Changes in the surface electrocardiogram during the onset of spontaneous ventricular fibrillation in man

The aim of this study was to quantify electrocardiographic changes during the onset and early stages of ventricular fibrillation. Thirty recordings of ventricular fibrillation (mean duration 57 s, range 24–160 s) were obtained from 23. Coronary Care Unit patients. Each recording was investigated using frequency analysis on 1 s epochs of data. A significant rise in the mean dominant frequency of ventricular fibrillation from 3·9 Hz (SD 0·8 Hz) to 5·9 Hz (SD 1·0 Hz) was observed between 1 s and 30 s ( P