Minituarized accelerometers attached to the heart can monitor heart function continuously during and after surgery. The potential clinical applicability of such sensors is increased as a result of Ole-Johannes Holm Nielsen Grymyr‘s PhD research.

MAIN RESULTS:

1. 3D signals from miniturized acceleratometers attached to the epicardium correspond very well to changes in global and regional left ventricular function, and increases the applicability of the accelerometers in cardiac surgery.
2. 3D accelerometers can assess global and regional function in a postoperative closed-chest model.
3. The accelerometers can detect myocardial dysfunction during weaning from cardiopulmonary bypass in patients undergoing aortic valve replacement.

THESIS DEFENCE:

Thesis: Myocardial function and 3D motion analysis using a three-axis accelerometer during cardiac surgery
Candidate: Ole-Johannes Holm Nielsen Grymyr
Time: September 1, 2017 at 13:15
Place: Oslo University Hospital, Rikshospitalet B: Blue Auditorium
Link to university website (in Norwegian)

SUMMARY:

(1) A new method to process the three-dimensional signals from minituarized accelerometers attached to the heart, does not require the precise alignment of the sensors required by the previous one-axis processing method. Thus, the potential clinical applicability of the accelerometers to detect alternations in cardiac function during surgery is increased.

The new method was tested on 20 open-chest pigs, and the accelerometer signals corresponded very well to changes in global and regional left ventricular function.

(2) Furthermore, the technique may be used for continuous postoperative monitoring after cardiac surgery. In 13 closed-chest pigs, miniaturized 3D accelerometers detected both global and regional heart dysfunction, but showed reduced ability to localize ischaemia.

(3) The third study was conducted on 18 patients with severe aortic stenosis undergoing isolated aortic valve replacement. The accelerometers identified a substantial proportion of patients with myocardial dysfunction during weaning from cardiopulmonary bypass.

REFERENCES:

(1) Grymyr, O. J. H., Remme, E. W., Espinoza, A., Skulstad, H., Elle, O. J., Fosse, E., & Halvorsen, P. S. (2014). Assessment of 3D motion increases the applicability of accelerometers for monitoring left ventricular function. Interactive cardiovascular and thoracic surgery, 20(3), 329-337.

(2) Grymyr, O. J. H., Nguyen, A. T. T., Tjulkins, F., Espinoza, A., Remme, E. W., Skulstad, H., Fosse, E., Imenes, K., & Halvorsen, P. S. (2015). Continuous monitoring of cardiac function by 3-dimensional accelerometers in a closed-chest pig model. Interactive cardiovascular and thoracic surgery, 21(5), 573-582.

(3) Grymyr, O. J. H., Beitnes, J. O., Eidet, J., Tølløfsrud, S., Fiane, A., Skulstad, H., Fossen, E., & Halvorsen, P. S. (2016). Detection of intraoperative myocardial dysfunction by accelerometer during aortic valve replacement. Interactive CardioVascular and Thoracic Surgery, 24(2), 188-195.