Patent ID: 8175704

Claim:
A method comprising: acquiring cardiac electrical activity information using at least two electrodes positioned on a surface of a distal end of a lead implanted adjacent cardiac tissue, wherein the lead includes at least one opening through the surface on which the at least two electrodes are positioned, wherein the opening is positioned between the at least two electrodes; detecting cardiac events within the information including T waves, QRS complexes and P waves; measuring impedance between two of the electrodes; and when the impedance measurement indicates the at least one opening is in cardiac tissue, delivering matter to the heart through the at least one opening through the surface on which the at least two electrodes are positioned, wherein the opening is positioned between the at least two electrodes, wherein delivery occurs at a time between a detected T wave and its immediately subsequent QRS complex, and when the impedance measurement indicates the at least one opening is not in cardiac tissue, prohibiting the delivery of matter to the heart through the at least one opening; wherein the measuring and delivering occur repeatedly and incrementally after the detection of the cardiac events.