Diagnosis of paced electrocardiograms by inverse computer modeling of pacemaker actions

The explanation and interpretation of ECGs recorded from paced patients may be very difficult because of pacemaker specification, programmed parameters, and idiosyncrasy and also because of hidden interactions between the device and its environment. Moreover, the recent development of very sophisticated pacemakers makes the heart-pacemaker interaction (HPI) difficult to understand even when the recorded ECG is accompanied by an event marker. A computer system providing an automatic analysis of the HPI based on ECG data has been developed and implemented on an IBM PC AT computer. The system evaluates all possible combinations of HPI events and establishes whether they correspond to the pacemaker. The system inputs interactively the description of the pacemaker mode and programming, and the description of the analyzed ECG in the form of timing of "definite" and "possible" sensing events and generator pulses. The computer performs the analysis and establishes whether the device operates correctly within its permitted error. The system has been tested by evaluating different examples of paced ECGs. The presented examples confirm the ability of the system and show the potential for its future clinical use. Future development of the system and the provision of computer support for the understanding of the HPI of complex DDDR pacemakers are discussed.