Electrocardiographic Abnormalities and In-Hospital Mortality in COVID-19 Patients

Overview

During the COVID-19 pandemic, physicians observed that many hospitalized patients developed heart complications. Elevated troponin levels quickly became a key marker for severe disease and were strongly linked to higher mortality.

However, researchers still wanted to understand why some patients experienced cardiac injury while others did not.

A multicenter study titled “Electrocardiographic abnormalities in COVID-19 patients visiting the emergency department: a multicenter retrospective study” by Hugo De Carvalho et al. explored whether specific ECG abnormalities could predict the risk of death in these patients.

Background

COVID-19 primarily affects the lungs, but it can also damage the cardiovascular system. Severe infection may lead to myocardial injury, arrhythmias, or conduction disorders. Despite these findings, identifying which patients are at greatest risk has remained a challenge.

The study authors proposed that electrocardiograms (ECGs) could help clinicians detect early signs of cardiac involvement. Therefore, they examined whether abnormal ECG findings might indicate a higher chance of in-hospital mortality.

Study Design and Participants

The research was conducted across three hospitals in France — Nantes University Hospital, La Roche sur Yon Hospital, and Saint Nazaire Hospital — between February 1 and May 31, 2020.

A total of 472 adult patients (aged 18 years or older) with confirmed COVID-19 participated. Every patient received an ECG upon arrival at the emergency department and a positive PCR test for SARS-CoV-2.

Participant Characteristics

• Mean age: 70 ± 16 years

• 43% were women

• 42% had hypertension

• 21% had chronic kidney disease

• 15% had heart failure

• 14% had coronary heart disease

• 13% presented with chest pain

• 32% required oxygen therapy

Troponin Levels and Mortality

Troponin was measured in 171 patients (62% of the total sample). The average level was 33 ± 59 ng/L, and 8.4% showed elevated values (> 52 ng/L).
Overall, in-hospital mortality reached 14% (n = 37).

Electrocardiographic Findings

Two physicians — either emergency doctors or cardiologists — analyzed 275 ECGs. Although their interpretations differed in about 15% of cases, the general results remained consistent.

Common ECG Patterns

• Mean heart rate: 85 ± 16 bpm

• PR interval: 160 ± 40 ms

• QRS duration: 98 ± 29 ms

• 87% of patients were in normal sinus rhythm

• 10% presented atrial fibrillation or flutter

• 16.6% had an abnormal electrical axis (5% left, 1% right)

• 16% showed intraventricular conduction disorders (5% RBBB, 4% LBBB)

• 40% had repolarization abnormalities, mainly negative T waves (21%)

• ST-segment elevation was uncommon (6%)

Repolarization Abnormalities and Troponin

Interestingly, troponin levels were similar between patients with and without repolarization abnormalities (39 vs 31 ng/L; p = 0.45).

Key Associations

After adjusting for confounding factors, two ECG findings stood out as significant predictors:

• Abnormal axis – nearly a fourfold higher risk of in-hospital mortality (adjusted OR 3.9; 95% CI 1.1–11.5; p = 0.02).

• Left Bundle Branch Block (LBBB) – a sevenfold increase in mortality (adjusted OR 7.1; 95% CI 1.9–25.1; p = 0.002).

Therefore, both LBBB and abnormal axis patterns emerged as strong indicators of poor outcomes.

Clinical Implications

Performing an ECG at admission provides immediate insight into a patient’s cardiac status. When findings such as LBBB or axis deviation are detected, clinicians can anticipate complications and adjust treatment early.

In addition, combining ECG analysis with biomarker testing (for example, troponin) improves accuracy in identifying high-risk patients.
Consequently, early ECG evaluation should be part of routine emergency care for individuals with confirmed COVID-19.

Conclusions

The findings confirm that ECGs serve not only as diagnostic tools but also as predictive markers for hospital outcomes in COVID-19 patients.

• Abnormal axis and LBBB significantly increased in-hospital mortality.

• ST-segment elevation was rare, indicating that most cardiac injuries were non-ischemic.

• Routine ECG screening in emergency departments can enhance early detection and improve patient survival rates.

Reference

De Carvalho H. et al. Electrocardiographic abnormalities in COVID-19 patients visiting the emergency department: a multicenter retrospective study.
European Heart Journal, 2022.

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