NEW INDICATIONS OF CARDIAC PACING

New indications have recently appeared for cardiac pacing with haemody namic and antiarrhythmic objectives without any symptomatic bradycardi a. The best documented indication, though relatively rare, is stimulat ion of obstructive hypertrophic cardiomyopathy; initially reserved for cases with favorable results of an acute haemodynamic test, it is now used in other cases without this criterion; hypertrophic cardiomyopat hy without permanent obstruction, atrial fibrillation or left bundle b ranch block. The improvement observed during follow-up is always great er as a real remodeling of the myocardium seems to occur with ventricu lar dilatation and/or septal thinning. However, the position of the at rial, and above all, of the ventricular pacing catheters is critical a s is regulation of the pacemaker which should allow complete ventricul ar capture with an AV delay allowing good filling. The follow-up of th ese patients must therefore be regular and the effects on longevity ar e unknown. DDD pacing has also been proposed in dilated cardiomyopathy . The results are contradictory and only very selected cases with left bundle branch block and long PR interval seem justified with, again, optimisation of the pacing sites with high septal or biventricular sti mulation. Recurrent atrial tachycardia, special algorithms preventing extrasystoles have been tried with variable results. In cases with int eratrial block, atrial resynchronisation by bi-atrial stimulation has been assessed with promising results but many technical problems remai n unsolved.