Inverse relation of body-surface activation-recovery interval and recoverytime to activation time in normal subjects: Stronger correlation and more heterogeneous distribution in activation-recovery interval than in recoverytime

The activation-recovery interval (ARI), measured directly from the myocardi um, has shown a good correlation with the action potential duration (APD) i n experiments. APD has been reported to be inversely related to the activat ion time (AT), However, no studies have examined the correlation between th e body-surface ARI and AT in normal subjects. Fifty normal subjects (25 men and 25 women) were studied to elucidate the relationship between the body- Surface ARI and AT. The body-surface AT was defined as the duration between the QRS onset and the minimum dV/dt of the QRS wave, and ARI as the interv al between the minimum dV/dt of the QRS wave and the maximum dV/dt of the T wave in each lead of an 87 unipolar lead system. We also measured the reco very time (RT) defined as the duration between the QRS onset and the maximu m dV/dt of the T wave. ARI was inversely correlated with AT (r = -0.73). RT was also inversely correlated with AT (r = -0.61), however, RT had a less heterogeneous distribution than ARI (148 ms vs 159 ms). There were no diffe rences between male and female subjects in the relation between ARI and RT or in the body-surface distribution of ARI and RT. These findings suggest t hat the body-surface ARI may reflect recovery properties over the cardiac s urface and that APD may distribute inhomogeneously over the human cardiac s urface with a longer RT over an area with a shorter AT. ARI calculated from body-surface ECG may be a useful noninvasive and repeatedly measurable est imate of APD.