Key result
Temporary ICD reprogramming to AAI pacing resolves Twiddler’s syndrome-induced right phrenic nerve stimulation and spasms.
Why the study?
Phrenic nerve stimulation is an uncommon complication of CIEDs, with right-sided stimulation being particularly rare, and lead retraction from Twiddler's syndrome may cause extracardiac stimulation.
Twiddler's syndrome can cause cranial migration of an ICD RV lead resulting in rare right phrenic nerve stimulation, which can be managed with timely device reprogramming and lead revision.
Right phrenic stimulation suggests Twiddler's syndrome in ICD patients; extends lead migration phenotypes and supports initial reprogramming.
Background Phrenic nerve stimulation is an uncommon complication of cardiac implantable electronic devices (CIEDs), and right-sided stimulation is particularly rare. Twiddler’s syndrome causes lead retraction that may result in extracardiac stimulation. Case Summary An 87-year-old man with a dual-chamber ICD presented with five days of persistent upper abdominal contractions. Examination showed rhythmic diaphragmatic spasms synchronized with ventricular pacing spikes. Electrocardiography revealed ventricular pacing spikes without myocardial capture. Chest radiograph demonstrated right ventricular lead displacement into the superior vena cava, consistent with Twiddler’s syndrome. Temporary reprogramming to AAI pacing eliminated symptoms, and definitive RV lead revision restored normal device function. Although the patient did not attend in-person follow up due to relocation to another state, communication with the patient’s family approximately one month after discharge confirmed no recurrence of diaphragmatic spasms. Discussion This case demonstrates a rare mechanism of right phrenic nerve stimulation due to cranial migration of an ICD RV lead. Recognition and timely device reprogramming are essential for the resolution of diaphragmatic spasms.
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Asjad et al. (2026) studied this question. Right phrenic nerve stimulation caused by Twiddler’s syndrome was successfully resolved by temporary reprogramming of the ICD to AAI pacing, eliminating diaphragmatic spasms.
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