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Atrial Appendage (atrial + appendage)
Kinds of Atrial Appendage Selected AbstractsIMAGE SECTION: Stunning of Left Atrial Appendage after Spontaneous Conversion of Atrial FibrillationECHOCARDIOGRAPHY, Issue 3 2008Mikko Savontaus M.D. No abstract is available for this article. [source] Role of Echocardiography in Percutaneous Occlusion of the Left Atrial AppendageECHOCARDIOGRAPHY, Issue 4 2007Mráz M.D. Percutaneous occlusion of the left atrial appendage (LAA) is a modern alternative for the treatment of patients with atrial fibrillation (AF) and with a high risk of stroke who are not eligible for long-term anticoagulation therapy. Echocardiography plays a significant role in selecting patients, guiding the procedure, and in the postprocedural follow-up. Objectives and methods: To test the role of transesophagoeal echocardiography (TEE) and intracardiac echocardiography (ICE) in facilitating and shortening the procedure. Results: ICE represents a more convenient approach in patients who are not under generally anesthesia and helps to facilitate transseptal puncture. On the other hand, TEE, having the ability to rotate the image plane, helps to better determine the position of the occluder. Conclusions: Echocardiographic guidance of this procedure is essential. Which approach will be preferred will depend on the development of these two methods. [source] Congenital Aneurysm of Left Atrial Appendage: A Case ReportJOURNAL OF CARDIAC SURGERY, Issue 1 2010Sanjeev Gupta M.S. We report a case of a two-year-old child with congenital aneurysm of the LAA with a large thrombus in it. He presented with an episode of seizures with left-sided hemiparesis. Diagnosis was based on transthoracic echocardiography and magnetic resonance imaging. The patient was successfully treated by surgical resection of the aneurysm and removal of the thrombus.(J Card Surg 2010;25:37-40) [source] A Tissue-Specific Model of Reentry in the Right Atrial AppendageJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009JICHAO ZHAO Ph.D. Introduction: Atrial fibrillation is prevalent in the elderly and contributes to mortality in congestive heart failure. Development of computer models of atrial electrical activation that incorporate realistic structures provides a means of investigating the mechanisms that initiate and maintain reentrant atrial arrhythmia. As a step toward this, we have developed a model of the right atrial appendage (RAA) including detailed geometry of the pectinate muscles (PM) and crista terminalis (CT) with high spatial resolution, as well as complete fiber architecture. Methods and Results: Detailed structural images of a pig RAA were acquired using a semiautomated extended-volume imaging system. The generally accepted anisotropic ratio of 10:1 was adopted in the computer model. To deal with the regional action potential duration heterogeneity in the RAA, a Courtemanche cell model and a Luo-Rudy cell model were used for the CT and PM, respectively. Activation through the CT and PM network was adequately reproduced with acceptable accuracy using reduced-order computer models. Using a train of reducing cycle length stimuli applied to a CT/PM junction, we observed functional block both parallel with and perpendicular to the axis of the CT. Conclusion: With stimulation from the CT at the junction of a PM, we conclude: (a) that conduction block within the CT is due to a reduced safety factor; and (b) that unidirectional block and reentry within the CT is due to its high anisotropy. Regional differences in effective refractive period do not explain the observed conduction block. [source] Focal Atrial Tachycardia Originating from the Left Atrial Appendage: Electrocardiographic and Electrophysiologic Characterization and Long-Term Outcomes of Radiofrequency AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2007WANG YUN-LONG M.D. Introduction: This study sought to investigate electrophysiologic characteristics and radiofrequency ablation (RFA) in patients with focal atrial tachycardia (AT) arising from the left atrial appendage (LAA). Methods: This study included seven patients undergoing RFA with focal AT. Activation mapping was performed during tachycardia to identify an earlier activation in the left atria and the LAA. The atrial appendage angiography was performed to identify the origin in the LAA before and after RFA. Results: AT occurred spontaneously or was induced by isoproterenol infusion rather than programmed extrastimulation and burst atrial pacing in any patient. The tachycardia demonstrated a characteristic P-wave morphology and endocardial activation pattern. The P wave was highly positive in inferior leads in all patients. Lead V1 showed upright or biphasic (±) component in all patients. Lead V2,V6 showed an isoelectric component in five patients or an upright component with low amplitude (<0.1 mV) in two patients. Earliest endocardial activity occurred at the distal coronary sinus (CS) ahead of P wave in all seven patients. Mean tachycardia cycle length was 381 ± 34 msec and the earliest endocardial activation at the successful RFA site occurred 42.3 ± 9.6 msec before the onset of P wave. RFA was acutely successful in all seven patients. Long-term success was achieved in seven of the seven over a mean follow-up of 24 ± 5 months. Conclusions: The LAA is an uncommon site of origin for focal AT (3%). There were consistent P-wave morphology and endocardial activation associated with this type of AT. The LAA focal ablation is safe and effective. Long-term success was achieved with focal ablation in all patients. [source] Morphologic Characteristics of the Left Atrial Appendage, Roof, and Septum: Implications for the Ablation of Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2006WANWARANG WONGCHAROEN M.D. 