Computer analysis of right ventricular pressure for improved discrimination of ventricular tachyarrhythmias

A computer algorithm suitable for an implantable device is devised that incorporates analysis of both right ventricular electrogram and pressure to assess the hemodynamic stability of a ventricular tachycardia. The algorithm was tested on recordings from 5 patients during pretachycardia control (N=5), stable (N=9) and unstable tachycardias (N=6) induced during electrophysiological studies and after tachycardia termination (N=10). Computer measurements of beat-by-beat and 5-beat averages of cycle length and hemodynamic parameters (pulse pressure, maximum positive dP/dt, and maximum negative dP/dt) at 5, 10, 15, and 30-second intervals after tachycardia induction and termination agreed to within 5% of manual measurements. Right ventricular pulse pressure, when normalized to pretachycardia control and expressed as a ratio, could perfectly distinguish hemodynamically stable from unstable ventricular tachycardia, both within individual patients and in the group, in as early as five seconds after tachycardia induction