TRANSVENOUS CATHETER DEFIBRILLATION: COMPARISON OF A HALF-SINUSOIDAL AND TRAPEZOIDAL WAVEFORM.

Permanently implantable automatic defibrillators are electronic devices designed for ambulatory patients who have a high risk of sudden cardiac death from ventricular fibrillation. Implantable automatic defibrillators will probably utilize transvenous electrode catheters alone or in combination with a subcutaneous plate as the second permanently implanted electrode. This study compares transvenous electrode catheters' defibrillation effectivness when using the trapezoidal waveform and when using the damped half-sinusoidal waveform, at comparable energy levels. Five greyhounds were used in some 272 fibrillation/defibrillation trials. Neither total energy, peak current, nor peak voltage could be absolutely correlated with percent effectiveness for transvenous defibrillation. However, for a given waveform, an increase in delivered energy was associated with a large and statistically significant increase in percent success.