| 摘要 |
Multi-site cardiac pacing systems that pace and sense in at least a first site in the heart and sense conducted electrical signals at a second site in the heart and measure and accumulate electrical conduction times between the first and second sites to derive trend data indicative of the state of heart failure. Preferably the sites are right heart chamber and left heart chamber sites, e.g., right and left atrial sites or right and left ventricular sites. In a ventricular embodiment, a V-V conduction time is measured from a ventricular sense (VS) event or a ventricular pace (VP) pulse delivered to a selected one of first and second ventricular sites to the VS event at the other one of the first and second ventricular sites. The measured V-V conduction time can be one or more of a VS-VS conduction time, a VP-VS conduction time and a VS/VP-VS conduction time. In each case, a single data point measured V-V conduction time may be obtained and stored or the high and low measured V-V conduction times and an average V-V conduction time can be obtained from a series of measured V-V conduction times. The measured V-V conduction time or times as well as related data including a date and time stamp of the measurement event, the prevailing heart rate, and the activity level of the patient or other indicator of physiologic need for cardiac output are stored in IMD memory during each measurement session for subsequent analysis. Trend data evidencing any change in the intrinsic conduction time between the first and second ventricular sites gathered over a period of days, weeks and months provides a valuable indication as to whether the heart failure state is improving, worsening or staying about the same.
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