the thickness of the LLR was an independent positive predictor of an AF recurrence (P = 0.041). The structure of the left atrium and PVs exhibited a variety of myocardial thicknesses in the different regions. Of those, only the measurement of the LLR thickness was associated with an AF recurrence.     

16.

Anatomic characteristics of the left atrial isthmus in patients with atrial fibrillation: lessons from computed tomographic images     

Chiang SJ  Tsao HM  Wu MH  Tai CT  Chang SL  Wongcharoen W  Lin YJ  Lo LW  Chen YJ  Sheu MH  Chang CY  Chen SA 《Journal of cardiovascular electrophysiology》2006,17(12):1274-1278

Introduction: Left atrial (LA) isthmus ablation was reported to improve the success rate of catheter ablation of paroxysmal atrial fibrillation (AF). LA isthmus ablation could also cure a subset of LA flutter. Therefore, understanding the anatomy of the LA isthmus is important for performing the ablation effectively.
Methods and Results: Group I included 45 patients (40 male, mean age = 50 ± 13 years) with paroxysmal AF who underwent catheter ablation. Group II included 45 patients (37 male, mean age = 54 ± 10 years) without a history of AF. They underwent a 16-slice multidetector computed tomography (MDCT) scan to delineate the LA structures before the ablation procedure. The average length of the LA isthmus was longer in group I than in group II (lateral isthmus: 3.30 ± 0.68 vs 2.71 ± 0.60 cm, P < 0.001; medial isthmus: 5.12 ± 0.94 vs 4.45 ± 0.63 cm, P < 0.001), and morphological patterns of lateral and medial isthmus were similar between groups. In addition, the average depth of lateral isthmus was similar between groups (0.62 ± 0.32 vs 0.55 ± 0.33 cm, P = 0.41), but the average depth of medial isthmus was larger in group I than in group II (0.60 ± 0.32 vs 0.44 ± 0.25 cm, P = 0.01). The medial isthmus had more ridges, as compared to the lateral isthmus (13% vs 0%, P = 0.026). Furthermore, the distances between esophagus and lateral isthmus were longer in group I than in group II (at the middle of isthmus and mitral annulus level: 21.0 ± 4.8 vs 18.4 ± 6.0 mm, P < 0.001; and 37.1 ± 5.7 vs 29.6 ± 8.1 mm, P < 0.001, respectively).
Conclusion: The LA isthmus was longer in the AF patients. The morphology of the isthmus was variable. Compared with the lateral isthmus, the medial isthmus was longer and had more ridges. A peculiar configuration of the isthmus provided by CT images could influence the ablation strategy.     

17.

Filling defects of the left atrial appendage on multidetector computed tomography: their disappearance following catheter ablation of atrial fibrillation and the detection of LAA thrombi by MDCT     

Mika Hioki  Seiichiro Matsuo  Kenichi Tokutake  Kenichi Yokoyama  Ryohsuke Narui  Keiichi Ito  Shinichi Tanigawa  Michifumi Tokuda  Seigo Yamashita  Ikuko Anan  Keiichi Inada  Toru Sakuma  Ken-ichi Sugimoto  Michihiro Yoshimura  Teiichi Yamane 《Heart and vessels》2016,31(12):2014-2024

Filling defects of the left atrial appendage (LAA) on multidetector computed tomography (MDCT) are known to occur, not only due to LAA thrombi formation, but also due to the disturbance of blood flow in the LAA of patients with atrial fibrillation (AF). The purpose of this study was to evaluate the impact of the maintenance of sinus rhythm via ablation on the incidence of LAA filling defects on MDCT in patients with AF. A total of 459 consecutive patients were included in the present study. Prior to ablation, MDCT and transesophageal echocardiography (TEE) were performed. AF ablation was performed in patients without LAA thrombi confirmed on TEE. The LAA filling defects were evaluated on MDCT at 3 months after ablation. LAA filling defects were detected on MDCT in 51 patients (11.1 %), among whom the absence of LAA thrombi was confirmed in 42 patients using TEE. The LAA Doppler velocity in patients with LAA filling defects was lower than that of patients without filling defects (0.61 ± 0.19 vs. 0.47 ± 0.21 m/s; P < 0.0001). The sensitivity, specificity and negative predictive value of MDCT in the detection of thrombi were 100, 91 and 100 %, respectively. No LAA filling defects were observed on MDCT at 3 months after ablation in any of the patients, including the patients in whom filling defects were noted prior to the procedure. MDCT is useful for evaluating the presence of LAA thrombi and the blood flow of the LAA. The catheter ablation of AF not only suppresses AF, but also eliminates LAA filling defect on MDCT suggesting the improvement of LAA blood flow.     

