[Effects of filtering techniques on time-domain analysis of signal-averaged ECG after acute myocardial infarction: a multicenter study, GISS-3 arrhythmia sub-project].
OBJECTIVE
To evaluate the influence of different filtering techniques on the measurement of ventricular late potentials (VLP) the Sottoprogetto Aritmie of GISSI-3 collected signal-averaged ECG (SAECG) from 647 patients.


METHODS
Data were recorded after myocardial infarction (10 +/- 4 days) in 20 Italian Coronary Units. Three main filtering algorithms were used in the different commercial devices: Bidirectional Filter (ART, Aerotel, Fidelity Medical) (BF: 340 Patients), Spectral Filter (Marquette) (SF: 258 Patients) and Del Mar Filter (Del Mar Avionics) (DF: 49 Patients). QRS duration (QRSD), low amplitude signal duration (LAS40) and root mean-square-voltage (RMS40), were measured with various filters set at 40-250 Hz high and low pass frequencies.


RESULTS
After correction for clinical variables the measurements of VLP in the three different groups were different. QRSD value obtained by BF (100.6 +/- 13 ms) was shorter than that obtained by SF (109.1 +/- 12 ms). No differences were found in LAS40 and RMS40 values between SF and BF, while DF gave longer LAS40 and lower RMS40 than SF and BF. Residual noise was lower in BF (0.3 +/- 0.1 muV). than in SF and DF (0.5 +/- 0.1 muV). Applying standard criteria DF gave a higher prevalence of VLP (48.9%) than BF (23.8%) and SF (19%) groups.


CONCLUSIONS
This study demonstrates that the use of different filters produces discordant result on VLP measurements. For correct application of SAECG analysis in risk stratification after myocardial infarction, normal and abnormal values must be specifically established for the different filter techniques.
Del Greco
M
M
Divisione di Cardiologia, Ospedale di Rovereto.
Nollo
G
G
Disertori
M
M
Sanna
G
G
Maggioni
A P
AP
Santoro
E
E
Tarantino
F
F
Della Mea
M T
MT
Antolini
R
R
Micciolo
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D002316:Cardiotonic Agents / Q000494:pharmacology / Q000627:therapeutic use; D003627:Data Interpretation, Statistical; D004562:Electrocardiography; D005260:Female; D005374:Filtration; D006321:Heart / Q000187:drug effects; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D017706:Lisinopril / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D009574:Nitro Compounds / Q000494:pharmacology / Q000627:therapeutic use; D012815:Signal Processing, Computer-Assisted
D000806:Angiotensin-Converting Enzyme Inhibitors; D002316:Cardiotonic Agents; D009574:Nitro Compounds; D017706:Lisinopril
Effetti delle techniche di filtraggio sull'analisi nel dominio del tempo del signal-averaged ecg dopo infarto miocardico acuto: studio multicentrico, GISSI-3 sottoprogetto aritmie. GISSI-3 Sottoprogetto Aritmie (Elenco dei Centri in ultima pagina).