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. [source] Coronary Artery Fistulas: A Review of the Literature and Presentation of Two Cases of Coronary Fistulas with Drainage into the Left AtriumCONGENITAL HEART DISEASE, Issue 3 2007Scott Ceresnak MD Abstract We report 2 cases of infants presenting with a murmur shortly after birth and diagnosed with coronary artery fistulas with drainage into the left atrium. The first infant had a fistulous communication between the left main coronary artery and the left atrial appendage and presented with signs and symptoms of heart failure. The infant was repaired surgically in the first week of life. The second infant was asymptomatic and had a fistulous communication between the right coronary artery and the left atrium. The infant will have the fistula closed in the cardiac catheterization laboratory when the child is older. The literature on coronary artery fistulas is reviewed, and the diagnosis and management of coronary artery fistulas is discussed. [source] Cor Triatriatum Sinister with and without Left Ventricular Inflow Obstruction: Visualization of the Entire Supravalvular Membrane by Real-time Three-dimensional Echocardiography.CONGENITAL HEART DISEASE, Issue 6 2006Impact on Clinical Management of Individual Patient ABSTRACT We present 4 cases of cor triatriatum in whom the diagnosis was correctly made by 2-dimensional transthoracic echocardiography, which showed the supravalvular left atrial membrane that divides the left atrium into 2 chambers. The pulmonary veins were connected normally to the proximal left atrial chamber and the left atrial appendage was connected to the distal left atrial chamber. In 1 patient there was evidence of severe pulmonary venous obstruction to the mitral valve by Doppler examination, while in the other three, there was no venous obstruction. Patients were then examined by real-time 3-dimensional echocardiography (RT3DE, using ×4 matrix array transducer connected to Sonos 7500 echocardiographic system Phillips, Andover, Mass, USA). This showed the exact morphology of the membrane and led to cancellation of planed surgical intervention in 1 case in which the membrane was only a broad band crossing the left atrial cavity. In addition to delineating the exact morphology of the intracavitary anomaly, this novel echocardiographic imaging modality should be an additive tool to better understand the natural history of these nonobstructive left atrial membranes via longitudinal follow-up of these patients. [source] Unusual Left Atrial Appendage Mass: Atypical Presentation of Papillary FibroelastomaECHOCARDIOGRAPHY, Issue 5 2008Miroslawa Jablonski-Cohen M.D. Papillary fibroelastomas are small, histologically benign neoplasms that are typically found on the valvular endocardium. We report a patient with a papillary fibroelastoma in an unusual location: the left atrial appendage. Although the mass was visualized both by computed tomography (CT) and transesophageal echocardiography, the diagnosis was histologically confirmed after surgical excision. [source] Role of Echocardiography in Percutaneous Occlusion of the Left Atrial AppendageECHOCARDIOGRAPHY, Issue 4 2007Mráz M.D. Percutaneous occlusion of the left atrial appendage (LAA) is a modern alternative for the treatment of patients with atrial fibrillation (AF) and with a high risk of stroke who are not eligible for long-term anticoagulation therapy. Echocardiography plays a significant role in selecting patients, guiding the procedure, and in the postprocedural follow-up. Objectives and methods: To test the role of transesophagoeal echocardiography (TEE) and intracardiac echocardiography (ICE) in facilitating and shortening the procedure. Results: ICE represents a more convenient approach in patients who are not under generally anesthesia and helps to facilitate transseptal puncture. On the other hand, TEE, having the ability to rotate the image plane, helps to better determine the position of the occluder. Conclusions: Echocardiographic guidance of this procedure is essential. Which approach will be preferred will depend on the development of these two methods. [source] Relationship between Slow Coronary Flow and Left Atrial Appendage Blood Flow VelocitiesECHOCARDIOGRAPHY, Issue 1 2007Recep Demirbag M.D. Aims: This study was undertaken to assess whether slow coronary flow (SCF)is related to low left atrial appendage (LAA) blood flow velocities. Methods: Study subjects consist of 44 patients with SCF and 11 volunteer subjects with normal coronary angiogram. The diagnosis of SCF was made using the TIMI frame count method. The blood flow velocities were obtained by placing a pulsed-wave Doppler sample volume inside the proximal third of the LAA. Results: The mean LAA emptying velocities (MEV)were significantly lower in patients than control subjects (34.5 ± 9.9 cm/sec vs 84.0 ± 12.1 cm/sec; P < 0.001). In bivariate analysis, significant correlation was found between MEV, and systolic pulmonary venous flow, mean TIMI frame count, deceleration time, and isovolumetric relaxation time (P < 0.05). By multiple linear regression analysis, mean TIMI frame count (ß=,0.865, P < 0.001) was identified as independent predictors of MEV. Conclusion: This study indicates that SCF phenomenon may be related to low LAA blood flows. [source] The Use of Anatomic M-Mode Echocardiography to Determine the Left Atrial Appendage Functions in Patients with Sinus RhythmECHOCARDIOGRAPHY, Issue 2 2005Yekta Gurlertop M.D. Left atrial appendage (LAA) contractile dysfunction is associated with thrombus formation and systemic embolism. LAA function is determined by its flow velocities and fractional area change. This