18.

Relationships between the severity of cirrhosis and haemodynamic values in patients with cirrhosis     

HONG-CHIANG MENG  HAN-CHIEH LIN    YANG-TE TSAI  FA-YAUH LEE  DONG-MING LIAO  HSIAO-CHUNG HSIA  WEN-JEH LIN  TING-TSUNG CHANG  CHII-SHYAN LAY  SUN-SANG WANG  SHOU-DONG LEE  KWANG-JUEI LO 《Journal of gastroenterology and hepatology》1994,9(2):148-153

Abstract The relationship between the severity of cirrhosis and systemic and hepatic haemodynamic values was evaluated in 193 patients with cirrhosis, most of whom were diagnosed with post-necrotic cirrhosis. It was found that the hepatic venous pressure gradient and cardiac output in Pugh's A patients (13.6 ± 4.8 mmHg and 6.2 ± 1.6 L/min, mean ± s.d.) were significantly lower than in both Pugh's B (16.8 ± 4.3 mmHg and 7.3 ± 2.1 L/min) and Pugh's C (18.8 ± 5.5 mmHg and 7.4 ± 2.3 L/min) patients ( P < 0.01), respectively. In contrast, the systemic vascular resistance in Pugh's A patients (1232 ± 369 dyn/s per cm⁵) was significantly higher than in both Pugh's B (1016 ± 345 dyn/s per cm⁵) and Pugh's C (935 ± 234 dyn/s per cm⁵) patients ( P < 0.01), respectively. Additionally, not only was there a positive correlation found between Pugh's score and cardiac output and hepatic venous pressure gradient, but a negative correlation was found between Pugh's score and systemic vascular resistance. It was also confirmed that the degree of portal hypertension and the hyperdynamic circulation were more severe in patients with ascites than in those without ascites. However, there were no statistically significant differences in hepatic venous pressure gradient among patients with F1, F2 and F3 esophageal varices (15.7 ± 4.0, 17.0 ± 4.8 and 18.0 ± 4.8 mmHg, respectively). It is concluded that in those patients with cirrhosis, the severity of cirrhosis is closely related to the degree of the hyperkinetic circulatory state and portal hypertension.     

19.

Quantification of Atherosclerotic Burden in the Descending Aorta by Transesophageal Echocardiography: Inter- and Intraobserver Variability     

Khoury Z  Rinat C  Benhorin J  Stern S  Keren A 《Echocardiography (Mount Kisco, N.Y.)》1998,15(1):59-66

Atherosclerotic plaques had been imaged but not quantitated in the thoracic aorta using transesophageal echocardiography. The aim of this study was to describe a method for measuring the atherosclerotic plaque area in the descending aorta by transesophageal echocardiography (TEE) and to evaluate its reproducibility. TEE examinations were performed by two independent sonographers, in 21 patients with angiographically proven coronary artery disease. Two hundred fifty-six transverse segments (mean 12 ± 3 patient) of the descending aorta were adequately recorded. In each segment the plaque and the lumen areas in the half of the aortic segment distant from the transesophageal probe were measured by one reader in the two studies (intersonographer reproducibility). Interreader reproducibility was also evaluated. The correlation coefficient between the first and second study (intersonographer reproducibility) was 0.81. The standard deviation of the difference between examinations equaled 0.137 cm² and the mean absolute difference between examinations was 0.003 cm² (95% CI: –0.015; 0.021; P = 0.75). The correlation coefficient between the two readers was 0.86, the standard deviation of the difference between readers was 0.175 cm² and the mean absolute difference was 0.006 cm² (95% CI: –0.029; 0.018; P = 0.63). A method for quantitative measurement of aortic atherosclerotic plaque area was evaluated and found to have high intersonographer and intereader reproducibilities. This method might be used in the future for noninvasive evaluation of regression or progression of aortic atherosclerosis.     

