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Increased Intra‐QRS Fragmentation in Magnetocardiography as a Predictor of Arrhythmic Events and Mortality in Patients with Cardiac Dysfunction After Myocardial Infarction
Author(s) -
KORHONEN PETRI,
HUSA TERHI,
TIERALA ILKKA,
VÄÄNÄNEN HEIKKI,
MÄKIJÄRVI MARKKU,
KATILA TOIVO,
TOIVONEN LAURI
Publication year - 2006
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2005.00332.x
Subject(s) - medicine , cardiology , qrs complex , ejection fraction , myocardial infarction , magnetocardiography , sudden cardiac death , signal averaged electrocardiogram , heart failure
Increased intra‐QRS fragmentation score (FRA) in magnetocardiography (MCG) has shown association with sustained ventricular arrhythmias in post‐MI patients suggesting its relation to arrhythmia substrate. The aim of this study was to investigate whether increased FRA in MCG predicts arrhythmic events and mortality after acute myocardial infarction (MI) with cardiac dysfunction. Methods and Results: A series of 158 patients with acute MI and left ventricular ejection fraction (LVEF) <50% were studied. Their age was 60 ± 10 years and LVEF 40 ± 6%. MCG was registered and FRA was computed. For comparison, QRS duration in 12‐lead ECG was measured. In a mean follow‐up of 50 ± 15 months, 32 (20%) patients died and 18 (11%) had an arrhythmic event. Both arrhythmic event rate and all‐cause mortality were significantly higher in patients with increased FRA (P < 0.001 for both). In contrast, increased QRS duration in ECG predicted all‐cause mortality (P < 0.05) but not arrhythmic events. In multivariate analysis, FRA was an independent predictor of both arrhythmic events and all‐cause mortality. Using a combined criterion of increased FRA and LVEF < 30% yielded positive and negative predictive accuracies of 50% and 91% for arrhythmic events. Conclusion: In post‐MI patients with left ventricular dysfunction, increased intra‐QRS fragmentation in high‐resolution magnetocardiography predicts arrhythmic events, whereas QRS duration in 12‐lead ECG predicts all‐cause mortality. Analysis of intra‐QRS fragmentation by MCG may assist in guiding therapy of post‐MI patients, for example, by selecting those who would benefit most from prophylactic implantable cardioverter‐defibrillator therapy.