title: Detection of intraoperative myocardial dysfunction by accelerometer during aortic valve replacement.
abstract: Myocardial dysfunction may occur during weaning from cardiopulmonary bypass (CPB). Epicardial accelerometers have been shown to be useful in continuous monitoring of myocardial ischaemia during beating-heart surgery. We aimed to investigate whether an accelerometer can detect myocardial dysfunction during weaning from CPB.
  
  
  
  In 23 patients undergoing isolated aortic valve replacement (AVR), a three-axis accelerometer was attached to the left ventricle and 3D velocity was calculated from the signals. Peak early systolic velocity (Vsys) and velocity at aortic valve closure (Vavc) were measured. Measurements were undertaken during normothermia with 50% bypass flow and atrial pacing (90 beats/min) before aortic cross-clamping and after cross-clamp removal. Myocardial dysfunction was defined as Vsys < Vavc, and patients were classified as having normal function or dysfunction. Left ventricular (LV) stroke work via pulmonary artery catheter and systolic velocity by echocardiography were compared between groups and used as reference methods.
  
  
  
  The accelerometer identified a substantial proportion of patients with myocardial dysfunction during weaning from CPB, 56% of patients compared with 11% before aortic cross-clamping. Patients classified with normal myocardial function during weaning significantly improved their LV stroke work and systolic velocity by echocardiography in response to AVR, whereas those classified with dysfunction did not. Accelerometer classification of normal function predicted an increase in echocardiographic systolic velocity [r = 0.63, regression coefficient 1.98, 95% CI (0.57, 3.40) (P < 0.01)].
  
  
  
  The accelerometer detected myocardial dysfunction during weaning from CPB in accordance with measures obtained by echocardiography and pulmonary artery catheter.
  
  
  
  NCT01926067. https://clinicaltrials.gov/.
authors.affiliation: The Intervention Centre, Oslo University Hospital, Oslo, Norway.|Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Anaesthesiology, Oslo University Hospital, Oslo, Norway.
authors.forename: Ole-Johannes H N
authors.initials: OH
authors.lastname: Grymyr
authors.affiliation: Department of Cardiology, Oslo University Hospital, Oslo, Norway.
authors.forename: Jan O
authors.initials: JO
authors.lastname: Beitnes
authors.affiliation: The Intervention Centre, Oslo University Hospital, Oslo, Norway.|Department of Anaesthesiology, Oslo University Hospital, Oslo, Norway.
authors.forename: Jo
authors.initials: J
authors.lastname: Eidet
authors.affiliation: Department of Anaesthesiology, Oslo University Hospital, Oslo, Norway.
authors.forename: Stein
authors.initials: S
authors.lastname: Tølløfsrud
authors.affiliation: Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Cardiothoracic Surgery, Oslo University Hospital, Oslo, Norway.
authors.forename: Arnt
authors.initials: A
authors.lastname: Fiane
authors.affiliation: Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Cardiology, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Helge
authors.initials: H
authors.lastname: Skulstad
authors.affiliation: The Intervention Centre, Oslo University Hospital, Oslo, Norway.|Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Erik
authors.initials: E
authors.lastname: Fosse
authors.affiliation: The Intervention Centre, Oslo University Hospital, Oslo, Norway.|Department of Anaesthesiology, Oslo University Hospital, Oslo, Norway.
authors.forename: Per S
authors.initials: PS
authors.lastname: Halvorsen
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000601:surgery*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D004452:Echocardiography; D005240:Feasibility Studies; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D007431:Intraoperative Complications / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000209:etiology; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology
keywords: Aortic valve replacement; Cardiac monitoring; Left ventricular function; Motion sensor