Abstract: Methods and systems for determining an optimal defibrillation shock waveform for application to the heart of a patient may include measuring and/or collecting information for a cardiac waveform of a patient, produced as a result of either an electrical stimulus applied to a heart of the patient, which may be a pacing shock/stimulus and/or a defibrillation shock waveform, or as the result of intrinsic cardiac activation; determining a characteristic of the cardiac waveform; comparing the determined characteristic of the cardiac waveform to a plurality of values for the characteristic with optional reference to the defibrillator system impedance, wherein each value of the characteristic is associated with a predetermined value for a parameter of an optimal defibrillation shock waveform; and selecting the predetermined value for the parameter of the optimal defibrillation shock waveform based on the comparison.

Abstract: Embodiments of the invention present methods and systems for determining an optimal defibrillation shock waveform for application to the heart of a patient to stop a rhythm abnormality such as ventricular fibrillation or ventricular tachycardia.

Abstract: Aspects of the invention include methods for determining a vulnerable window for the induction of fibrillation. The method includes obtaining an intracardiac waveform from a subject's heart; measuring an interval between a plurality of time points on the intracardiac waveform; and evaluating the morphology of the waveform so as to determine the optimal vulnerable window for the induction of fibrillation. Also provided are methods for delivering a stimulus to the heart of a subject during the determined vulnerable window.