Public Defence: Itai Schalit

MD Itai Schalit at Institute of Clinical Medicine will be defending the thesis “Accelerometer-based monitoring of left ventricular assist device: tromboembolism and pump thrombosis detection in HeartWare HVAD” for the degree of PhD (Philosophiae Doctor).

Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.

Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Associate Professor Michael Broomé, Karolinska Institutet, Sweden
  • Second opponent: Professor Lars Magne Lundheim, Norwegian University of Science and Technology (NTNU)
  • Third member and chair of the evaluation committee: Professor II Mona Elisabeth Skjelland, University of Oslo

Chair of the Defence

Professor II Kjetil Sunde, University of Oslo

Principal Supervisor

Professor II Per Steinar Halvorsen, University of Oslo


End stage heart failure is a major challenge in the developed countries. Heart transplantation, the treatment of choice, is limited by organ supply. Left ventricular assist device (LVAD) support for the heart, is an alternative treatment. It has, however, severe complications, including stroke and pump thrombosis. Accurate diagnosis of These complications is lacking. Increased third harmonic (pump speed x 3) amplitude on pump sounds analysis has been shown to correlate with pump thrombosis. However, it’s intermittent nature and varied signal quality led to low reproducibility between studies.

In this thesis we tested in vitro (paper I, III) and in vivo (paper II, III) a novel accelerometer-based detection of thromboembolism and pump thrombosis in LVAD. We hypothesized that an accelerometer would detect changes in vibration pattern under thromboembolism and pump thrombosis.

LVAD vibrations were recorded by an accelerometer attached to the LVAD housing. Signal changes under thromboembolism were compared with control interventions.

Thromboembolism detection: Thromboembolic events led to acute significant increased amplitude in the third harmonic (paper I and paper II) (ROC analysis area under the curve > 90%). Analyzing changes in the nonharmonic frequencies further improved the positive predictive value of the method by 8.3% (paper III).

Pump thrombosis detection: A subgroup of the thromboembolic events led to persistent signal changes indicating pump thrombosis, which affected either the third harmonic (21.6%), or the nonharmonic frequencies (8.3%). Using both signal changes led to 36% improvement in the positive predictive value of the method (paper III).

The novel accelerometer based LVAD monitoring detected both pump thrombosis and thromboembolic events. It is suitable for real-time continuous monitoring and may open the door to early diagnosis and potentially better response to treatment.

Additional information

Contact the research support staff.

Published Oct. 14, 2022 10:59 AM - Last modified Oct. 27, 2022 7:41 AM