study was performed in order to determine the LAA functions with the anatomic M-mode echocardiography (AMME). Our study comprised 74 patients who had sinus rhythm and underwent transesophageal echocardiography (TEE) for various reasons. LAA fractional change (LAAFAC) was measured by manual planimetry in a transverse basal short-axis approach and LAA emptying and filling velocities also were measured. The AMME values were determined by an M-mode cross section from a cursor placed beneath the orifice of the LAA in transverse basal short-axis imaging. From these values LAA fractional shortening (LAAFS) and ejection fraction (LAAEF) were calculated. LAAEF was calculated by the Teicholz method. The comparisons were conducted, and no correlations between the LAA late filling and the anatomic M-mode values were found (for LAAFS r = 0.18; P > 0.05 and for LAAEF r = 0.19; P > 0.05). There were significant but poor correlations among the LAA late emptying with the anatomic M-mode measurements (for LAAFS r = 0.26; P < 0.05 and for LAAEF r = 0.30; P < 0.01), whereas, there were significant and good correlations between the LAAFAC and the anatomic M-mode values (for LAAFS r = 0.75; P < 0.01 and for LAAEF r = 0.78; P < 0.01). There were significant differences between the valvular heart disease group and the normal group, and between the valvular heart disease group and the ASD group (for LAAFAC P < 0.01, for LAAEF P < 0.01, for LAAFS P < 0.01). There was no difference between the normal group and the ASD group. Our study showed that the LAAEF and LAAFS in patients with sinus rhythm obtained via anatomical M-mode echocardiography is a new method, which can be used instead of left atrial appendage area change. [source] Course of Intraatrial Thrombi Resolution Using Transesophageal EchocardiographyECHOCARDIOGRAPHY, Issue 2 2003Jennifer A. Larsen M.D. Thromboembolic events are associated with atrial fibrillation and with cardioversion to sinus rhythm. Although studies have demonstrated the risk of this complication is reduced by a 3-week period of anticoagulation prior to cardioversion, limited data have suggested a longer period of anticoagulation is necessary for thrombus resolution. We identified and followed 25 patients noted to have intraatrial thrombi on an initial transesophageal echocardiogram (TEE) who subsequently had a follow-up TEE. The majority of patients had a single thrombus, often but not uniformly located in the left atrial appendage with the largest found in those patients with mitral stenosis. Repeat TEE was performed at a mean of 4 ± 6 months and persistent thrombus was noted in 19 of 25 patients (76%). Seven of 19 patients with persistent thrombi were cardioverted and one of these patients had a neurologic event following the procedure (14%). The only findings associated with persistent thrombus were the presence of mitral valve disease and atrial fibrillation.. Our findings suggest that intraatrial thrombi do not generally resolve following several weeks of anticoagulation and that persistent left-sided intraatrial thrombi may be associated with an increased risk for events following cardioversion. Given that a TEE-guided approach to cardioversion is being utilized more frequently, it may be important to determine thrombus characteristics on follow-up that would be predictive of embolic events following cardioversion. (ECHOCARDIOGRAPHY, Volume 20, February 2003) [source] Effect of Inotropic Stimulation on Left Atrial Appendage Function in Atrial Myopathy of Chronic Atrial FibrillationECHOCARDIOGRAPHY, Issue 4 2000MASOOR KAMALESH M.D. Atrial fibrillation (AF) leads to remodeling of the left atrium (LA) and left atrial appendage (LAA), resulting in atrial myopathy. Reduced LA and LAA function in chronic AF leads to thrombus formation and spontaneous echo contrast (SEC). The effect of inotropic stimulation on LAA function in patients with chronic AF is unknown. LAA emptying velocity (LAAEV) and maximal LAA area at baseline and after dobutamine were measured by transesophageal echocardiography in 14 subjects in normal sinus rhythm (NSR) and 6 subjects in AF. SEC in the LA was assessed before and after dobutamine. LAAEV increased significantly in both groups. However, the LAAEV at peak dobutamine in patients with AF remained significantly lower than the baseline LAAEV in patients who were in NSR (P= 0.009). Maximal LAA area decreased significantly with dobutamine in both groups, but LAA area at peak dose of dobutamine inpatients with AF remained greater than baseline area in those in NSR (P= 0.01). Despite the increase in LAAEV, SEC improved in only two of five patients. We conclude that during AF, the LAA responds to inotropic stimulation with only a modest improvement in function. [source] Surgical Ablation of Atrial Fibrillation: The Columbia Presbyterian ExperienceJOURNAL OF CARDIAC SURGERY, Issue 5 2006Veli K. Topkara M.D. However, it is not widely applied due to its complexity, increased operative times, and the risk of bleeding. Various energy sources have been introduced to simplify the traditional "cut and sew" approach. Methods: This study involves patients undergoing surgical atrial fibrillation ablation (SAFA) at a single institution from 1999 to 2005. Type of concomitant procedures, preoperative clinical characteristics, and chronicity of AF were evaluated in overall patient population. Parameters including surgical approach, lesion pattern, and energy source used were collected intraoperatively. Clinical outcomes examined were postoperative rhythm success, stroke, early mortality, and long-term survival. Results: Three hundred thirty-nine patients were identified. Three hundred twenty-eight (96.8%) patients had associated cardiac disease and underwent concomitant