| 摘要 |
An implantable multi-chamber cardiac stimulation device and method are provided for accurately sensing cardiac activity from three or four heart chambers using passive sensing electrodes placed in each heart chamber. Multiple intra-chamber or inter-chamber sensing vectors are established between passive sensing electrodes. Sampled sensing vector signals are processed such that a cardiac depolarization may be accurately detected, as well as its origin and direction of propagation. Time intervals between detected depolarization signals may be used to determine conduction time or heart rate. Diagnostic indicators of heart failure condition normally obtained from a 12-lead surface ECG study, such as P-wave or R-wave duration, may also be determined from the sensing vectors. Based on precise and detailed evaluation of sensing vector signals, stimulation therapy may be provided immediately upon a detected change in heart rhythm or heart failure condition.
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