20.

Initial experience in the use of integrated electroanatomic mapping with three-dimensional MR/CT images to guide catheter ablation of atrial fibrillation   总被引：17，自引：0，他引：17  

Dong J  Dickfeld T  Dalal D  Cheema A  Vasamreddy CR  Henrikson CA  Marine JE  Halperin HR  Berger RD  Lima JA  Bluemke DA  Calkins H 《Journal of cardiovascular electrophysiology》2006,17(5):459-466

INTRODUCTION: No prior studies have reported the use of integrated electroanatomic mapping with preacquired magnetic resonance/computed tomographic (MR/CT) images to guide catheter ablation of atrial fibrillation (AF) in a series of patients. METHODS AND RESULTS: Sixteen consecutive patients with drug-refractory AF underwent catheter ablation under the guidance of a three-dimensional (3D) electroanatomic mapping system (Carto, Biosense Webster, Inc., Diamond Bar, CA, USA). Gadolinium-enhanced MR (n = 8) or contrast-enhanced high-resolution CT (n = 8) imaging was performed within 1 day prior to the ablation procedures. Using a novel software package (CartoMerge, Biosense Webster, Inc.), the left atrium (LA) with pulmonary veins (PVs) was segmented and extracted for image registration. The segmented 3D MR/CT LA reconstruction was accurately registered to the real-time mapping space with a combination of landmark registration and surface registration. The registered 3D MR/CT LA reconstruction was successfully used to guide deployment of RF applications encircling the PVs. Upon completion of the circumferential lesions around the PVs, 32% of the PVs were electrically isolated. Guided by a circular mapping catheter, the remaining PVs were disconnected from the LA using a segmental approach. The distance between the surface of the registered 3D MR/CT LA reconstruction and multiple electroanatomic map points was 3.05 +/- 0.41 mm. No complications were observed. CONCLUSIONS: Three-dimensional MR/CT images can be successfully extracted and registered to anatomically guided clinical AF ablations. The display of detailed and accurate anatomic information during the procedure enables tailored RF ablation to individual PV and LA anatomy.     

Changes in left atrial anatomy due to respiration: impact on three-dimensional image integration during atrial fibrillation ablation

Introduction: Patient respiration influences the accuracy of image integration approaches used during atrial fibrillation (AF) ablation procedures. We assessed both absolute and relative changes in left atrial (LA) and pulmonary venous (PV) anatomy due to respiration and their implications for 3D image integration.
Methods and Results: Intensity-based segmentation of the LA and PVs was performed on cardiac computed tomography (CT) images obtained during both inspiration and expiration in 16 patients referred for AF ablation. A 3D LA-PV surface model was reconstructed for each respiratory phase. Absolute and relative respiratory motion components were evaluated from corresponding landmarks in both models. The mean 3D respiratory motion distance for all four PVs was 19 ± 9 mm. The most important motion component was in the inferior direction, with a mean inferior motion distance of 15 ± 8 mm. The mean 3D respiratory motion of the PV centers due to relative geometrical changes was small at the ostial level (2.6 ± 1.4 mm, 95% CI 2.3-3.0 mm) but significantly larger at the level of the first PV bifurcation (4.0 ± 2.3 mm, 95% CI 3.4-4.6 mm, P < 0.001). Relative geometrical changes of the LA body were most pronounced in regions near the mitral valve, resulting in a changed configuration of the mitral annulus during inspiration.
Conclusions: Respiration causes important movements of the PVs and LA. Relative changes in LA–PV geometry are most pronounced in the distal PVs and in the LA body near the mitral valve. Therefore, these regions should be avoided during registration of pre- and per-procedural images unless they are acquired in the same phase of respiration.     

