To the Editor.
—We read with interest the recent article by Morris and colleagues1 that reported a fairly low rate of developing complete heart block (CHB) during Swan-Ganz (SG) catheterization in patients with left bundle-branch block (LBBB). We feel that this is an important finding since several sources, including recent advanced cardiac life support procedural guidelines, recommend prophylactic placement of a temporary transvenous pacemaker prior to pulmonary artery catheterization.2,3 Although CHB and hemodynamically significant bradycardia during this procedure may be uncommon, its occurrence can be quite dangerous and even catastrophic.There are several additional points that should be mentioned. The data presented by Morris and associates emanate from SG procedures in a critically ill population. It should be emphasized that these data may not be applicable to patients with more extensive conduction system disease, eg, patients with LBBB and a history of syncope and patients with LBBB undergoing