740-6 Short A-V Delay Interval Improves Filling in DDD Pacing of Patients with Left Ventricular Hypertrophy and Normal Ejection Fraction

DDD pacing maintains physiological atrio-ventricular synchrony improving filling, performance and reducing wall stress independently from A-V delay in normal heart. We tested the effects of A-V delay modification on Doppler derived filling pattern in 7 hypertensive patients (pts) who implanted DDD pacemaker (Cosmos II Intermedicsl for Sick Sinus Syndrome (SSS). All had normal ejection fraction (64±6%), but abnormal filling pattern (at nominal values of 200 msec) due either to left ventricular hypertrophy and electrically induced left bundle branch block. This group was compared with a similar one of 7 pts (group 21 with DDD-PM for SSS but normal filling pattern. (Deceleration time Group 1=302.86±42, Group 2=212.86±17.04 p=0.01). Group 1 normalized filling pattern reducing Dec t and A peak increasing E peak velocity at 100msec A-V delay, with less modification at 75 and 150msec, whereas group 1 showed umpredictable modification.DDD pacing of pts with abnormal filling presented a “normalised pattern”, at 100 A-V delay probably due to increased atrial pressure resulting from anticipation of ventricular spike, which avoids complete atrial relaxation and makes mitral valve to open earlier. It seems that DDD pacing of pts with LV hypertrophy, abnormal relaxation and normal performance needs of short A-V delay to improve filling, whereas pts with normal filling at nominal values, do not