Transient Decrease in Ventricular Sensing Secondary to Left Lung Collapse.

When interrogating a pacemaker, there are multiple elements that can be measured to provide insight into a pacemaker's integrity and function. Changes in any of those elements outside the normal range may indicate complications such as lead malfunction, lead detachment, or even cardiovascular structural changes. We present a unique case of a patient who underwent permanent dual-chamber pacemaker placement following a bradycardia-induced cardiac arrest. On the first day post-procedure, the patient developed a complete whiteout of the left lung due to a mucus plug, leading to low impedance and low ventricular sensing values on pacemaker interrogation. Remarkably, the sensing values normalized following the resolution of the left lung whiteout after a bronchoalveolar lavage (BAL) successfully removed the mucus plug from the left airway.