Permanent pacing from the middle cardiac vein produced an unusual left bundle branch block pattern of ventricular depolarization, facilitated by a high posterior infarct.
Case Report
An unusual left bundle branch block pattern can occur during pacing from the middle cardiac vein, indicating that ECG patterns alone may not reliably diagnose electrode malposition.
This report documents the unusual occurrence of a left bundle branch block pattern of ventricular depolarization during permanent pacing from the middle cardiac vein. All previous reports of ventricular pacing from the middle cardiac vein have described a right bundle branch block pattern of ventricular activation (dominant R-waves in the right precordial leads), except in one case where both right and left bundle branch block patterns occurred at separate times. A high posterior infarct allowed early activation of the right ventricle from the middle cardiac vein. Undue reliance on the electrocardiogram may detract from the diagnosis of electrode malposition.
Barold et al. (Sun,) conducted a case report in Permanent pacing from the middle cardiac vein. Permanent pacing from the middle cardiac vein was evaluated on Electrocardiographic pattern of ventricular depolarization. Permanent pacing from the middle cardiac vein produced an unusual left bundle branch block pattern of ventricular depolarization, facilitated by a high posterior infarct.