Interatrial septal thickness as a marker of structural and functional remodeling of the left atrium in patients with atrial fibrillation

BACKGROUND/AIMS: There have been reports that interatrial septal (IAS) thickness is increased in patients with atrial fibrillation (AF). This study was performed to investigate whether IAS thickness determined by transthoracic echocardiography (TTE) represents the amount of left atrium (LA) structural and functional remodeling. METHODS: The study population consisted of 104 consecutive patients who underwent catheter ablation (CA) for AF (paroxysmal atrial fibrillation [PAF], 82; persistent atrial fibrillation [PeAF], 22). IAS thickness and left atrium volume (LAV) using TTE, and LA voltage (LAVOL) using 3-dimensional electroanatomical mapping system were assessed during sinus rhythm. RESULTS: IAS thickness was significantly correlated with maximal LAV (LAVmax) (r = 0.288, p = 0.003), mean LAVOL (r = -0.537, p or = 2) compared to other groups according to CHA2DS2-VASc score (p = 0.019). During a follow-up of 19.6 months, 23 subjects (22.1%; PAF, 17; PeAF, 6) had recurrence of arrhythmia. Univariate analysis showed that LAVmax, minimal LAV, mean LAVOL, LVEFtotal, LVEFactive, and IAS thickness were associated with recurrence of arrhythmia. However, on multivariate analysis, only mean LAVOL and LAEFactive were independent risk factors for recurrence. CONCLUSIONS: Although IAS thickness showed significant correlations with parameters for LA structural and functional remodeling, this parameter alone could not independently predict recurrence of arrhythmia after CA for AF.

Time-Related Alterations of Endogenous Ouabain in DOCA-Salt Hypertensive Rats

BACKGROUND AND OBJECTIVES: Controversy exists regarding the role of endogenous ouabain in the pathogenesis of DOCA-salt induced hypertension. The purpose of this study was to investigate the role of endogenous ouabain in the development of hypertension in DOCA-salt rats. MATERIALS AND METHODS: The mean blood pressure and heart rate were recorded in 1, 2 and 4 week old control and DOCA-salt treated rats. The endogenous levels of ouabain in the plasma, hypothalamus, pituitary and adrenal glands of the 1, 2 and 4 week old control and DOCA-salt treated rats were also measured using a radioimmunoassay. RESULTS: The mean blood pressures in the 2 and 4 week old DOCA-salt treated rats were significantly higher than those of the controls. There was no significant change in the heart rate between the DOCA-salt treated and control groups. In the 4 week old DOCA-salt treated rats, the endogenous level of ouabain in the adrenal glands was higher than that in the control rats, but this was only weakly significant. The endogenous level of ouabain in the hypothalamus was significantly higher in the 1 week old DOCA-salt treated rats than in the control, but this significance disappeared in the 2 and 4 week old DOCA-salt treated rats. CONCLUSION: These results suggest that the endogenous level of ouabain contributes to the development and maintenance of high blood pressure in DOCA-salt rats. Further studies will be required to elucidate the relationship between the endogenous level of ouabain and DOCA-salt hypertension.

The Relationship between Serum Adiponectin, Essential Hypertension, LV Mass Index, and LV Diastolic Function

BACKGROUND AND OBJECTIVES: Adiponectin is known for its anti-inflammatory and anti-atherogenic effects. The purpose of this study is to characterize the relationships among serum adiponectin, essential hypertension (EH), left ventricular mass index (LVMI), and LV diastolic function. SUBJECTS AND METHODS: Serum adiponectin by RIA and body mass index were measured in 275 patients (M: F=137: 138). We calculated LVMI, E/A ratio, deceleration time (DT), and isovolumetric relaxation time (IVRT) by using echocardiograms. RESULTS: The serum adiponectin level of the hypertensive group was significantly lower than that of the non-hypertensive group (9.9+/-9.8 ug/mL vs. 12.9+/-9.5 ug/mL, p<0.05). Plasma adiponectin was negatively correlated with LVMI (r=-0.329, p<0.001), BMI (r=-0.290, p<0.001), and IVRT (r=-0.485, p<0.05), but was positively correlated with E/A (r=+0.359, p<0.001). CONCLUSION: These results suggest that a decrease in serum adiponectin is associated with an increase in blood pressure and BMI, progress of LVH, and decrease in LV diastolic function.

Changes of Mitral Inflow According to Position in Patients with Dilated Cardiomyopathy

BACKGROUND AND OBJECTIVES: Dilated cardiomyopathy(DCMP) probably is the end result of myocardial damage produced by various causes and shows various clinical manifestations. Some patients with DCMP experience more shortness of breath when change their position especially in left lateral decubitus position. We investigated whether the symptomatic changes according to position in DCMP patients were related to the changes of mitral inflow pattern. MATERIALS AND METHOD: DCMP patients with New York Heart Association functional class III or IV, who felt more shortness of breath when changed their position, were studied. The patients with atrial fibrillation or with moderate and severe valvular heart disease were excluded. Early and late atrial left ventricular filling velocities and time velocity integrals(TVI) and it's ratios of mitral inflow, heart rates, isovolumic relaxation time(IVRT), decelaration time(DT) of early mitral inflow were analysed in each decubitus position. RESULTS: 4 men and 3 women were included and their mean age was 60.3 years. 6 patients had mild mitral regurgitation and 4 patients had mild aortic regurgition. All patients felt more shortness of breath in left lateral decubitus position. Peak velocity and TVI of early mitral inflow were not changed significantly according to position. Peak velocity of late mitral inflow was increased significantly with right lateral decubitus position(Lt; 39.0+/- 14.1cm/sec, Rt; 49. 4+/-23.6cm/sec, p<0.05). TVI of late mitral inflow was increased significantly with right lateral decubitus position(Lt; 2.8+/-1.1cm, Rt; 3.8+/-1.9cm, p<0.05). Ratio of early and late mitral inflow peak velocity was decreased significantly with right lateral decubitus position(Lt; 2.13+ 0.34, Rt: 1.62+/-0.57, p<0.05). Ratio of early and late mitral inflow TVI was decreased significantly with right lateral decubitus position(Lt; 3.13+/-1.49, Rt; 2.13+/-1.32, p<0.01). Heart rate, IVRT, DT were not changed significantly according to position. CONCLUSION: In DCMP patients with symptomatic relief in right lateral position, mitral inflow patterns were changed. And this finding suggests that symptomatic relief may be related to decreased left ventricular filling pressure.