Occasionally, the pacing lead meant for the right ventricle (RV) can be inadvertently placed in the left ventricle (LV) instead. There are several ways this can happen- through inadvertent transarterial catheterisation rather than transvenous, through an existing PFO or ASD, or through puncture of the interventricular septum.
Such misplacement of the ventricular lead is not benign. LV leads are thrombogenic and can be a nidus for thrombus formation and embolisation, leading to stroke.
So how can you tell?
ECG and Xray with a LAO view are the most useful.
Take a look at the following ECG. The top ECG reflects pacemaker lead inadvertently placed in the left ventricle, while at the bottom, the lead has been re-sited in the right ventricle.
Not unexpectedly, the precordial leads reflect a RBBB pattern rather than LBBB. While the RBBB pattern can persist in V1 and V2, even after repositioning the lead in the right ventricle(through open surgery- the LV lead should never be "pulled out"), V3 is the key. V3 will always be positive when the lead is in the LV, and will always be negative, when the lead is in the RV. With LV placement of lead, the frontal plane axis is usually between 0 and -90 degrees, but is often in the "northwestern" quadrant, as in this case.
This picture of apparent RBBB, suggesting a wrongly placed lead in the LV, can sometimes be mimicked even if the lead is in its rightful place in the RV. Again, V3 is the key. Even if V1 and V2 are upright (positive), V3 will always be negative with a correctly placed RV lead. The ECG can be "corrected" by placing the precordial leads one interspace lower, as in the following figure:
The lateral view on Xray is useful when the ventricular lead is in LV rather than RV. The lead is more posterior than when it is in the RV and curves away from the vertebral column, as shown in the following reference:
https://www.mdedge.com/ccjm/article/155202/cardiology/detecting-and-managing-device-leads-inadvertently-placed-left/page/0/1
Of course, such aberrant placement can be confirmed by echocardiography, but should really be picked up on the post-placement ECG.
Reference:
https://www.mdedge.com/ccjm/article/155202/cardiology/detecting-and-managing-device-leads-inadvertently-placed-left/page/0/1
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