procedures; 75.8% of patients had persistent AF. Energy sources used were microwave (49.8%), radiofrequency (42.2%), and laser (8.0%). In 41.9% of cases a pulmonary vein encircling lesion was the only lesion created. Combination lesion sets were performed in the remaining cases. Rhythm success rates at 3, 6, 12, and 24 months were 74.1%, 68.2%, 74.5%, and 71.1%, respectively. Patients who underwent surgical removal of left atrial appendage by means of stapling or simple excision had no early postoperative stroke. Early mortality was 4.9%. Postoperative survival rates at 1, 3, and 5 years were 89.6%, 83.1%, and 78.0%. Conclusions: Surgical ablation of atrial fibrillation is a safe and effective procedure in restoring sinus rhythm with excellent postoperative survival rates. Further advancements in the field will eventually result in minimally invasive procedures with higher success rates. [source] Robot-Assisted Isolation of the Pulmonary Veins with Microwave EnergyJOURNAL OF CARDIAC SURGERY, Issue 1 2006F.A.C.S., J. Michael Smith M.D. This study evaluated the feasibility of performing a minimally invasive left atrial isolation on a beating heart using the da Vinci Robotic Surgical System and a flexible microwave probe (Flex 10 by AFx, Inc., Fremont, CA, USA), and the reliability of exit block pacing to confirm transmurality of the lesions created. Methods: On six canines, the Flex 10 probe was passed around the left atrium posterior to the superior vena cava, through the transverse sinus, and back through the oblique sinus via a right-chest-only approach using the da Vinci Robotic Surgical System. Prior to ablation, pacing outside the atrial cuff was confirmed. Ablation was then carried out on the beating heart and repeated (as needed) until electrical isolation was demonstrated by exit block pacing. Probe position was confirmed at the completion of the procedure via sternotomy. Analysis included acute histologic and gross examination of the targeted area. Results: There was no significant difference (p = 0.110) in procedure time, although it decreased 39.6% from the first three cases to the last three cases. Electrical evidence of electrical left atrial isolation was achieved in all subjects. Acute histologic examination confirmed transmurality inconsistently. Additionally, in two animals, the Flex 10 probe was found to be anterior to the left atrial appendage. All animals survived the procedure. Conclusion: A minimally invasive left atrial isolation procedure using monopolar microwave energy with the da Vinci Robotic Surgical System is simple and feasible. However, despite creating an electrical block, transmurality was not demonstrated consistently and further confirmation of catheter positioning is necessary during a right-chest-only approach. [source] Left Atrial Appendage Tip: An Unusual Site of Successful Ablation After Failed Endocardial and Epicardial Mapping and AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2010LUIGI DI BIASE M.D. Left Atrial Appendage Tip. Uncommon sites of ablation for arrhythmias can be the cause of failed ablations. This series includes 4 cases requiring ablation at the tip of the left atrial appendage after both endocardial and epicardial mapping and ablation failed. (J Cardiovasc Electrophysiol, Vol. 21, pp. 203-206, February 2010) [source] A Tissue-Specific Model of Reentry in the Right Atrial AppendageJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009JICHAO ZHAO Ph.D. Introduction: Atrial fibrillation is prevalent in the elderly and contributes to mortality in congestive heart failure. Development of computer models of atrial electrical activation that incorporate realistic structures provides a means of investigating the mechanisms that initiate and maintain reentrant atrial arrhythmia. As a step toward this, we have developed a model of the right atrial appendage (RAA) including detailed geometry of the pectinate muscles (PM) and crista terminalis (CT) with high spatial resolution, as well as complete fiber architecture. Methods and Results: Detailed structural images of a pig RAA were acquired using a semiautomated extended-volume imaging system. The generally accepted anisotropic ratio of 10:1 was adopted in the computer model. To deal with the regional action potential duration heterogeneity in the RAA, a Courtemanche cell model and a Luo-Rudy cell model were used for the CT and PM, respectively. Activation through the CT and PM network was adequately reproduced with acceptable accuracy using reduced-order computer models. Using a train of reducing cycle length stimuli applied to a CT/PM junction, we observed functional block both parallel with and perpendicular to the axis of the CT. Conclusion: With stimulation from the CT at the junction of a PM, we conclude: (a) that conduction block within the CT is due to a reduced safety factor; and (b) that unidirectional block and reentry within the CT is due to its high anisotropy. Regional differences in effective refractive period do not explain the observed conduction block. [source] Complex Fractionated Electrogram Distribution and Temporal Stability in Patients Undergoing Atrial Fibrillation AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2008JEAN-FRANÇOIS ROUX M.D. Background: Targeting of complex fractionated electrograms (CFEs) has been described as an approach for catheter ablation of atrial fibrillation (AF); however, the distribution and temporal stability of CFE regions remain poorly defined. Methods: In patients with persistent AF referred for ablation, we performed two consecutive left atrial (LA) CFE maps prior to AF ablation. Bipolar electrograms were acquired during AF, and the mean AF cycle length and electrogram voltage were automatically determined at each