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LA Size (la + size)
Selected AbstractsThe role of cell death in sexually dimorphic muscle development: Male-specific muscles are retained in female bax/bak knockout miceDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2008Dena A. Jacob Abstract The bulbocavernosus (BC) and levator ani (LA) muscles are present in males but absent or severely reduced in females, and the fate of these muscles controls the survival of motoneurons in the sexually dimorphic spinal nucleus of the bulbocavernosus. However, the mechanism underlying the sex difference in BC and LA development has been controversial. We examined the role of cell death in sexual differentiation of the bulbocavernosus BC/LA muscles in mice. Muscle development was mapped from embryonic day 16 (E16) to postnatal day 5 (P5). A sex difference (male > female) first arose on E17 (BC) or E18 (LA), and increased in magnitude postnatally. TUNEL labeling revealed dying cells in the BC and LA muscles of both sexes perinatally. However, females had a significantly higher density of TUNEL-positive cells than did males. A role for the proapoptotic factors, Bax and Bak, in BC/LA development was tested by examining mice lacking one or both of these proteins. In females lacking either Bax or Bak, the BC was absent and the LA rudimentary. Deletion of both bax and bak genes, however, rescued the BC, increased LA size ,20-fold relative to controls, and virtually eliminated TUNEL-positive cells in both muscles. We conclude that cell death plays an essential role in sexual differentiation of the BC/LA muscles. The presence of either Bax or Bak is sufficient for cell death in the BC/LA, whereas the absence of both prevents sexually dimorphic muscle cell death. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008. [source] Clinical Assessment and Rest and Stress Echocardiography for Prediction of Long-Term Prognosis in African Americans with Known or Suspected Coronary Artery DiseaseECHOCARDIOGRAPHY, Issue 5 2009Stephen G. Sawada M.D. Background: There is limited information on noninvasive risk stratification of African Americans, a high-risk group for cardiovascular events. We investigated the value of clinical assessment and echocardiography for the prediction of a long-term prognosis in African Americans. Methods: Dobutamine echocardiography was performed in 324 African Americans. Two-dimensional measurements were performed at rest, and rest and stress wall motion was assessed. A retrospective follow-up was conducted for cardiac events: myocardial infarction (MI) or cardiac death (CD). Results: The mean age was 59 ± 12 years, and 83% of patients had hypertension. The follow-up was obtained in 318 (98%) patients for a mean of 5.3 years. The events occurred in 107 (33%) subjects. The independent predictors of events were history of MI (P = 0.001, risk ratio [RR] 2.04), ischemia (P = 0.007, RR 1.97), fractional shortening (P = 0.033, RR 0.08), and left atrial (LA) dimension (P = 0.034, RR 1.39). An LA size of 3.6 cm and a fractional shortening of 0.30 were the best cutoff values for the prediction of events. Prior MI, ischemia, LA size >3.6 cm, and fractional shortening <0.30 were each considered independent risk predictors for events. The event rates were 13%, 21%, 38%, 59%, and 57% in patients with 0, 1, 2, 3, and 4 risk predictors, respectively. Event-free survival progressively worsened with an increasing number of predictors: 0 or 1 versus 2 predictors, P < 0.001; 2 versus 3 or 4 predictors, P = 0.003. Conclusion: The long-term prognosis of African Americans can be accurately predicted by clinical assessment combined with rest and stress echocardiography. [source] Age- and Sex-Related Differences in the Tissue Doppler Imaging Parameters of Left Ventricular Diastolic DysfunctionECHOCARDIOGRAPHY, Issue 6 2007Hyeun S. Park M.D. Background: The effect of age and gender on tissue Doppler imaging measurements comparing the septal and mitral annulus needs to be investigated. Methods: We investigated in 276 outpatients in a university cardiology practice the relationship of age and gender to left atrial (LA) size, LA volume, mitral pulse-wave Doppler E/A ratio, E/Ea ratios by tissue Doppler image of mitral annular velocity (TDI), and left ventricular diastolic dysfunction (LVDD) by TDI. Results: Mitral E/A inflow was statistically decreased with age. E/Ea ratios of the lateral and mean of both lateral and septal annulus showed a statistical increase with age, while the E/Ea ratio of the septal annulus did not correlate with age. When comparing men and women of all ages, the mean LA volume for men was 59.2 cm3± 24.36 cm3 versus 48.54 cm3± 16.14 cm3 (P-value < 0.0001) and the