Activity of myocardial sympathico-adrenal system in various volume of viable myocardium in chronic cardiac failure

Abstract

Aim. To estimate sympathetic activity in patients with ischemic heart disease (IHD) complicated by chronic cardiac failure (CCF) depending on the volume of viable myocardium measured by dobutamine stress echocardiography (DSE). Material and methods. Planar myocardial I-231-MIBG scintigraphy and dobutamine stress echocardiography were made in 16 patients (9 males and 7 females) aged 43-75 years with CCF (NYHA class II- III) and ejection fraction under 35%. The ratio maximal MIBG absorption in the left ventricular myocardium to maximal MIBG absorption in the mediastenum (H/M) and lung (H/L) were estimated. Results. By DSE the patients were divided into two groups: responders in whom contractility improved by 4 and more points (9 patients) and non-responders in whom contractility improved by less than 4 scores (7patients). The groups did not differ by clinical and hemodynamic parameters but group 2 patients had significantly lower H/M and H/L than group 1 patients (1.38 ± 0.02 and 1.08 ± 0.06 against 1.61 ± 0.09 and 1.25 ± 0.12, respectively, p < 0.05). A direct correlation was found between MIBG absorption (H/M, H/L) and ejection fraction on minimal dobutamine doses (r = 0.77, p < 0.01; r = 0.87, p < 0.001), gain in ejection fraction (r = 0.77, p < 0.01; r = 0.45, p < 0.05), and inverse correlation between MIBG absorption (H/M, H/L) and dyssynergia index on minimal dobutamine doses (r = -0.80, p < 0.001; r = -0.87, p < 0.0001). Conclusion. Patients with CCF demonstrate a correlation between sympathetic activity and volume of viable myocardium, inotropic reserve.

Keywords

• sympathico-adrenal system
• viable myocardium
• chronic cardiac failure
• planar myocardial scintigraphy