A comparison of thermodilution coronary sinus blood flows and krypton myocardial blood flows in the intact dog

Abstract
In closed-chest anaesthetized dogs simultaneous measurements of coronary sinus blood flow (CSBF) by thermodilution and myocardial blood flow with 85Krypton (MBF) were compared. Although reproducibility of the two methods was comparable control CSBFs averaged only 60% of total left ventricular flow (obtained by MBF and post-mortem left ventricular weights). Frequent marked discrepancies between percent changes in the two methods followed various interventions. Differences in results obtained by the two methods could be explained on the basis of the anatomy of the canine cardiac venous system and shifts in thermistor position relative to coronary sinus tributaries and right atrium following interventions and catheter softening.