Technological developments have dramatically influenced diagnostic and therapeutic innovation in all medical disciplines, none more so than in cardiology.  In parallel with these developments have been major advances in information technology.

Key milestones in all of this include the appearance of the transistor followed by solid state circuitry, and the impact of computer technology.  Modern circuitry and improved power sources have revolutionised implantable devices such as implantable pacemakers and ICDs.
When Jim Baird carried the hospital's only external defibrillator to an emergency 50 years ago, he could not have imagined a vastly more sophisticated device that could be implanted in a patient at risk.

Cardiological equipment in use at the start of my career tended to be bulky, at least in part because preamplifiers utilised older valve technology.   The early monitoring screens were cathode ray tubes and typically were small and single channel.   As screens became larger and multichannel, they were still based on cathode ray technology and were therefore bulky.   Now, with flat-screen technology, monitors take up much less space.