UCSF

Significance: Early studies showed that premature ventricular complexes (PVCs) were associated with lethal arrhythmias (ventricular tachycardia (VT) and ventricular fibrillation (VF)) and death in patients with acute myocardial infarction (MI). However, the Cardiac Arrhythmia Suppression Trial (CAST) showed that treatment of PVCs with antiarrhythmics was associated with death. As a result, aggressive pharmacological treatment of PVCs was no longer standard practice. Nevertheless, continuous monitoring for PVCs remains routine care in the intensive care unit (ICU), mainly due to clinicians’ fear of missing patients at risk for developing lethal arrhythmias. Although studies examining the significance of PVCs in outpatient settings exist, similar evidence is lacking in hospital settings, especially in the ICU.

Methods: We performed a literature review of the evidence of the diagnostic and prognostic significance of PVCs utilizing the frameworks for scoping review by Arksey and O’Malley and the Joanna Briggs Institute (JBI). We synthesized the results and described the significance of PVCs in patients with and without cardiac disease in the community and hospital settings. We evaluated occurrence rates of PVC alarms in 446 ICU patients and determined whether demographics (age, sex, race) and clinical characteristics (medical history, presence of PVC and atrial fibrillation on baseline 12-lead ECGs, serum potassium, ejection fraction, and primary diagnosis) were associated with six PVC types (i.e., isolated, bigeminy, trigeminy, couplet, R-on-T, and run PVC). Using logistic regression modeling, we determined if any of the six PVC types were associated with the occurrence of lethal arrhythmias (ventricular tachycardia and ventricular fibrillation), code blue, and death.

Results: Existing evidence largely examined the prognostic value of PVCs in the outpatient settings on several patient outcomes, such as left ventricular dysfunction, arrhythmia development, and mortality. Only three studies, done in the 1970s, evaluated the significance of PVCs in acute MI. Isolated PVCs were the most common type, accounting for 81.3% (646,666 out of 797,072 individual PVC alarms), and were concentrated in a small subgroup of patients. We found that none of the six PVC types were associated with VT events and death. Due to the small sample size, we could not determine a similar association for VF and code blue outcomes.

Conclusion: This dissertation represents current “real-world” clinical practice regarding PVC monitoring from a large time-series dataset during continuous ECG monitoring in the ICU. PVC monitoring was shown to be non-specific and likely not clinically meaningful, leading to an increased alarm burden and alarm fatigue. Therefore, the clinical team should strategize and develop different alarm strategies to minimize nuisance (i.e., true but not clinically significant) PVC alarms.