Relation of fibrillatory wave amplitude with hemostatic abnormality and left atrial appendage dysfunction in patients with chronic nonrheumatic atrial fibrillation

Large left atrium (LA) and LA appendage (LAA) dysfunction are known to relate to cardiogenic thromboembolism, so the present study investigated the relation of the atrial fibrillatory wave (F wave) amplitude to hemostatic markers and LAA function. Transthoracic and transesophageal echocardiographic studies were performed in 82 consecutive patients with chronic, nonrheumatic atrial fibrillation (AF). Patients were divided into 2 groups according to F wave amplitude in lead V1 on the 12-lead ECG: coarse AF (the greatest amplitude of F wave > or =1 mm, n=44) and fine AF (<1 mm, n=38). Plasma levels of thrombin-antithrombin III complex, D-dimer, platelet factor 4 and beta-thromboglobulin were determined. Compared with patients with coarse AF, those with fine AF had lower LAA peak flow velocity (p<0.05) and higher prevalence of embolic cerebral infarction (50% vs 27%, p<0.05). Platelet activity did not differ between the 2 groups; however, plasma levels of thrombin-antithrombin III complex and D-dimer were significantly higher in patients with fine AF than in those with coarse AF (p<0.05). Multiple logistic regression analysis showed that fine AF was independently associated with cerebral embolism. Therefore, the presence of fine F wave in V1 would be a useful marker of LAA dysfunction and hypercoagulability, and indicate a risk for cerebral embolism in patients with chronic, nonrheumatic AF.     

Aging dilates atrium and pulmonary veins: implications for the genesis of atrial fibrillation

BACKGROUNDS: Aging plays a critical role in the pathophysiology of atrial fibrillation (AF). The left atrium (LA) and pulmonary veins (PVs) are essential components for the genesis and maintenance of AF. The purpose of this study was to investigate the effects of aging on the AF substrate and the initiator (PVs). METHODS: A total of 180 patients undergoing multidetector CT were enrolled and classified into six groups according to the decade of their age. LA, LA appendage (LAA), and orifice of the four PVs were measured. RESULTS: The LA anterior-posterior diameter and wall thickness became increased with aging after the age of 50 years (p < 0.001). Similarly, the LAA and four PV trunks also became dilated after the patients were > 50 years old (p < 0.001). The anterior wall was consistently thicker than the posterior wall in each group. Aging also increased both anterior and posterior wall thickness after the patients became > 50 years old. However, LA diameter, PV diameter, and LA wall thickness in the patients aged 70 to 79 years and > 80 years did not significantly differ. Age correlated well with the four PVs, LA diameter, and wall thickness with linear regression. CONCLUSIONS: Age significantly determines LA and PV structures. These findings show the important contributing effects involved in aging-induced AF in the general population.     

Incidence and Predictors of Left Atrial Thrombus Prior to Catheter Ablation of Atrial Fibrillation

Background: Transesophageal echocardiography (TEE) is commonly used prior to catheter ablation of atrial fibrillation (AF) in order to exclude left atrial (LA) thrombus. However, the incidence and predictors of LA thrombus detected with TEE have not been systematically examined in this setting.
Methods: This study included 732 cases (mean age 57 ± 11 years; 23% female; 353 persistent AF) in 585 consecutive patients referred for catheter ablation of AF. Patients were anticoagulated for at least 4 weeks prior to the procedure and then bridged with enoxaparin. TEE was performed in all cases within 24 hours prior to ablation.
Results: Preprocedural TEE revealed LA thrombus in 12 of 732 cases (1.6%), all located in the LA appendage. Among these 12 patients, 9 had persistent AF and 3 had paroxysmal AF. All patients with thrombus had an LA size ≥ 4.5 cm. LA thrombus was present in 0.3%, 1.4%, and 5.3% of patients with CHADS₂ scores of 0, 1, and ≥ 2, respectively. In multivariate analysis, a CHADS₂ score ≥ 2 and larger LA diameter remained significant predictors of LA thrombus.
Conclusions: Despite oral anticoagulation treatment, there is a small but significant incidence of LA thrombus by TEE prior to AF ablation. A CHADS₂ score ≥ 2 and larger LA diameter are independent predictors of LA thrombus in this patient population, while type of AF or rhythm at the time of TEE is not. The risk of LA thrombus is low in patients with a CHADS₂ score of 0 and in patients with an LA diameter < 4.5 cm.     

