Clinical and electrocardiographic features of complete heart block after blunt cardiac injury: A systematic review of the literature

The underlying mechanisms and temporal course of complete heart block (CHB) after blunt cardiac injuries (BCIs) are poorly understood, and a systematic analysis of available data is lacking. In this systematic review, PubMed was searched for publications of reported cases of CHB-BCI analyzing clinical findings, electrocardiographic features, temporal course, and outcomes. Case reports on CHB-BCI were available for 50 patients, mainly secondary to traffic or sport accidents. A fatal outcome occurred in 10 of 50 (20%) of patients, while a structural damage of the atrioventricular (AV) conductive system was evident in 4 of 8 (50%) of necropsy studies. Clinical manifestation of CHB-BCI occurred within 72 hours of injury in 38 of 47 (similar to 80%) of patients, and 1:1 AV conduction was restored within 7-10 days in about half of early survivors. Permanent pacemaker implantation was indicated in 22 of 42 (similar to 50%) of early survivors because of recurrent or permanent CHB. Cardiac troponins,when analyzed, were elevated in 12 of 13 (similar to 90%) of patients, and electrocardiographic features of aberrancy were present in 29 of 40 (> 70%) of patients. In conclusion, CHB secondary to BCI is associated with 20% mortality mainly occurring in the early post-traumatic period and most of the deaths are due to or triggered by this malignant arrhythmia. Recurrent or permanent CHB requiring pacemaker implantation occurs in similar to 50% of survivors. A structural damage of the AV conductive system can be found in 50% of necropsy studies.