Among 3,970 patients treated during the early months of the pandemic, new onset AF/AFL was seen in 4%, matching the 4% incidence found in a historic cohort of patients hospitalized with influenza.
On the other hand, mortality was similarly high in both groups of patients studied with AF/AFL, showing a 77% increased risk of death in COVID-19 and a 78% increased risk in influenza, a team from Icahn School of Medicine at Mount Sinai in New York reported.
“We saw new onset Afib and flutter in a minority of patients and it was associated with much higher mortality, but the point is that this increase is basically the same as what you see in influenza, which we feel is an indication that this is more of a generalized response to the inflammatory milieu of such a severe viral illness, as opposed to something specific to COVID,” Vivek Y. Reddy, MD, said in the report, published online Feb. 25 in JACC: Clinical Electrophysiology.
“Here we see, with a similar respiratory virus used as controls, that the results are exactly what I would have expected to see, which is that where there is a lot of inflammation, we see Afib,” said John Mandrola, MD, of Baptist Medical Associates, Louisville, Ky., who was not involved with the study.
“We need more studies like this one because we know SARS-CoV-2 is a bad virus that may have important effects on the heart, but all the of research done so far has been problematic because it didn’t include controls.”
Atrial arrhythmias in COVID and flu
Dr. Reddy and coinvestigators performed a retrospective analysis of a large cohort of patients admitted with laboratory-confirmed COVID-19 during Feb. 4-April 22, 2020, to one of five hospitals within the Mount Sinai Health System.
Their comparator arm included 1,420 patients with confirmed influenza A or B hospitalized between Jan. 1, 2017, and Jan. 1, 2020. For both cohorts, automated electronic record abstraction was used and all patient data were de-identified prior to analysis. In the COVID-19 cohort, a manual review of 1,110 charts was also performed.
Compared with those who did not develop AF/AFL, COVID-19 patients with newly detected AF/AFL and COVID-19 were older (74 vs. 66 years; P < .01) and had higher levels of inflammatory markers, including C-reactive protein and interleukin-6, and higher troponin and D-dimer levels (all P < .01).
Overall, including those with a history of atrial arrhythmias, 10% of patients with hospitalized COVID-19 (13% in the manual review) and 12% of those with influenza had AF/AFL detected during their hospitalization.
Mortality at 30 days was higher in COVID-19 patients with AF/AFL compared to those without (46% vs. 26%; P < .01), as were the rates of intubation (27% vs. 15%; relative risk, 1.8; P < .01), and stroke (1.6% vs. 0.6%, RR, 2.7; P = .05).
Despite having more comorbidities, in-hospital mortality was significantly lower in the influenza cohort overall, compared to the COVID-19 cohort (9% vs. 29%; P < .01), reflecting the higher case fatality rate in COVID-19, Dr. Reddy, director of cardiac arrhythmia services at Mount Sinai Hospital, said in an interview.
But as with COVID-19, those influenza patients who had in-hospital AF/AFL were more likely to require intubation (14% vs. 7%; P = .004) or die (16% vs. 10%; P = .003).
“The data are not perfect and there are always limitations when doing an observational study using historic controls, but my guess would be that if we looked at other databases and other populations hospitalized for severe illness, we’d likely see something similar because when the body is inflamed, you’re more likely to see Afib,” said Dr. Mandrola.
Dr. Reddy concurred, noting that they considered comparing other populations to COVID-19 patients, including those with “just generalized severe illness,” but in the end felt there were many similarities between influenza and COVID-19, even though mortality in the latter is higher.
“It would be interesting for people to look at other illnesses and see if they find the same thing,” he said.
Dr. Reddy reported having no disclosures relevant to COVID-19. Dr. Mandrola is chief cardiology correspondent for Medscape.com. He reported having no relevant disclosures. MDedge is a member of the Medscape Professional Network.