Case Report
Case 1
A 34-year-old man motorcyclist was hit by a lorry rear bumper over his anterior chest wall. He presented to Emergency Department (ED) of a university hospital two hours after the accident and complained of moderate chest pain with verbal numerical rating score (VNRS) of seven. Pain worsened on inspiration and it radiated to the back. His blood pressure (BP) was 190/114 mmHg, heart rate (HR) was 83 per minute, afebrile, oxygen saturation under room air (sPO2) was 98% and respiratory rate (RR) of 19 per minute. Other systemic examinations were unremarkable. Extended Focal Abdominal Sonography for Trauma (eFAST) found no abnormality. Bedside echocardiography showed no abnormality. Chest X-ray was normal. Initial electrocardiography (ECG) showed ST segment elevation of lead V2 and V3 (J point = 3mm elevation) and T inversion over lead I and V6 (Figure 1). The initial creatine kinase (CK) was minimally raised (169 U/L), but troponin T was normal. He was administered intravenous tramadol and the chest pain resolved (VNRS zero). Patient was admitted to ED short-stay ward (EDSSW) for 24 hours observation. The subsequent serial of ECG’s did showed resolution of ST-segment elevation to baseline at lead V2 & V3 with persistent T inversion at lead I & V6. Repeated CK after 6 hours showed no further increment and the troponin T still remained undetectable. Patient was discharged after 24 hours of observation. The ECG on discharge showed normalised ST segment and T wave in all leads (Figure 1). CK level repeated three days later was 285 U/L. The troponin T and ECG remained normal.
Case 2
A 21-year-old male car driver was brought in to ED after a head on collision with another car. He did not fasten his seatbelt. His anterior chest hit the steering wheel. He presented to ED of with the complaint of right sided headache & central chest pain with VNRS of eight. His BP was 127/67 mmHg, HR was 88/min, RR was 18/min and sPO2 was 97% under room air. His Glasgow Coma Scale score was 14 out of 15. There were multiple abrasion wounds over his face and tenderness over the right iliac fossa. Other systemic examinations were unremarkable. Initial ECG showed ST segment elevation on lead V2 (J point = 3mm elevation) and V3 (J point = 1.5mm elevation) (Figure 2). EFAST examination showed no abnormality. Computer tomography of brain and cervical spine were performed and reported as normal. His initial CK level was raised (265 U/L) but troponin T level was undetectable (<0.013ug/L). Other blood investigations were normal. He was given intramuscular anti-tetanus toxoid and intravenous analgesia. The chest pain was resolved (VNRS zero). He was then admitted to EDSSW for cerebral concussion care and cardiac concussion monitoring. The serial of ECG had shown resolution of ST segment V2 and V3 to baseline (Figure 2). A repeat CK and troponin T after 14 hours post-accident showed mild elevation of CK level (306 U/L) and troponin T remained undetectable. He was discharged well after 24 hours of observation in EDSSW. A follow-up telephone call to patient was made three days later showed uneventful recovery.
Discussion
There are cases which do not fit in the current cardiac concussion definitions domain which are illustrated by the above two cases. These patients have regional ECG changes. They do not fulfil the diagnosis of cardiac concussion (commotiocordis) whereby the ECG changes are global. Therefore, the diagnosis of “focal” cardiac concussion should be considered. The current practice in diagnose and manage “focal” cardiac concussions are mainly based on acute coronary syndrome (ACS) modality. In these cases, the history and significant changes in the anterior ECG leads may indicate that they had cardiac concussion localized to the anterior wall of the heart. Linton et al. described the elevation of the ST segment indicates direct contact of a specific area of myocardium (Bishop et al. 1956). However, “focal” cardiac concussion differs from ACS in term of pathophysiology. “Focal” cardiac concussion involved electrophysiological component compare to ACS, which involved both myocardium perfusion and electrophysiological changes Therefore, the definition of ‘focal’ cardiac concussion should take into account both electrophysiological and microcellular pathophysiological changes.
Existing biomarker of cardiac damage is based on injury to the cardiac muscle. They may not necessarily reflect dysfunction of the electrophysiological component of the myocardium. Nonetheless, immune-histochemical changes may be present (Dettmeyer 2011). In a canine experimental study, patchy focal loss of the myocardial myoglobin, CK-MM and CK-BB were identified with these substances scattered deposited of between myocardial fibres (Dettmeyer 2011). The CK levels were elevated with normal troponin T level. The diagnosis of focal cardiac concussion maybe more appropriate in cases of regional ST segment elevation in ECG with normal troponin T level. A new diagnostic modality and approach should be developed. Further experimentation is recommended to develop a more accurate definition of cardiac concussion. In terms of patient’s disposition, there is a dilemma as the prognosis is uncertain. Therefore, managing this group of patients is rather challenging. They were both successfully managed in EDSSW. Thus, it reduces in–hospital admission and can be cost effective.
Conclusion
We propose the diagnosis of focal cardiac concussion for these two cases. We also highlighted the ability of ED to manage these patients in EDSSW.
Acknowledgement
The authors thank the doctors, assistance medical officer, nurses, technical and administrative support staff in the Emergency Department, Universiti Kebangsaan Malaysia for their assistance in this study.