Association of reduced PR-AC interval with ventricular early potentials in XXXX .

@entity1 @entity339 @entity384 @entity5036 @entity67
We studied 31 @entity1 with @entity384 , correlating mitral valve cusp motion with the continuous wave Doppler signal of @entity339 and the signal averaged electrocardiogram (ECG). Sixteen @entity1 had a B point (early partial closure) on the mitral echogram and 15 did not. Fifteen normal cases were used as controls. The duration of ventricular early potentials (< 40 microV) was measured on the signal averaged ECG of the QRS complex. The PR interval was increased in @entity1 with a B point (190 (33) ms vs. 145 (16) ms in normal, P < 0.01) and PR-AC interval was reduced (25 (71) ms vs. 65 (11) ms in normal, P < 0.05). The B point itself was effectively synchronous with the onset of low velocity early systolic @entity339 , and followed the Q wave of the succeeding beat by 20 ms or less. Early low velocity on @entity339 was not present in @entity1 without a B point. The duration of early potentials was greatly increased in @entity1 with a B point (43 (26) ms) compared both to those without (17 (20) ms, P < 0.01) and to normals (12 (7) ms, P < 0.01) and their duration correlated with B-C interval (r = 0.6, P < 0.02). We conclude that a B point on the mitral echogram in @entity1 with left @entity67 is due to early systolic low velocity @entity339 which itself results from an abnormal pattern of left ventricular activation, probably @entity5036 . Once established, this low velocity jet delays complete mitral valve closure.
