Relationship between electrocardiographic abnormalities and in-hospital mortality in patients with COVID-19

It has been evident that the high level of troponin in patients hospitalized for COVID-19  is an independent variable that, however, is  associated with hospital mortality,  and that it rises the risk of  various  complications. The objective of the study  "Electrocardiographic abnormalities in COVID-19 patients visiting the emergency department: a multicenter retrospective study"  by Hugo De Carvalho et al.  was finding an answer to this. Here is a summary of their most relevant findings.

One of the complications of the coronavirus (SARS-CoV-2) is that the severe acute respiratory syndrome it causes may be associated with a myocardial injury. Despite that, it is not yet clear how to identify patients who are at risk of suffering such an injury, nor what are the underlying mechanisms of cardiac involvement. 

The authors of this study (which was carried out among patients the ER of three hospitals in France) believe that abnormalities in EKGs could become a useful tool to identify patients who are at risk of a poor prognosis.  For this reason, their efforts focused on assessing whether specific EKG patterns could be related to in-hospital mortality.

This multicenter study was carried out in three hospitals in France: Nantes University Hospital, La Roche sur Yon Hospital, and Saint Nazaire Hospital, between

February 1st - May 31st, 2020. The sample included a total of 472 adult patients (≥ 18 years of age) who presented in the ER of those hospitals. All of them had an ECG performed when they entered the emergency room, and a positive PCR test to diagnose COVID-19 performed in the same place. These are some of the main characteristics of the participants:

• The mean age was 70 ± 16 years
• 43% were women
• 21% had chronic kidney disease
• 13% had diabetes mellitus
• 42% suffered from hypertension
• 15% had congestive heart failure
• 14% suffered from coronary heart disease
• 13% of patients who went to the emergency room had chest pain
• 2% reported palpitations
• 32% received oxygen

Likewise, the troponin of 171 patients was measured (that is, 62% of the sample); the mean was 33 ± 59 ng/L.  In 23 patients (8.4%) a troponin level higher than 52 ng/L was detected; 13 of them had a history of cardiac pathologies. 32% of patients received oxygen. The in-hospital mortality rate was 14% (n = 37).

For this study, two emergency physicians or an emergency physician and a cardiologist interpreted 275 EKGs. In 41 studies (14.9%) the interpretation of the two doctors was discordant. Overall, these were the findings:

• Baseline electrocardiographic features included a mean heart rate of 85 ± 16 bpm, with a mean PR interval of 160 ± 40 ms and a mean QRS interval of 98 ± 29 ms. 
• 87% of the ECGs were in normal sinus rhythm.
• 10% of patients had atrial fibrillation/flutter on the ECG that was performed on them at ER admission.
• The abnormal axis was n = 16.6%, with 5% having left axis deviation and a 1%  right axis deviation.
  
•  Abnormal intraventricular conduction was found in 16% of patients, with RBBB (right bundle branch block) in 5% and LBBB ( in 4%.
  
• The most common findings were repolarization abnormalities (40%). Negative T waves were 21% of all anomalies.
  
• It is important to point out that ST-segment elevation was rare (n = 6%).

• ·  When comparing patients with repolarization abnormalities to patients without them, troponin levels did not significantly differ (39 vs 31 ng/L, p = 0.45). 

REFERENCIA https://bmcemergmed.biomedcentral.com/articles/10.1186/s12873-021-00539-8