Detecting and managing device leads inadvertently placed in the left ventricle

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Release date: January 1, 2018
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Inadvertent malpositioning of a cardiac implantable electronic device lead into the left ventricle is a rare complication of transvenous pacing and defibrillation. Rapid identification of lead position is critical during implantation and just after the procedure, with immediate correction required if malpositioning is detected. If lead misplacement is discovered late after implantation, the lead should be surgically removed or chronic anticoagulation with warfarin should be instituted.


  • During device implantation, fluoroscopy in progressively lateral left anterior oblique views should be used to ensure correct lead position.
  • After implantation, malposition can almost always be detected promptly by examining a 12-lead electrocardiogram for the paced QRS morphology and by lateral chest radiography.
  • Echocardiography and computed tomography may enhance diagnostic accuracy and clarify equivocal findings.
  • Late surgical correction of a malpositioned lead is best done when a patient is undergoing cardiac surgery for other reasons.
  • Long-term warfarin therapy is recommended to prevent thromboembolism if malpositioning cannot be corrected.



Although rare, inadvertent placement of a pacemaker or defibrillator lead in the left ventricle can have serious consequences, including arterial thromboembolism and aortic or mitral valve damage or infection. 1–4

This article discusses situations in which lead malpositioning is likely to occur, how to prevent it, how to detect and correct it immediately, and how to manage cases discovered long after implantation.


In 2011, Rodriguez et al 1 reviewed 56 reported cases in which an endocardial lead had been mistakenly placed in the left ventricle. A few more cases have been reported since then, but some cases are not reported, so how often this occurs is unknown.

A large single-center retrospective study 2 reported a 3.4% incidence of inadvertent lead placement in the left side of the heart, including the cardiac veins.


Risk factors for lead malpositioning include abnormal thoracic anatomy, underlying congenital heart disease, and operator inexperience. 2

Normally, in single- and double-lead systems, leads are inserted into a cephalic, subclavian, or axillary vein and advanced into the right atrium, right ventricle, or both. However, pacing, sensing, and defibrillation leads have inadvertently been placed in the left ventricular endocardium and even on the epicardial surface.

Leads can end up inside the left ventricle by passing through an unrecognized atrial septal defect, patent foramen ovale, or ventricular septal defect, or by perforating the interventricular septum. Another route into the left ventricle is by gaining vascular access through the axillary or subclavian artery and advancing the lead retrograde across the aortic valve.

Epicardial lead placement may result from perforating the right ventricle 5 or inadvertent positioning within the main coronary sinus or in a cardiac vein.


The best way to manage lead malpositioning is to prevent it in the first place.

Make sure you are in a vein, not an artery! If you are working from the patient’s left side, you should see the guidewire cross the midline on fluoroscopy. Working from either the left or the right side, you can ensure that the guidewire is in the venous system by advancing it into the inferior vena cava and then all the way below the diaphragm (best seen on anteroposterior views). These observations help avoid lead placement in the left ventricle by an inadvertent retrograde aortic approach.

Suspect that you are taking the wrong route to the heart (ie, through the arterial system) if, in the anteroposterior view, the guidewire bends as it approaches the left spinal border. This sign suggests that you are going backwards through the ascending aorta and bumping up against the aortic cusps. Occasionally, the wire may pass through the aortic valve without resistance and bending. Additional advancement toward the left chest wall will make contact with the left ventricular endocardium and may result in ventricular ectopy. Placement in the left ventricle is best seen in the left anterior oblique projection; the lead will cross the spine or its distal end will point toward the spine in progressive projections from farther to the left.


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