Author + information
- Received April 26, 1995
- Revision received August 11, 1995
- Accepted August 17, 1995
- Published online January 1, 1996.
- Lutz Reinhardt, MSca,**,
- Markku Mäkijärvi, MDa,
- Thomas Fetsch, MDa,
- Juha Montonen, MSc*,
- Gilberto Sierra, PhDa,
- Antoni Martínez-Rubio, MDa,
- Toivo Katila, PhD*,
- Martin Borggrefe, MDa and
- Günter Breithardt, MD, FESC, FACCa
- ↵**Address for correspondence: Dr. Lutz Reinhardt, Medizinische Klinik und Poliklinik, Innere Medizin C, Westfälische Wilhelms-Universität Münster, D-48129 Münster, Germany.
Objectives. This study sought to evaluate the prognostic value of wavelet correlation functions of the signal-averaged electrocardiogram (ECG) for arrhythmic events in patients after myocardial infarction.
Background. Wavelet transform of the signal-averaged ECG has been shown to be a nonstationary analysis technique describing the time evolution of frequency spectra throughout the QRS complex. To quantify the wavelet transform, we introduced the new concept of the wavelet correlation function.
Methods. The relation among wavelet correlation functions, ventricular late potentials and the site of infarction was investigated in 769 men <66 years old who survived the acute phase of myocardial infarction (351 [46%] anterior, 418 [54%] inferior infarctions). Signal-averaged ECG recordings were obtained 2 to 3 weeks after infarction. During 6 months of follow-up, 33 patients (4.3%) experienced a malignant arrhythmic event. Wavelet correlation functions of the signal-averaged ECG were evaluated in a time-frequency plane ranging from 25 ms before QRS onset to 25 ms after QRS offset in the frequency range between 40 and 100 Hz.
Results. Patients with an anterior infarction had lower mean wavelet correlation coefficients (p < 0.001) and a lower incidence of ventricular late potentials than patients with an inferior infarction (32.3% vs. 42.7%, p = 0.003). The combination of wavelet correlation functions and late potentials increased the total predictive accuracy from 52% to 72% for inferior and from 64% to 76% for anterior infarctions.
Conclusions. Spectral changes in the signal-averaged QRS complex are more prominent in anterior than inferior infarctions. Combination of late potential analysis and wavelet correlation functions increases the prognostic value for serious arrhythmic events after myocardial infarction.
This study was supported by Grant Br759/2-2 from the Deutsche Forschungsgemeinschaft, Grant HKP314 from the Bundesministerium für Forschung und Technologie (BMFT) and by the Deutscher Akademischer Austauschdienst (DAAD), Bonn, Germany; the Academy of Finland Helsinki, Finland; the European Union Human Capital and Mobility Programme (BIRCH-European Large Scale Facility in Biomagnetic Research at Helsinki University of Technology), Brussels, Belgium; and the Franz-Loogen-Stiftung for Cardiological Research, Düsseldorf, Germany. Dr. Mäkijärvi was supported by a Research Fellowship Grant from the European Society of Cardiology, Sophia Antipolis, France. Dr. Sierra is a Research Fellow of the Central Institute of Digital Research, Havana, Cuba and is supported by the Deutscher Akademischer Austauschdienst (DAAD), Bonn, Germany.
- Received April 26, 1995.
- Revision received August 11, 1995.
- Accepted August 17, 1995.
- American College of Cardiology