The Left Ventricular Apex (LVA) represents a significant site for the study of cardiac kinematics. The assessment of LVA movements throughout the cardiac cycle could be useful for evaluating the state of health of the heart. We propose a method based on a real-time 3D magnetic tracking system, for the analysis of LVA movements relatively to a static Cartesian frame of reference in order to evaluate cardiac global kinematics. An adult female sheep was used for the study. Left Ventricular Pressure (LVP) was acquired with a pressure catheter inserted in the left ventricle and used to derive the hemodynamic index of cardiac contractility (LVdP/dtMAX). LVA kinematics was assessed by using a real-time 3D magnetic tracking system (microBIRD, Ascension Technology Corp.), whose receiving sensor was epicardially glued on the exposed LVA. Acquired x, y, z coordinates described LVA displacement defined as 3-Dimensional Apex Path (3DAP). Two indexes were calculated: the Path Length (3DAPL) and the Path Volume (3DAPV), length of 3DAP and volume containing 3DAP, respectively. Data were collected during baseline condition and acute ischemia, experimentally induced by coronary artery ligation. During acute ischemia, the trend of the LVdP/dtMAX was opposite to those of 3DAPL and 3DAPV: a decrease of LVdP/dtMAX values from 876±3 mmHg/s (baseline) to 552±10 mmHg/s (ischemia) occurred, while an increase of 3DAPL and 3DAPV was observed, from 33.0±1.0 mm (baseline) to 41.1±0.7 mm (ischemia), from 4319±281 mm3(baseline) to 10872±468 mm3 (ischemia), respectively. Results suggest the existence of a link between cardiac efficiency and LVA kinematics: in the impaired heart, 3DAPL and 3DAPV values are greater than during baseline, because of abnormal apex movements. However, this altered kinematics seems to waste energy, as showed by the drop in the cardiac hemodynamic function (LVdP/dtMAX). The new 3DAPL and 3DAPV appeared to be valid indexes of global cardiac function. Further investigation is required to confirm these preliminary results.

Assessment of the 3-dimensional left ventricular apex path with a magnetic tracking system

MARCELLI, EMANUELA;CERCENELLI, LAURA;PLICCHI, GIANNI
2008

Abstract

The Left Ventricular Apex (LVA) represents a significant site for the study of cardiac kinematics. The assessment of LVA movements throughout the cardiac cycle could be useful for evaluating the state of health of the heart. We propose a method based on a real-time 3D magnetic tracking system, for the analysis of LVA movements relatively to a static Cartesian frame of reference in order to evaluate cardiac global kinematics. An adult female sheep was used for the study. Left Ventricular Pressure (LVP) was acquired with a pressure catheter inserted in the left ventricle and used to derive the hemodynamic index of cardiac contractility (LVdP/dtMAX). LVA kinematics was assessed by using a real-time 3D magnetic tracking system (microBIRD, Ascension Technology Corp.), whose receiving sensor was epicardially glued on the exposed LVA. Acquired x, y, z coordinates described LVA displacement defined as 3-Dimensional Apex Path (3DAP). Two indexes were calculated: the Path Length (3DAPL) and the Path Volume (3DAPV), length of 3DAP and volume containing 3DAP, respectively. Data were collected during baseline condition and acute ischemia, experimentally induced by coronary artery ligation. During acute ischemia, the trend of the LVdP/dtMAX was opposite to those of 3DAPL and 3DAPV: a decrease of LVdP/dtMAX values from 876±3 mmHg/s (baseline) to 552±10 mmHg/s (ischemia) occurred, while an increase of 3DAPL and 3DAPV was observed, from 33.0±1.0 mm (baseline) to 41.1±0.7 mm (ischemia), from 4319±281 mm3(baseline) to 10872±468 mm3 (ischemia), respectively. Results suggest the existence of a link between cardiac efficiency and LVA kinematics: in the impaired heart, 3DAPL and 3DAPV values are greater than during baseline, because of abnormal apex movements. However, this altered kinematics seems to waste energy, as showed by the drop in the cardiac hemodynamic function (LVdP/dtMAX). The new 3DAPL and 3DAPV appeared to be valid indexes of global cardiac function. Further investigation is required to confirm these preliminary results.
Congresso Nazionale di Bioingegneria - Atti
483
484
E. Marcelli; S. Spolzino; L. Cercenelli; P. Bagnoli; M.L. Costantino; N. Malagutti; R. Fumero; G. Plicchi
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/70715
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