Extreme intracardiac coiling of a transvenous pacemaker: a case report.

We report an unusual complication of transvenous pacing: extreme coiling of a pacemaker catheter, which formed a redundant, twisted loop protruding into the right ventricular outflow tract. This may be a result of "twiddling" (rotation) of the pacemaker generator by the patient and/or inadequate fixation of the catheter at the venous entry site. Careful fixation of the generator to the venous entry site within the subcutaneous pocket may prevent such a complication.