[Frequency analysis of the single beat electrocardiogram in the diagnosis of ventricular tachycardias].
High frequency components of the surface electrocardiogram have been found in patients with sustained ventricular tachycardia. However, evaluation of these signals has required signal averaging and highly sophisticated filter techniques. In order to overcome the limitations of averaging and apriori filtering, we performed a single beat analysis of the total and terminal QRS and ST-segment of surface electrocardiograms with fast Fourier transformation (512 points, Blackman-Harris window) after high gain, low noise amplification (0-300 Hz). Fourteen patients with previous myocardial infarction and spontaneous and electrically inducible sustained ventricular tachycardia, twelve patients with previous infarction but without clinical arrhythmias, and fifteen control subjects were studied. The frequency content of the terminal QRS, expressed as area under the spectral plot, was significantly lower in patients with ventricular tachycardia compared to patients without arrhythmias (p less than 0.01). The frequency content of the ST-segment in the range 10 to 40 Hz was higher in patients with ventricular tachycardia than in patients without arrhythmias and control subjects (p less than 0.01). The spectral representation at very low (0-10 Hz) and high frequencies (greater than 60 Hz) of the ST-segment and analysis of the total QRS did not allow separation of patients with ventricular tachycardia. Thus, spectral analysis of single beat electrocardiograms offers promise for the non-invasive identification of patients prone to sustained ventricular tachycardia due to coronary artery disease.
D000368:Aged; D003936:Diagnosis, Computer-Assisted; D004562:Electrocardiography / Q000295:instrumentation; D005260:Female; D005583:Fourier Analysis; D006352:Heart Ventricles; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008838:Microcomputers; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications; D013610:Tachycardia / Q000175:diagnosis*
Frequenzanalyse des Einzelschlag-Elektrokardiogrammes zur Diagnostik von Kammertachykardien.