Does high pacemaker output alter the morphology of the paced QRS complex compared to low output in patients with bipolar pacemakers?
High pacemaker output in bipolar pacemakers can significantly alter the paced QRS complex morphology and electrical axis, likely due to additional stimulation from the proximal electrode.
The influence of pacemaker output on the morphology of the paced QRS complex was studied from standard lead electrocardiograms in 69 patients with bipolar pacemakers. In 40 of the 69 patients (58%), there was a significant (P less than 0.001) change in electrical axis, from -75 degrees at the low output setting (2.7 V, 0.15 msec) to -67 degrees at the high output setting (8.1 V, 2.29 msec). In 30 patients, these changes were also associated with changes in the QRS morphology and in the T-wave. This phenomenon may be explained by additional stimulation from the proximal electrode at high output, thus altering the pattern of depolarization.
GELDER et al. (Sun,) studied this question.
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