ACUTE PNEUMOPERICARDIUM AFTER AN UNEVENTFUL DUAL PACEMAKER INSERTION

EKG revealed a paced rhythm with a ventricular rate of 62 bpm, and CT angiography of the chest ruled out a pulmonary embolus. However, a small amount of air was incidentally noted within the pericardium. Chest X-ray was negative for acute disease, cardiac enzymes were negative and 2D echocardiogram was essentially unremarkable. The patient improved symptomatically and was discharged home the following day. The provisional diagnoses were uncomplicated pneumopericardium and upper extremity deep venous thrombosis.

Discussion:

The mechanism responsible for pneumopericardium is the ‘Macklin effect’ – there is initially an increased pressure gradient between the alveoli and the interstitial space, with eventual migration of air along this gradient into the pericardial space.  Acute complications after pacemaker insertion are not uncommon, occurring in 4%–7% of cases, and most frequently consist of lead displacement, traumatic pneumothorax, hemopneumothorax and pericardial effusion/tamponade.  There has been only one case report in the literature of pneumopericardium after uncomplicated pacemaker placement.

Conclusions:

The etiology of the pneumopericardium in the present case remains elusive, although we suspect the possibility that the access sheath might have accidentally perforated either the wall of the superior vena cava in its intrapericardial tract or one of the chambers, with subsequent air embolism from the sheath and migration of air into the pericardium through weak points in the pericardial reflection over the great vessels.