point. Sites with mean CL ,120 ms were considered CFE positive. The two maps were then compared qualitatively and quantitatively. Results: A total of 15 patients (93% male, age 56.1 ± 9.0 years) undergoing AF ablation were studied. The two maps were separated in time by 31 ± 10 minutes. There was no significant difference in the number of CFE-positive regions (12.3 ± 5.2 vs 11.3 ± 4.7; P = 0.06) between the maps. While CFEs were widely distributed within the LA, the PV/left atrial junction (73%) and left atrial appendage (77%) were most often CFE positive. The presence of CFEs at each region was concordant 78% of the time. There was a significant correlation between the two maps (r = 0.35 ± 0.21, range 0.1,0.84; P < 0.001) with a percent difference of 17.5 ± 9.4%. Conclusions: During persistent AF, most CFE regions are found in the vicinity of the PVs. There is a significant correlation between two CFE maps constructed 31 minutes apart, with 78% concordance of CFE sites. [source] Focal Atrial Tachycardia Originating from the Left Atrial Appendage: Electrocardiographic and Electrophysiologic Characterization and Long-Term Outcomes of Radiofrequency AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2007WANG YUN-LONG M.D. Introduction: This study sought to investigate electrophysiologic characteristics and radiofrequency ablation (RFA) in patients with focal atrial tachycardia (AT) arising from the left atrial appendage (LAA). Methods: This study included seven patients undergoing RFA with focal AT. Activation mapping was performed during tachycardia to identify an earlier activation in the left atria and the LAA. The atrial appendage angiography was performed to identify the origin in the LAA before and after RFA. Results: AT occurred spontaneously or was induced by isoproterenol infusion rather than programmed extrastimulation and burst atrial pacing in any patient. The tachycardia demonstrated a characteristic P-wave morphology and endocardial activation pattern. The P wave was highly positive in inferior leads in all patients. Lead V1 showed upright or biphasic (±) component in all patients. Lead V2,V6 showed an isoelectric component in five patients or an upright component with low amplitude (<0.1 mV) in two patients. Earliest endocardial activity occurred at the distal coronary sinus (CS) ahead of P wave in all seven patients. Mean tachycardia cycle length was 381 ± 34 msec and the earliest endocardial activation at the successful RFA site occurred 42.3 ± 9.6 msec before the onset of P wave. RFA was acutely successful in all seven patients. Long-term success was achieved in seven of the seven over a mean follow-up of 24 ± 5 months. Conclusions: The LAA is an uncommon site of origin for focal AT (3%). There were consistent P-wave morphology and endocardial activation associated with this type of AT. The LAA focal ablation is safe and effective. Long-term success was achieved with focal ablation in all patients. [source] Fibrillating Areas Isolated within the Left Atrium after Radiofrequency Linear Catheter AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2006THOMAS ROSTOCK M.D. Introduction: Nonpulmonary vein sources have been implicated as potential drivers of atrial fibrillation (AF). This observational study describes regions of fibrillating atrial tissue isolated inadvertently from the left atrium (LA) following linear catheter ablation for AF. Methods and Results: We report four patients with persistent/permanent AF who underwent pulmonary vein isolation with additional linear lesions and who presented with recurrent AF (mean AF cycle length [AFCL] 175,270 ms). Further catheter ablation resulted in the inadvertent electrical isolation of significant areas of the LA in which AF persisted at the same AFCL as was measured prior to disconnection, despite the restoration of sinus rhythm (SR) in all other left and right atrial areas, strongly suggesting that these islands were driving the remaining atria into fibrillation. The disconnected areas were located in the lateral LA, including the left atrial appendage (LAA) in three patients (limited to the LAA in one) and in the posterior LA in one patient. These isolated fibrillating regions represented 15,24% of the global LA surface, as estimated by electroanatomic mapping. Conclusion: Fibrillation can be maintained within electrically isolated regions of the LA following catheter ablation of AF, demonstrating the importance of atrial drivers in the maintenance of AF. Further mapping of these drivers is needed to characterize their mechanism and thereby allow for a more specific ablation strategy. [source] Three-Dimensional Anatomy of the Left Atrium by Magnetic Resonance Angiography: Implications for Catheter Ablation for Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2006MOUSSA MANSOUR M.D. Background: Pulmonary vein isolation (PVI) has become one of the primary treatments for symptomatic drug-refractory atrial fibrillation (AF). During this procedure, delivery of ablation lesions to certain regions of the left atrium can be technically challenging. Among the most challenging regions are the ridges separating the left pulmonary veins (LPV) from the left atrial appendage (LAA), and the right middle pulmonary vein (RMPV) from the right superior (RSPV) and right inferior (RIPV) pulmonary veins. A detailed anatomical characterization of these regions has not been previously reported. Methods: Magnetic resonance angiography (MRA) was performed in patients prior to undergoing PVI. Fifty consecutive patients with a RMPV identified by MRA were included in this study. Ridges associated with the left pulmonary veins were examined in an additional 30 patients who did not have a RMPV. Endoluminal views were reconstructed from the