Irregularly Irregular Heartbeats Occur Regularly in the ICU*

Abstract

A mong the scourges that beset ICU patients are atrial fibrillation (AF) and atrial flutter, which are the most common cardiac arrhythmias found among adult ICU patients. AF can be either preexisting or of new onset. The former situation is not unexpected as the prevalence of chronic AF increases with age, rising from 0.7% in 55-to 59-year olds to 17.8% in those who are 85 years old or older (1). As of 2014, 2-3% of the European and North American population were afflicted with AF. Aging causes degenerative changes in atrial tissues, changes in atrial electrophysiology, atrial stiffening, and fragmentation of the atrial excitation waveform. Therefore, many older ICU patients have persistent or paroxysmal AF. Such patients may have reduced cardiac reserve secondary to atrial dysfunction, have increased risk of stroke, and be receiving anti-coagulation and taking medications with hemodynamic consequences. Therefore, they present a special challenge when suffering from critical illnesses and often have greater morbidity and mortality than their counterparts with normal sinus rhythm. Furthermore, AF-associated embolic strokes treated with thrombolytic or neurointerventional techniques, along with hemorrhagic complications of the anticoagulation therapy intended to prevent such strokes, often result in ICU admission.However, it is the patients who develop AF for the first time while in the ICU that constitute a special population. Patients with new-onset AF can be divided into two groups: those with and those without pathology within the chest cavity. Direct surgical, penetrating, and blunt traumas to the thorax are associated with significant incidences of AF. After thoracic and cardiac surgery, AF occurs with regularity. It occurs in 12-45% of patients after pulmonary and esophageal surgery, where, compared with patients without such arrhythmias, it is associated with more pulmonary complications, greater risk of stroke, higher mortality, longer hospital stays, and higher hospital costs. Age 60 years old or older is the most strongly associated independent variable associated with postthoracic surgery AF (2). Within 2-3 days after cardiac surgery, up to 80% of patients develop AF, with a higher frequency after valvular than coronary artery surgery. The highest incidence occurs after combined bypass and valvular procedures (60-80%). Many of these episodes of AF are self-limited to the days immediately after surgery but are associated with longer ICU and hospital lengths of stay and greater in-hospital and long-term mortality (3).New-onset AF in ICU patients without major chest cavity problems is common. In a three-center Canadian study of 3,081 medical and noncardiac surgical ICU patients, newonset AF occurred in 139 patients (4.5%) and was preexisting in 186 patients (6.0%). Hemodynamic instability developed in 37% and 10% of patients with new-onset AF and preexisting AF, respectively (4). Among 66 medical ICU patients with septic shock who underwent Holter monitoring, 29 (44%) developed new-onset AF which upon mult...

Impact of Norepinephrine Weight-Based Dosing Compared With Non–Weight-Based Dosing in Achieving Time to Goal Mean Arterial Pressure in Obese Patients With Septic Shock

“…Therefore, although this study did not find a difference in development of atrial fibrillation, these data are difficult to capture retrospectively. 32 Previous studies such as the Sepsis Occurrence in Acutely Ill Patients (SOAP II) trial and the Sepsis and Mean Arterial Pressure (SEPSISPAM) trial have demonstrated a relationship between higher median doses of norepinephrine and a higher risk for atrial fibrillation. 12,33 Additionally, the SEPSISPAM trial similarly demonstrated prolonged duration of catecholamine infusion in the group of patients randomized to the high MAP target group compared with the low MAP target group, consistent with the results of our study.…”