Ann Thorac Surg 2003;76:1757-1758
© 2003 The Society of Thoracic Surgeons
How to do it
Management of phrenic nerve stimulation caused by epicardial pacemaker leads in children
Winfield J. Wells, MDa*,
Anjan S. Batra, MDa
a Divisions of Cardiothoracic Surgery and Pediatric Cardiology, Keck School of Medicine, University of Southern California, and Childrens Hospital Los Angeles, Los Angeles, California, USA
Accepted for publication March 17, 2003.
* Address reprint requests to Dr Wells, Division of Cardiothoracic Surgery, Childrens Hospital Los Angeles, 4650 Sunset Blvd, MS 66, Los Angeles, CA 90027, USA
e-mail: wwells{at}chla.usc.edu
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Abstract
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To find a suitable site with good sensing and low pacing thresholds, it may be necessary to place an epicardial pacemaker lead in close proximity to the phrenic nerve. To prevent phrenic stimulation, a silastic patch can be sewn over the area of the pacing electrode to shield it from the nerve. This simple technique prevents diaphragm contraction and has not interfered with long-term pacemaker lead function.
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Introduction
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Epicardial pacing is most frequently used in children where small size or anatomic factors preclude a transvenous lead. Occasionally, it may be difficult to find a suitable site for atrial epicardial pacing that is not in close proximity to the phrenic nerve. We describe a simple technique for preventing phrenic nerve stimulation by securing a silastic patch to shield the phrenic nerve from an area of epicardial pacing.
We have used this technique in 3 patients over the past 5 years and do not recommend that it be performed routinely for prophylaxis against nerve stimulation.
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Technique
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After median sternotomy, steroid-eluding epicardial pacing leads (Medronic, Minneapolis, MN) are tested at mutiple sites on the atrium and ventricle to define the site with the best sensing and pacing thresholds. In most cases, a suitable site away from the phrenic nerve can be found. However, in rare instances, the only acceptable location may be adjacent to the phrenic nerve. When this occurs, even low pacing current may stimulate the diaphragm. To correct this problem, a patch of silastic material (Benteck Medical, Woodland, CA) can be sutured over the electrode and adjacent cardiac tissue using interrupted fine polypropylene. A single patch should be sufficient (Fig 1), though on rare occasions, a second patch may be used on the inner surface of the pericardium to further shield the nerve (Fig 2).
In the cases where this technique has been used, there has been no diaphragm stimulation or evidence of phrenic nerve injury and no problem with long-term epicardial lead function.
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Fig 1. Silicone elastomer patch sutured over the area of an epicardial pacemaker lead in a patient with corrected transposition of the great vessels and ventricular septal defect who developed postrepair complete heart block. The best site for sensing and pacing was on the left atrium in close proximity to the phrenic nerve. The left atrium is retracted rightward for this picture.
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Fig 2. In addition to a silastic patch sewn over the epicardial atrial pacing electrode, a second patch has been tacked to the pericardium to further shield the phrenic nerve.
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Comment
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Pacemaker implantation techniques have evolved considerably since the first devices were introduced for management of complete heart block [1]. Despite advances, phrenic nerve stimulation with diaphragm contraction has continued to be a potential complication. Early reports described left phrenic involvement related to epicardial pacing systems [2, 3]. As implantation of transvenous endocardial leads became more prevalent, the right phrenic nerve emerged as the more common problem [4, 5].
Phrenic nerve stimulation associated with epicardial leads is usually apparent during the intraoperative or immediate postoperative period. In the past, we have encountered situations where phrenic stimulation was not apparent until after chest closure. For this reason, we recommend release of sternal or chest wall retraction before finally committing to an epicardial pacing site. Occasionally, an electrode location that is not a problem with the retractor in place will produce phrenic stimula-tion when the heart comes in closer contact with the pericardium as retraction is released.
It is also our practice to control the level of neuromuscular blockade when testing for possible phrenic nerve stimulation. Because dense blockade may mask potential diaphragm movement, the level of neuromuscular inhibition is kept at 50% or less as monitored by the anesthesiologist using a peripheral nerve stimulator. The electrode is tested at a pacing threshold of 10 milliamps with the pulse width set at 0.5 ms, and the diaphragms are observed for movement.
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References
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- Chardack W.M., Gage A.A., Greatbatch W. Correction of complete heart block by a self-contained and subcutaneously implanted pacemaker. J Thorac Cardiovasc Surg 1962;42:814-818.
- Buda J., Peleska B. Stimulation of the phrenic nerve as a complication of implanted battery pacemaker: management without thoracotomy. J Cardiovasc Surg 1965;6:477-481.[Medline]
- Sprinkle J.D., Takaro T. Phrenic nerve stimulation of the implantable cardiac pacemaker. Circulation 1963;28:114-116.[Free Full Text]
- Kumar A., McKay C.R., Rahimtoola S.H. Pacemaker Twiddler’s syndrome: an important cause of diaphragmatic pacing. Am J Cardiol 1985;56:797-799.[Medline]
- Khan A.A., Nash A., Ring N.J., Marshall A.J. Right hemidiaphragmatic twitching: a complication of bipolar atrial pacing. Pacing Clin Electrophysiol 1997;20:1732-1733.[Medline]
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Abstract
Introduction
