There are two main pacemaker systems used in controlling the cardiac rate in Severe heart-block patients: (1) asynchronous, and (2) synchronous or P-wave actuated.These pacemakers transmit current to the electrodes by direct wire or electromagnetic communications.The main techniques of applying the myocardial electrodes to the ventricles are: (1) transvenously into the right ventricle, or (2) onto the cardiac surface via a thoracotomy.The safety extension wires are a useful means of testing, stopping, bypassing, or increasing output of the pacemaker without disrupting its position or contents.The most common complication is wire fracture. Useful clues in detecting breaks require observation for muscle twitching due to current leaks from the fractured wire. Roentgenograms of the suspected area, taken with different obliquities, are a necessity.Battery exhaustion is anticipated by persistent pulse changes but a radiographic method of analysis can depict various stages of mercury battery depletion.A polyviny...