Presence of prolonged QT interval on ECG in hospitalized patients with Covid-19 is associated with increased risk of myocardial injury and death, according the findings of a study presented at EHRA 2022, the annual congress of the European Heart Rhythm Association (EHRA) of the European Society of Cardiology (ESC).^1,2

This prospective study enrolled 335 patients hospitalized with Covid-19, who had an ECG done at the time of admission. Their troponin levels were measured and echocardiography was done to assess cardiac function. Elevated troponin and reduced cardiac function were indicative of myocardial injury. The study objectives were to detect any association between prolonged QT interval and myocardial injury and also between QT prolongation and long-term mortality.

Out of the 335 participants, 109 (32.5%) had a prolonged QT interval, while 226 (67.5%) had a normal QT interval.

Patients with a prolonged QT interval had more severe Covid-19. They were older than those with normal QT interval (70 years vs 63 years) and were more likely to have comorbid conditions such as diabetes, hypertension, congestive heart failure.

About 71.6% of patients with prolonged QT interval had myocardial injury compared to 48.7% of those with normal QT interval. The risk of myocardial injury was increased two times due to prolonged QT after adjusting for age, co-existing conditions and severity of Covid-19. According to the authors, almost half of these patients with myocardial injury did not have raised troponin levels implying that relying on troponin alone could miss many patients with myocardial injury.

Again, after adjusting for age, co-existing conditions and severity of Covid-19, patients with prolonged QT interval were 1.85 times more likely to die within a year. Mortality at one year was 41% patients with prolonged QT interval vis-à-vis 17% in the normal QT interval group.

Patients who had myocardial injury along with prolonged QT interval were 6.6-times more likely to diet within one year compared to patients without prolonged QT interval and no myocardial injury.

A prolonged QT is associated with an increased risk of ventricular arrhythmias, which are potentially fatal. This study highlights the utility of ECG, a simple, inexpensive and readily available tool, in detecting Covid-19 patients at high risk of mortality. It points out prolonged QT interval as a risk factor for myocardial injury and mortality at one year and suggests that all Covid-19 patients should undergo an ECG at the time of hospital admission for risk stratification and management of the patient according to their risk level.

References

1. Ariel Banai, et al. QT interval prolongation is a novel predictor of one year mortality in patients with coronavirus disease-19 infection. April 4, EHRA 2022.

2.    ESC Press release, April 4, 2022. https://www.escardio.org/The-ESC/Press-Office/Press-releases/Study-identifies-hospitalised-COVID-19-patients-at-elevated-mortality-risk