Diaphragmatic Myopotential Inhibition in Multiprogrammable Unipolar and Bipolar Pulse Generators

Summary

Diaphragmatic myopotential inhibition in multiprogrammable pacemakers was tested in 119 patients with implanted devices from six different manufacturers. There were 105 VVI pulse generators (46 bipolar and 59 unipolar) and 14 unipolar DVI pulse generators. Diaphragmatic myopotential inhibition was tested by observing the effect of a maximal deep inspiration in the supine position with the pulse generator programmed at various sensitivities. Inhibition was demonstrated in four of 46 bipolar VVI units (8.7%) and twelve of 59 unipolar VVI units (20.3%). Inhibition was also demonstrated in four of 14 unipolar DVI systems from the one manufacturer (28.6%). This form of interference appears to be a benign clinical problem and rarely if ever leads to prolonged asystole. It should be considered in the differential diagnosis of pacemaker pauses, particularly in patients with multi programmable pulse generators programmed at higher sensitivities.