The effect of nonisodiametric design on the ease of extracting chronically implanted pacemaker leads

Extracting permanently implanted transvenous pacemaker leads is often difficult because a fibrous sheath tends to trap the lead at various points along its course. Because many leads have bulbous or nonisodiametric portions, extraction may be rendered even more troublesome, because it is difficult to pull the larger portion through the narrow areas of the sheath. Furthermore, forceful extraction may have dire consequences, such as cardiac laceration. A study was undertaken in animals to evaluate the effect of lead isodiametricity on lead extraction. The results show that any increase in the diameter of the lead tip greatly reduces the ease of its removal. Consequently, leads designed to be isodiametric throughout their entire lengths will greatly enhance their removability.