Serial change of sympathetic nerve activity of the patients with HOCM treated with PTSMA

Abstract

Background: PTSMA is a effective non-surgical technique for achieving the reduction of the pressure gradients of LV outflow and patients symptoms dramatically. However, the effect of this approach to the sympathetic activity is not well known. Purpose and Methods: To investigate the time course of the sympathetic nerve activity, we evaluate the sympathetic activity by MIBG scintigraphy performed just before, 1week after, and 3 months after the procedure in 6 patients with severe HOCM. H/M ratio in early and delayed images and washout rate was used as the indexes showing sympathetic function. Results: The procedures were all successful without severe complications. CPK release ranged from 976 to 3642 IU. LV outflow PG decreased markedly from 110 ± 16mmHg to 45 ± 31mmHg and concomitant improvement of NYHA classification was evident ( pre-PTSMA:2.5 ± 0.8 post-PTSMA:1.2 ± 0.4). MIBG demonstrates the transient increase of washout (pre:34 ± 5% post:44 ± 6%) and decrease of H/M ratio of delayed images (pre:1.9 ± 0.8, post:1.7 ± 0.2) at 1week after procedures. 3 months after procedure, significant decrease of washout(3M:30 ± 8%) and increase of H/M ratio(3M:2.0 ± 0.3) was observed. Conclusion: Transient overactivation of sympathetic nerve probably associated with iatrogenic infarction was observed early after PTSMA. However, sympathetic activity was gradually reduced at chronic phase suggesting the favorable effect of this therapy on loading conditions of the hypertrophied heart.