Percutaneous Mitral Commissurotomy in Acute Pulmonary Edema

From January 1994 to July 1998, percutaneous mitral commissurotomy was performed in 520 patients. Of these patients, 7 (4 men and 3 women aged 31 ± 5.6 years) were dilated in an emergency situation of intractable pulmonary edema caused by severe mitral stenosis. Three patients required mechanical ventilatory support. Percutaneous mitral commissurotomy was performed with the Inoue balloon. The dilatation of the valve was undertaken even though the echocardiographic score of the valve was high. Percutaneous mitral commissurotomy resulted in an increase in the mitral valve area from 0.72 ± 0.18 cm² to 1.95 ± 0.18 cm² (P = 0.011) with a concomitant reduction in pulmonary artery systolic pressure from 82.5 ± 16.4 mmHg to 46.7 ± 11.6 mmHg (P = 0.018). One patient died (he had two cardiac arrests before the dilatation). During follow-up (mean 18 months), one patient presented with a restenosis, one an aggravation of mitral insuflciency grade, and four were in NYHA functional Class II. Thus, percutaneous mitral commissurotomy can be considered as a treatment of choice in patients with intractable pulmonary edema caused by severe mitral stenosis.     

P wave dispersion and left atrial appendage function for predicting recurrence after conversion of atrial fibrillation and relation of p wave dispersion to appendage function

BACKGROUND: We investigated P wave dispersion and left atrial appendage (LAA) function for predicting atrial fibrillation (AF) relapse, and the relationship between P wave dispersion and LAA function. METHODS: Sixty-four consecutive patients with AF lasting /=5 days, LA size >/=45 mm, maximum P wave duration >/=112 ms, P wave dispersion >/=47 ms, spontaneous echo contrast, minimum LAA area >/=166 mm(2), and LAA emptying velocity <36 cm/sec were univariate predictors of recurrence (each P < 0.05). By multivariate analysis, LA size (P = 0.02), P wave dispersion (P < 0.001), and LAA emptying flow (P = 0.01) identified patients with recurrent AF. Their positive predictive values were 91, 97, and 72%, respectively. CONCLUSION: The increased P wave dispersion in addition to the dilated LA and the depressed LAA emptying flow can identify patients at risk of recurrent AF after cardioversion.     

Left atrial thickness under the catheter ablation lines in patients with paroxysmal atrial fibrillation: insights from 64-slice multidetector computed tomography

A detailed understanding of the left atrial (LA) anatomy in patients with atrial fibrillation (AF) would improve the safety and efficacy of the radiofrequency catheter ablation. The objective of this study was to examine the myocardial thickness under the lines of the circumferential pulmonary vein isolation (CPVI) using 64-slice multidetector computed tomography (MDCT). Fifty-four consecutive symptomatic drug-refractory paroxysmal AF patients (45 men, age 61 ± 12 years) who underwent a primary CPVI guided by a three-dimensional electroanatomic mapping system (Carto XP; Biosense-Webster, Diamond Bar, CA, USA) with CT integration (Cartomerge; Biosense-Webster) were enrolled. Using MDCT, we examined the myocardial thickness of the LA and pulmonary vein (PV) regions in all patients. An analysis of the measurements by the MDCT revealed that the LA wall was thickest in the left lateral ridge (LLR; 4.42 ± 1.28 mm) and thinnest in the left inferior pulmonary vein wall (1.68 ± 0.27 mm). On the other hand, the thickness of the posterior wall in the cases with contact between the esophagus and left PV antrum was 1.79 ± 0.22 mm (n = 30). After the primary CPVI, the freedom from AF without any drugs during a 1-year follow-up period was 78 % (n = 42). According to the multivariate analysis, the thickness of the LLR was an independent positive predictor of an AF recurrence (P = 0.041). The structure of the left atrium and PVs exhibited a variety of myocardial thicknesses in the different regions. Of those, only the measurement of the LLR thickness was associated with an AF recurrence.     

