Delayed development of complete heart block after a blunt chest trauma

Abstract

A 56-year-old-woman was hospitalised because of worsening effort fatigue and dizziness. Fifteen days before admission she was involved in a car accident and was subjected to a deceleration injury from the seat belt. Initial examination in the emergency room of another hospital revealed chest echymosis but no rib or sternum fractures. Laboratory tests performed approximately 2 h after the accident, including full blood count and serum markers of myocardial injury (i.e. creatine kinase-MB isoenzyme and Troponin-I), as well as an electrocardiogram (ECG), were normal. The patient has been well for 12 days when worsening effort fatigue and dizziness developed. She was finally referred to our institution because of a near-syncope episode. At admission, an ECG showed complete A-V block with narrow QRS complexes at a rate of approximately 40 bpm. (Fig. 1A). The blood pressure was 150/80. The results of haematologic and blood chemical analysis were unremarkable, and the serum markers of myocardial injury in serial determinations in the two following days always ranged within normal limits. A chest radiogram was normal while a transthoracic echocardiography revealed a small pericardial effusion in the posterior pericardial space. On day 2 the patient developed right bundle branch block (RBBB) that lasted for 24 h (Fig. 1B). Due to the persistence of the complete A-V block a week later a permanent dual chamber pacemaker was implanted. At 4-month follow-up visits the patient was symptom free but still in heart block. A further echocardiographic study performed 3 months after the accident did not reveal pericardial effusion.