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SUMMARY:Development of a virtual heart - Part ll - Zhang\, H (Manchester)
DTSTART:20090720T134500Z
DTEND:20090720T140000Z
UID:TALK19180@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Virtual tissue engineering of cardiac electrical activity requ
 ires detailed descriptions of local cell\nproperties  their action potenti
 al (AP) mechanisms\, local intercellular coupling\, spatial\nheterogeneiti
 es\, and their spatial and geometric relations. Over the last decade\, we 
 have developed a\nnew family of single cell AP models for all distinctive 
 regions of the rabbit heart. These single cell\nmodels include the centre 
 and periphery of the sinoatrial node (SAN) (1)\, the right atrium (RA) and
 \nleft atrium (LA) (2)\, crista terminalis and pectinate muscles (3)\, Bac
 hmanns bundle\, pulmonary vein\nand coronary sinus (4)\, fast and slow pat
 hways of the atrioventricular node (AN and N of the AVN)\nand His bundle (
 NH) (5)\, Purkinje fibers (PF)\, endocardial (Endo)\, middle (M) and epica
 rdial (Epi)\nlayers of the left ventricle (LV) (6). These single cell mode
 ls were based on and validated against\nexperimental data. Using these sin
 gle cell models\, we have developed a 1D model for the whole heart\nconduc
 tion system that incorporates regional differences in both cellular electr
 ical properties and\nintercellular electrical coupling among major distinc
 tive regions of the rabbit heart\, including the\nSAN\, atrium muscle\, AV
 N\, PF and ventricle. The model reproduces the normal activation sequence\
 nof the heart with an endogenous SAN driven rate of ~180 beats/min. The ac
 tivation is first initiated in\nthe centre of the SAN. Once initiated\, it
  propagates towards the periphery of the atrium and then to\nthe AVN via t
 he rapid conduction pathway of the crista terminalis. The AVN then transmi
 ts the\nexcitation to the PF and then to the ventricle. The AP conduction 
 velocities ranging from ~0.1 m/s in\nthe SAN to 1.5 m/s in the PF\, which 
 are consistent with experimental data. The whole heart model\nalso produce
 s a pseudo-ECG with intervals (R-R=333 ms\, Q-T=214 ms\, P-R=85 ms) that f
 all in the\nrange seen in isolated Langendorff perfused rabbit heart. Simu
 lated effect of acetylcholine (ACh)\, a\nneurotransmitter released from va
 gal nerves upon stimulation\, is also consistent with the measurement\nfro
 m Langendorff perfused rabbit heart.
LOCATION:Seminar Room 1\, Newton Institute
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