Transthoracic cardiac stimulation thresholds for short pulses

The most common cause of death due to electric shock is ventricular fibrillation (VF). This work reviews applicable results from the literature and provides an estimation model for the risk of VF with short-duration pulses. Methods and Results - For 1 ms pulses, the predicted current and charge thresholds required for successful transthoracic cardiac stimulation were 1.12 A and 1.12 mC, respectively. For pulses of 0.1 ms durations, the transthoracic current and charge thresholds predicted by the model are 10.9 A and 1.09 mC, respectively. Conclusion - In humans, the charge required for single-response cardiac capture using transthoracic electrodes and 0.1 ms pulses is at least 0.5 mC. The transthoracic charge required to trigger repetitive ventricular responses in humans is at least several times higher than that for single responses. Hence, in adult humans, the transthoracic charge threshold required to induce repetitive ventricular responses, tachycardia, or fibrillation, with 0.1 ms pulses is expected to be significantly greater than 1 mC.