No abstract

Supraventricular tachycardia attacks, including atrial fibrillation (AF), occur after both external and internal cardioversions. These attacks of atrial fibrillation after direct-current (DC) shock may be related to hemodynamic impairment, thromboembolic events, or enhanced electrical instability of the ventricular and atrial myocardium, especially in predisposed patients. In this study, the authors aimed to show the importance of P-wave dispersion (PWD), which lead the atrium to fibrillate, in predicting post-DC shock AF after external cardioversion. Thus physicians may be able to choose the patients with high risk for AF occurrence and apply some other therapeutic modalities to those patients. The authors identified 18 patients in whom an AF attack was induced by urgent or elective cardioversion for a ventricular tachycardia attack and compared these patients with a control group composed of 40 patients without AF in regard to some clinical, echocardiographic, and electrocardiographic parameters. Left atrial diameters were greater (4.3+/-0.3 vs 3.5+/-0.5 cm, p = 0.001), left ventricular ejection fractions (LVEF) were lower (45.2+/-8.2 vs 54.9+/-7.5, p = 0.001), the energy needed for successful cardioversion was higher (166.6+/-59.4 vs 80.8+/-51.6 J, p = 0.001), and P max (135.2+/-7.4 vs 118.7+/-10.5 ms, p = 0.001) and PWD (53.8+/-12.2 vs 23.8+/-9.5 ms, p = 0.001) values were higher in patients with AF when compared to those without AF. Thus, the patients with higher PWD values had a greater risk for development of AF after a DC shock.

No abstract

Elevated sympathetic nerve activity in patients with mitral stenosis (MS) may be an index of the severity of the disease. Percutaneous mitral balloon commissurotomy (PMBC) is now a standard treatment for many patients with symptomatic MS. We aimed to show the effects of PMBC on autonomic nervous system activity in the patients with MS by heart rate variability (HRV) analysis. Fifty-four consecutive patients with mitral stenosis and sinus rhythm who underwent percutaneous mitral commissurotomy were enrolled. Apart from significant haemodynamic improvements, mean heart rate (HR), LF day, LF night, LF/HF day and night significantly decreased and SDNN, RMSSD, PNN50, HF day and night significantly increased in the early period after PMBC and these changes were preserved for up to one month. SDNN was positively correlated with left ventricle ejection fraction (LVEF) but negatively correlated with mean valve area (MVA), left atrial (LA) diameter and pressure, right atrial (RA) pressure; LF/HF day ratio was positively correlated with LA diameter and pressure, mean transmitral gradient and negatively correlated with LVEF; LF/HF night ratio was positively correlated with LA pressure and mean transmitral gradient. The increase in SDNN was correlated with the change in LA and RA pressure. The decrease in LF/HF ratio after PMBC was significantly correlated with the changes in the mean transmitral gradient, LA pressure and RA pressure. As a result, the heart rate variability and autonomic nervous system function in patients with mitral stenosis are correlated with the atrial pressures and left ventricular function. These parameters significantly change in the early period after PMBC and are preserved at one month. The improvement in the heart rate variability and sympatho-vagal balance are significantly affected by the early changes in atrial pressures after PMBC.

This study demonstrated for the first time that the high level of lipoprotein (a) negatively affects the formation of coronary collateral vessels in human beings. Reduced production or bioactivity of vascular endothelial cell growth factor caused by high levels of lipoprotein (a) may be the possible responsible mechanisms of hyperlipoprotein (a)-related poor collateral formation.