The activity of type B left atrial receptors was recorded from slips of the left cervical vagus in chloralose anesthetized, open chest dogs. The SA node was crushed and the heart was paced by bipolar electrodes attached to the right atrial appendage. Heart rate was varied between 60 and 240 beats/min in steps of 30 beats/min. Left atrial pressure was increased at each heart rate by the intravenous infusion of warm isotonic saline. As heart rate was increased, the number of discharges/cardiac cycle decreased at any given left atrial pressure. However, at any given left atrial pressure, the number of discharges per min (heart rate x discharge/cardiac cycle) remained relatively constant over the range of heart rate studied. The relationship between discharge/min and left atrial 'v' wave pressure for all experiments exhibited a positive correlation (y = 80.6x + 53.4; r = 0.88). The decrease in discharge/cardiac cycle at high heart rates was most likely related to the decreased time available for atrial filling. These data suggest that the total number of discharge/min do not vary significantly during atrial tachycardias.
|Original language||English (US)|
|Pages (from-to)||No. 961|
|State||Published - 1975|
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