Abnormal axis and LBBB present on an ECG have been shown to be highly predictive of in-hospital mortality in patients with COVID-19
The presence of abnormal axis and left bundle branch block (LBBB) on an electrocardiogram (ECG) have been found to be independent predictors of in-hospital mortality among patients with COVID-19, according to researchers from the Department of Emergency Medicine, Nantes, France.
It has been already established that almost all patients (93%) who are critically ill with COVID-19 will show changes on their ECG. However, given that these data were obtained from those who were most ill, there is some degree of uncertainty whether such findings are generalisable to those with less severe COVID-19.
For the present study, the US team set out to retrospectively examine whether there were any specific ECG patterns or changes that could be associated with in-hospital mortality from COVID-19. The study was conducted in three French hospitals in adults (>18 years of age) and who presented to an emergency department, with a PCR confirmed infection with COVID-19 and for whom an ECG was undertaken. The team collected demographic details and co-morbidities and set the primary outcome as in-hospital mortality. The ECGs were independently assessed by two emergency care physicians (one of whom was a cardiologist) who documented rhythms, the presence of atrial fibrillation and any abnormal axis changes and conduction blocks.
A total of 275 patients with a mean age of 70 years (56% male) had an ECG upon admission to the emergency department. Overall, 21% of patients had chronic kidney disease, 13% diabetes and 14% cardiovascular disease. Interestingly, 13% of those presenting at the department reported chest pain and 2%had palpitations. From the 275 patients, 14% died at hospital.
Among those who survived (n = 238) 89% were in sinus rhythm compared with 12% of those who died. An abnormal axis was rare and observed in only 6% of the cohort and LBBB in 4%. However, both changes were higher among those who subsequently died compared to survivors (14% (both abnormalities) vs 4% and 3% respectively).
Using univariate and then multivariate regression analysis, only an abnormal axis and LBBB were significantly associated with in-hospital mortality. For an abnormal axis, the adjusted odds ratio, OR was 3.9 (95% CI 1.1 – 11.5, p = 0.02) and for LBBB the OR was 7.1 (95% CI 1.9 – 25.1, p = 0.002).
Commenting on their findings, the authors emphasised the importance of detecting for cardiac impairment upon admission to an emergency department and in particular, an abnormal axis and LBBB. Nevertheless, they recognised that due to the retrospective nature of their study, it was not always possible to determine if the ECG abnormalities were due to COVID-19 or a prior cardiopathy.
They concluded by calling for a prospective study to evaluate ECG monitoring in COVID-19 prognosis and whether the specific abnormalities that they detected during infection with the virus, constitute a risk factor for a subsequent cardiovascular event.
De Carvalho H et al. Electrocardiographic abnormalities in COVID-19 patients visiting the emergency department: a multicenter retrospective study BMC Emerg Med 2021