mean LA size was 4.0 + 0.51 cm for men and 3.65 + 0.47 for women (P-value < 0.0001). There was no statistical difference between men and women when looking at mitral E/A inflow ratio, deceleration time, E/Ea ratio of the septal annulus, E/Ea ratio of the lateral annulus, E/Ea ratio of the mean of both septal and lateral annulus, and grades of LVDD. Conclusion: In patients 70 years of age or older, the mean diastolic grade was mild-to-moderate LVDD when using lateral or mean of septal and lateral annular measurements. When only the septal annular measurements were used to determine diastolic grade, all four age groups showed a mean of mildly to moderately impaired LVDD and showed no correlation with age. There were no differences in tissue Doppler imaging measurements between men and women. [source] ORIGINAL INVESTIGATIONS: Comparison of Left Atrial Dimensions by Transesophageal and Transthoracic EchocardiographyECHOCARDIOGRAPHY, Issue 10 2005Harshinder Singh M.D. Transesophageal echocardiography (TEE) is an established cardiovascular diagnostic technique. Left atrial (LA) size, as measured by transthoracic echocardiography (TTE), is associated with cardiovascular disease and is a risk factor for atrial fibrillation, stroke, death, and the success of cardioversion. Assessment of LA size has not been as well validated on TEE as on TTE. We determined LA size measurements in four standard views in 122 patients undergoing TEE and TTE at the same setting. In this study, we found that measurement of LA dimensions by TEE suffers from significant limitations in all views except the basal long-axis view (mid-esophageal level) with transducer plane at 120,150 degrees. This view had the best correlation with transthoracic LA measurements: r = 0.79 for TEE long axis (CI 0.71,0.85), P <.0001. (ECHOCARDIOGRAPHY, Volume 22, November 2005) [source] The Relationship Between Endocardial Voltage and Regional Volume in Electroanatomical Remodeled Left Atria in Patients with Atrial Fibrillation: Comparison of Three-Dimensional Computed Tomographic Images and Voltage MappingJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009JAE HYUNG PARK B.Sc. Background: Long-standing atrial fibrillation (AF) changes left atrial (LA) morphology, and the LA size is related to recurrence after radiofrequency catheter ablation (RFCA). We hypothesize that LA morphology, based on embryological origin, affects the outcome of RFCA. Methods: We analyzed 3D computed tomographic (CT) images of LA in 70 patients with AF (54 males, 55.6 ± 10.5 years old, paroxysmal AF (PAF):persistent AF (PeAF) = 32:38) who underwent RFCA. Each LA image was divided into venous atrium (VA), anterior LA (ALA), LA appendage (LAA), and both antrum. Absolute and relative volumes were calculated, and the lengths of linear ablation sites were measured. Results: (1) In patients with the mean LA voltage , 2.0 mV, LA volume, especially ALA, was larger (P < 0.01) compared to those with LA voltage > 2.0 mV. (2) The total LA volume was significantly larger (P < 0.01) and LAA voltages (P < 0.05) and conduction velocities (P < 0.05) were lower in patients with PeAF than in those with PAF. (3) In patients with recurrence, LA volume was generally larger (P < 0.01) than in those without recurrence. In PAF patients with recurrence, the relative volume of ALA was significantly larger (P < 0.01) than those without recurrence. Conclusions Morphologically remodeled LA has low endocardial voltage, and enlargement of ALA is more significant in electroanatomically remodeled LA. The disproportional enlargement of ALA was observed more often in PAF patients with recurrence after ablation than those without recurrence. [source] Do the Left Atrial Substrate Properties Correlate with the Left Atrial Mechanical Function?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2008A Novel Insight from the Electromechanical Study in Patients with Atrial Fibrillation Background: The atrial substrate is the determinant of occurrence and maintenance of atrial fibrillation (AF), which can induce remodeling of atrial function and structure. This study investigated the relationship between the left atrial (LA) substrate properties and LA mechanical function. Methods: Forty-four consecutive patients (50.3 ± 10.7 years old, 33 men) who presented with sinus rhythm during echocardiographic study before receiving catheter ablation for AF were enrolled. The LA diameter, LA volume, ratio of early and late transmitral filling flow velocities (E/A), LA appendage flow velocity, and transmitral velocity-time integral (VTI) were measured by the echocardiography. The LA empty fraction (LAEF), which was obtained via dividing the difference between maximal and minimal LA volume