Clinical Research Directory

Inclusion Criteria: * Have been suspected of a circulatory arrest for any cause. * Have had HeartStart HS1 Defibrillator with electrodes: Adult SMART Pads Cartridge \[REF: M5071A\], Infant/Child SMART Pads Cartridge (REF:M5072A) applied to their body and powered up with HS1 battery (Model M5070A), regardless of whether a defibrillation shock was delivered Exclusion Criteria: * Subjects will be excluded if any of the following are present: * AED or pad use other than the HeartStart HS1 Defibrillator with above referenced Philips electrode pads. Note: Use of a device other than the Philips HeartStart HS1 AED does not preclude enrollment if the AED or an Advanced Life Support defibrillator was used after the HeartStart HS1 AED. * AED used for training purposes.