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An Automatic Microcomputer System for Analysis of Monophasic Action Potentials
Author(s) -
KANAAN NABIL,
JENKINS JANICE,
KADISH ALAN
Publication year - 1990
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1990.tb05070.x
Subject(s) - medicine , microcomputer , action (physics) , telecommunications , chip , physics , quantum mechanics , computer science
A computer system for rapid measurement and analysis of monophasic action potentials (MAPs) recorded in vivo was developed. MAPs recorded from the epicardium of mongrel dogs using a contact electrode were digitized by analog‐to‐digital conversion at a sampling rate of 1 kHz per channel for computer data acquisition. Activation time was detected using a sliding 10‐point window at the location where the average positive dV/dT exceeds an adjustable threshold value in order to eliminate spurious detection due to baseline variability or motion artifact. Action potential duration fAPDJ was determined at 50% and 90% (APD 50 , APD 90 ) repolarization levels at the first sample point below these defection levels. In addition, a tangent algorithm (APD, tan ) that detects peak negative dV/dT during repolarization was developed. APD tan was determined from the location of onset of activation to the intersection of the tangent and baseline. APD tan allowed estimation of APD in the presence of subsequent premature beats when APD 80 was not measurable. To validate activation time measurements, 4,600 action potentials were analyzed during fixed rate pacing. Over a range of paced coupling intervals from 200 to 1000 msec, an R 2 value of 0.99968 and a slope of 0.9959 were obtained by linear regression between paced and calculated intervals. To validate APD measurements, 5035 action potentials were analyzed in five animals during fixed rate pacing (longer than 3 minutes) when action potential duration should be constant. Average coefficients of variation of 1.25%, 1.65%, and 1.14% were obtained for APD 50 , APD 90 , and APD tan , respectively. This algorithm provides a rapid and accurate method to analyze MAP activation and duration for basic physiological studies such as the determination of initiation of arrhythmias.