Right atrial temperature and electrical activity during cardioplegic cardiac arrest

In 18 patients undergoing coronary artery bypass surgery the relation between right atrial temperature and right atrial electrical reactivation during cardioplegic cardiac arrest was studied. The administration of cardioplegic solution induced immediate ventricular and atrial arrest in all patients. No recurrence of ventricular activity was observed while right atrial activity subsequently recurred in 11 patients. Activity at the surface ECG was recorded only in one patient with right atrial reactivation. No right atrial electrical activity was found below 19 degrees C. The average atrial temperature was 21.5 degrees C while the average apex temperature was 15 degrees C. The study has confirmed previous observations that during cardioplegic cardiac arrest the right atrium is not as well protected as the ventricular tissue against rewarming. Monitoring of the right atrial electrical activity or right atrial temperature is essential to ensure atrial arrest during the entire period of cardioplegic cardiac arrest.