EFFECT OF PACING ON VENTRICULAR KINETICS - CONTRIBUTION TO THE TREATMENT OF CARDIOMYOPATHIES

Cardiac pacing using the apex of the right ventricle as site of excita tion induces asynchronous contraction between the right ventricle and the left ventricle as well as inversion of the normal left ventricular activation sequence. These two phenomena are responsible for alterati on of septal kinetics and overall contractility. It has recently been demonstrated that these alterations can be used to advantage to reduce the degree of subaortic obstruction of patients suffering from hypert rophic and obstructive cardiomyopathy, and to improve their exercise t olerance. Using an opposite approach, consisting of reducing the degre e of asynchronous contraction related to the presence of intraventricu lar conduction disorders, while optimizing atrioventricular synchronis m, new pacing methods have recently been able to improve cardiac outpu t and functional tolerance of some patients suffering from dilated car diomyopathy. Although cardiac pacing can now be considered to be an al ternative a surgery for the treatment of refractory forms of hypertrop hic and obstructive cardiomyopathy, it still constitutes a reserch tec hnique in the field of dilated cardiomyopathy.