Patent ID: 7162299

Claim:
A cardiac stimulation device to prevent initiation of ventricular fibrillation (VF), the device comprising: a microprocessor; a pulse generator coupled to the microprocessor and adapted to deliver stimulation pulses to selected cardiac sites; and a sensing circuit electrically coupled to the microprocessor and to selected chambers of the heart and adapted to sense electrical activity in the selected chambers; wherein the microprocessor monitors cardiac electrical activity to assess ventricular fibrillation (VF) prognostics predictive of the onset of an arrhythmia of the heart; wherein the microprocessor is operative to monitor an occurrence of R-waves and to calculate a statistical indicia related to a plurality of immediate past occurring consecutive R—R intervals; wherein if the monitored VF prognostics fall within a prescribed high risk level of cardiac activity, the microprocessor is operative to compare a current R—R interval to the indicia, and to prevent initiation of ventricular fibrillation by triggering the pulse generator to deliver a single high amplitude pacing pulse to at least one cardiac site if the current R—R interval exceeds the indicia by a prescribed amount; and wherein the microprocessor is operative to compare a current R—R interval to the indicia to confirm the necessity of delivering the single high amplitude pacing pulse once the monitored VF prognostics fall within a prescribed high risk level of cardiac activity to avoid response to false positives.