OBJECTIVETo evaluate left atrial function in essential hypertension patients with different patterns of left ventricular geometric models by real time three-dimensional echocardiography (RT-3DE) and left atrial tracking (LAT).

METHODSOne hundred and thirty-three patients with essential hypertension were divided into four groups according to criteria proposed by Ganau et al: 36 patients in normal pattern group (I), 34 patients in concentric remodelling pattern group (II), 33 patients in concentric hypertrophy pattern group (III), and 30 patients in eccentric hypertrophy pattern group (IV). Thirty-two healthy volunteers were enrolled in this study. RT-3DE and LAT were used to obtain the volume-time and emptying fraction curves, and then the maximal volume, minimal volume, stroke volume, presystolic volume, ejection fraction, systolic filling rate, early diastolic emptying rate and late diastolic emptying rate of the left atrium were measured. Conduit volume and passive emptying volume of the left atrium were calculated.

RESULTSLeft atrial indexes, conduit volume, passive emptying volume, and early diastolic emptying rate decreased, while the other indices increased in the group I compared with the control group (all P<0.05). Compared with the control group, I and II groups, the left atrial volume parameters manifested change in the group III and group IV (all P<0.01). Left atrial ejection fraction measured by RT-3DE or LAT, and late diastolic emptying rate were lower in the group IV compared with the group III (all P<0.05). There was no difference in left atrial conduit volume, passive emptying volume, and early diastolic left atrial emptying rate between the group II and group I (all P>0.05). There was a positive correlation between RT-3DE and LAT in evaluating left atrial function.

CONCLUSIONSLeft atrial booster pump function decreases in the eccentric hypertrophy pattern. Left atrial conduit function is unchanged in the normal pattern and the concentric remodelling pattern groups. RT-3DE and LAT technology can be used for quantitative evaluation of left atrial volume and function.

Adult ; Aged ; Atrial Function, Left ; Cardiomegaly ; diagnostic imaging ; physiopathology ; Echocardiography, Three-Dimensional ; Female ; Heart Atria ; diagnostic imaging ; physiopathology ; Humans ; Hypertension ; diagnostic imaging ; physiopathology ; Male ; Middle Aged ; Models, Cardiovascular

Left anterior fascicular block (LAFB) is a heart disease identifiable from an abnormal electrocardiogram (ECG). It has been reported that LAFB is associated with an increased risk of heart failure. Non-specific intraventricular conduction delay due to the lesions of the conduction bundles and slow cell to cell conduction has also been considered as another cause of heart failure. Since the location and mechanism of conduction delay have notable variability between individual patients, we hypothesized that the impaired conduction in the ventricular myocardium may lead to abnormal ECGs similar to LAFB ECG patterns. To test this hypothesis, based on a computer model with a three dimensional whole-heart anatomical structure, we simulated the cardiac exciting sequence map and 12-lead ECG caused by the block in the left anterior fascicle and by the slowed conduction velocity in the ventricular myocardium. The simulation results showed that the typical LAFB ECG patterns can also be observed from cases with slowed conduction velocity in the ventricular myocardium. The main differences were the duration of QRS and wave amplitude. In conclusion, our simulations provide a promising starting point to further investigate the underlying mechanism of heart failure with LAFB, which would provide a potential reference for LAFB diagnosis.
Adult ; Bundle-Branch Block/diagnostic imaging* ; Computer Simulation ; Electrocardiography ; Heart/diagnostic imaging* ; Heart Atria/diagnostic imaging* ; Heart Conduction System/physiopathology* ; Heart Failure/diagnostic imaging* ; Heart Ventricles/diagnostic imaging* ; Humans ; Male ; Models, Anatomic ; Models, Theoretical ; Muscle Cells ; Myocardium ; Phantoms, Imaging ; Poisson Distribution

The value of the left atrial volume tracking (LAVT) method in the evaluation of left atrial (LA) function in patients with diabetes mellitus (DM) was examined in this study. Fifty-eight DM patients as DM group and 40 healthy people as normal control group were enrolled in this study. EUB-6500 echocardiographic imaging system with LAVT was applied to display and analyze the LA volume curve imaging on LV apical two and four chamber views. The maximal LA volume at end-systole (LAV(max)), LA volume at the onset of ECG-P wave (LAV(p)), the minimal LA volume at end-diastole (LAV(min)) from the LA volume curve were acquired and recorded. All values above were standardized by body surface area (BSA). Then the passive, active and total LA volume (LAVIpass, LAVIact, LAVItotal) and empting rate (%LAVIpass, %LAVIact, %LAVItotal), effective passive and active empting rate (%eLAVIpass, %eLAVIact), and the proportionality of passive empting volume and active empting volume were calculated. The LAVIp, LAVIact, LAVItotal, %LAVIact, %LAVItotal and %eLAVIact were significantly higher in the DM group than those in the control group, whereas the LAVIpass, %LAVIpass, %eLAVIpass and LAVIpass/act were lower (all P<0.05). For the LA volume change in DM, the active empting volume was enhanced at end-diastole. It was concluded that LAVT is a potentially useful tool to evaluate the function of LA.
Adult ; Aged ; Atrial Function, Left ; physiology ; Case-Control Studies ; Diabetes Mellitus, Type 2 ; physiopathology ; Echocardiography, Doppler ; methods ; Female ; Heart Atria ; diagnostic imaging ; pathology ; Humans ; Male ; Middle Aged ; Organ Size

Prolonged P-wave duration has been observed in diabetes. However, the underlying mechanisms remain unclear. The aim of this study was to elucidate the possible mechanisms. A rat model of type 2 diabetes mellitus (T2DM) was used. P-wave durations were obtained using surface electrocardiography and sizes of the left atrium were determined using echocardiography. Cardiac inward rectifier K+ currents (I(k1)), Na+ currents (I(Na)), and action potentials were recorded from isolated left atrial myocytes using patch clamp techniques. Left atrial tissue specimens were analyzed for total connexin-40 (Cx40) and connexin-43 (Cx43) expression levels on western-blots. Specimens were also analyzed for Cx40 and Cx43 distribution and interstitial fibrosis by immunofluorescent and Masson trichrome staining, respectively. The mean P-wave duration was longer in T2DM rats than in controls; however, the mean left atrial sizes of each group of rats were similar. The densities of I(k1) and I(Na) were unchanged in T2DM rats compared to controls. The action potential duration was longer in T2DM rats, but there was no significant difference in resting membrane potential or action potential amplitude compared to controls. The expression level of Cx40 protein was significantly lower, but Cx43 was unaltered in T2DM rats. However, immunofluorescent labeling of Cx43 showed a significantly enhanced lateralization. Staining showed interstitial fibrosis was greater in T2DM atrial tissue. Prolonged P-wave duration is not dependent on the left atrial size in rats with T2DM. Dysregulation of Cx40 and Cx43 protein expression, as well as fibrosis, might partly account for the prolongation of P-wave duration in T2DM.
Action Potentials ; Animals ; Blotting, Western ; Connexin 43/metabolism ; Connexins/metabolism ; Diabetes Mellitus, Type 2/*physiopathology ; Disease Models, Animal ; Echocardiography ; Electrocardiography ; Fibrosis/pathology ; Heart Atria/*diagnostic imaging/physiopathology ; In Vitro Techniques ; Male ; Membrane Potentials ; Microscopy, Fluorescence ; Patch-Clamp Techniques ; Potassium Channels/metabolism ; Rats ; Rats, Wistar