A pacemaker lead in the left ventricle: An "unexpected" finding?

Abstract

Inadvertent malposition of a pacemaker lead in the left ventricle is uncommon, but it should not be misdiagnosed. We report the case of a 68-year-old woman with symptomatic sick-sinus syndrome requiring pacemaker implantation. Shortly afterwards the lead was extracted and a new pacemaker was contralaterally implanted due to pocket hematoma and suspected lead fracture. Three months later, she was referred to our echocardiography laboratory complaining of asthenia. At transthoracic echocardiography an echo-bright linear structure was recognized in left atrium, passing through the mitral valve and leaning against the posterior left ventricular wall. In short-axis and apical views, the lead apparently crossed the interatrial septum through patent foramen ovale. The QRS-paced electrocardiogram showed right bundle branch block morphology. The lead was apparently well positioned, examining the chest X-ray postero-anterior view. On the contrary, by latero-lateral view and left-anterior oblique view, lead curvature was consistent with misplacement into the left ventricle. Malposition was confirmed by transesophageal echocardiography. Given the relatively recent implant, system revision with lead extraction was scheduled and completed without complications. This case report is intended to improve our awareness in the prevention and in the prompt detection of misplaced pacemaker leads in order to manage an immediate correction. <Learning objective: During lead implantation, fluoroscopic left-anterior oblique view should be always used to ensure correct positioning. At least 3-6 limb leads should be carefully monitored during the procedure, and a 12-lead standard electrocardiogram should be performed shortly afterwards for the paced QRS morphology. Lateral chest X-ray should always be taken after implantation. In cases of doubt, echocardiography (transthoracic or transesophageal) may confirm abnormal lead placement defining the route covered by the catheter.>.

Keywords: Echocardiography; Lead extraction; Lead malposition; Left ventricle; Pacemaker implantation.

Fig. 1

Composite image of echocardiographic views from transthoracic echocardiography long-axis (A) and apical window (B) and transesophageal echocardiography 30° short-axis view (C,D). The pacing lead can be seen passing from right atrium (RA) to left atrium (LA) through the interatrial septum and then into the left ventricle (LV); a left-to-right shunt proved to be exactly at the site of the lead crossing the interatrial septum. PFO, patent foramen ovale; RA, right atrium.

Fig. 2

(A) 12-lead electrocardiogram (ECG) during ventricular pacing showing right bundle branch block morphology of the QRS complex with a frontal plane axis of −120°. (B) Standard 12-lead ECG recorded after the last pacemaker implantation. Note the left-axis deviation in the limb leads. The QRS duration is only slightly enlarged, due to a mid-septal position of the lead tip and to a fusion between spontaneous and paced electrical activation of the ventricle.

Fig. 3

In the upper box: patient’s chest X-ray: postero-anterior (PA) view (A); latero-lateral view (B), with blow-up indicating the pathway of the lead in the two projections; in the lower box: fluoroscopic images: 40° left anterior oblique view (C); 30° right anterior oblique view (D); PA view (E); a schematic representation of the lead malpositioned in the left ventricle, based on the PA projection; the location of the coronary sinus is depicted by the dotted line (F).