gadolinium-enhanced, breath-hold three-dimensional MRA data sets. Measurements were performed using electronic calipers. Results: The width of the ridge separating the LPV from the LAA was found to be 3.7 ± 1.1 mm at its narrowest point. The segment of this ridge with a width of 5 mm or less was 16.6 ± 6.4 mm long. The width of the ridges separating the RMPV from the RSPV and the RIPV was found to be 3.0 ±1.5 mm and 3.1 ±1.8 mm, respectively. There were no significant differences between LPV ridges for patients with versus without a RMPV. Conclusion: The width of the ridges of atrial tissue separating LPV from the LAA and the RMPV from its neighboring veins may explain the technical challenge in obtaining stable catheter positions in these areas. A detailed assessment of the anatomy of these regions may improve the safety and efficacy of catheter ablation at these sites. [source] Catheter Ablation of Long-Lasting Persistent Atrial Fibrillation: Critical Structures for TerminationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2005MICHEL HAÏSSAGUERRE M.D. Background: The relative contributions of different atrial regions to the maintenance of persistent atrial fibrillation (AF) are not known. Methods: Sixty patients (53 ± 9 years) undergoing catheter ablation of persistent AF (17 ± 27 months) were studied. Ablation was performed in a randomized sequence at different left atrial (LA) regions and comprised isolation of the pulmonary veins (PV), isolation of other thoracic veins, and atrial tissue ablation targeting all regions with rapid or heterogeneous activation or guided by activation mapping. Finally, linear ablation at the roof and mitral isthmus was performed if sinus rhythm was not restored after addressing the above-mentioned areas. The impact of ablation was evaluated by the effect on the fibrillatory cycle length in the coronary sinus and appendages at each step. Activation mapping and entrainment maneuvers were used to define the mechanisms and locations of intermediate focal or macroreentrant atrial tachycardias. Results: AF terminated in 52 patients (87%), directly to sinus rhythm in 7 or via the ablation of 1,6 intermediate atrial tachycardias (total 87) in 45 patients. This conversion was preceded by prolongation of fibrillatory cycle length by 39 ± 9 msec, with the greatest magnitude occurring during ablation at the anterior LA, coronary sinus and PV-LA junction. Thirty-eight atrial tachycardias were focal (originating dominantly from these same sites), while 49 were macroreentrant (involving the mitral or cavotricuspid isthmus or LA roof). Patients without AF termination displayed shorter fibrillatory cycles at baseline: 130 ± 14 vs 156 ± 23 msec; P = 0.002. Conclusion: Termination of persistent AF can be achieved in 87% of patients by catheter ablation. Ablation of the structures annexed to the left atrium,the left atrial appendage, coronary sinus, and PVs,have the greatest impact on the prolongation of AF cycle length, the conversion of AF to atrial tachycardia, and the termination of focal atrial tachycardias. [source] Enalapril Preserves Sinus Node Function in a Canine Atrial Fibrillation Model Induced by Rapid Atrial PacingJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2005MASAO SAKABE M.D. Effects of enalapril on canine sinus node (SN) dysfunction induced by long-term rapid atrial pacing were investigated. Methods and Results: Seventeen beagles were pretreated with either placebo (group I, n = 9) or enalapril 1 mg/kg/day (group II, n = 8) and paced at 500/min from the right atrial appendage for 4 weeks. Every week, corrected sinus node recovery time (CSNRT) and sinus cycle length (SCL) were measured. Quantitative analysis of interstitial fibrosis (IF) and adipose tissue (AT) in the SN was performed with Masson's trichrome stain, and apoptosis of the sinus nodal cells were detected with terminal deoxynucleotidyl transferase nick end-labeling. In group I, rapid atrial pacing prolonged both CSNRT and SCL. After 4 weeks of pacing, CSNRT and SCL were significantly shorter in group II (CSNRT, 410 ± 37 msec; SCL, 426 ± 34 msec) than in group I (CSNRT, 717 ± 52 msec, P < 0.005; SCL, 568 ± 73 msec, P < 0.05). Both IF and AT of the SN were greater in group I (IF, 9.7 ± 1.9%; AT, 32.6 ± 5.9%) than in seven sham dogs (IF, 2.4 ± 0.9%, P < 0.05; AT, 4.0 ± 1.7%, P < 0.05) and in group II dogs (IF, 4.0 ± 2.0%, P < 0.05; AT, 4.0 ± 1.7%, P < 0.05). End-labeling assay was positive in three of nine dogs in group I, but negative in group II and sham dogs. Conclusions: Rapid atrial pacing impaired SN function through IF and AT of the SN. Enalapril prevented these pacing-induced degenerative changes and improved SN function. [source] Detection of Inadvertent Catheter Movement into a Pulmonary Vein During Radiofrequency Catheter Ablation by Real-Time Impedance MonitoringJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2004PETER CHEUNG M.D. Introduction: During radiofrequency ablation to encircle or isolate the pulmonary veins (PVs), applications of radiofrequency energy within a PV may result in stenosis. The aim of this study was to determine whether monitoring of real-time impedance facilitates detection of inadvertent catheter movement into a PV. Methods and Results: In 30 consecutive patients (mean age 53 ± 11 years) who underwent a left atrial ablation procedure, the three-dimensional geometry of the left atrium, the PVs, and their ostia were reconstructed using an electroanatomic mapping system. The PV ostia were identified based on venography, changes in electrogram morphology, and manual and fluoroscopic feedback as the catheter was withdrawn from the PV into the left atrium. Real-time impedance was measured at the ostium, inside the PV at approximately 1 and 3 cm from the ostium, in the left atrial appendage, and at the posterior left atrial wall. There was an impedance gradient from the distal PV (127 ± 30 ,) to the proximal PV (108 ± 15 ,) to the ostium (98 ± 11 ,) in each PV (P < 0.01). There was no significant impedance difference between the ostial and left atrial sites. During applications of radiofrequency energy, movement of the ablation catheter into a PV was accurately detected in 80% of the cases (20) when there was an abrupt increase of ,4 , in real-time impedance. Conclusion: There is a significant impedance gradient from the distal PV to the left atrium. Continuous monitoring of the real-time impedance facilitates detection of inadvertent catheter movement into a PV during applications of radiofrequency energy. