1. A method of cardiac signal analysis comprising: capturing a cardiac event along first and second sensing vectors using electrodes implanted in a patient to yield first and second event representations, along each of the first and second sensing vectors respectively, of the cardiac event, wherein: the first sensing vector is defined between an implantable cardiac stimulus device (ICSD) canister and a first electrode on a lead attached to the implantable cardiac stimulus device canister; the second sensing vector is defined between the ICSD canister and a second electrode on the lead; and the ICSD canister is disposed at a lateral position on the left side of the patient's ribcage inferior to the arm and the lead extends to a parasternal location such that the first electrode is superior to the heart, each of the ICSD canister, with the lead disposed subcutaneously between the ribs and the skin of the patient without entering a blood vessel or contacting the heart of the patient; analyzing the cardiac event by use of the first event representation to reach a first result; observing whether the first result is determinative and, if not, analyzing the cardiac event by use of the second event representation; wherein: the step of determining whether the first result is determinative is performed in a manner wherein, if the first result unambiguously indicates a non-malignant cardiac rhythm, the first result is found to be determinative and the second event representation is not analyzed.