| 摘要 |
A rate responsive pacemaker uses isovolumic contraction time (IVCT) as a control signal responsive to metabolic demands. This control signal is injected into the timing circuit of a standard rate adaptive pacemaker to enhance the pacer's ability to respond in direct relation to the patient's changing metabolic needs as he performs his daily activities. A typical configuration, uses the duration of either right or left heart IVCT for rate control. The device has two inputs to measure IVCT: one, signaling the onset of mechanical activation of the ventricle, and another, signaling the onset of ejection. The time interval between these two signals is the duration of IVCT, which is processed by the pacemaker to determine the escape interval.
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