Fragmented QRS in prediction of cardiac deaths and heart failure hospitalizations after myocardial infarction.
BACKGROUND
Increased QRS fragmentation in visual inspection of 12-lead ECG has shown association with cardiac events in postmyocardial infarction (MI) patients. We investigated user-independent computerized intra-QRS fragmentation analysis in prediction of cardiac deaths and heart failure (HF) hospitalizations after MI.


METHODS
Patients (n = 158) with recent MI and reduced left ventricular ejection fraction (LVEF) were studied. A 120-lead body surface potential mapping was performed at hospital discharge. Intra-QRS fragmentation was computed as the number of extrema (fragmentation index FI) in QRS. QRS duration (QRSd) was computed for comparison.


RESULTS
During a mean follow-up of 50 months 15 patients suffered cardiac death and 23 were hospitalized for HF. Using the mean + 1 SD as cut-point both parameters were univariate predictors of both end-points. In multivariate analysis including age, gender, LVEF, previous MI, bundle branch block, atrial fibrillation, and diabetes FI was an independent predictor for cardiac deaths (HR 8.7, CI 3.0-25.6) and HF hospitalizations (HR 3.8, CI 1.6-9.3) whereas QRSd only predicted HF hospitalizations (HR 4.6, CI 2.0-10.7). In comparison to QRSd, FI showed better positive (PPA) and equal negative (NPA) predictive accuracy for both end-points, and PPA was further improved when combined to LVEF < 40%. Limiting fragmentation analysis to 12-lead ECG or a randomly selected 8-lead set instead of all 120 leads resulted in an almost similar prediction.


CONCLUSIONS
Increased QRS fragmentation in post-MI patients predicts cardiac deaths and HF progression. A computer-based fragmentation analysis is a stronger predictor than QRSd.
Korhonen
Petri
P
Helsinki University Hospital, Finland. petri.korhonen@hus.fi <petri.korhonen@hus.fi>
Husa
Terhi
T
Konttila
Teijo
T
Tierala
Ilkka
I
Mäkijärvi
Markku
M
Väänänen
Heikki
H
Ojanen
Janne
J
Vehtari
Aki
A
Toivonen
Lauri
L
D003643:Death; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted