Preoperative Evaluations: The Very Last Chance To Identify a Problem With a Pacemaker or Implanted Cardioverter-Defibrillator

(A) A chest x-ray from a dual-chamber pacing system with a discontinuous atrial lead. This is the natural progression of subclavian crush syndrome. (B) A chest x-ray from the same patient taken 18 months prior showing the onset of subclavian crush syndrome. (C) A portion of a 12-lead electrocardiogram obtained from outside sources for this patient from 13 months prior. The closed, downward arrow shows an R-on-T pace that resulted from blanking while the pacemaker was pacing on the atrial channel. As a result, the spontaneous ventricular depolarization was not sensed (this is functional undersensing), and the pacemaker emitted a ventricular pace 175 milliseconds later. The open, downward arrow shows a paced ventricular event that resulted from undersensing the previous QRS, suggesting a problem with the ventricular lead as well.

The initial screen from an ICD evaluation. The patient's last ICD check had been more than 3 years prior, and the ICD was more than 5 years old. This single-chamber ICD was nonfunctional for both pacing (VVI mode) and shock therapy.

A real-time telemetry strip from a St Jude single-chamber pacemaker with a marginal ventricular pacing lead. This tracing is the intracardiac electrogram from the ventricular lead while the patient moved her arm ipsilateral to the generator pocket over her head. The interpretation (called the marker channel) is displayed on the top line. The lower strip is the continuation of the upper strip. “V” means a pacemaker pace, and “R” indicates that the pacemaker sensed a ventricular depolarization. The pacemaker identifies an R-R interval as too short by showing an inverse “R.” The paper is standard 25 mm/sec, so the time period of 1 large box is 200 milliseconds. This intracardiac electrogram is significant for 3 serious issues: first, there is considerable noise causing ventricular oversensing, and second, there is failure to capture with the standard autocapture algorithm present in this pacemaker. Note that all but two “V” markers are followed quickly by a second “V,” indicating that the autocapture algorithm has detected a pacing noncapture and emitted a 4.5-V backup pulse. This issue was also found on the stored autocapture long-term threshold record (not shown). Third, the autocapture algorithm failed to detect two noncaptured events (asterisks).

A chest x-ray depicting an improperly placed atrial lead is shown. Note that the distal tip of the atrial lead (ie, the pacing end) likely remains in the superior vena cave. Additionally, the right ventricular pacing lead lacks redundancy and might be under traction.

(A) A posterior-anterior chest x-ray of a patient with a dual-lead left-sided pacemaker and 2 abandoned right-sided pacemaker leads is shown. The proximal end of the original right-sided atrial pacing lead is frayed and is in the left subclavian vein near the subclavian-caval junction. The original proximal end of the right-sided ventricular pacing lead is frayed and can be seen in the pulmonary artery. A review of previous chest films (not shown) suggested that the proximal end of the right-sided atrial lead is continuing to migrate inward. (B) The companion lateral chest x-ray from the Figure 5A examination is shown. The leads are 1: left-sided (and active) atrial lead and 2: original right-sided atrial lead. The lead redundancy in the right atrium has increased over time when reviewing older films; 3: the left-sided (and active) ventricular pacing lead and 4: the original right-sided ventricular pacing lead whose proximal end has now migrated from the right subclavian vein and into the pulmonary artery.

A chest x-ray from a jaundiced 71-year-old man about to undergo endoscopic retrograde pancreaticocholangiogram with total intravenous anesthesia shows an atrial lead dislodgement into the ventricle. His dislodgement was confirmed during interrogation by pacing the lead designated “atrial” and obtaining wide complex QRS events in the form of a right bundle-branch block. The ventricular capture with this lead was not stable, suggesting that the lead was not truly fixed in the ventricle.

A chest x-ray from an asymptomatic 70-year-old woman who was 4 years post surgery and chemotherapy for a gynecologic cancer. The chest film was part of her routine follow-up, and it shows perforation of the right ventricular apex by a recently placed right ventricular pacing lead. Her system had been placed a few weeks earlier for bradycardia.