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

@entity1 @entity943 @entity1540 @entity299
BACKGROUND: @entity1 who develop critical @entity943 during left ventricular assist device (LVAD) perfusion have a low survival rate. For diagnosis of unexpected @entity299 , new heart-monitoring methods are required for @entity1 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 @entity1540 ( @entity1540 ). 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 @entity299 . This method can be used for various @entity299 , even those in which the cardiac output is heavily affected by LVAD operation.
