[Cardiac pacing in cardiomyopathy].

Pacing is useful not only for therapies of arrhythmias but also for other cardiac disorders. In this article, the pacing therapies for idiopathic cardiomyopathies were reviewed. AV sequential pacing has been reported as beneficial methods to improve symptoms of hypertrophic obstructive cardiomyopathy(HOCM) patients, but the mechanisms and expectancy of efficacy of pacemaker implantation are not clarified. Prospective double blind studies to see the efficacy of pacing on HOCM patients were done and reported in the two continents, one was PIC study in Europe and the other was M-PATHY in the north America. Although they had the almost same protocol, the conclusions were opposite. However the results of the two studies showed the same tendency. The LVOTPG(left ventricular outflow pressure gradient) and QOL at the end of study after 6 months of DDD pacing were significantly improved in those two studies. But in double blind periods M-PATHY showed significant QOL improvement by AAI pacing as sham test, and so little significant in PIC study was. There were slight decrease of LVOTPG noticed by AAI pacing in the both studies. It seemed to be inappropriate to have chosen AAI pacing as a sham test, because implantation of leads in the heart might affect the right ventricular functions which would affect the left ventricular performance. It must be reconsidered to do prospective double blind test with employing real sham test like as implantation of generator without leads again. With all gained data so far, pacing therapy seemed effective and still one of alternative options for therapy of HOCM. On the other hands, effects of conventional DDD pacing on DCM is so limited but multisite pacing which is developing in recent, will be also one of options for therapy of CHF due to DCM.