Definition:
In this study NOAF was defined as episodes of paroxysmal or persistent
AF occurred during ICU stay with no previous diagnosis of AF. All
patients were attached to continuous cardiac monitor and episodes were
confirmed on 12 lead electrocardiography. Chronic kidney disease was
classified in stages by eGFR according to the KDIGO (Kidney Disease:
Improving Global Outcomes) clinical practice guidelines. Acute kidney
injury was also classed according to the KDIGO clinical practice
guidelines.
Acute cardiac injury was diagnosed if serum levels of cardiac biomarker
(Troponin T) were above the 99th percentile of the
upper reference range and if new abnormalities were shown in
echocardiography or electrocardiogram. Patients with heart failure with
reduced ejection fraction (HFrEF) as per ESC guidelines (left
ventricular ejection fraction less than 40%) were classed under chronic
heart failure. The linear dimension (anteroposterior measurement on
parasternal long axis view) was taken into consideration for measuring
left atrial (LA) size and was categorised according to the reference
values from British Society of Echocardiography. Extra corporeal
membrane oxygenation (ECMO) was offered to patients with acute severe
and potentially reversible respiratory failure despite ventilator
support who fulfilled the NHS England ECMO guidelines (version 1-
revised in response to the COVID-19 pandemic). All documented diagnoses
of pulmonary embolism (PE) were confirmed radiologically following
computed tomography pulmonary angiogram (CTPA). The highest value of the
laboratory markers prior to the AF episode were taken into account for
the purpose of analysis in table 2.