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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 (∼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 (∼50%) of early survivors because of recurrent or permanent CHB. Cardiac troponins, when analyzed, were elevated in 12 of 13 (∼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 posttraumatic period and most of the deaths are due to or triggered by this malignant arrhythmia. Recurrent or permanent CHB requiring pacemaker implantation occurs in ∼50% of survivors. A structural damage of the AV conductive system can be found in 50% of necropsy studies.

The relevance of the temporal relationship between a unipolar electrogram (UEGM) and a bipolar electrogram (BEGM) in determining the site of origin (SOO) of focal arrhythmias has been largely demonstrated.We sought to demonstrate that a negative concordance in the initial forces of these EGMs is also helpful in predicting the SOO of premature ventricular contractions (PVCs).Mapping and radiofrequency (RF) ablation were performed in 41 patients with symptomatic PVCs in the absence of structural heart disease. Simultaneous recordings of the minimally filtered (0.5-500 Hz) UEGM and filtered BEGM (30-500 Hz) were analyzed at 247 mapping sites, where RF was attempted. EGMs of 63 mechanically induced PVCs were separately analyzed as a validation group. All ablation sites had a QS pattern in the UEGM. Acute PVC suppression was defined as a complete disappearance of ventricular ectopic beats after a 60-second pulse of RF.RF ablation obtained PVC suppression (RF+) in 33 of 247 sites (13.3%). A negative concordance pattern (NCP) during the initial 20 ms of both UEGM and BEGM was observed in 31 of 33 (94%) RF+ sites compared with 10 of 214 (4%)RF- sites (P.0001). The NCP criterion demonstrated to be an additional powerful predictor of acute RF success with sensitivity, specificity, positive predictive value, and negative predictive value of 94%, 95%, 76%, and 99%, respectively. Similarly to RF+ sites, the NCP was observed in 60 of 63 sites (95.2%) in the mechanical PVC group.An NCP in both UEGM and BEGM may be an additional criterion that helps to localize the SOO of focal ventricular arrhythmias.