Anatomic characteristics of the left atrial isthmus in patients with atrial fibrillation: lessons from computed tomographic images

Introduction: Left atrial (LA) isthmus ablation was reported to improve the success rate of catheter ablation of paroxysmal atrial fibrillation (AF). LA isthmus ablation could also cure a subset of LA flutter. Therefore, understanding the anatomy of the LA isthmus is important for performing the ablation effectively.
Methods and Results: Group I included 45 patients (40 male, mean age = 50 ± 13 years) with paroxysmal AF who underwent catheter ablation. Group II included 45 patients (37 male, mean age = 54 ± 10 years) without a history of AF. They underwent a 16-slice multidetector computed tomography (MDCT) scan to delineate the LA structures before the ablation procedure. The average length of the LA isthmus was longer in group I than in group II (lateral isthmus: 3.30 ± 0.68 vs 2.71 ± 0.60 cm, P < 0.001; medial isthmus: 5.12 ± 0.94 vs 4.45 ± 0.63 cm, P < 0.001), and morphological patterns of lateral and medial isthmus were similar between groups. In addition, the average depth of lateral isthmus was similar between groups (0.62 ± 0.32 vs 0.55 ± 0.33 cm, P = 0.41), but the average depth of medial isthmus was larger in group I than in group II (0.60 ± 0.32 vs 0.44 ± 0.25 cm, P = 0.01). The medial isthmus had more ridges, as compared to the lateral isthmus (13% vs 0%, P = 0.026). Furthermore, the distances between esophagus and lateral isthmus were longer in group I than in group II (at the middle of isthmus and mitral annulus level: 21.0 ± 4.8 vs 18.4 ± 6.0 mm, P < 0.001; and 37.1 ± 5.7 vs 29.6 ± 8.1 mm, P < 0.001, respectively).
Conclusion: The LA isthmus was longer in the AF patients. The morphology of the isthmus was variable. Compared with the lateral isthmus, the medial isthmus was longer and had more ridges. A peculiar configuration of the isthmus provided by CT images could influence the ablation strategy.     

Filling defects of the left atrial appendage on multidetector computed tomography: their disappearance following catheter ablation of atrial fibrillation and the detection of LAA thrombi by MDCT

Filling defects of the left atrial appendage (LAA) on multidetector computed tomography (MDCT) are known to occur, not only due to LAA thrombi formation, but also due to the disturbance of blood flow in the LAA of patients with atrial fibrillation (AF). The purpose of this study was to evaluate the impact of the maintenance of sinus rhythm via ablation on the incidence of LAA filling defects on MDCT in patients with AF. A total of 459 consecutive patients were included in the present study. Prior to ablation, MDCT and transesophageal echocardiography (TEE) were performed. AF ablation was performed in patients without LAA thrombi confirmed on TEE. The LAA filling defects were evaluated on MDCT at 3 months after ablation. LAA filling defects were detected on MDCT in 51 patients (11.1 %), among whom the absence of LAA thrombi was confirmed in 42 patients using TEE. The LAA Doppler velocity in patients with LAA filling defects was lower than that of patients without filling defects (0.61 ± 0.19 vs. 0.47 ± 0.21 m/s; P < 0.0001). The sensitivity, specificity and negative predictive value of MDCT in the detection of thrombi were 100, 91 and 100 %, respectively. No LAA filling defects were observed on MDCT at 3 months after ablation in any of the patients, including the patients in whom filling defects were noted prior to the procedure. MDCT is useful for evaluating the presence of LAA thrombi and the blood flow of the LAA. The catheter ablation of AF not only suppresses AF, but also eliminates LAA filling defect on MDCT suggesting the improvement of LAA blood flow.     

Relationships between the severity of cirrhosis and haemodynamic values in patients with cirrhosis