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1-5, June 2004) [source] Fractionation of Electrograms and Linking of Activation During Pharmacologic Cardioversion of Persistent Atrial Fibrillation in the GoatJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2004ZHAOLIANG SHAN M.D. Introduction: During atrial fibrillation (AF), there is fractionation of extracellular potentials due to head-to-tail interaction and slow conduction of fibrillation waves. We hypothesized that slowing of the rate of AF by infusion of a Class I drug would increase the degree of organization of AF. Methods and Results: Seven goats were instrumented with 83 epicardial electrodes on the left atrium, left atrial appendage, Bachmann's bundle, right atrium, and right atrial appendage. AF was induced and maintained by an automatic atrial fibrillator. After AF had persisted for 4 weeks, the Class IC drug cibenzoline was infused at a rate of 0.1 mg/kg/min. AF cycle length (AFCL), the percentage of fractionated potentials, conduction velocity (CV), and direction of propagation of the fibrillation waves were measured during baseline, after AFCL was increased by 20, 40, 60, and 80 ms, and shortly before cardioversion. Infusion of cibenzoline increased the mean of the median AFCLs from 96 ± 6 ms to 207 ± 43 ms (P < 0.0001). The temporal variation in AFCL in different parts of the atria was 8% to 20% during control and, with the exception of Bachmann's bundle, was not significantly reduced during cibenzoline infusion. CV decreased from 76 ± 14 ms to 52 ± 9 cm/s (P < 0.01). Cibenzoline increased the percentage of single potentials from 81%± 4% to 91%± 4% (P < 0.01) and decreased the incidence of double potentials from 14%± 4% to 7 ± 5% (P < 0.01) and multiple potentials from 5%±% to 1%± 2% (P < 0.001). Whereas during control, linking (consecutive waves propagating in the same direction) during seven or more beats occurred in 9%± 15% of the cycles, after cibenzoline the degree of linking had increased to 40%± 33% (P < 0.05). During the last two beats before cardioversion, there was a sudden prolongation in AFCL from 209 ± 37 ms to 284 ± 92 ms (P < 0.01) and a strong reduction in fractionated potentials (from 22%± 12% to 6%± 5%, P < 0.05). Conclusion: The Class IC drug cibenzoline causes a decrease in fractionation of fibrillation electrograms and an increase in the degree of linking during AF. This supports the observation that Class I drugs widen the excitable gap during AF. (J Cardiovasc Electrophysiol, Vol. 15, pp. 572-580, May 2004) [source] Prolonged Atrial Action Potential Durations and Polymorphic Atrial Tachyarrhythmias in Patients with Long QT SyndromeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2003PAULUS KIRCHHOF M.D. Introduction: Prolongation of the QT interval and torsades de pointes tachycardias due to altered expression or function of repolarizing ion channels are the hallmark of congenital long QT syndrome (LQTS). The same ion channels also contribute to atrial repolarization, and familial atrial fibrillation may be associated with a mutated KVLQT1 gene. We therefore assessed atrial action potential characteristics and atrial arrhythmias in LQTS patients. Methods and Results: Monophasic action potentials (MAPs) were simultaneously recorded from the right atrial appendage and the inferolateral right atrium in 10 patients with LQTS (8 with identifiable genotype) and compared to 7 control patients. Atrial arrhythmias also were compared to MAPs recorded in patients with persistent (n = 10) and induced (n = 4) atrial fibrillation. Atrial action potential durations (APD) and effective refractory periods (ERP) were prolonged in LQTS patients at cycle lengths of 300 to 500 msec (APD prolongation 30,41 msec; ERP prolongation 26,52 msec; all P < 0.05). Short episodes of polymorphic atrial tachyarrhythmias (polyAT, duration 4,175 sec) occurred spontaneously or during pauses after pacing in 5 of 10 LQTS patients, but not in controls (P < 0.05). P waves showed undulating axis during polyAT. Cycle lengths of polyAT were longer than during persistent and induced atrial fibrillation. Afterdepolarizations preceded polyAT in 2 patients. The electrical restitution curve was shifted to longer APD in LQTS patients and to even longer APD in LQTS patients with polyAT. Conclusion: This group of LQTS patients has altered atrial electrophysiology: action potentials are prolonged, and polyAT occurs. PolyAT appears to be a specific arrhythmia of LQTS reminiscent of an atrial form of "torsades de pointes."