Follow-up experience with permanent endocardial tined pacemaker electrodes.

At the Mayo Clinic, 100 patients received permanent endocardial tined leads during an 8 month period from June, 1978, to January, 1979. Acute mean bipolar stimulation thresholds of 0.47 +/- 0.17 V and 0.85 +/- 0.36 mA utilizing this lead are significantly lower than with our previously used systems. During implantation, significant ventricular irritability with short bursts of ventricular tachycardia was seen in four patients. This did not require any treatment except for gentle manipulation of the catheter. One patient experienced acute perforation with tamponade. He subsequently underwent thoracotomy with placement of epicardial electrodes. During a mean follow-up of 20 +/- 9 weeks, three patients required additional pacemaker operations, one for recurrent ventricular ectopy and two for intermittent failure to pace and sense. In no instance was there roentgenographic evidence of catheter displacement, and the pacing system problems encountered were considered to be secondary to microdislodgement. In our experience, the use of this catheter has been associated with low stimulation thresholds and excellent lead stability. It may be particularly beneficial in patients at high risk for electrode dislodgement.