Continuing evolution in cardiac stimulation today imposes on PM manufacturers the need to submit their products under new criteria, such as: contained dimensions, functional complexity and longer periods of patient care. PM electronic circuity plays a determinant role in meeting the best solution of these problems. Thick film hybrid technology has been chosen by the Authors because it is deemed to be the best compromise for the present goals, such as: low power consumption, low weight and small size, electrical parameters stability, functional complexity and high circuitry density, Hi-Rel performance for longer working life. A little space has been reserved for schematic diagrams of the manufacturing cycle and the applied technology; particular evidence has been shown concerning selection criteria for circuitry component selection and Hi-Rel tests for the end product. Hi-Rel and qualification standards have been selected by the Authors from MIL-STD 883 methods and AAMI-FDA pacemakers standards. Practical results of the application of this methodology can be summarised as follows: only 44-50% of the total circuits pass the complete cycle of tests and thus are used for PM manufacture; electronic failure rate in the implanted units is 0.024% failure per month.