Limits...
Heart monitoring using left ventricle impedance and ventricular electrocardiography in left ventricular assist device patients.

Her K, Ahn CB, Park SM, Choi SW - Biomed Eng Online (2015)

Bottom Line: Left ventricular impedance (LVI) is useful for monitoring heart movement but does not show abnormal action potential in the heart muscle.Simultaneous v-ECG and LVI data were compared to detect heart volume changes during the Q-T period when the heart contracted.To evaluate the accuracy of the new method, the results obtained were compared to normal ECG data and cardiac output measured simultaneously using commercial devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiovascular and Thoracic Surgery, Soonchunhyang University Hospital, Bucheon-si, South Korea. hktree@schmc.ac.kr.

ABSTRACT

Background: Patients who develop critical arrhythmia during left ventricular assist device (LVAD) perfusion have a low survival rate. For diagnosis of unexpected heart abnormalities, new heart-monitoring methods are required for patients supported by LVAD perfusion. Ventricular electrocardiography using electrodes implanted in the ventricle to detect heart contractions is unsuitable if the heart is abnormal. Left ventricular impedance (LVI) is useful for monitoring heart movement but does not show abnormal action potential in the heart muscle.

Objectives: To detect detailed abnormal heart conditions, we obtained ventricular electrocardiograms (v-ECGs) and LVI simultaneously in porcine models connected to LVADs.

Methods: In the porcine models, electrodes were set on the heart apex and ascending aorta for real-time measurements of v-ECGs and LVI. As the carrier current frequency of the LVI was adjusted to 30 kHz, it was easily derived from the original v-ECG signal by using a high-pass filter (cutoff: 10 kHz). In addition, v-ECGs with a frequency band of 0.1 - 120 Hz were easily derived using a low-pass filter. Simultaneous v-ECG and LVI data were compared to detect heart volume changes during the Q-T period when the heart contracted. A new real-time algorithm for comparison of v-ECGs and LVI determined whether the porcine heartbeats were normal or abnormal. Several abnormal heartbeats were detected using the LVADs operating in asynchronous mode, most of which were premature ventricle contractions (PVCs). To evaluate the accuracy of the new method, the results obtained were compared to normal ECG data and cardiac output measured simultaneously using commercial devices.

Results: The new method provided more accurate detection of abnormal heart movements. This method can be used for various heart diseases, even those in which the cardiac output is heavily affected by LVAD operation.

No MeSH data available.


Related in: MedlinePlus

Placement of electrodes for measurement of v-ECGs and LVI in the LV (upper) and pulsatile left ventricular assist device (lower).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4374380&req=5

Fig1: Placement of electrodes for measurement of v-ECGs and LVI in the LV (upper) and pulsatile left ventricular assist device (lower).

Mentions: The electrodes were placed at the inlet and outlet of the VAD, in contact with the apex and aortic tissue, as shown in Figure 1. The electrodes were made of stainless steel with smooth surfaces to prevent thrombogenesis and tissue adhesion. Although separate animal experiments showed neither thrombogenesis nor tissue adhesion for over 45 days, long-term clinical trials may be needed to improve the performance and safety of the electrodes [16]. In this study, the electrode material had no impact on v-ECG or LVI measurements, and no measurement-induced damage or deformation of the electrodes occurred.Figure 1


Heart monitoring using left ventricle impedance and ventricular electrocardiography in left ventricular assist device patients.

Her K, Ahn CB, Park SM, Choi SW - Biomed Eng Online (2015)

Placement of electrodes for measurement of v-ECGs and LVI in the LV (upper) and pulsatile left ventricular assist device (lower).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4374380&req=5

Fig1: Placement of electrodes for measurement of v-ECGs and LVI in the LV (upper) and pulsatile left ventricular assist device (lower).
Mentions: The electrodes were placed at the inlet and outlet of the VAD, in contact with the apex and aortic tissue, as shown in Figure 1. The electrodes were made of stainless steel with smooth surfaces to prevent thrombogenesis and tissue adhesion. Although separate animal experiments showed neither thrombogenesis nor tissue adhesion for over 45 days, long-term clinical trials may be needed to improve the performance and safety of the electrodes [16]. In this study, the electrode material had no impact on v-ECG or LVI measurements, and no measurement-induced damage or deformation of the electrodes occurred.Figure 1

Bottom Line: Left ventricular impedance (LVI) is useful for monitoring heart movement but does not show abnormal action potential in the heart muscle.Simultaneous v-ECG and LVI data were compared to detect heart volume changes during the Q-T period when the heart contracted.To evaluate the accuracy of the new method, the results obtained were compared to normal ECG data and cardiac output measured simultaneously using commercial devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiovascular and Thoracic Surgery, Soonchunhyang University Hospital, Bucheon-si, South Korea. hktree@schmc.ac.kr.

ABSTRACT

Background: Patients who develop critical arrhythmia during left ventricular assist device (LVAD) perfusion have a low survival rate. For diagnosis of unexpected heart abnormalities, new heart-monitoring methods are required for patients supported by LVAD perfusion. Ventricular electrocardiography using electrodes implanted in the ventricle to detect heart contractions is unsuitable if the heart is abnormal. Left ventricular impedance (LVI) is useful for monitoring heart movement but does not show abnormal action potential in the heart muscle.

Objectives: To detect detailed abnormal heart conditions, we obtained ventricular electrocardiograms (v-ECGs) and LVI simultaneously in porcine models connected to LVADs.

Methods: In the porcine models, electrodes were set on the heart apex and ascending aorta for real-time measurements of v-ECGs and LVI. As the carrier current frequency of the LVI was adjusted to 30 kHz, it was easily derived from the original v-ECG signal by using a high-pass filter (cutoff: 10 kHz). In addition, v-ECGs with a frequency band of 0.1 - 120 Hz were easily derived using a low-pass filter. Simultaneous v-ECG and LVI data were compared to detect heart volume changes during the Q-T period when the heart contracted. A new real-time algorithm for comparison of v-ECGs and LVI determined whether the porcine heartbeats were normal or abnormal. Several abnormal heartbeats were detected using the LVADs operating in asynchronous mode, most of which were premature ventricle contractions (PVCs). To evaluate the accuracy of the new method, the results obtained were compared to normal ECG data and cardiac output measured simultaneously using commercial devices.

Results: The new method provided more accurate detection of abnormal heart movements. This method can be used for various heart diseases, even those in which the cardiac output is heavily affected by LVAD operation.

No MeSH data available.


Related in: MedlinePlus