Clinical Features and Short-Term Outcomes in Virus-Induced Bradycardia: Comparison Between Covid and non-Covid Infected Patients (preprint)

ABSTRACT

Covid-19 outbreak has drawn attention to the fact that viral infections might present with clinical bradycardia. Seeking its clinical significance, not yet unveiled by the literature, we come across other viral infections that also show clinical bradycardia during its clinical course, such as dengue fever and viral diarrhea. The clinical presentation of the latest seems to be severe, often presenting with orthostatic intolerance and fatigue symptoms, requiring expert consultation irrespective of the infection stage, and in case of dengue fever, frequently during the recovery phase. Meanwhile, in Covid-19 infected patients, the bradycardia observed is mild, frugal, and usually asymptomatic. Thus, we conducted a comparison between two different groups of patients with viral infection displaying clinical bradycardia during hospital stay Covid and non-Covid patients regarding clinical and Holter monitoring parameters. All patients had other causes of bradycardia excluded and echocardiography and cardiac biomarkers ruled out acute myocarditis. The results showed that non-Covid patients presented with significantly lower mean and minimum heart rates (HR) on Holter monitoring, as well as longer times in with HR < 50 beats per minute (bpm).  SDNN and pNN>50% were also significantly higher in non-Covid patients. The minimum systolic BP was significantly lower in non-Covid patients. The study shows that Covid-19 is not the only viral infection that may display with clinical bradycardia, but it’s much milder than other viral infections such as dengue fever and viral diarrhea. It remains unclear the mechanism throughout Covid-related bradycardia comes about.