Abstract The relationship between the severity of cirrhosis and systemic and hepatic haemodynamic values was evaluated in 193 patients with cirrhosis, most of whom were diagnosed with post-necrotic cirrhosis. It was found that the hepatic venous pressure gradient and cardiac output in Pugh's A patients (13.6 ± 4.8 mmHg and 6.2 ± 1.6 L/min, mean ± s.d.) were significantly lower than in both Pugh's B (16.8 ± 4.3 mmHg and 7.3 ± 2.1 L/min) and Pugh's C (18.8 ± 5.5 mmHg and 7.4 ± 2.3 L/min) patients ( P < 0.01), respectively. In contrast, the systemic vascular resistance in Pugh's A patients (1232 ± 369 dyn/s per cm⁵) was significantly higher than in both Pugh's B (1016 ± 345 dyn/s per cm⁵) and Pugh's C (935 ± 234 dyn/s per cm⁵) patients ( P < 0.01), respectively. Additionally, not only was there a positive correlation found between Pugh's score and cardiac output and hepatic venous pressure gradient, but a negative correlation was found between Pugh's score and systemic vascular resistance. It was also confirmed that the degree of portal hypertension and the hyperdynamic circulation were more severe in patients with ascites than in those without ascites. However, there were no statistically significant differences in hepatic venous pressure gradient among patients with F1, F2 and F3 esophageal varices (15.7 ± 4.0, 17.0 ± 4.8 and 18.0 ± 4.8 mmHg, respectively). It is concluded that in those patients with cirrhosis, the severity of cirrhosis is closely related to the degree of the hyperkinetic circulatory state and portal hypertension.     

Quantification of Atherosclerotic Burden in the Descending Aorta by Transesophageal Echocardiography: Inter- and Intraobserver Variability

Atherosclerotic plaques had been imaged but not quantitated in the thoracic aorta using transesophageal echocardiography. The aim of this study was to describe a method for measuring the atherosclerotic plaque area in the descending aorta by transesophageal echocardiography (TEE) and to evaluate its reproducibility. TEE examinations were performed by two independent sonographers, in 21 patients with angiographically proven coronary artery disease. Two hundred fifty-six transverse segments (mean 12 ± 3 patient) of the descending aorta were adequately recorded. In each segment the plaque and the lumen areas in the half of the aortic segment distant from the transesophageal probe were measured by one reader in the two studies (intersonographer reproducibility). Interreader reproducibility was also evaluated. The correlation coefficient between the first and second study (intersonographer reproducibility) was 0.81. The standard deviation of the difference between examinations equaled 0.137 cm² and the mean absolute difference between examinations was 0.003 cm² (95% CI: –0.015; 0.021; P = 0.75). The correlation coefficient between the two readers was 0.86, the standard deviation of the difference between readers was 0.175 cm² and the mean absolute difference was 0.006 cm² (95% CI: –0.029; 0.018; P = 0.63). A method for quantitative measurement of aortic atherosclerotic plaque area was evaluated and found to have high intersonographer and intereader reproducibilities. This method might be used in the future for noninvasive evaluation of regression or progression of aortic atherosclerosis.     

Initial experience in the use of integrated electroanatomic mapping with three-dimensional MR/CT images to guide catheter ablation of atrial fibrillation

INTRODUCTION: No prior studies have reported the use of integrated electroanatomic mapping with preacquired magnetic resonance/computed tomographic (MR/CT) images to guide catheter ablation of atrial fibrillation (AF) in a series of patients. METHODS AND RESULTS: Sixteen consecutive patients with drug-refractory AF underwent catheter ablation under the guidance of a three-dimensional (3D) electroanatomic mapping system (Carto, Biosense Webster, Inc., Diamond Bar, CA, USA). Gadolinium-enhanced MR (n = 8) or contrast-enhanced high-resolution CT (n = 8) imaging was performed within 1 day prior to the ablation procedures. Using a novel software package (CartoMerge, Biosense Webster, Inc.), the left atrium (LA) with pulmonary veins (PVs) was segmented and extracted for image registration. The segmented 3D MR/CT LA reconstruction was accurately registered to the real-time mapping space with a combination of landmark registration and surface registration. The registered 3D MR/CT LA reconstruction was successfully used to guide deployment of RF applications encircling the PVs. Upon completion of the circumferential lesions around the PVs, 32% of the PVs were electrically isolated. Guided by a circular mapping catheter, the remaining PVs were disconnected from the LA using a segmental approach. The distance between the surface of the registered 3D MR/CT LA reconstruction and multiple electroanatomic map points was 3.05 +/- 0.41 mm. No complications were observed. CONCLUSIONS: Three-dimensional MR/CT images can be successfully extracted and registered to anatomically guided clinical AF ablations. The display of detailed and accurate anatomic information during the procedure enables tailored RF ablation to individual PV and LA anatomy.