title: Comparison of electrical velocimetry and cardiac magnetic resonance imaging for the non-invasive determination of cardiac output.
abstract: A novel algorithm of impedance cardiography referred to as electrical velocimetry (EV) has been introduced for non-invasive determination of cardiac output (CO). Previous validation studies yielded diverging results and no comparison with the non-invasive gold standard cardiac magnetic resonance imaging (CMR) has been performed. We therefore aimed to prospectively assess the accuracy and reproducibility of EV compared to CMR. 152 consecutive stable patients undergoing CMR were enrolled. EV measurements were taken twice before or after CMR in supine position and averaged over 20 s (AESCULON(®), Osypka Medical, Berlin, Germany). Bland-Altman analysis showed insufficient agreement of EV and CMR with a mean bias of 1.2 ± 1.4 l/min (bias 23 ± 26 %, percentage error 51 %). Reproducibility was high with 0.0 ± 0.3 l/min (bias 0 ± 8 %, percentage error 15 %). Outlier analysis revealed gender, height, CO and stroke volume (SV) by CMR as independent predictors for larger variation. Stratification of COCMR in quintiles demonstrated a good agreement for low values (<4.4 l/min) with bias increasing significantly with quintile as high as 3.1 ± 1.1 l/min (p < 0.001). Reproducibility was not affected (p = 0.71). Subgroup analysis in patients with arrhythmias (p = 0.19), changes in thoracic fluid content (p = 0.51) or left heart failure (p = 0.47) could not detect significant differences in accuracy. EV showed insufficient agreement with CMR and good reproducibility. Gender, height and increasing CO and SV were associated with increased bias while not affecting reproducibility. Therefore, absolute values should not be used interchangeably in clinical routine. EV yet may find its place for clinical application with further investigation on its trending ability pending.
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Trinkmann
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Berger
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.|DZHK (German Center for Cardiovascular Research) Partner Site, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Doesch
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.|DZHK (German Center for Cardiovascular Research) Partner Site, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Theano
authors.initials: T
authors.lastname: Papavassiliu
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.|DZHK (German Center for Cardiovascular Research) Partner Site, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.|DZHK (German Center for Cardiovascular Research) Partner Site, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Borggrefe
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: Jens J
authors.initials: JJ
authors.lastname: Kaden
authors.affiliation: 1st Department of Medicine (Cardiology, Angiology, Pneumology, Intensive Care), University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany. jsaur@uni-mannheim.de.
authors.forename: Joachim
authors.initials: J
authors.lastname: Saur
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac; D001827:Body Height; D002302:Cardiac Output; D002307:Cardiography, Impedance / Q000379:methods*; D017097:Electric Impedance; D005260:Female; D006321:Heart / Q000502:physiology; D006333:Heart Failure; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011446:Prospective Studies; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods; D013318:Stroke Volume; D013997:Time Factors; D055815:Young Adult
keywords: Cardiac magnetic resonance imaging; Cardiac output; Electrical velocimetry; Impedance cardiography; Non-invasive