J. Haas et al., Late fields in magnetcardiography and late potentials in electrocardiography after acute myocardial infarction, Z KARDIOL, 88(8), 1999, pp. 566-573
Citations number
24
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
A high specificy and a high positive prediction has been reached in risk st
ratification for sudden cardiac death after acute myocardial infarction (AM
I) by combining multiple methods. But sensitivity and negative prediction a
re still not satisfying. There are the same physiological processes underly
ing magnetcardiography (MCG) and electrocardiography (ECG). Nevertheless, t
he signals in each method contain different information.
Methods: We studied the cardiac magnetic fields in 50 patients after AMI an
d in 32 probands and calculated the magnetic late field (LF), according to
Simsons late potential (LP) analysis. We defined normal values, according t
o the 95 % confidence interval of the probands (QRS < = 97 ms, RMS > = 0.6,
LAS < 25 ms).
Results: We compared the results of LF and LP analysis regarding pathologic
-nonpathologic and found 76 % of the patients with the same results in both
methods. Four patients had magnetic signals with low amplitude in the ST s
egment in contrast to the ECG result, while 6 patients with a "LP positive"
diagnosis based on RMS and LAS only, did not show LF. In addition, we have
found the magnetic QRS complex to be shorter than the electrical one.
Discussion: In general the results of LF measurement are similar to the one
s of LP measurement. Presumably, there are intracardial currents, which are
not detectable by EGG, Further studies are needed to evaluate the prognost
ic value in patient at high risk for cardiac arrhythmias.