Abstract: The present invention provides diverse methods and apparatus for in vivo monitoring, detecting and/or predicting potential failure modes or deleterious trends of chronically implanted medical electrical leads prior to actual failure of said leads. Certain embodiments of the invention involve applying a relatively increased data sampling rate at various time intervals (e.g., periodically, randomly, and/or manually-triggered and the like) prior to actual detection of a deleterious trend, to thereby increase the probability of detecting one or more parameters indicative of a potential lead performance issue. At least some of the parameters are utilized because they are not typically reliably detected at relatively lower data sampling rates.