PHRENIC NERVE STIMULATION: AN UNEXPECTED COMPLICATION OF IMPLANTABLE CARDIOVERTER DEFIBRILLATOR (ICD).

Abstract

(This article may be cited as Tadakamalla A  Karthik, Kanaan Mohammed, Besur Siddesh, Talluri S Kumar. Phrenic Nerve Stimulation: An unexpected complication of Implantable Cardioverter Defibrillator (ICD). E-Journal of cardiology 2011; 1(1):20-24.)

Diaphragmatic pacing secondary to phrenic nerve stimulation is a rare complication of implantable cardioverter defibrillator (ICD).

Phrenic nerve stimulation has been described to be the result of lead or generator displacement.  We report 2 patients with ICDs presenting with hiccups and abdominal cramps due to diaphragmatic pacing secondary to phrenic nerve stimulation without lead or generator displacement. Twiddler’s syndrome, a rare complication of pacemaker and ICD is a result of twisting or rotation of the device in its pocket. The simplest and the most important diagnostic tool is chest X-ray, where the leads can be seen wrapped around the pulse generator.

In the two patients we described above, there was no lead displacement on chest X-ray.

We believe that the anatomical location of the phrenic nerve in relation to epicardial veins makes it susceptible to stimulation by high amplitude of the left ventricular lead even without displacement. Non-invasively decreasing the pacing output at the bedside can eliminate stimulation of the phrenic nerve and resolve the symptoms.