(J Cardiovasc Electrophysiol, Vol. 14, pp ***-***, October 2003) [source] Spatial Distribution and Frequency Dependence of Arrhythmogenic Vagal Effects in Canine AtriaJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2000OLEG F. SHARIFOV Ph.D. Arrhythmogenic Vagal Effects in Dog Atria. introduction: Prior studies in isolated canine atria demonstrated that acetylcholine-induced reentrant atrial fibrillation (AF) was triggered by multifocal activity in the area of normal impulse origin (sinus node-crista terminalis). The aim of this study was to investigate the activation sequence in AF induced by vagal stimulation (VS) in intact dog hearts. Methods and Results: VS (10 to 50 Hz, 1 msec, 15 V, 5-sec trains) induced single or multiple atrial premature depolarizations (APDs), and/or AF in 8 of 10 open chest dogs. Occurrence of APDs and AF increased with increasing VS intensity. Epicardial mapping (254 unipolar electrodes) of both atria showed that APDs as a rule emerged from ectopic sites, often from the right atrial appendage. Activation mapping of the first 10 cycles of AF showed that only a small number (<3 to 4) of unstable reentrant circuits were possible at the same moment. Moreover, most sustained VS-induced AFs were accounted for by a single leading stable reentrant circuit that activated the remainder of the atria. Conclusion: (1) Occurrence of vagally induced APDs and AF increases with increasing frequency of VS. (2) VS-induced focal ectopic APDs are widely distributed over the atria. (3) A single APD can be sufficient for initiation of reentrant AF. (4) Despite its high rate of sustained AF, it may be maintained by single stable reentrant circuit. (5) The atrial septum can play an important role in both the initiation and the maintenance of VS-induced AF. [source] Percutaneous Treatment for Mitral Regurgitation: The QuantumCor SystemJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2008RICHARD R. HEUSER M.D. Aims:Percutaneous edge-to-edge techniques and annuloplasty have been used to treat mitral regurgitation (MR). However, neither intervention can be performed reliably a second time and, with annuloplasty, a foreign body is left behind. The mitral and tricuspid annuli are areas of dense collagen (Fig. 1); treatment with radiofrequency (RF) energy in sheep reduces their size, and can be repeated without affecting the coronary sinus. RF energy may also be used in leaflet procedures. Our aim was to improve mitral valve competence using techniques that can be incorporated into a minimally invasive approach. Figure 1. This trichrome stain slide shows the amount of collagen present in the mitral annulus (in green). Methods:In open-heart procedures in 16 healthy sheep (6 with naturally occurring MR), we used a malleable probe (QuantumCor, Inc., Lake Forest, CA) that conforms to the annular shape to deliver RF energy via a standard generator to replicate a surgical mitral annular ring. Four segments of the posterior mitral valve annulus were treated while on cardiopulmonary support via a left thoracotomy with access via the atrial appendage. Seven sheep were followed chronically. Results:All sheep underwent intracardiac echocardiography (ICE) or direct circumferential measurement of the mitral annulus before and after RF therapy. RF therapy was administered in less than 4 minutes in each case, and the mean anteroposterior (AP) annular distance was reduced by a mean of 5.75 ± 0.86 mm (23.8% reduction, P< 0.001). In the 6 sheep with nonischemic MR, regurgitation was eliminated. Acute histopathology (HP) demonstrated no damage to the leaflets, coronary sinuses, or coronary arteries. At 30 days, the AP distance continued to be reduced in the 7 surviving sheep (mean 5.0 ± .6 mm, 21.4% reduction, P< 0.001). Conclusions:In a sheep model, RF energy applied for less than 4 minutes per case at subablative temperatures in four quadrants of the posterior mitral valve annulus reduced the AP and circumferential annular distances significantly, and eliminated nonischemic MR. Results will need to be confirmed in follow-up studies to determine safety and efficacy. RF energy administered as a novel, percutaneous method of mitral valve annuloplasty may have the potential to reduce morbidity and mortality associated with current surgical techniques. [source] Acute and Chronic Pulmonary Vein Reconnection after Atrial Fibrillation Ablation: A Prospective Characterization of Anatomical SitesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2008KIM RAJAPPAN M.D. Background:Arrhythmia recurrence after atrial fibrillation (AF) ablation is often associated with pulmonary vein reconnection (PVR). We prospectively examined anatomical sites of both acute and chronic PVR. Methods:One hundred and fifty AF patients underwent PV wide encirclement and sites where immediate electrical isolation (EI) occurred were tagged using electroanatomic mapping/CT integration (CartomergeÔ, Biosense Webster, Diamond Bar, CA, USA). After 30 minutes PVs were checked and acute PVR sites marked at reisolation. Chronic PVR sites were marked at the time of repeat procedures. Results:On the left, immediate EI sites were predominantly on the intervenous ridge (IVR) and PV-left atrial appendage (PV-LAA) ridge. On the right they were at the roof, IVR, and floor of the PVs. Ninety-eight of one hundred and fifty patients had PVs checked after >30 minutes. Thirty-two of ninety-eight had acute PVR. This was mostly on the IVR and PV-LAA ridge on the left (88%), and on the roof and IVR on the right (78%). At repeat procedure, 38/39 patients had chronic PVR, predominantly on the IVR (61%) and PV-LAA ridge (21%) on the left, and on the roof, IVR, and floor of the right PVs (79%). There was minimal acute or chronic PVR posteriorly. Acutely PVR occurred close to the immediate EI site 60% of the time, but only 30% of the time chronically. Conclusion:Acute and chronic PVR sites have a preferential distribution. This may be determined by anatomical and technical factors. Knowledge of immediate EI sites may be beneficial acutely, but with chronic PVR a careful survey is required. These findings may help target ablation, improving safety and success. [source] | |||||||||||||||||||||||||