by maximal LA volume, was calculated as a parameter of the global LA contractile function. The LA global contact voltage mapping (NavX system) was performed before pulmonary vein isolation. Results: Mean LA voltage and LA low voltage zone index (LVZ index, area with voltage < 0.5 mV, divided by total LA surface area) showed significant correlation with LA diameter and volume, but only the LA LVZ index showed significant correlation with A-wave velocity, transmitral A-wave VTI, and LAEF (r =,0.340, ,0.411, ,0.426; P = 0.024, 0.006, 0.005, respectively). We divided the LA LVZ index into three groups (< 10%, 10,20%, > 20%). The LAEF got worse and the transmitral A-wave VTI percentage (divided by transmitral VTI) decreased as LA LVZ index increased. Conclusions: The LA substrate properties showed close correlation with LA size, but only the LA LVZ index correlated with the LA mechanical function. [source] Electrophysiological Differences of the Spontaneous Onset of Paroxysmal and Persistent Atrial FibrillationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2007STEFAN WEBER M.D. Background: Information about the spatiotemporal organization of atrial activity at the onset of atrial fibrillation (AF) is still limited. Methods: AF mapping was performed in 30 patients with AF (mean age 53 ± 9 years, 26 males) by deploying a noncontact mapping balloon in the left atrium (LA). Twenty-four patients had paroxysmal AF and six patients had persistent AF. Three types of AF episodes were analyzed: nonsustained AF (lasting , 30 seconds), sustained AF (lasting > 30 seconds, with spontaneous conversion or requiring internal cardioversion and subsequent stable sinus rhythm), and persistent AF episodes (stable sinus rhythm lasting , 1 minute after cardioversion). Results: A total of 101 spontaneous AF onset episodes were analyzed. Analysis of AF onset showed that there was a progressive shortening of the initial cycle lengths from nonsustained episodes to sustained episodes and to persistent AF episodes. There was an earlier and more rapid reduction in the cycle lengths from persistent episodes to sustained episodes and to nonsustained episodes of AF (P < 0.05 for persistent vs sustained and for sustained vs nonsustained episodes). The development of multiwavelet activity and disorganization of conduction occurred earlier in persistent and sustained episodes than in nonsustained AF episodes. LA size was greater in patients with persistent AF episodes compared with patients with sustained or nonsustained AF episodes. Conclusions: Electrophysiological events that develop at the onset of AF seem to be different in different types of AF. A more rapid degeneration into the fibrillatory activity was observed in persistent and sustained AF than in nonsustained AF episodes. [source] Atypical Electrocardiographic Features of Cavotricuspid Isthmus-Dependent Atrial Flutter Occurring during Left Atrial Fibrillation AblationANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2010Janice Y. Chyou M.D. Background: Patients who have undergone percutaneous catheter ablation for atrial fibrillation (AF) may develop cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), which can occur either spontaneously during left atrial (LA) ablation for AF or by induction from sinus rhythm during the procedure. The electrocardiographic (ECG) characteristics of CTI-dependent AFL occurring during LA ablation have not been described. The purpose of this study was to describe the ECG features of CTI-dependent AFL occurring during percutaneous LA catheter ablation for AF. Methods and Results: Of 223 patients presenting for first AF ablation at our institution between May 2004 and February 2008, 20 patients (9%) developed CTI-dependent AFL during LA ablation for AF. CTI-dependent AFL developed spontaneously in 4 patients (20%) and was induced in 16 patients (80%). Among these 20 patients, 3 (15%) had typical ECG patterns and 17 (85%) had atypical ECG patterns. Flutter waves in the inferior leads were biphasic in 10 patients (50%), downward in 3 patients (15%), positive in 3 patients (15%), and not fitting the above classifications in 4 patients (20%). There was no statistically significant association between AFL pattern and LA size, left ventricular ejection fraction, total ablation time, duration of prior AF, or type of prior AF. Conclusion: A majority of patients with CTI-dependent AFL occurring during LA ablation have atypical ECG patterns. Biphasic flutter waves in the inferior leads are common ECG features, occurring in one-half of patients. Right atrial CTI-dependent AFL should be suspected even if the ECG appearance is atypical. Ann Noninvasive Electrocardiol 2010;15(3):200,208 [source] | ||||||||||